Electrical help please

[nicknorman]

Can't you have pass-through without charger? You certainly could on the elderly one my last boat.

 

Yes, you can, but why would you want to?

Whoops yes 1%

 

Clearly leaving just the Victron on would give better charge regime control, but you can't just turn off the alternator when engine is running, hence the suggestion. However, if the Victron voltage is set above the alternator, you have effectively turned off the alternator since it will not produce any current (towards the end of the charge, at least)

Regarding your statement about surface charge. Surely the reason for the current dropping rapidly is because the surface charge has not had time to be taken deeper into the plates, and ensuing gassing reduces the charge current. Yes, that's what I meant though I don't think it results in significant gassing. Our batteries never need water. Some reduction in battery life may result as well although I accept that its a balance between charge time and battery life. True, but as you say its a compromise and charging on the fast side has a minor impact compared to sulphation.

Edited February 20, 2013 by nicknorman

[Eeyore]

To the OP.

 

What hasn't been specifically mentioned so far is that with the 170 amp alternator and the TP powering the Victron's charger (assuming it is) you will have 170 + 120 = 290 amps potential charge current available for a 550 Ah battery bank. This will give the symptoms you describe.

 

The bulk phase on the Victron will be very short.

 

It will prematurely go to float mode. The charge volts will remain high though supported by the alternator which I assume doesn't have a multi-stage DAR, so will work at its regulated 14+ volts.

 

Furthermore the batteries will not be able to absorb this very high charge current quickly and you will be reducing their life.

 

Can I suggest you run without the Victron charger. Just use the alternator and extend your charge time. Check the charge current shown by your BMV600 and when that drops to say 10% of battery capacity = 5.5 amps, your batteries will be near fully charged. Don't trust the SOC reading unless its recently been calibrated.

Hi By'eck

It was mentioned in post #10.

I just get a warm feeling knowing that someone else thought of the same thing

Steve (Eeyore)

[Keith M]

Hi, I’m looking for some advice from electrical experts and/or people who use Dometic Travel Power with a Victron Multiplus inverter/charger.

 

The boat was new in June 2012 and has been used as a liveaboard since October. The set up is as follows:

 

Beta 43 with 170amp alternator, 3.5KW Travel Power and Victron Multiplus 12/3000/120, Victron BMV600 battery monitor. Battery bank is 550ah (110 x 5 leisure batteries). No shore power available.

 

Battery usage is around 60ah per day (12v TV, 12v radio, Shoreline fridge/freezer, LED lights, pumps, occasional inverter use for small items).

 

I have been having some concerns that there may be some problems with the electrical installation, and wondered if people could help with a few questions.

 

1) If I switch the Multiplus to ‘charger only’ mode with the Travel Power running, the inverter switches on, which seems to be at odds with the instruction manual. Any ideas?

 

2) The batteries are charged daily with the engine running at 1200rpm and with the Travel Power running the battery charger. The charger stays on ‘bulk’ for only a couple of minutes and then switches to ‘absorption’ mode. This generally only lasts around 30 minutes and then switches to ‘float’, which I understood to be fully charged. It’s obviously great if the batteries are charging that quickly but I worry that they might not actually be charging fully. If I switch the charger off then on again a few minutes later, the absorption phase still takes as long – eg another 30 minutes. Any thoughts? Is there any point running the engine any longer once float is reached, as no active charging seems to be happening?

 

3) If I charge up late afternoon and check the voltage the following morning, it is often down to around 12.3 volts, after only 40-50ah discharge. This seems to be getting towards 50% discharge, which seems very high? There also seems to be a voltage drop on the monitor of up to 0.2 volts when the fridge kicks in. Heavy duty cabling was specified. Is this excessive drop?

 

4)The Victron manual states that the charger will reduce the charging voltage once the batteries reach float, but this does not seem to happen. Is this because the alternator is charging in the background?

 

5) How do you know that the Travel Power is running for example the washing machine, rather than the inverter doing it, as it seems that the inverter needs to be on to get ac out of the TP? I think the inverter can cleverly tell, but how do you know this is happening?

 

Sorry for such detailed questions, any help very welcome as I am worried I am doing something wrong.

 

Hi Monsoon

 

 

If the inverter light is coming the inverter is do one of two things

 

Either it is losing the AC in put or the combi has been set up to power assist which may indicate a load in excess of 3.5 Kilo watts?

