Battery Chargers

[chris w]

I've checked the specs of the B&D unit and, on paper, they seem good. If i had to be picky, then I would pick on the following:

 

1. 30A max may be a bit low for some installations (the quoted 80A is ONLY for start battery emergencies not for regular charging)

 

2. Only one set of batteries can be charged at any one time rather than the domestic bank AND the start battery

 

3. It doesn't state whether it can be used in a "power pack" mode.

 

However, it is £100 cheaper than an equivalent 30A sterling charger with all the bells and whistles so if you don't want the extras it may be a good buy. I would certainly not advocate using the croc clips though for risk of sparks or the leads' dropping off. It needs to be permanently wired in.

 

Chris

[carlt]

Cheers

 

I found your original post on the subject btw:

 

This a good charger if you take a look at the spec BUT it is not a power pack. A proper multistage charger (eg: Sterling or Victron etc) will act as a power pack and will run your boat from a shore mains connection or generator regardless of whether your batteries are connected or not. ie: whilst the unit is ON it will charge the batteries and supply all the DC needs of the boat up to its current limit.

 

The Black & Decker one will charge the batteries on a multistage cycle but will not act as a power pack, so the batteries are supplying the DC current to run the boat. A true multistage charger acts like an alternator on a car. Once the engine is started, all the curent demands of your car are supplied by the alternator not the battery. The battery only contributes if the the alternator's current limit is reached.

 

Chris

[magnetman]

/quote Chris w/

 

"all the curent demands of your car are supplied by the alternator not the battery"

 

but the system would not work without the battery in place on a car would it??

 

Why, when I'm charging my battery at say 25 amps, with this charger, would it not replace power I am taking out, like a car alternator would?

 

Confused.

[chris w]

/quote Chris w/

 

"all the curent demands of your car are supplied by the alternator not the battery"

 

but the system would not work without the battery in place on a car would it??

 

Why, when I'm charging my battery at say 25 amps, with this charger, would it not replace power I am taking out, like a car alternator would?

 

Confused.

 

The reason it would be catastrophic to remove the battery from an alternator and try to run the car on just the alternator, is that the alternator output, without a battery present, will rise to its maximum voltage which will be in excess of 100V! (Alternators need to generate this kind of voltage internally to be able to drive large charging currents through the resistance of the stator windings etc.)

 

A charger with "power pack" mode will not take anything out of the batteries. In fact you could remove your batteries and the charger would run the boat's 12v system perfectly (up to its maximum current limit). Without a power pack mode, the charger will replenish the batteries, of course, but it's the batteries that are running the boat not the charger.

 

Chris

[magnetman]

The reason it would be catastrophic to remove the battery from an alternator and try to run the car on just the alternator, is that the alternator output, without a battery present, will rise to its maximum voltage which will be in excess of 100V! (Alternators need to generate this kind of voltage internally to be able to drive large charging currents through the resistance of the stator windings etc.)

 

A charger with "power pack" mode will not take anything out of the batteries. In fact you could remove your batteries and the charger would run the boat's 12v system perfectly (up to its maximum current limit). Without a power pack mode, the charger will replenish the batteries, of course, but it's the batteries that are running the boat not the charger.

 

Chris

 

 

I understand that, it was just when you said this: "A true multistage charger acts like an alternator on a car. Once the engine is started, all the curent demands of your car are supplied by the alternator not the battery" which implied you could remove the battery from a car, which you can't, of course. Maybe by 'true multistage charger' you were not referring to one with the 'power pack' option?

 

I would say that ANY charger acts like an alternator on a car in that it is supplying the power using the battery as a 'buffer'.

 

Am I missing something?

[chris w]

Wrong Bluebottle, you should read it properly, and my post, you don't need remote sensing with a good installation as there's little if anything to compensate for, that's why most alternators are machine sensed. Do it properly and you don't need to fix it with lots of add on bits that can fall off and lose control. KISS and keep learning!

