In general, it is pretty simple, never exceed the max or min voltage.
For li ion for instance max charge is 4.2v min is 2.8v advised is max 4.0v and min 3.0v for longer lifespan
Your charger should be capable of li ion, a normal cc cv charger wil do it for days before it is full, keep a eye on the max c rate, 1c is in general very safe.
NiMh has a v span of 0.9 to 1.35v but needs to charge beyond the delta voltage aka 1.35 to 1.45 some even up to 1.6.
I have some in my Powerwall, my settings are 1.0v to 1.35v, oke just like with li ion i use 80% of the cell capacity.
But the charging curve and the c rate what they can handle is different.
lifepo4 min v is 2.5 up to 2.8(depends on manufactory) to max 3,5v to 3.65v (depends on manufactory)
Nicad is similar to nimh, but nicads i dont have.
I have a total of 178kwh in my Powerwall.... combined chemistries (all with their own bmsés!).....
BUT
The li ion will give in, due to lifespan and not cycle life(with me) within 5 years, i already took out a 20kwh of storage, was getting old aka the storage capacity dropped below 60% soh, not good for a Powerwall, but still good for a hobby locomotive or remote or whatever low consumption device.
The next 80kwh i think in this or next year will be removed. ( my total on li ion is/was 100kwh storage)
With use they die fast, even if not cycled!
Without use i think the cycle life and own life will greatly be approved if used in our hobby(propperly charge and discharge)
Cycle life can be up to 2500 cycles from new cells if 70% soc is maintained...
Nimh or nicads, great chemistry, will not die, if handled good. but the storage capacity is per volume very low.
Very very low, but every (zinc)bromine cell is lower, a nickel/iron cell is higher than bromine, but they life forever.
But need way different charging charaistics....way different chargers than li ion.
I wish i had more nimh cells in my powerwal (15kwh) or even nicads(0kwh)
They can be used in our hobby, it is a very save and old chemstry, very safe, it will boil water off when mistread badly...and become usless.
Lifepo4(60kwh),
The only lithium chemistry i thrust inside my house, will not catch fire when mistreated, just a lot of hissing and smoke.
But before that happens the safety guard(bms) will terminate the in and out going currant....or c or what ever....li ion will go a wall
Li ion when it is time it is time when mistreated...it will catch fire if not handle properly.
I use li ion with confident in my house, but the self-life is too short, and the safety thingies are too much, aldo in hobby things they are perfect, but keep your boundaries.
So li ion is out except for hobby projects.
My powerwall was total:
100kwh+ li ion (tested on 7 points)
60kwh+ lifepo4
15kwh+ nimh
18kwh nmc(nickel magnese cobalt)
You can charge all of them with a cc cv charger....all chemistries...but keep the max v.
Any dc dc converter can do the trick!
And cut off at the min v that is required to keep the cell happy!
Oke with a 1a dc dc converter charging a 280Ah cell x 16.....could take a couple of weeks...
When they are full the a will fall back!
With best regards Igor
