Diy Lifepo4 charger high powers and more

DiyNuke

New Member
Diy Lifepo4 charger 30A +/- 100$

Alright ive started with making my own lifepo4 chargers and for now its still the semi manual timer based one.
so for now i have 30A max however i am selecting an list of stuff to make an 100A 24v charger which would have an automatic cutoff based on charge current. so if current drops (cells almost full) then terminate and as an option an timer to continue 1h in the float stage so get it almost completly full.

And since it pretty hard to find these kind of chargers for filling the battery bank really quick if you want to charge an small EV or an big solar bank because its low on juice. I want to experiment some more. however there are a load of genius people here which know allot. so i would like you all to join my journey to make an good and cheap fast charger which would not burn down my house. i am gonna order all the parts and make an schematic and then explain it a bit.

cost will probaly be around 600$ using 4 of my 30A chargers would be a bit cheaper however it will be huge and thus an pain to bring with you/store it.
 

Positronium

Solar Enthusiast
I do not know much about RVs but yikes! 100A @ 24V plus conversion losses is a serious current draw from grid. You are looking at 20A @ 120V before considering conversion losses. I will leave this to the RV guys.
 

DiyNuke

New Member
I do not know much about RVs but yikes! 100A @ 24V plus conversion losses is a serious current draw from grid. You are looking at 20A @ 120V before considering conversion losses. I will leave this to the RV guys.
I live in the EU/netherlands where the grid is 230v and 16A so i can draw 3680W max and without losses its 2400w so i still have some headroom.


Happy that i dont have 120v power😂 seems like allot more hassle to get everything to work reliable.

So yeah it sort ofexplains why i am looking into it and all. For me its just an plug and play charger like any other small charger
 

DJSmiley

Solar Enthusiast
No sure if it's cheaper to make such a charger. High-current electronics aren't cheap, and even if you start with a 'basic' switched power supply as source, it's gonna be $$
Include electronics, cooling, case, prototyping PCBs.. it will add up pretty fast.
Also, 'bring with you / store': Does this mean it needs to be removable? Pay extra attention to plugs, go for Anderson or so, especially with those high currents.
In your video i saw some cheap chinese powersupplies. Won't trust those to leave unattended (Crappy quality as you already noticed).

Also, if you want to hookup it on campsites, many in NL are limited to either 6 or 10A. (10A is more expensive)
Not sure what size your battery bank is, but even with 'only' 40A, a fully flat 280Ah bank will be full within 7 hours. (and its unlikely you won't fully deflate 280Ah, so in reality its 5 hours or so to charge)

Have a look at MeanWell. They provide nice chargers. Yes, it's still a bunch of $$ (euro actually) but I doubt if you can do it cheaper (and with comparable quality)
Their 600W+ power supplies can be set to either 3 or 2-stage charging.
Also, I do trust Meanwell for reliability and rugged case/design, they are used in a lot of industrial applications. I doubt if your DIY project can match those ratings (unless you have very good electronics design skills and testing equipment. Take eg also EMC noise in consideration....)

The biggest beast (DBU-3200) https://www.meanwell.com/webapp/product/search.aspx?prod=DBU-3200 is 600 euro @ Conrad, and slightly cheaper if you're able to buy at a wholesaler. (24V / 110A)

If you want to be able to charge anywhere, also on 6A campsites like a lot in Europe / Netherlands, the PB-1000 is max (Draws 5.3A), 24V / 35A is 345 euro at Conrad (incl VAT/BTW)

There is also a 1600W version, RPB-1600-24, providing 55A @ 24V, for 465 euro, but that one draws 8.5A, so a 6A campsite won't work.

Edit: I saw the youtube video, anderson connectors are already in use, great. with 100+A i would suggest using genuine Andersons, no chinese fake ones.

some notes: those 40A buck convertors: I have those myself also, but haven't been able to get them above 20A. In the 'datasheets' (well, the Ali listing) the 40A applies to the the input, not to the output.

If you really want to go big: I have some massive powersupplies, if you need one feel free to let me know. I have 3, but don't need all 3 of them
( https://static6.arrow.com/aropdfcon...c2fa108f0818aba92ffdd560/apcms28powerrack.pdf )
Each powersupply provides up to 60V output, 50A.
(I'm from the Netherlands, powersupplies are leftovers from our routers, have them in the office in Harderwijk)
 
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