 

You have NOT answered the question as to why you believe that machine sensing is more accurate and more reliable than battery sensing. That's because you can't. The reason that virtually all alternators are produced as machine sensing is not because that's better in any way but because virtually the total world output of alternators goes into vehicles where battery vs machine sensing is not an issue (there only being normally one battery situated right next to the alternator).

 

Gibbo's site does NOT support your argument for machine sensing..... just the opposite. He argues against split charge diodes (and I agree with him on this). If your boat already has split charge diodes however, most people will leave them in.

 

However, he also argues against machine sensing and I agree with him on this too. Even without diodes, battery sensing takes account of any cable and connection losses as Gibbo points out in his article. Machine sensing cannot do this but still you think it is better. Huh?

 

To quote Gibbo's site: "One last benefit of external controllers is that they convert the alternator to battery sensing as opposed to machine sensing. What this means is that the controller regulates the alternator output to maintain the correct voltage at the batteries. A machine sensing alternator (the normal type) regulates the voltage at the alternator. The 2 may not be the same. For instance insufficient cable size will cause voltage drops. And of course the worst cuplrit is the split charge diode. An external alternator controller will compensate for the voltage drop across the diode thus ensuring that the batteries receive the correct charge voltage"

 

Now show me the bit where he supports your contention that machine sensing is better than battery sensing. You won't find it because it doesn't exist.

 

You keep making statements which you can't justify and just come back and try to ridicule the proponent. However, rather than mud-slinging why don't you answer the question for once.

 

Question to TerryL "Why is machine sensing better and more reliable than battery sensing"? Over to TerryL for the answer............................. not

Edited October 24, 2008 by chris w

[blackrose]

You only need two stages and if the batteries were large enough I could leave the woolies chargers on but I don't use them for that. My boat charger can be left on if I wish to and need the power whilst away onboard in a marina but if I'm not using it then the windgenerator takes care of things. I don't live onboard but when I did on my barge my UPS with it's two stage charger was on all the time before I installed a 40 amp shore power supply. The batteries don't need to be float charging all the time if not needed.

 

Are you asking this because you have never experienced anything but new chargers and don't understand what they do or can you not comprehend that batteries were being charged well before modern electronics and the recent gimmicks were available which lead gullible inoccent people to believe that they can't manage without them?

 

I was asking because I was interested. My experience with old fashioned chargers was having to be very careful not to leave them on for too long to avoid damaging the batteries. Are you really saying that anyone with a modern 3 stage charger is innocent & gullible? We can certainly manage without modern electronics, just as we managed without mobile phones & computers, however most of us find ourselves using these devices for reasons of convenience.

[Morby]

You only need 10 amps to charge in 8 hours or so, 20 amps max. I think you would be better off charging from the engine than a generator with the added expense for little capacity. Wind and solar energy would be more efficient.

 

 

Hey Terry,

 

I want to hook up some Wind and solar stuff a bit longer down the line, my engine is quite old really (1978) and I dont think I would be very popular with my neighbours if I kept it running at all hours, especially if anyone had any washing out. Bunty smokes a wee bit when first started.

 

Be Seeing You

Morby

Currently Hoping That Differing Opinions Make For An Interesting World

 

I've checked the specs of the B&D unit and, on paper, they seem good. If i had to be picky, then I would pick on the following:

 

1. 30A max may be a bit low for some installations (the quoted 80A is ONLY for start battery emergencies not for regular charging)

 

2. Only one set of batteries can be charged at any one time rather than the domestic bank AND the start battery

 

3. It doesn't state whether it can be used in a "power pack" mode.

 

However, it is £100 cheaper than an equivalent 30A sterling charger with all the bells and whistles so if you don't want the extras it may be a good buy. I would certainly not advocate using the croc clips though for risk of sparks or the leads' dropping off. It needs to be permanently wired in.

 

Chris

 

 

Hey Chris,

 

I have looked at the black and Decker unit, but it struck me that it would have to be left out on deck, all I need to know is how much bargaining power do I have when it comes to quotes for jobs which include a battery charger.

 

I didnt know when I first posted my question that it would cause a bone of contention. I wondered why I was being advised (by the quoter) to have a rather expensive charger, and would a cheaper 12amp 30v Charger really be nescessary for my needs.