 

By using both the travel power via the combi and the alternator you will get conflict between the two DC voltages causing all sorts of funny faults, take the advice of Roger he knows what he is talking about.

 

I would suggest that the monitor may have been incorrectly set up and the install may also not be correct

 

To get to float is anywhere from 6 / 12 hours

 

If you are using the TP the mains on light will be activated on the front of the combi

 

I hope the above helps

 

 

 

Keith

[nicknorman]

 

By using both the travel power via the combi and the alternator you will get conflict between the two DC voltages causing all sorts of funny faults, take the advice of Roger he knows what he is talking about.

 

 

Since I routinely use my TP / Combi and engine alternator at the same time to charge, without any "funny faults" I can't agree, but OP will have to decide which of us to believe.

[Keith M]

Since I routinely use my TP / Combi and engine alternator at the same time to charge, without any "funny faults" I can't agree, but OP will have to decide which of us to believe.

 

 

And what is the total current output?

 

You will never get full output from both items for any length of time to be to be of any great value.

 

The higher output voltage always wins

 

I have drive many miles sorting out interaction between TP & Combi and on-board alternators in the course of my work and for Mastervolt.

[bowten]

And what is the total current output?

 

You will never get full output from both items for any length of time to be to be of any great value.

 

The higher output voltage always wins

 

I have drive many miles sorting out interaction between TP & Combi and on-board alternators in the course of my work and for Mastervolt.

So would you switch off the T/P and use the alternator only or would you use the T/P only or both.

[Keith M]

So would you switch off the T/P and use the alternator only or would you use the T/P only or both.

 

I would only use the alternator its difficult to switch of the alternator

 

The best system is TP & three battery changing combi if you could switch of the alternator

 

Keith

[aread2]

I've seen similar behaviour on our system. We have TP+Victron and the alternator wins every time. Victron goes to absorbtion very quickly. The installation was orignally supplied with the domestic alternator indicator light disconnected to prevent the alternator from confusing the Victron. I discovered this when the TP threw its drive belt and after a day at slightly over tickover the batteries went flat. The only way to get the alternator working was to blip the throttle hard enough to get it to excite.

Edited February 20, 2013 by aread2

[Monsoon merchant]

One other thing to consider is that if you have adaptive charging on rather than a timed charge it wii see the O/P of the alternator and assume that tne batteries do not need that much charge.

Adaptive charging does NOT work you would be best to turn it off.

 

Do people agree that adaptive charging does not work with TP? If so, this has been a pretty expensive mistake. This was sold as a way to reduce charging times by using intelligent charging, as if on shorepower. If it is being suggested that this be overridden by setting fixed charge times or (worse) by just using the alternator to charge, this seems to render the TP pretty useless for charging purposes?

 

How unreliable do people think the adaptive charging is with TP? When the Victron switches immediately to absorption when starting to charge, does this mean that batteries are at 80% plus already, or is this meaningless?

 

Thanks again for the replies.

[Chris Pink]

Normally a charging battery reaches absorption voltage at 80% but it's current dependent and with relatively large charging currents it gets fizzy earlier. So 100% charging times are generally the same whatever current. It's only really the bulk stage that benefits from higher current.

 

Which is why most liveaboards live in the 50-80% range with additional periodic full charges taking 6-8 hours and monthly equalisation charges - low current high voltage. Though this last can be less frequent if solar is fitted.

Edited February 20, 2013 by Chris Pink

[nicknorman]

And what is the total current output?

 

Obviously it depends! But not the theoretical maximum output.

 

You will never get full output from both items for any length of time to be to be of any great value.

No, however it allows sharing of the load between the alternator and charger (ie reduces the load on each), and it allows adjustment (upwards) of the final voltage during Absorption.

 

The higher output voltage always wins

 

Up to a point, yes, but at higher currents, the voltage regulation is "soft" for both devices and, if set to similar voltages, will share the load fairly evenly. If the Combi is set to a higher voltage, it will max out and the alternator will provide the rest.

 

I have drive many miles sorting out interaction between TP & Combi and on-board alternators in the course of my work and for Mastervolt.

 

I don't know why, since mine play together nicely. What was the issue?

 

I would only use the alternator its difficult to switch of the alternator

 

The best system is TP & three battery changing combi if you could switch of the alternator

 

Keith

But you can't switch off the alternator. You are in effect saying that the TP shouldn't be used, which makes fitting it seem rather pointless! At least, not without turning the combi charging current down to zero. I just don't see what the issue is with them both working together as mine do, unless it is some quirk of the Victron that the MV doesn't suffer from?

