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.
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.
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...
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.
Can you specify AGM battery types, or else choose the bulk/float voltages?
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.
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.
There are several Trace 4024s on ebay right now.
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.
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
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.
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.
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.
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.
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...
Has anyone used Powermax chargers? The amazon reviews make it sound like they fall apart if they work at all, but I've seen these at a great price. Probably one of those "too good to be true":
https://www.amazon.com/Powermax-PM3-50-24LK-Power-Supply-Converter/dp/B01NBRCA85/ref=sr_1_1?keywords=powermax+24v&qid=1564435997&s=gateway&sr=8-1#customerReviews
50A at 24V for $250?!?
Here's an Iota 40A for $213
https://www.solar-electric.com/iota-engineering-dls-27-40-x-battery-charger.html
Seems to have good reviews.
That looks like it might be my solution!
Does anyone know if I can run it in parallel with my SW4024 charger if I have two separate AC voltage sources?
It would be nice if there was a way to also selectively limit the input to 15A (30A VDC output) for when I only have a NEMA 15A outlet to plug into, but I don't think that's an option with this charger.
Two separate AC sources are irrelevant to the charging function, the chargers don't care. You can run chargers in parallel at the same time if they are not "smart" chargers. If they are, they tend to fake each other into thinking the bank is fully charged when it isn't. Remember that you can have a charger with infinite ampacity, but if you don't have a load that needs the current, it won't flow. You mention you have a large battery bank and AGM batteries - while they can accept a high charge rate, they don't need it. One thing is that you have links to both "chargers" and "converters". In the RV world a converter is often optimized to supply steady 13.6 volt source to house loads, and oh by the way charge the batteries. A charger is optimized to charge the batteries, and can supply quite high voltages to do it - enough to piss off some common house loads. The two are not equal.
I must have missed it - how big is your battery bank, and are they indeed AGM batteries? What type?
Quote from: daveola on July 29, 2019, 02:37:16 PM
Has anyone used Powermax chargers? The amazon reviews make it sound like they fall apart if they work at all, but I've seen these at a great price. Probably one of those "too good to be true":
https://www.amazon.com/Powermax-PM3-50-24LK-Power-Supply-Converter/dp/B01NBRCA85/ref=sr_1_1?keywords=powermax+24v&qid=1564435997&s=gateway&sr=8-1#customerReviews
50A at 24V for $250?!?
I have the smaller version, PowerMax PM4 45A 110V AC to 12V DC 45 Amp.
https://www.amazon.com/PowerMax-PM4-55A-Converter-Battery/dp/B01ER3LH3O/ref=sr_1_fkmrnull_2?keywords=PM4%2B55A&qid=1556659129&s=gateway&sr=8-2-fkmrnull&th=1 (https://www.amazon.com/PowerMax-PM4-55A-Converter-Battery/dp/B01ER3LH3O/ref=sr_1_fkmrnull_2?keywords=PM4%2B55A&qid=1556659129&s=gateway&sr=8-2-fkmrnull&th=1)
When I bought new start Batteries, I moved the old 8D's to be my temporary house batteries (a year ago), this Power supply/ charger, works great, keeps the batteries charged and supplies all the 12-volt power I need for the lights and water pump.
Will probably need to upgrade the batteries when/if I get an Inverter.
Peter
Quote from: bevans6 on July 30, 2019, 02:50:46 PM
You can run chargers in parallel at the same time if they are not "smart" chargers. If they are, they tend to fake each other into thinking the bank is fully charged when it isn't... One thing is that you have links to both "chargers" and "converters"... I must have missed it - how big is your battery bank, and are they indeed AGM batteries? What type?
1) Good point - so I probably can't use one of these with the charger in my Trace SW4024 at the same time. I'll probably just try to find a large enough single charger to do the work then
2) Also a good point - I'm looking for a charger, not a converter, so I'll have to pay more attention to that
3) The bank is quite large and indeed AGM. I have 10 group 8D AGM batteries, which I believe can take somewhere between 60-80A during bulk, though I admit it's been a bit since I did the math on that. I do know that my SW4024 often maxes out at it's 31A max charge.
I have had an Iota DLS 27-25m w/IQ-4 on my starting batteries (4 group 31) for almost 10 years and no problems, I'm quite happy with it and would highly recommend this company. I also have an Iota DLS-55 13.4V @55 amps on my 12V house system. These may not be the best out there, but are cost effective and so far reliable. The best will cost more $. Iota has done the job for me at a good price and I would buy again if they fail and they all will fail at some point.
Best of luck. Gerry H
Going from the Trojan data sheet for 8D AGM dual purpose batteries, they are 230 AH @20 hr. The maximum bulk charge rate is 20% of that, so if you have 10 batteries in series/parallel for 24 volts, you have 1150 AH @20 hr so the maximum absorption charge rate is 230 amps at 28.8 volts. Which is a lot of amps. That's 6624 watts, or 55 amps at 120 volts AC before losses. The question is - how often will you drain your house bank to the point that it will draw that kind of current? And for how long will it draw that? The answer is it will switch to absorption charging as soon as the bank reaches a pre-set voltage limit (in the example, 28.8 volts), and at that point the charging is current limited. The bulk charge stage might only last 10 minutes before it starts absorption charging and the charge current is dropping.
Bottom line is you ain't gonna get too large a charger, and if anything you'll be limited by the power you can put into a charger. Lower capacity chargers will increase the bulk time, and absorption will take longer as well because it will initially be limited to the maximum the charger can put out, not the regulated current limit of 20% of capacity.
Bulk charging is variable voltage, current limited charging. In this example, a battery bank at 50% SOC would start out at 24.5 volts, and be charged at 230 amps until the battery voltage reached 28.8 volts.
Absorption charging is constant voltage, variable current charging. In this example, as soon as the battery bank reaches the set point of 28.8 volts, voltage is kept constant at that level and current begins to fall as the battery absorbs the energy and "pushes back" at the charger. In a realistic scenario, with a 50 amp charger the voltage will sit at 28.8 volts and 50 amps for a decent period of time as the battery bank catches up to the capacity of the charger, and thein current will fall off to a couple of amps. As soon as the current falls to a set point, the charger switches to Float charging.
Float charging is when the battery bank has reached 100% SOC, or very near that. It is constant voltage, variable current, with the voltage set to 27.2 volts. Charge current will vary, but will be very low.