 

 

Be Seeing You

Morby

Currently Holding Out For A Hero

[wonderdust]

What is your budget for the charger?

 

Hey Terry,

 

I want to hook up some Wind and solar stuff a bit longer down the line, my engine is quite old really (1978) and I dont think I would be very popular with my neighbours if I kept it running at all hours, especially if anyone had any washing out. Bunty smokes a wee bit when first started.

 

Be Seeing You

Morby

Currently Hoping That Differing Opinions Make For An Interesting World

 

 

 

 

Hey Chris,

 

I have looked at the black and Decker unit, but it struck me that it would have to be left out on deck, all I need to know is how much bargaining power do I have when it comes to quotes for jobs which include a battery charger.

 

I didnt know when I first posted my question that it would cause a bone of contention. I wondered why I was being advised (by the quoter) to have a rather expensive charger, and would a cheaper 12amp 30v Charger really be nescessary for my needs.

 

 

Be Seeing You

Morby

Currently Holding Out For A Hero

[Guest TerryL]

You have NOT answered the question as to why you believe that machine sensing is more accurate and more reliable than battery sensing. That's because you can't. The reason that virtually all alternators are produced as machine sensing is not because that's better in any way but because virtually the total world output of alternators goes into vehicles where battery vs machine sensing is not an issue (there only being normally one battery situated right next to the alternator).

 

Gibbo's site does NOT support your argument for machine sensing..... just the opposite. He argues against split charge diodes (and I agree with him on this). If your boat already has split charge diodes however, most people will leave them in.

 

However, he also argues against machine sensing and I agree with him on this too. Even without diodes, battery sensing takes account of any cable and connection losses as Gibbo points out in his article. Machine sensing cannot do this but still you think it is better. Huh?

 

To quote Gibbo's site: "One last benefit of external controllers is that they convert the alternator to battery sensing as opposed to machine sensing. What this means is that the controller regulates the alternator output to maintain the correct voltage at the batteries. A machine sensing alternator (the normal type) regulates the voltage at the alternator. The 2 may not be the same. For instance insufficient cable size will cause voltage drops. And of course the worst cuplrit is the split charge diode. An external alternator controller will compensate for the voltage drop across the diode thus ensuring that the batteries receive the correct charge voltage"

 

Now show me the bit where he supports your contention that machine sensing is better than battery sensing. You won't find it because it doesn't exist.

 

You keep making statements which you can't justify and just come back and try to ridicule the proponent. However, rather than mud-slinging why don't you answer the question for once.

 

Question to TerryL "Why is machine sensing better and more reliable than battery sensing"? Over to TerryL for the answer............................. not

 

I see you have deliberately snipped the article to put it out of context, it goes on to advocate standard regulators, no mention of remote sensing being advocate here, in fact it says there is no need unless you've got split charging diodes or insufficient cable sizes!

 

Continued..........(almost - see here for an explanation of why they don't quite do what is required).

 

Now then, I've sung the praises of alternator controllers and explained what they do, how they do it, and the benefits when installed on an old (13.8 volt) alternator with old batteries. i.e. from the period of 10 to 15 years ago when these devices became common. They were an excellent idea.

 

So why do I say they are not always needed?

 

Simple. Most modern alternators already charge at 14.2, 14.4 or even 14.6 volts. That is how they come from the factory.

 

For some reason that we cannot fathom there seem to be various people who (for whatever reason) will not accept (or admit) that modern alternators already charge at these higher voltages, as they come from the factory, without any modification. They simply refuse to believe it. All one has to do is measure one with a voltmeter!

 

Modern batteries do not use excess water if charged at these higher voltages for long periods of time. If they did, then all the truck and car batteries round the world would be dying very quickly because they are charged continuously at higher voltages. They aren't all dying. If anything, they are lasting longer than they used to.

 

Times have changed. Batteries have changed. Alternators have changed. Alternator controllers are not required on modern systems. They will achieve nothing.

 

So, we are left with a situation that the only installations that may benefit from an external alternator controller are systems with an old style alternator or.....

