Alternator Paralleler Circuit

[pistnbroke]

hi

 

very interested in this topic as i have been thinking about paralleling my altenators instead of buying an alternator controller. i have got lost wading through 25 pages. does the original basic circuit work OK the discusssion is about auto drop out? and secondly is there a problem of pushing 100A + through the the battery and buckling the plates?

 

cheers

 

roger

 

These people are talking of banks of 400ah capacity which is 25 A per 100ah which is fine

[pistnbroke]

 

 

 

When start battery reaches voltaage deterimined by variable resistor ( 14.4 say) the zenner conducts charging 10 uf ...When this cap reaches 0.6v it discharges into the Unijunction which switches on the SCR ..the scr closes the contactor .

 

Even if start battery voltage falls when it gets connected to the bank the scr cannot switch off so the relay holds ....when ign turned off Relay and scr turn off and it all re sets ....may need slight adjustment but you aint paying me ....

Edited August 20, 2009 by pistnbroke

[rogerc]

These people are talking of banks of 400ah capacity which is 25 A per 100ah which is fine

 

yes but if the start battery voltage is less than the domestics (eg if you start again after charging all day) all the charge will go to the start battery. which i think is why the original circuit had a manual start so you could allow the engine battery to recharge if necescary.

[pistnbroke]

no it wont ...the start battery will be slightly down from cranking and the two will not connect until the start battery voltage reaches say 14.2 as set by VR ....so if all batteries are fully charged there will be little current anyway be it from one or 2 alternators .( in any case one alternator will have its regulator slightly lower than the other if only by a tiny amount so will cease charging first ....) Still see no reason why it will not work fine.

 

What is not given enough weight in the past 26 pages is that you must have your voltage regulator in the range 14.4 v min to 14.7 or you will seriously reduce the life of the batteries as they will never be fully charged and sulphate

Edited August 20, 2009 by pistnbroke

[rogerc]

"the two will not connect until the start battery voltage reaches say 14.2 as set by VR ...."

is VR the voltage across the 10uF cap in your post #502? and this circuit will keep the alternators latched till the ignition is turned off? Is this a problem if you don’t have an external regulator boosting the charge voltage?

 

Aren’t the voltage regulators built into the alternators and preset? hopefully in the range 14.4-14.7.

 

If I understand the thread right, the idea is to quickly 80% charge the domestic battery eg when stationary - with a secondary benefit that there is more load on the engine-. The battery will get fully charged when cruising when there would be no need to parallel the alternators. Is this right?

 

cheers

 

roger

[WotEver]

If I understand the thread right, the idea is to quickly 80% charge the domestic battery eg when stationary - with a secondary benefit that there is more load on the engine-. The battery will get fully charged when cruising when there would be no need to parallel the alternators. Is this right?

 

More or less. Chris W's original circuit is designed to use the spare capacity available from his engine start battery alternator to double the charge current available to the domestic batteries once the engine start battery was into acceptance phase. He switched it on manually with the push button once he saw that the start battery voltage was up to around 14V and then switched it off after say 90 minutes once a decent charge had been put into the domestics.

 

All the subsequent posts have been about how to make the system fully automatic (apart from a brief foray into theoretical versus practical mathematics, exponential versus linear curves and how to package up a battery's internal resistance and post it to Gibbo)

 

T.

[pistnbroke]

There is a point in switching it off at 80%..IF you are tied up charging . but there is no reason not to have the circuit fully automatic and use it when cruising as the currents will have fallen and in the end only one alternator will be charging and determining the final max voltage .... so just use my circuit and fit and forget

[Smelly]

There is a point in switching it off at 80%..IF you are tied up charging . but there is no reason not to have the circuit fully automatic and use it when cruising as the currents will have fallen and in the end only one alternator will be charging and determining the final max voltage .... so just use my circuit and fit and forget

 

One point of the auto start was not to overcharge the engine start battery by paralleling it to a number of discharged batteries and then holding it at 14.8 volts with an alternator regulator... That was the whole point of the auto shut off which seems to have been missed and the jist of the entire debate has been in acceptance that the system will be charging at or above the gassing voltage of the batteries depending which controller you're using.

