Charger help

[Hardergamer]

Hi, First I have been using a BST900 DC-DC to charge my ebike lithium battery from solar power at home as a slow charger, but sometimes the BST900 DCDC blows up as I connect to the batteries BMS, Is there any way of stopping this from happening, like putting a diode in series, etc? or do I need a better DCDC...

Next, My battery is a 21s 19p using 399 Samsung 50E v2 cells, and I'm having problems finding a charger that's 86v 20-30a that's not silly money, even finding 2x 48v 20a+ used Meanwells PSUs for under £280 seems imposable.

My bike has a built-in small charger for traveling 86.6v 5a, But this will take forever to charge a 95ah battery.

Any way of getting a faster charger/PSU for around £100-150? or any other way of charging on a low budget...

Il just add, my BMS has active balancing with cell level display, and I only charge to 4.1v cell, and I'm limited to just 30a by my BMS.

Aaron

 

[john61ct]

It is normal for a decent quality actual charger that is both high voltage and high current, to cost hundreds, certainly more than the new price of the packs it is designed to charge.

Brusa, Elcon, DeltaQ, Thunderstruck are examples.

Also, best to avoid serial-connecting your source units, unless explicitly designed for that, e.g. Grin Technologies charger "Cycle Satiator"

Model #7205 would be an excellent choice for paralleling, but $300 per 5A.

Apparently Chargery makes good value chargers

…

You might want to roll the dice on a cheap-Chinese Ali sourced unit, search for

Dongguan yalan electronic technology co. LTD

https://endless-sphere.com/forums/viewtopic.php?t=105762

https://endless-sphere.com/forums/viewtopic.php?p=1593576#p1593576

…

Using a dumb source like a PSU or DC converter is dangerous, unless you rig a good quality and adjustable HVC control, usually cutting the unit's input power.

Do not rely on the BMS for this, that should be the "redundant belt & suspenders" backup only for when the HVC fails.

IMO not helpful for you at this point but FFR the best way to cheaply charge high-voltage packs, is to design them to break down into 6S to 8S sub-packs so you can use standard RC Hobby balancing chargers.

Also maybe DIY using laptop chargers

https://www.diyelectriccar.com/threads/build-your-own-diy-charger.205048

https://www.diyelectriccar.com/index.php?posts/1072885