 

(and I find this interesting...)

 

Systems using split charge diodes. Which, as most people have now realised, are all but useless. And of course poor installations with lots of voltage drop.

 

It is also interesting that the only people left advocating the use of split charge diodes are manufacturers and suppliers of external alternator controllers (or perhaps people who haven't caught up with developments in technology). Because, in most cases, split charge diodes are the only reason to fit one to a modern installation, in order to compensate for the voltage drop across the split charge diode.

 

It took a long time for the alternator regulator manufacturers to convince the public that they were a good thing (which they were), the public's ideas were stuck, ingrained. Now the same thing has happened again. The public's idea is stuck, ingrained, but this time that alternator controllers are required when in actual fact, most of the time, they are not.

 

Luckily this is changing. As evidenced by sales of the SmartBank split charge system. Many of our customers are fleet builders, they have all learnt that external controllers now do nothing. They make no difference whatsoever to the charge rate or battery life. They no longer fit them.

 

In actual fact, in many cases, entire fleets of operatonal vehicles are being recalled to the factories and having alternator controllers and split charge diodes removed, to be replaced with standard alternator regulators and SmartBank split charge systems. Because the performance is better and the reliability is better.

 

There you go, standard regulators have better performance and are more reliable. Does that answer your question or do you want to quote something else out of context and mislead people even more? Are you trying to convince yourself you are right Bluebottle?

[Guest TerryL]

The reason it would be catastrophic to remove the battery from an alternator and try to run the car on just the alternator, is that the alternator output, without a battery present, will rise to its maximum voltage which will be in excess of 100V! (Alternators need to generate this kind of voltage internally to be able to drive large charging currents through the resistance of the stator windings etc.)

 

A charger with "power pack" mode will not take anything out of the batteries. In fact you could remove your batteries and the charger would run the boat's 12v system perfectly (up to its maximum current limit). Without a power pack mode, the charger will replenish the batteries, of course, but it's the batteries that are running the boat not the charger.

 

Chris

 

It really amazes me how you continue to spout rubbish about things you know nothing about! You can run an alternator without a battery, the regulator doesn't like it and the output is unstable but the more load you put on it the better it becomes, it does not produce in excess of 100 volts, you've never tried it have you? Total crap!

 

When connected to batteries any charger of sufficient output will act as the supply, I thought we'd agreed that, but not all chargers will work without a battery to initiate them. When will you stop deceiving people and pretending you know everything?

[Guest TerryL]

I understand that, it was just when you said this: "A true multistage charger acts like an alternator on a car. Once the engine is started, all the curent demands of your car are supplied by the alternator not the battery" which implied you could remove the battery from a car, which you can't, of course. Maybe by 'true multistage charger' you were not referring to one with the 'power pack' option?

 

I would say that ANY charger acts like an alternator on a car in that it is supplying the power using the battery as a 'buffer'.

 

Am I missing something?

 

No, you are right. A straight forward charger and a so called three stage charger has one constant voltage throughout until it gets to the float stage then the battery voltage needs to drop sufficiently to take the charger out of float mode to supply the power so it does need the battery as a buffer.

[chris w]

It really amazes me how you continue to spout rubbish about things you know nothing about! You can run an alternator without a battery, the regulator doesn't like it and the output is unstable but the more load you put on it the better it becomes, it does not produce in excess of 100 volts, you've never tried it have you? Total crap!

 

The esaist way to blow an alternator is to disconnect it from the battery when running. An alternator is easily capable of outputting over 100V. Many alternators are modified to produce high voltage DC for welders etc. I have modded alternators to make a high frequency, high voltage AC supply.

 

If you bother to run the maths, you would understand why an alternator MUST be able to produce this kind of voltage in order to drive maybe 80A or more through the stator windings. If the total resistance of the staor windings is just 1 ohm, and its an 80A alternator, I make that at least 80v across the stator, plus the battery voltage (say 12v) + 1v for the positive output diode drop plus 1v for the negative diode drop. That makes 94v just for an 80A alternator as a minimum and in practice they will go to 120v. For a higher amperage alternator, it's even higher.