[Nige123]

Not according to the link you supplied. Both diagrams in that link show the box as being nothing more than an external Alternator Controller for a single alternator.

 

This thread is about paralleling two alternators to get extra charging power.

 

Regards,

Tony

 

like the post below your reply says it DOES SAY you can connect 2 alt's to this I know as my boat has this set up with 2 alt's fitted.......

 

& you could save £200.00 but the cost of replacing my 6 110ah batteries if I got it wrong would put me off a DIY fitting even if the fact that in any event of a fire my insurance would not pay up!

 

I would hate to save £200.00 & end up £40k out of pocket.................

 

 

the unit is quite small & the 2 alt' cables (about 25mm) connect into it & a very large (75mm or so) cable runs a few feet to my bank of 6 110ah batteries & it charges them real quick as it has 2 80amp inputs & a 160amp charging output.....

 

it does what you want it to do & is made for the job comes with warranty & tech' help from experts & if your boat does catch fire & it's due to the product you can take them to court......

 

sorry your trying to re-invent the round thing that cars roll on out of rocks here ;O)

[pistnbroke]

Seem to have upset somone by solving all the problems in one hit ...you carnt overcharge anything if the volt regs are set to 14.4-14,7 ...I think you are just upset I sorted it in about 2 min as as doodle on a bit of paper .....you need to increase the capaicitor to suit the SCR and may be a 100K across the capacitor would be a good idea OK its 1980 component technology but it ticks all the boxes and its cheap .....

 

 

If you dont like it who cares...... go re invent the wheel ......... on a real techinical forum.. wwww. Boat design .net they love it ........

 

have a nice day with your soldering iron ............ha ha

[WotEver]

you could save £200.00 but the cost of replacing my 6 110ah batteries if I got it wrong would put me off a DIY fitting

 

Then don't do it

 

Simples.

 

CW's circuit would cost in the region of £45. Pistnbroke's about the same.

 

A better bet would be to purchase a SG, which any self-respecting boat should have anyway and then you can do it (automatically) for even less

 

T

[Gibbo]

When start battery reaches voltaage deterimined by variable resistor ( 14.4 say) the zenner conducts charging 10 uf ...When this cap reaches 0.6v it discharges into the Unijunction which switches on the SCR ..the scr closes the contactor .

 

Even if start battery voltage falls when it gets connected to the bank the scr cannot switch off so the relay holds ....when ign turned off Relay and scr turn off and it all re sets ....may need slight adjustment but you aint paying me ....

 

You might as well just have the relay energised all the time the engine is running.

 

The WHOLE point of the original circuit was that it disconnected the two battery banks once the overall voltage rose to the acceptance voltage of the alternator controller on the domestic alternator. This is to prevent the engine start battery being held at the elevated voltage of the external controller for hours on end thus using up lots of water.

 

Your circuit doesn't do that. In fact all it will do do is connect the relay as soon as the engine alternator reaches the preset voltage which will be almost instantly unless you have a knackered engine and tiny alternator.

 

Gibbo

[mayalld]

Seem to have upset somone by solving all the problems in one hit ...you carnt overcharge anything if the volt regs are set to 14.4-14,7 ...I think you are just upset I sorted it in about 2 min as as doodle on a bit of paper .....you need to increase the capaicitor to suit the SCR and may be a 100K across the capacitor would be a good idea OK its 1980 component technology but it ticks all the boxes and its cheap .....

 

 

If you dont like it who cares...... go re invent the wheel ......... on a real techinical forum.. wwww. Boat design .net they love it ........

 

have a nice day with your soldering iron ............ha ha

 

You seem to be very protective of the design.

 

One might alnost imagine that you have some "connection" to the original poster.

[WotEver]

You seem to be very protective of the design.

 

One might alnost imagine that you have some "connection" to the original poster.

