12s, 14s or 16s BMS high current application

Hi

I regularly need BMS for high amps discharge for ≈ 48V projects.
Like tractor, ATV or stationary battery with peak discharge current around 400A to 1000A.
In the past I used with great success the Zeva BMS16 (https://www.zeva.com.au/index.php?product=140) who work super well for 12S to 16S NMC or LFP cells.
After few search it seem like the Tiny BMS (https://www.energusps.com/shop/product/tiny-bms-s516-150a-750a-36) and the GWL BMS (https://shop.gwl.eu/Battery-Management/GWL-Cell-Performance-Monitor.html) could do similar work.

Questions: Is there any other simple BMS available for my applications today?
I'm looking for the simplest/cheapest BMS for my needs.
Thanks

do CP separately

and use robust appropriately sized external contactors

BMS only operating the **voltage** based functionalities, opening / closing the contactors with small amps, signal level

actual power currents not flowing through the BMS

then the latter can be very inexpensive, even with full adjustability, displays or comms facilities etc

Just plan your failure modes, fault tolerance, redundancies, since the cheaper units will of course be less reliable

you can find the chargery bms16 (with 300 amp shunt) on ebay for 109. I been using the the chargery bms8 (similar to the bms16) for the past year and been very impressed with its performance. Easy to program from the bright LCD screen, you have to supply your own contactors, so it can handle whatever amps your contactor can handle.

chargery bms8, the bms16 has a larger control box

Yeah, the chargery 16S seem to be a good low cost choice.
So, if I don't connect current sense to the unit and use appropriate contactor for high amp, the BMS still work well for HV/LV protection without problem?

john61ct said:

do CP separately
and use robust appropriately sized external contactors

Click to expand...

Ummm! can you give more details. I don't know what you are talking about.

I do not know what pieces you don't understand.

The Chargery is designed to work the way I'm talking about, maybe there's a manual to DL?

Or do some more reading of past threads, googling of terminology etc then come back with specific questions?

Good DC contactors (big mechanical relays) are $100+ unless you keep an eye out on eBay

The shunt is used to count amps in/out of battery. It can also be used to pull the relay if the current/amp use is too high in/out and that setting can be set to "0" so it doesn't do anything either way, except count amps.

I unplugged my shunt sensor wire from the control box while battery being charged, everything still worked, battery still being charged. Only thing happen the amps were no longer being counted.

The chargery is fail safe, if it loses power, the relays are de-energized. The contactor/relays to use are the ones that are "normally open" , when the contactors/relays are passing current they have to have power. I leave my chargery on 24/7, I added a toggle switch to the relay to turn it off at night time. There is a good manual to download on the chargery website that explains all the features.

You don't have to buy the contactors from chargery, any contactor /relay that can be triggered by 12 volts can be used, I been using a 4 dollar 30 amp automotive relay on my system.

john61ct said:

I do not know what pieces you don't understand.

Click to expand...

I understand everything except CP.
CP is for: Current path? Current p...pp... flow (phlow)? Circuit party? :lol:
I think I have my answer, thanks

More seriously, the chargery unit seem really interesting for the price.
Except it don't balance cells, is there other disadvantage for this unit over the more expensive zeva BMS16 or the Tiny BMS I don't see?

Current protection.

Joey says the Chargery handles that.

With the usual cheap BMS bypassing the MOSFETS to use external relays, a fuse is often a decent solution to protect both the pack and the wiring.

There are dedicated balancer devices aka "non protective BMS" that do a great job, better than any cheap all-in-one BMS.

Just wire an extra set of per-cell leads out, big enough to handle the max balance current *1.2.

Or wire them so one BMS gets swapped out for the other at balancing time.

jonyjoe303 said:

I been using a 4 dollar 30 amp automotive relay on my system.

Click to expand...

What actual cont vs peak current do they actually handle?

Their failure mode is to weld closed (connecting mode), correct?

> You don't have to buy the contactors from chargery, any contactor /relay that can be triggered by 12 volts can be used

OP use case will require more robust, expensive proper contactors:

yabert said:

peak discharge current around 400A to 1000A

Click to expand...

Looks like the BMS24T/BMS24 Pro include balancing function

Without the T or Pro means protective functions only.

chargery does balance cells, it balances at 1.2 amps per cell, comparable to a good balance charger. You can even customized at what voltage you want it to balance. Since I have active balancers on my battery pack, I disable the balance feature on the chargery.
It also has two temp sensors, a loud audio alarm and flashing light to warn you when the limits are exceeded besides pulling the relay.

The only disadvantage I notice is the SOC, it counts amps but uses "watt hours" instead of amps. Its useless as a coulombmeter. Another disadvantage is that its large, you have to have room for it.

I had mine connected to my solar system (220ah lifepo4 battery) 24/7 for the past year. After setting it up last year, I haven't had to mess with it. It just works. Once in a while it activates to stop the charge on the battery.