 

If you disconnect the alternator whilst running, the output diodes will usually blow due to their PIV (peak inverse voltage) being exceeded. You're the one who knows Jack sh*t about alternators.

 

Here's a challenge...... you pick a group of us to come along to see your car. We'll start the engine and while it's running, we'll disconnect the alternator from the battery. If you are right, nothing untoward will happen. In reality, YOU will be buying a new rectifier and possibly a new regulator for your alternator. Are you up to the challenge? I bet not!!!

 

 

 

There you go, standard regulators have better performance and are more reliable. Does that answer your question or do you want to quote something else out of context and mislead people even more? Are you trying to convince yourself you are right Bluebottle?

 

 

I'm not arguing that Gibbo thinks standard regulators are better. That's not the issue here. The issue is that he also declares that battery sensing is better.

 

We're not discussing the merits of alternator controllers. We're discussing your idiotic statement that machine sensing is better than battery sensing.

 

Now show me the bit where he supports your contention that machine sensing is better than battery sensing. You won't find it because it doesn't exist.

 

You keep making statements which you can't justify and just come back and try to ridicule the proponent. However, rather than mud-slinging why don't you answer the question for once.

 

Question to TerryL "Why is machine sensing better and more reliable than battery sensing"? Over to TerryL for the answer............................. not

 

 

Just simply say why.................... you always skirt around the issue, because you are trying to defend the indefensible.

[paulcatchpole]

I know nothing about these but they are in the right price range perhaps

http://cgi.ebay.co.uk/CONNECT-AND-FORGET-1...id=p3286.c0.m14

 

I've got one of those - bought from Ebay about a month ago.

 

So far, so good, it stays cool and acts as a power pack for all the 12v stuff.

 

Only real criticism is the lack of a manual in the box, and the fan is quite noisy when you put it under load.

 

PC

[Guest TerryL]

name='chris w' post='288034' date='Oct 25 2008, 09:24 AM' The esaist way to blow an alternator is to disconnect it from the battery when running. An alternator is easily capable of outputting over 100V. Many alternators are modified to produce high voltage DC for welders etc. I have modded alternators to make a high frequency, high voltage AC supply.

 

If you bother to run the maths, you would understand why an alternator MUST be able to produce this kind of voltage in order to drive maybe 80A or more through the stator windings. If the total resistance of the staor windings is just 1 ohm, and its an 80A alternator, I make that at least 80v across the stator, plus the battery voltage (say 12v) + 1v for the positive output diode drop plus 1v for the negative diode drop. That makes 94v just for an 80A alternator as a minimum and in practice they will go to 120v. For a higher amperage alternator, it's even higher.

 

If you disconnect the alternator whilst running, the output diodes will usually blow due to their PIV (peak inverse voltage) being exceeded. You're the one who knows Jack sh*t about alternators.

 

Here's a challenge...... you pick a group of us to come along to see your car. We'll start the engine and while it's running, we'll disconnect the alternator from the battery. If you are right, nothing untoward will happen. In reality, YOU will be buying a new rectifier and possibly a new regulator for your alternator. Are you up to the challenge? I bet not!!!

 

You seem to be forgetting that my alternator and most peoples alternators are not set up for welding or any other use and they have a regulator installed to limit output. If as you say the diode PIV is exceeded which it won't because there will be no field current with no load, and they will blow then how do you explain your contradictory claim that they can be modified for high voltage DC welding? Isn't this exceeding the PIV?

 

Run the maths, run the maths is all you ever say, what about the regulator and load in the maths. You're all bad theory and no substance. There is no high voltage on any alternator unless you modify it for that, give it full field current and leave it completely open circuit, and that does not happen just by disconnecting the battery! Oh dear, you are using battery sensing aren't you? If the sensing lead gets disconnected you've lost voltage control haven't you? That's not as reliable as machine sensing is it?

 

As it happens disconnecting the battery on my cars while running is precisely what I do when I need to change it, it saves setting everything up again. Anyone is more than welcomed to a demonstration. This is an old wives tale and you are the biggest old wife of them all.