[smileypete]

Do people agree that adaptive charging does not work with TP? If so, this has been a pretty expensive mistake. This was sold as a way to reduce charging times by using intelligent charging, as if on shorepower. If it is being suggested that this be overridden by setting fixed charge times or (worse) by just using the alternator to charge, this seems to render the TP pretty useless for charging purposes?

 

How unreliable do people think the adaptive charging is with TP? When the Victron switches immediately to absorption when starting to charge, does this mean that batteries are at 80% plus already, or is this meaningless?

As mentioned, the batts are fully charged when the charge current (at the correct absorption charge voltage) falls below 5% of batt bank capacity.

 

BUT doing this every day from engine or generator as a liveaboard without shoreline can be impractical, so most liveaboards charge to a lesser level daily, then a full charge once a week.

 

So best work out what needs to be done, THEN how best to set up and use the installed kit to do it.

 

cheers, Pete.

~smpt~

[nicknorman]

Do people agree that adaptive charging does not work with TP? If so, this has been a pretty expensive mistake. This was sold as a way to reduce charging times by using intelligent charging, as if on shorepower. If it is being suggested that this be overridden by setting fixed charge times or (worse) by just using the alternator to charge, this seems to render the TP pretty useless for charging purposes?

 

Yes, this is why you should ignore the advice to not use the TP! However, I believe there are issues with the adaptive charging setting of the Victron - but it can be disabled with the DIP switches (no laptop required). Then you are back to a "normal" 4 stage charger which can be better than charging from an alternator (if set up correctly!)

 

How unreliable do people think the adaptive charging is with TP? When the Victron switches immediately to absorption when starting to charge, does this mean that batteries are at 80% plus already, or is this meaningless?

 

Its pretty meaningless - it just means that the alternator is doing more work than the Victron due to the relative voltage settings. But it can be adjusted with a laptop.

Thanks again for the replies.

 

Normally a charging battery reaches absorption voltage at 80%

 

I think it would be a mistake to put a figure on it, since it depends on the current capability of the charger vs the bank size, set voltage, resistive losses etc. Imagine a very small charger and a huge bank - the batteries might be nearly fully charged (after a long time!) before the current fell below the capability of the charger, and hence it went into Absorption.

Edited February 20, 2013 by nicknorman

[GUMPY]

Do people agree that adaptive charging does not work with TP? If so, this has been a pretty expensive mistake. This was sold as a way to reduce charging times by using intelligent charging, as if on shorepower. If it is being suggested that this be overridden by setting fixed charge times or (worse) by just using the alternator to charge, this seems to render the TP pretty useless for charging purposes?

 

How unreliable do people think the adaptive charging is with TP? When the Victron switches immediately to absorption when starting to charge, does this mean that batteries are at 80% plus already, or is this meaningless?

 

Thanks again for the replies.

Adaptive charging doent work no matter where you power the charger from if you search back through the forum you will find gibbos explanation

[Chris Pink]

I think it would be a mistake to put a figure on it, since it depends on the current capability of the charger vs the bank size, set voltage, resistive losses etc. Imagine a very small charger and a huge bank - the batteries might be nearly fully charged (after a long time!) before the current fell below the capability of the charger, and hence it went into Absorption.

 

One likes a rule of thumb and this is a good one. Obviously it is only true for one charging ratio, I have absolutely no idea what, possibly 10-15% of bank size but it's a useful figure nonetheless.

 

It is my opinion backed by experience that it's generally more efficient not to use oversized chargers or alternators when you run the 'bulk' cycling system.

[nicknorman]

One likes a rule of thumb and this is a good one. Obviously it is only true for one charging ratio, I have absolutely no idea what, possibly 10-15% of bank size but it's a useful figure nonetheless.

 

It is my opinion backed by experience that it's generally more efficient not to use oversized chargers or alternators when you run the 'bulk' cycling system.

In the case of my setup, it comes out of bulk almost immediately (immediately, if I run the TP, subject to the minimum bulk time set on the Combi) since the definition of not being in bulk is when maximum possible charge current is not being used. However, it doesn't matter.

 

It depends on what you mean by "more efficient". It is useful to be able to belt in 200A to take the batteries up from say 50% to say 70%. However, I think there is some truth in the thought that the time taken to reach 100% is barely affected by having large charging devices, and of course there is an element of damage acrued by fast charging, but I don't think its much especially when the bats are used to run big loads on the inverter - both these things are not good for long battery life, but I put up with that for the convenience of using the electric kettle etc.

