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Could this be a $60 70A bulk charger for a LFP 280 battery?

Terrapin

Terrapin

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I am looking for a very inexpensive way to bring a 12v 280ah battery from its BMS programmed low of 25% DOD to it's top 75%DOD. The battery BMS is set for long life and far from the safe extremes.

Will this do that?

The purpose is to, in a camper, have a "last line of defense" quick charge option off a dual fuel inverter generator that only puts out continuous 110V 1600W. (14A)

I just found this, has anyone seen one or used it? https://www.ebay.com/itm/Car-Maintenance-free-Battery-Charger-12V-24V-70A-Output-For-Electric-Vehicles/254793931218?_trkparms=aid=1110012&algo=SPLICE.SOIPOST&ao=1&asc=20201210111451&meid=69665a768c794e2a87ad5482381772f8&pid=101196&rk=1&rkt=6&mehot=pf&sd=254687267950&itm=254793931218&pmt=1&noa=0&pg=2047675&algv=PromotedSellersOtherItemsV2WithMLRv3&brand=Unbranded&_trksid=p2047675.c101196.m2219


Can anyone offer other suggestions under $100. They would be very welcome!
 
Last edited:
please don't buy this,
what batteries do you have, I am guessing EVE 280AH cells ?
Get the IOTA Charger in the deals section, set the voltage or use the jumper and use the BMS cut off feature.

Snoobs, the man here, took sometime to explain to the options for options.
For charging, I would use a source that I can use max charging voltage to set my max charge level and not have to depend on the BMS alone.

MAKE sure your bms does cut off, aka bench test it now and every so often.
 
sshibly said:
please don't buy this,
what batteries do you have, I am guessing EVE 280AH cells ?
Get the IOTA Charger in the deals section, set the voltage or use the jumper and use the BMS cut off feature.

Snoobs, the man here, took sometime to explain to the options for options.
For charging, I would use a source that I can use max charging voltage to set my max charge level and not have to depend on the BMS alone.

MAKE sure your bms does cut off, aka bench test it now and every so often.
Click to expand...
I will need to try and search again for Snoob's post TY. He's saved my butt more than once here already.

Good point on BMS being the week link and keystone... I wonder about a high amperage PWM controller filling two needs now... IDK. ...this saving money long term as getting sideways short term
 
FYI: I charged mine at 50a and they did warm up a bit around 8F after an hour.
Charging at 30a is fine and the cells warmed up only by couple of degress.

50% DOD rise = 140ah
@ 50a it will take around 3 hours.

If you want to Zaaaap them faster, you can get a mean well RSP-600-15
 
DOD vs SOC they are not the same thing... when dealing with LFP, one must forget Leadisms... Took me a while as I started with big heavy Rolls Surette Lead. There is an LFP Voltage Chart link in my signature, you should download that, it will simplify life for you. LFP Voltage Range is 2.500-3.6500 BUT the Voltage Curve is 3.000-3.450 and that is what most folks set the BMS to with Lo cutoff being a bit lower to 2.750 or so because If a surge demand hits the quick voltage Sag could drop it low for a moment and trigger a cutoff.

Next, LFP Only requires CC/CV (Constant Current / Constant Voltage) no equalisation / desulphation and float must be below your max voltage setting by at least 1 volt. IE: 12V Battery Pack full at 3.45 per cell - 13.8V the float should be at 12.8.

Have a look at Will's Charger Page here: https://www.mobile-solarpower.com/battery-chargers.html He really likes the AIMS one at the bottom of the page which is correct for LFP. He did have a similar one to what you linked to and it fried a Nice Big Battery - a bad moment for sure.
 
AIMS is $$$,
A true 2 stage is what you need.
140 ah at 100 amp charge rate will still take 1.5 hours.
I am cheap and I have been trying out a bunch of the chargers. A good factory 2 stage charger is not that expensive compared to the Victron bluetooth ones which maxes out at 25A.
 
Before you go too far down this rabbit hole, consider if your generator can power a converter that produces the number of DC amps you're looking for.
 
FYI: OP posted that he has a 1600w genset

The purpose is to, in a camper, have a "last line of defense" quick charge option off a dual fuel inverter generator that only puts out continuous 110V 1600W. (14A)

1000w PS/charger will be do fine on a 1600w genset and still have room.

I have this, https://www.donrowe.com/powermax-pm3-55lk-converter-charger-p/pm3-55lk.htm
and it is pricey for 55amp and you have to use it in a PS mode to charge continuously till 75%
 
Steve_S said:
DOD vs SOC they are not the same thing... when dealing with LFP, one must forget Leadisms... Took me a while as I started with big heavy Rolls Surette Lead. There is an LFP Voltage Chart link in my signature, you should download that, it will simplify life for you. LFP Voltage Range is 2.500-3.6500 BUT the Voltage Curve is 3.000-3.450 and that is what most folks set the BMS to with Lo cutoff being a bit lower to 2.750 or so because If a surge demand hits the quick voltage Sag could drop it low for a moment and trigger a cutoff.

Next, LFP Only requires CC/CV (Constant Current / Constant Voltage) no equalisation / desulphation and float must be below your max voltage setting by at least 1 volt. IE: 12V Battery Pack full at 3.45 per cell - 13.8V the float should be at 12.8.

Have a look at Will's Charger Page here: https://www.mobile-solarpower.com/battery-chargers.html He really likes the AIMS one at the bottom of the page which is correct for LFP. He did have a similar one to what you linked to and it fried a Nice Big Battery - a bad moment for sure.
Click to expand...
YIKES! (good stuff too.)

Thanks all. I bit the bullet because of the variable output and dug deep for an AIMS. I found one about $40 less than everyplace else I saw them... At least I can say that to the divorce attorney when my Mrs. finds out.... ;-)
 
Divorce + Attorneys = Lawyers wealth fund support program.
Lawyers are only good for One Thing ! Target Practice or Live Fire Training.
 
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