 

 

I'm not arguing that Gibbo thinks standard regulators are better. That's not the issue here. The issue is that he also declares that battery sensing is better.

 

We're not discussing the merits of alternator controllers. We're discussing your idiotic statement that machine sensing is better than battery sensing.

 

Now show me the bit where he supports your contention that machine sensing is better than battery sensing. You won't find it because it doesn't exist.

 

You keep making statements which you can't justify and just come back and try to ridicule the proponent. However, rather than mud-slinging why don't you answer the question for once.

 

Question to TerryL "Why is machine sensing better and more reliable than battery sensing"? Over to TerryL for the answer............................. not

 

 

Just simply say why.................... you always skirt around the issue, because you are trying to defend the indefensible.

Standard regulators very rarely have battery sensing and if you read the article properly Gibbo does not support battery sensing but says the only need for it is with diodes or poor installations. If you don't have diodes and have a good low resistance system so there is very little voltage drop then you don't need battery sensing do you? What benefit is there?

 

In fact even with a poor system battery sensing has very limited benefits. It can't overcome the inherent losses in the system which is the main problem and the reason for the voltage drop when charging at higher currents. When the battery is taking a full charge the alternator voltage is determined by the load so sensing at the battery will not increase the output voltage during this stage will it? When the charge load reduces the voltage at the battery will have increased anyway so the voltage drop lessens considerably with less current doesn't it? So the actual voltage increase from battery sensing is very limited and cannot increase the charge current because of the limitations in the system that caused the voltage drop in the first place!

 

Another problem of trying to compensate for a bad system is if the alternator voltage does go artificially high then that will effect anything connected near the alternator and the starter battery will be overcharged, never thought of that did you?

 

Best to wire it properly! Is there anything else I can teach you today?

 

If you don't like being ridiculed Bluebottle then you shouldn't have set the standard in the first place.

Edited October 25, 2008 by TerryL

[smileypete]

What about battery temperature compensated charging that an alternator controller offers?

 

Is this worth having or not?

 

If it is worth having for some, what type of boat owner would benefit most from it, and in what circumstances?

 

cheers,

Pete.

Edited October 25, 2008 by smileypete

[magnetman]

We're not discussing the merits of alternator controllers. We're discussing your idiotic statement that machine sensing is better than battery sensing.

 

There I was innocently thinking we were discussing Battery Chargers. Oh well, do carry on

[chris w]

You seem to be forgetting that my alternator and most peoples alternators are not set up for welding or any other use and they have a regulator installed to limit output. If as you say the diode PIV is exceeded which it won't because there will be no field current with no load, and they will blow then how do you explain your contradictory claim that they can be modified for high voltage DC welding? Isn't this exceeding the PIV?

 

Run the maths, run the maths is all you ever say, what about the regulator and load in the maths. You're all bad theory and no substance. There is no high voltage on any alternator unless you modify it for that, give it full field current and leave it completely open circuit, and that does not happen just by disconnecting the battery! Oh dear, you are using battery sensing aren't you? If the sensing lead gets disconnected you've lost voltage control haven't you? That's not as reliable as machine sensing is it?

 

As it happens disconnecting the battery on my cars while running is precisely what I do when I need to change it, it saves setting everything up again. Anyone is more than welcomed to a demonstration. This is an old wives tale and you are the biggest old wife of them all.

 

I guessed you would come back with a daft argument. Your not being an electronics engineer but just a sparky, you think that the regulator will instantly kill any high voltage. In human terms, a regulator is instant. In electronic terms, it's very slow and in the maybe 10 milliseconds it takes to regulate, your diodes are already history as they will react much faster than the regulator.

 

The acknowledged expert on alternators on this Forum is Sir Nibble as that was his life for years.. Why don't you try telling him your crap and suggest that's he's wrong.

 

Pick any web article on alternators that goes into do's and dont's and they will all tell you never to disconnect the alternator from the battery whilst it's running because voltage spikes will fry the diodes.

