Charger - Bigger the better ... Help

ghostwriter66

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SO apparently the OSHA guy that came for a visit did not read the sign that said "DON'T LOOK IN HERE-IT WILL KILL YOU" and looked in our battery shack anyway ...

Apparently he did not like our chargers that we put together that would charge the battery from a generator in about 10 minutes if the battery was running low .. apparently words like fire and life hazard and dangerous and something about this being nothing more than a portable welder were mentioned in the report ...

anyway .... apparently when you are working around a few hundred thousand gallons of fuel they frown on this ... (pussies)

SOOOOO I need to find a way of charging 24V 580AH LiFePO4 batteries as fast as possible from a 30A or 50A portable generator... something apparently I can buy and not make ... something that is "safe" according to them ....

all joking aside but the generators that we have to charge our batteries are huge - way to big - but they won't give us anything else ... and for every minute they run my life gets a little harder out here ... so looking for something that I can rapidly charge -- even at 1C to maximize the generator time but have it run less time ...
 

smoothJoey

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There are generators that are portable as in they have wheels and a provision to be lifted into and out of a pickup bed with a small crane like device.
Is that portable enough?

This one is ~400 pounds
 

smoothJoey

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There are generators that are portable as in they have wheels and a provision to be lifted into and out of a pickup bed with a small crane like device.
Is that portable enough?

This one is ~400 pounds
You could pair that with some cheap high capacity rv converters in whatever series parallel configuration is required.
 

smoothJoey

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The Powermax converters can be configured for fixed voltage which is probably useful for this application.
On the other hand Powermax is the cheapest for a reason.
If the OSHA guy is sniffing around you might want to give Powermax a pass as their high capacity units are not UL listed.
 

time2roll

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Mastervolt and Victron make excellent chargers too if there is a budget. May as well connect an autostart on the generator while you are at it. Everybody has better things to do than run out and start a generator just to wait around to shut it off.

Have heard a lot of good reports on the MeanWell. I just hate sifting through 400 models to find what works.
 

ghostwriter66

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time2roll

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The Meanwell has a power factor of .95 vs .70 for the Powermax. So from a generator you need 25% more apparent power to get the same output. Meanwell can have the amps reduced to match generator output if things get marginal.
 

sunshine_eggo

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While I've been throwing around 125A, I should clarify that it's also power limited at 3000W. If charging to 28V, the peak current will be 107A.
 

DJSmiley

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I have good experiences with Meanwell.

Just recently installed a Meanwell RPB-1600-12 (on a 12V set) which provides 100A charge current.

The 24V version does something like 50A.

They also have a 3200W version ( https://www.meanwell.com/webapp/product/search.aspx?prod=DBU-3200 ) which does 110A.

You can parallel 2 of them to get 220A charging...

If you go for the rack version you can parallel 4 of them.. http://meanwell.co.za/wp-content/uploads/2018/04/DBUDBR-3200-DHB-1UT.pdf
and get 12800W... That's like 440A.
Not enough? Use multiple racks...

Maximum ten rack shelves can be connected in parallel operation. Total power is up to 128kW.


But probably both your grid/generator and wallet are the limiting factors :)


Issue will be the generator. A 30A generator (Assuming 110V) is something like 3300W.
As a general recommendation it's adviced to have the generator at least <power usage x 2> of minimum rating. So a single 1600W will probably work fine on that 30A generator, but a 3200 will probably not run fine (Generator might shutdown due to sudden high load when started)

Ow and as for charging current: Eve LF280K eg specifies 0.5C charge/discharge, 1C maximum.

0.5C @ 560Ah is still 280 amps... that's a lot. The BMS will be the limiting factor, since a lot of BMSses are 100A, and it's not recommended to run the full 100A for long periods. Fire risk? No. Those cells are made to handle these currents.
There is more risk in fire due to crappy wires and lugs than the actual cells.

Yes, LFP has a huge energy potential. You *can* weld with it. But to to a local truck dealership and make a short in one of those lead-acid batteries... That's not going to be any different...
 
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