High capacity alternators

[snowleopard]

I have twin engines with a 55A alternator on each, rigged through splitting diodes to both charge the domestic bank. I have a twin-engine Adverc controller and one 345AH battery bank. The most charge I've seen with both engines running has been 30A.

My question for those who have fitted high-capacity alternators is - do you actually see higher charging currents? or is it only possible if you let the batteries go almost flat?

 

[NPMR]

Just fitted a 120A/hr alternator but with new batteries. Highest charge seen was nowhere near capacity, so I suspect you'll need to have batteries in a more discharged state.

 

[npf1]

Yes. I've a 120amp alternator and have frequently seen 80/90amps going into the batteries during the absorption stage (with batteries not flat but around 50-70% SOC)

 

[pvb]

I have twin engines with a 55A alternator on each, rigged through splitting diodes to both charge the domestic bank. I have a twin-engine Adverc controller and one 345AH battery bank. The most charge I've seen with both engines running has been 30A.

That's not a lot, but it all depends on the state of the batteries. If they're fairly well charged to start with, you won't see a huge charge current.

You should check the charging voltage at the batteries and see whether the Adverc is working correctly. After a few minutes' running, it ought to start boosting the charge voltage to 14.4-14.8v (temperature dependent).

Unless you greatly increase the size of your battery bank, there'd be little point in fitting a bigger alternator.

 

[[2574]]

Yes. I've a 120amp alternator and have frequently seen 80/90amps going into the batteries during the absorption stage (with batteries not flat but around 50-70% SOC)

Likewise. 120A Balmar alternator with Maxcharge regulator serving 520AH AGM Lifeline batteries. When down below 70% SoC I have seen charging in excess of 80A. Just fitted a serpentine belt kit in place of single Vee belt in order to better manage the alternator drive load.

 

[RichardS]

I've got twin engines with 80 amp alternators and they usually start charging at around 55 amps but dropping to half that after an hour or so.

Richard

 

[Sandy Bottom]

I've got a 170A 24V alternator (i.e. 340A equivalent @ 12V) going into a 1,000ah bank - but that is too much just for charging and I never see it on full chat unless the (3kw) Inverter on on load (boiling a kettle etc.).

Your 2 X 55A going into 345Ah is plenty and 2 X 30A charging is in the right ballpark without cooking the batteries or stressing your alternators too much.

 

[geem]

I've got a 170A 24V alternator (i.e. 340A equivalent @ 12V) going into a 1,000ah bank - but that is too much just for charging and I never see it on full chat unless the (3kw) Inverter on on load (boiling a kettle etc.).

Your 2 X 55A going into 345Ah is plenty and 2 X 30A charging is in the right ballpark without stressing your alternators too much.

I am the other end of your spectrum. I have 480 ah at 24v with just a 60amp @24v alternator with no special regulator. I do have lots of solar and towed genny. Batteries rarely get depleted but we don't see more than 30 amps going into the batteries

 

[nigelmercier]

...Just fitted a serpentine belt kit in place of single Vee belt in order to better manage the alternator drive load.

Got any info on that?

 

[TQA]

I have a 100 amp Balmar with their 4 stage controller. 6 golf cart batteries give me a 675ah bank.

As I am in the Carib and have plenty solar I rarely use the engine for charging but when I need to the bank will be down to around 50% and I see 70 - 80 amps going in on absorption. I have a single V belt and it really gives the belt some hammer when it does this. A dual belt or a new style multi groove belt would be an improvement. For the moment I buy premium belts and keep them tight with two or three spares to hand.

 

[[2574]]

Got any info on that?

Nigel,

I think you responded to my post last year on the subject, see here: http://www.ybw.com/forums/showthrea...t-kit-for-high-capacity-alternator&highlight=

Seems there wasn't a kit for your engine?

Rob

 

[AndrewB]

Over the years I've upgraded my alternator from 35A to 50A to 70A. Charging rate certainly hasn't doubled, though as you say it is now a lot faster at the beginning. Once its well underway, the ammeter used to read about 20A, now typically reads about 30A. A 70A alternator is pretty well the maximum for my engine, beyond that I'd need twin belts at very least.

 

[snowleopard]

Yes. I've a 120amp alternator and have frequently seen 80/90amps going into the batteries during the absorption stage (with batteries not flat but around 50-70% SOC)

What regulator are you using?

That's not a lot, but it all depends on the state of the batteries. If they're fairly well charged to start with, you won't see a huge charge current.

You should check the charging voltage at the batteries and see whether the Adverc is working correctly. After a few minutes' running, it ought to start boosting the charge voltage to 14.4-14.8v (temperature dependent).

Unless you greatly increase the size of your battery bank, there'd be little point in fitting a bigger alternator.

Adverc runs at 14v with IIRC 5 mins in every 20 boosted to 14.4V. I might have been better off with a Sterling 3-stage charger but don't know if they do a twin-alternator version and one experience of asking Mr Sterling a technical question was enough to put me off asking anything else.

Your 2 X 55A going into 345Ah is plenty and 2 X 30A charging is in the right ballpark without cooking the batteries or stressing your alternators too much.

No, it's 30A going into the batteries whether 1 or 2 engines running.

Incidentally one of the internal regulators gave up a couple of years ago and overrode the Adverc. By the time I noticed the overcharge light it had been running at 16v+ for some time and killed the batteries.

 

[pvb]

Adverc runs at 14v with IIRC 5 mins in every 20 boosted to 14.4V. I might have been better off with a Sterling 3-stage charger but don't know if they do a twin-alternator version and one experience of asking Mr Sterling a technical question was enough to put me off asking anything else.

I think the Adverc should boost to more than 14.4v, and for more than 25% of the time. Mine used to boost to 14.8v for about 20 mins, then drop back for a few mins, then repeat the cycle. Voltages are of course dependent on battery temperature.

 

[Mudisox]

I've got twin engines with 80 amp alternators and they usually start charging at around 55 amps but dropping to half that after an hour or so.

Richard

Similar setup, similar outputs.

 

[nigelmercier]

I think you responded to my post last year on the subject, see here: http://www.ybw.com/forums/showthrea...t-kit-for-high-capacity-alternator&highlight= Seems there wasn't a kit for your engine?

Thanks Rob, I remember now. There is a kit for my engine, under Perkins, but still quite expensive.

 

[cliff]

This is what you need



Now that is what I call a serpentine belt!