 

Surely not, Dave. Not when reading comments such as "If I have been talking electircal techno crap I have doing it for 40 years and have degrees and certificates to prove its total crap"

 

[mayalld]

Surely not, Dave. Not when reading comments such as "If I have been talking electircal techno crap I have doing it for 40 years and have degrees and certificates to prove its total crap"

 

 

Hmmm.

 

Is it officially NORTY?

[WotEver]

Is it officially NORTY?

 

I'd have thought so, but I'm new here

[Gibbo]

Perhaps drinking too much cheap lager has affected his reading abilities because his circuit will indeed work. It just won't actually do what was wanted. In fact it won't actually do anything other than connect the relay. Which isn't what was wanted. So I suspect his (lack of) reading abilites are the real problem.

 

Gibbo

[RLWP]

Hmmm.

 

Is it officially NORTY?

 

No. Being Norty means you have to sit on the Norty step in the Virtual Pub.

 

Being contentious about electrical matters* gets you thrown out accompanied by a hail of rotten vegebles.

 

Richard

 

*other subjects are applicable

[mayalld]

No. Being Norty means you have to sit on the Norty step in the Virtual Pub.

 

Being contentious about electrical matters* gets you thrown out accompanied by a hail of rotten vegebles.

 

Richard

 

*other subjects are applicable

 

Ah, OK, but are you then allowed to come back as a stereotype?

[RLWP]

Ah, OK, but are you then allowed to come back as a stereotype?

 

You could try disguising yourself with a floppy hat and a false beard...

 

Richard

[mayalld]

You could try disguising yourself with a floppy hat and a false beard...

 

Richard

 

Pah, I have a floppy hat, and I grew a beard whilst we were out this year.

 

Does that mean I'm disguised now?

[WotEver]

Does that mean I'm disguised now?

 

Who said that?

[pistnbroke]

same the world over ..everybody knows everything about batteries ..old wives tales .fairy tails and information more suited to 1930 battery technology ....

 

the point is that the circuit will fire a thryristor only when the start battery is fully charged and it wont switch off until the engine is stopped ...switch what you like with it ...cost without heavy duty solenoid about five quid

Batteries dont gas unless you push them over 14.7 v

 

Starting battery left in parallel with the house bank will be at same voltage as the house bank ie will discharge into the house bank so disconnect it

[WotEver]

Batteries dont gas unless you push them over 14.7 v

 

[Gibbo]

same the world over ..everybody knows everything about batteries

 

Yes, I spotted that too.

 

..old wives tales .fairy tails and information more suited to 1930 battery technology ....

 

Hmmmm, interesting considering what else you write.

 

the point is that the circuit will fire a thryristor only when the start battery is fully charged

 

Er...... With a typical 100Ahr start battery and a 50 amp starter alternator the battery voltage will rise to the alternator acceptance voltage within 30 seconds of the alternator firing up, even with a completely flat engine start battery.

 

So if your circuit does that (which it will), the relay may as well simply be energised directly from the D+ terminal.

 

and it wont switch off until the engine is stopped

 

Which is not what is wanted.

 

...switch what you like with it ...cost without heavy duty solenoid about five quid

 

A mains plug is 38 pence at my local hardware shop. That's even cheaper. Oh wait, that won't do what is required either.

 

What relevance is the cost if it doesn't do what is required?

 

Batteries dont gas unless you push them over 14.7 v

 

Rubbish. The gassing voltage of a wet cell battery is an inverse function of the state of charge with an average gassing voltage throughout the range 50% to 100% of 14.4 volts.

 

But as you already know everything about batteries you already knew this. Oh hang on, you said it was always above 14.7 volts. Therefore you didn't know this. Therefore you don't know everything about batteries. But you thought you did.

 

Conclusion: You don't know as much as you think you do.

 

Starting battery left in parallel with the house bank will be at same voltage as the house bank

 

Did you work that out all on your own?

 

ie will discharge into the house bank so disconnect it

 

Duh

 

Gibbo