[bowten]

To the OP,if you want to use your charger as if you are on shore power,take off the alternator pulley and use the travel pack only.This is what I have done on my last 3 boats.My current boat as the 175 amp alternator connected but I have asked the same questions as you several times in the past and not really had a definitive answer.Before I go cruising for any length of time this season I will be disconnecting the pulley from the alternator and just using the T/P.I do think it is better for the batteries to be using the Victron charger only and as you say this is one of the reasons for investing in the T/P.

[nicknorman]

To the OP,if you want to use your charger as if you are on shore power,take off the alternator pulley and use the travel pack only.This is what I have done on my last 3 boats.My current boat as the 175 amp alternator connected but I have asked the same questions as you several times in the past and not really had a definitive answer.Before I go cruising for any length of time this season I will be disconnecting the pulley from the alternator and just using the T/P.I do think it is better for the batteries to be using the Victron charger only and as you say this is one of the reasons for investing in the T/P.

Again, why? But anyway, what about the warning light and alarm?

[bowten]

Again, why? But anyway, what about the warning light and alarm?

Because I think the O/P wanted in the first instance to use the Victron charger for the batteries as he would if on shore power therefore utilising the 4 stages of charging.The alarm and warning light is not a problem once the alternator is disconnected.

[bizzard]

Because I think the O/P wanted in the first instance to use the Victron charger for the batteries as he would if on shore power therefore utilising the 4 stages of charging.The alarm and warning light is not a problem once the alternator is disconnected.

I agree, why wear out the alternator when its not really needed.

[Keith M]

Because I think the O/P wanted in the first instance to use the Victron charger for the batteries as he would if on shore power therefore utilising the 4 stages of charging.The alarm and warning light is not a problem once the alternator is disconnected.

 

Good idea but how do you get around the water pump not operating over heating?

 

Keith

[nicknorman]

Good idea but how do you get around the water pump not operating over heating?

 

Keith

I guess you're not familiar with Beta 43 - it has dual alternators and the 175A domestic one's belt goes only round the crank. The smaller engine alternator's belt drives the water pump.

 

To OP, in summary:

 

1) adaptive charging is a bad idea and should be disabled. It is an especially bad idea if the engine alternator is running, as this will take it out of bulk very early and hence shorten absorption unduly. Once it goes to float the system will of course continue to charge from the engine alternator. It can be disabled by moving a DIP switch in the box, no need for a laptop.

2) Victron going into Absorbtion or even Float is no guide to state of charge, or indication of when to stop charging when engine alternator also running - look at the current going into the batts

3) raising the Victron absorption voltage will help the alternator and Victron work together and prevent the V going into Float early. This presumes basic open wet cell batteries. Laptop needed to do this

4) Victron inverter section coming on is likely to be due to UPS mode on, and Victron disliking the waveform from the TP. It should be disabled by DIP switch as a first step.

 

I agree, why wear out the alternator when its not really needed.

Because the alternator and TP/ Victron can play nicely together - eg if charging the batts, and wanting to do the washing, TP power can go to supplying mains and any limited extra power can charge bats via the Victron, with alternator doing most of the work. Or if just charging the bats (with Victron charge voltage raised a bit) they both share the load, making each run cooler. Towards the end of the charge, Victron can come up to say 14.9v to ward off sulphation if battery type can stand it.

 

Dear God, this thread is getting painful with people who have no experience of using this sort of configuration, speculating incorrectly! It's no wonder there are so many boats around with incorrectly configured but expensive electrical systems! I'm leaving this thread now because I can't stand it any more!

<Flounces off!>

Edited February 21, 2013 by nicknorman

[bargemast]

Please don't flounce off, I think that your knowledge, and advise is very usefull to many.

 

Peter.

[nicknorman]

Please don't flounce off, I think that your knowledge, and advise is very usefull to many.

 

Peter.

Don't worry, just flouncing off for dramatic effect, I expect I'll be back!

[Chris Pink]

 

Dear God, this thread is getting painful with people who have no experience of using this sort of configuration, speculating incorrectly!

 

Funny, when did you swap your Mastervolt for a Victron? Though I did notice you flounce off to read the manual yesterday after I pointed out your elementary mistake.

Edited February 21, 2013 by Chris Pink