Bulk chager Help please

HanzieO

1 mW
Joined
Dec 23, 2017
Messages
13
Hi

I have a 29P26S pack im building with Samsung 30Q's. For bulk charging I have some power supplies left from another project.

I have 7 x 13Vdc @30A standard PSU's and one 12Vdc @22A Meanwell HLG320H-12A. I plan to series all of them to get 92vDC at 30A and then add the meanwell in series as well to tpop it of to 104v(4V per cell) to finetune and limit the current to 20A.
2018-01-15 11.45.39.png
20A 2080W
2018-01-15 11.45.28-2.png
Will this work?
 
EDIT: teh below info still applies, but I forgot something, which I've posted here
https://endless-sphere.com/forums/viewtopic.php?f=14&t=92369&p=1351331#p1351331

As long as they're all isolated (DC outputs not connected at all to AC inputs), then yes, it should.

If any of the casings of the PSUs are connected electrically to any of their interior bits on the DC side, you'd want to be sure none of the cases ever touch each other.

Also, as long as the total AC input current doesn't exceed what your outlet/breaker is rated for. ;)
 
7 x 13v = 91v
91v + 12v= 103v

104v is the top voltage I am looking for for my 26s pack
 
Yes, you're got the top voltage covered...but what about charging the pack when it's need LVC? Will the PSUs and Meanwell be able to sag that low? maybe?
 
I hadn't thought about that when I made my previous reply. :/

What is the lowest voltage the HLG you have will go to during current limiting (at it's max current)?

If it goes down to say, half it's rated voltage, then that's 97V total.

At 26s, that's about 3.73v/cell, so somewhere along the flat(ish) part of the charge curve for your cells, meaning somewhere roughly around half charged.

If you assume around 3.2v is empty for your cells (to extend life by not completley discharging them or doing so at high rates), then you'd need a PSU setup that can go down to 83.2v at least, during curent limiting.

So the total voltage range you need is at least 104v - 83.2v = 20.8v. Assuming the HLG can drop to half it's rated voltage during limiting (I don't know), then you'd need a 42v+ version to absorb the difference between full and empty.


If your other MWs are also currrent-limiting types like the HLG, then it will still work fine.

If they are hiccup-limiting, it won't work.

You could also probably use several of the smaller HLGs like you already have, in series, so taht their total voltagerange during limiting equals or exceeds the difference in voltage you need from full to empty.
 
Thanks Amberwolf this is very helpful info. I will check how much the Meanwell can reduce its voltage and I suspect I will have to add a 2 or 3 more of them into the mix
 
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