 

And rather than quoting other people about battery or machine sensing, why not tell us why YOU can show that machine sensing is better than battery sensing. You still have NOT answered that one and everyone realises why. Because you don't know.

 

Question to TerryL "Why is machine sensing better and more reliable than battery sensing"? Over to TerryL for the answer............................. not

 

Just simply say why, here I will help you:

 

From TerryL: "Machine sensing is better than battery sensing because.........." All you have to do is fill in the words. Try some joined-up thinking for a change.

Edited October 25, 2008 by chris w

[chris w]

I've got one of those - bought from Ebay about a month ago.

 

So far, so good, it stays cool and acts as a power pack for all the 12v stuff.

 

Only real criticism is the lack of a manual in the box, and the fan is quite noisy when you put it under load.

 

PC

 

In the technical spec it only mentions a bulk phase and a float phase. If that's correct, it's missing out the absorption phase which would mean that your batteries will only be about 75% charged at the end of the bulk phase unless you're leaving them on float charge for about 3 days.

 

Chris

[Guest TerryL]

What about battery temperature compensated charging that an alternator controller offers?

 

Is this worth having or not?

 

If it is worth having for some, what type of boat owner would benefit most from it, and in what circumstances?

 

cheers,

Pete.

If you lived somewhere that had wild extremes of temperature then it may be beneficial, if your batteries live in a constant high temperature such as when the engine is running then you just reduce the charge voltage permanently. In reality variable temperature compensation has no benefit with a well installed and ventilated battery in the UK. Added to that where do you put the sensor? Stick it on the side and it can come off fooling the controller that the battery is cold and fitting it on a terminal does not give a true temperature reading for the whole battery.

 

All these additional "benefits" require extra wiring and sensing leads and equipment that can go wrong and only serve to complicate a fairly simple process. All they do is give you the illusion of a high charge rate then take it away when the battery supposedly gets hot, so why not just charge at the normal rate to start with? They are really only offered to part you from your hard earned and you can manage a lot better with just a standard alternator regulator at the right voltage.

[Guest TerryL]

I guessed you would come back with a daft argument. Your not being an electronics engineer but just a sparky, you think that the regulator will instantly kill any high voltage. In human terms, a regulator is instant. In electronic terms, it's very slow and in the maybe 10 milliseconds it takes to regulate, your diodes are already history as they will react much faster than the regulator.

 

The acknowledged expert on alternators on this Forum is Sir Nibble as that was his life for years.. Why don't you try telling him your crap and suggest that's he's wrong.

 

Pick any web article on alternators that goes into do's and dont's and they will all tell you never to disconnect the alternator from the battery whilst it's running because voltage spikes will fry the diodes.

 

And rather than quoting other people about battery or machine sensing, why not tell us why YOU can show that machine sensing is better than battery sensing. You still have NOT answered that one and everyone realises why. Because you don't know.

 

Question to TerryL "Why is machine sensing better and more reliable than battery sensing"? Over to TerryL for the answer............................. not

 

Just simply say why, here I will help you:

 

From TerryL: "Machine sensing is better than battery sensing because.........." All you have to do is fill in the words. Try some joined-up thinking for a change.

 

You don't actually read my posts do you? Otherwise you would remember I said the regulator doesn't like it and it's unstable until a load is put on! So what you are saying is my diodes are fine to do high voltage DC welding but not run a load without the battery. I love catching you out.

 

Er, isn't it you that's quoting other people here? The difference between you and me is I don't take other peoples word for things as gospel cos they're often wrong, so I use my own long experience, and that's where you are sadly lacking. When do you want to see my demonstration you asked for?

 

As for you repeating the same question, read my previous posts for the answer a number of times or perhaps you can tell us all why you don't agree with me. However as you never answer my questions we'll never know will we Bluebottle?

 

I'll make it easy for you... Battery sensing is better because..... try your own little brain rather than relying on me to teach you everything or give up the pretence.

[Guest TerryL]

In the technical spec it only mentions a bulk phase and a float phase. If that's correct, it's missing out the absorption phase which would mean that your batteries will only be about 75% charged at the end of the bulk phase unless you're leaving them on float charge for about 3 days.

