Suggestions for large 24V charger (like 80A DC charge or more?)

daveola · June 18, 2019, 12:15:59 PM

I have a very large 24V battery bank and I used to charge it with two SW4024 inverter/chargers, but one of my SW4024s self-destructed and they have become impossible to replace.

I don't generally need the AC output of both inverters, so I was thinking about just finding a large charger to take care of my shore power -> batteries, so I'm looking for a 24V charger that can do around 60 or 80A or even more if possible, so that i can completely replace the charging that my inverters were doing.

I have AGM batteries, so I'd want to be able to set the charge/float voltages.

daveola · June 18, 2019, 12:24:38 PM

I just did some searching on ebay. I seem to recall there were some cheap imports that could do 60-80A and I figured at least some of them must work for a few years - but I don't see any on ebay now.

daveola · June 18, 2019, 12:33:07 PM

Although another thought would be to put two 12V chargers in series across my two battery banks, which would (as long as the chargers stay consistent) somewhat help balance my banks - has anyone ever tried this? I could probably find 12V chargers more easily...

richard5933 · June 18, 2019, 01:05:06 PM

Not quite as large as you want, but 40 amps is pretty good.

https://www.progressivedyn.com/specialty/pd9240-24A-volt-power-converterbattery-charger/

I've got the 25 amp version and happy with it.

daveola · June 18, 2019, 03:20:48 PM

Can you specify AGM battery types, or else choose the bulk/float voltages?

richard5933 · June 18, 2019, 03:52:13 PM

I don't think so.

Here's what I found in the manual about the various charging voltage levels:

BOOST MODE: If the converter senses that the battery voltage has dropped below a preset level the output voltage
is increased to approximately 28.8 volts DC to rapidly recharge the battery.
NORMAL MODE: Output voltage set at approximately 27.2 volts DC.
STORAGE MODE: When the converter senses that there has been no significant battery usage for 30 hours the
output voltage is reduced to 26.4 volts DC for minimal water usage. When in storage mode the microprocessor
automatically increases the output voltage to 28.8 volts DC for 15 minutes every 21 hours to help reduce sulfation of
the battery plates.

richard5933 · June 18, 2019, 04:01:31 PM

Here's another option that has switches to choose your battery type:

https://www.donrowe.com/Samlex-SEC-2440UL-p/sec-2440ul.htm

Sounds like this might be more to your needs if you want to be able to change voltage levels. Manual is available on this page if you want.

Don't know much about this particular charger, but I've got a Samlex inverter and am quite impressed with the quality. Same for the folks at Don Rowe - they have good tech support and seem to be knowledgeable.

Lee Bradley · June 19, 2019, 01:21:17 PM

There are several Trace 4024s on ebay right now.

daveola · June 19, 2019, 01:26:19 PM

Quote from: Lee Bradley on June 19, 2019, 01:21:17 PM
There are several Trace 4024s on ebay right now.

At over $1k, I think it makes more sense to try to find a $300 charger. Plus, the 4024s can't do charge sharing, which is majorly disappointing. I am often connected to only 15A shore power and need short periods of just over 15A of power, and the 4024 stops using shore power entirely once you go over the shore current.

chessie4905 · June 19, 2019, 04:34:27 PM

Would something like this work?

https://www.ebay.com/itm/Energic-Plus-TSS-D-Traction-Forklift-Golf-Cart-Battery-Charger-24V-120A-Output/361781130820?hash=item543bd5f644:g:6wEAAOSw7ApZ1pJ5&redirect=mobile

richard5933 · June 19, 2019, 04:40:18 PM

How large is your battery bank?

One problem I see with the really large chargers, like the one in the previous post, is where are you going to plug it in. That one runs at 240v 17a, something not commonly available in a bus conversion.

A 24v 40a charger is probably about as large as you can safely run on a 20-amp 120v circuit. Possible a bit larger, but not much.

Lin · June 23, 2019, 11:03:19 AM

Correct me if I am misunderstanding. A 20 amp, 120 volt circuit would be good for 2400 watts minus efficiency losses. That would convert to 100 amps at 24 volts (again minus efficiency losses). Not knowing what those losses are, I would guess that an 80 amp charger would be almost possible, but a 60 or 70 amp charger could work on a 120v, 20amp circuit.

daveola · June 24, 2019, 04:39:38 PM

A forklift battery charger is not a bad idea - though are they settable for AGM batteries?

Here's my stats:

Generator is 10kW at 110V (so ~80+A)

Battery bank is 10 Group 8D AGMs - that's something like 36kWh of power.

So I'm pretty sure my bounds on charging are how much the batteries will take. I seem to recall they could easily pull 60A or more at bulk? Does anyone know where I can find this info? So maybe 2kW of charge, which will only pull a fraction of what my genset can pump out.

chessie4905 · June 24, 2019, 06:26:09 PM

Here: https://energicplus.com/en/products/traction-battery-chargers

Looks like they will work on all types of batteries. Looks like a deal on Ebay compared to the price of a new one.

daveola · June 25, 2019, 11:39:50 AM

Those do look like a heck of a deal. I should have mentioned before that my genset and bus are setup at 110V, and all the energic chargers look to be >110VAC.

I'm starting to think it might make sense to try to come up with 240V shore power cabling, since I think I can get 240V at the main location I need more power at - but then my larger charger would only work there...