How to get high charging rates from a generator

[john61ct]

And their Remote add-on allows for stopping charging (dropping to Float) based on reading trailing amps at the bank directly, rather than having to adjust Absorb Hold Time.

[PLeffe]

More of a question than a comment. If the boat has a house bank and a start battery would it work to take a 40a three bank charger and hook two outputs to the house to get 80a into the house. Wouldn’t this be the same/similar to using multiple chargers working together???? I have no idea but maybe someone knows. It would be an inexpensive way to get high charge rate to house.

Thanks to those of you who might just know the answer.
Regards,
Peter
S/V Dreamtime

[a64pilot]

Originally Posted by john61ct

And their Remote add-on allows for stopping charging (dropping to Float) based on reading trailing amps at the bank directly, rather than having to adjust Absorb Hold Time.

You have to have both the add on remote, which you need anyway to control all the features, and the battery monitor kit (BMK) which is very reasonably priced.
Without the remote the Inverter / Charger can’t really be controlled, so don’t think of it as optional.
If you desire you can also add the AGS or automatic generator start kit as well

[Sailmonkey]

Originally Posted by PLeffe

More of a question than a comment. If the boat has a house bank and a start battery would it work to take a 40a three bank charger and hook two outputs to the house to get 80a into the house. Wouldn’t this be the same/similar to using multiple chargers working together???? I have no idea but maybe someone knows. It would be an inexpensive way to get high charge rate to house.



Thanks to those of you who might just know the answer.

Regards,

Peter

S/V Dreamtime

Nope, doesn’t work that way. It’s 40amps period. The different outputs are just built in battery isolators.

[waterman46]

Originally Posted by billknny

There are actually many brands making charger only that spec out significantly greateer 60 amps. Of course they are all expensive, and not available on the shelf at your local west marine.

Dolphin makes 90 amp for 12 V and 100 amp for 24 volt.

Quick makes 100 amp for 12 and 24 volts

Victron also makes 100 amp chargers.

I just bought a 100A three stage charger for $250 from BatteryStuff.com. I doubt it is "marine" quality, but it will be used as a back-up and capacity expansion with the primary charger, Heart Freedom 2000 100A. We only have 400AH house bank, but our cold-plate reefer system draws about 28A and the watermaker 16A. We like to run all these at the same time we are running the Onan to charge the house bank. The house bank can accept all 100A from the Heart Freedom 2000 during bulk charge phase, so I got the second cheap charger to supply the additional current for the reefer and watermaker.


The bulk charge phase at 100A for our 400AH batteries discharged 50% seems to last about 1/2 hour so I'm thinking the additional charger will make a significant reduction in generator run time. BTW running all this stuff plus space heaters if needed, microwave, TV, etc. at the same time is just a walk in the park for that Onan.

[jgbrown]

Originally Posted by sailingharry

John,


The charge rate is a classic cruiser dilemma. The lower the charge rate, the longer the batteries last. But at the same time, the lower the load on the engine and the longer it runs. But, even at your suggested 300A, we have a challenge.


I pulled up one credible name, Mastervolt, their largest charger is 50 Amps. I also tried Magnum, no chargers from what I can tell.


I agree with you regarding the benefit of "stacking." Pure parallel works fine, and when something falls off, it's because it isn't needed. Unless you get some sort of harmonic fluctuation going, it doesn't matter. But regardless, 300 Amps is 6 of these 50A chargers in parallel! Is that what people do?


I understand the philosophical objection to combo units, but I've seen them in full time cruise use lasting 20+ years.


I do not know the exact limit or specs of the generator, but it is sized to support the A/C load of a 45 catamaran, so I'm sure it is around 10KW. 300A DC charge is around 4KW AC, give or take some rounding.


So, my question remains -- how do people cram large amps into a battery from a generator? Many people put 150-200A alternators on a main engine, and he's currently limited to 40A on shore power!


Harry

Look into the industrial marine brands. For example the Newmar 3000TQ-12 is an inverter charger that puts out 150 amps. Now you only need two, and have the benefit of 6KW cont, 13KW peak inverter.

[sailinglegend]

Here's my report on 10 years using a Fischer Panda 12v 4KW DC generator with my 1050Ah Lifeline AGM batteries. It has a maximum output of 280 amps - sustained o/p about 250 amps. After 14 years my new bank will be reduced to 630Ah.

Yes I have had some of the problems that have plagued these generators. Three times water has got into the exhaust valve has been the worst, but removing the head is quite an easy job. This has been down to poor installation and positioning of the waterlock, and FP and Vetus are to blame for lack of clear information. My problem is now solved and FP have produced a new exhaust output/mixer module.

A DC genset only runs at the speed it needs to produce the amps the batteries will except, so it runs very quietly and cannot be heard in the cockpit. I regularly use it via my Vicitron inverter/charger to power my Air Conditioning at anchor.

This is the 'DC Concept' as described by Victron in one of their many excellent online manuals - Energy Unlimited.

[stnick]

I use a marine Max 100 Amp charger . very happy with it I have two Industrial AGMs
easy 100 lbs each. very hard to handle There big Orange 4 inches wide 20 inches long and 15 high i had to lay them down and stack them ontop of each other as they will not fit in my battery locker. I have a 5 Kw generator also . with 220 solar panels. it all keeps me well charged up while cruising .