 

Chris

 

Oh dear, you really, really don't get it do you? You really are the dimwit of the class! I'm so dissapointed in you Bluebottle. Did we not have a little chat about all this a little while ago?

 

If you had paid attention you would have understood that a charger with a fixed voltage bulk charge also allows the battery to absorb a charge from this during the battery absorption stage up to nearly full charge just like an alternator. Nothing changes in the charger voltage until the two stage charger control decides to reduce the voltage to float charge. Is that difficult to understand?

 

An absorption charger stage does not and never has existed except as a marketing term, just like it does not exist on an alternator. Now wasn't that simple? You can get expensive and uneccessary all singing all dancing chargers with silly ideas of messing about with the charge voltage going on and off but we are not talking about them are we?

 

Tell me, did you actually pass your electronics degree course or just thought you did and when and where was it? You are just a amateur pretending to be knowledgable but are sadly lacking in experience and are manipulating everything to justify your lack of knowledge and blind fixed ideas that nobody usually challenges, I see right through you and I see all your mistakes.

[Guest]

Ihave read about modification to alternators whereby they can produce 110V for power tools.

 

Most welder/alternators that I have read about are modified thus:

 

http://home.comcast.net/~t.molnar/Obwelder1.htm

[chris w]

Ihave read about modification to alternators whereby they can produce 110V for power tools.

 

Most welder/alternators that I have read about are modified thus:

 

http://home.comcast.net/~t.molnar/Obwelder1.htm

 

Thanks for the link Catweasel. There are many links that utilise the high voltage that ALL alternators are capable of producing.

 

Here's an extract from page 2 of your link which specifically addresses the diodes' blowing up at high voltage.....

 

" Another bad thing I found out about these beasts is that while the rectifier diodes are able to handle over 140A they are only designed to handle 32 volts! That's right. They're designed to burn out at 32 volts as a form of protection. It's a bummer since we're hoping to generate over 100 volts here. I quickly found this out during the first test where at idle I got 30V and as soon as I throttled up a diode blew and the alternator started straining terribly almost killing the engine."

 

If one disconnects the battery output lead, (ie: instaneously, the output goes to zero) the output of the alternator goes sky-high in an attempt to redress the balance. Unfortunately, the regulator cannot switch fast enough before the output gets to a voltage that will blow the negative grounded diodes in the bridge rectifier. In the case above, the output only has to get to 32v before the diodes blow. The regulator will take a few milliseconds to react properly, the diodes will blow in a millisecond or less if their PIV is exceeded.

 

I hope and trust that everyone can see (except TerryL of course, "who's still on "Electricity for Beginners" chapter 1) that undoing the alternator main battery lead with the engine running will almost certainly blow your diodes. Removing the same lead with the engine off, then starting the engine and revving up will do the same thing. Please don't attempt it.

 

I also found this statement on Gibbo's website, viz..........................."Note that switching the alternator off using this method [breaking the field circuit] is perfectly safe and is in no way related to disconnecting the alternator output which can destroy it.

 

 

It's also obvious that TerryL still hasn't answered the question I posed him previously. Everyone knows that battery sensing is better than machine sensing except TerryL and he refuses to answer this question.

 

Question to TerryL "According to you, why is machine sensing better and more reliable than battery sensing"? Over to TerryL for the answer............................. not

 

Just simply say why, here I will help you:

 

From TerryL: "Machine sensing is better than battery sensing because.........." All you have to do is fill in the words. Try some joined-up thinking for a change.

 

Answer the question from an engineering viewpoint or admit you're wrong before you lose the last gram of credibility you may still have.

 

Chris

Edited October 26, 2008 by chris w

[chris w]

An absorption charger stage does not and never has existed except as a marketing term.................

 

This is nonsense...............

 

Here's another quote from Gibbo's website if you don't believe me...................

 

"Surface charge can also cause oversized chargers to terminate the acceptance [absorption] cycle too early and go into float charge well before the batteries are actually fully charged..............

 

..................A full, timed, acceptance [absorption] cycle is the way to cure this problem".