Which BMS?

Joined
Feb 15, 2017
Messages
13
Hi everyone,
I am ordering a 13s7p battery with Sanyo GA cells in a Reention DP-9 case.
I needed guidance on which bms should I pick for it. The seller says a 40A continous BMS won't fit (Daly with balancing), so is suggesting a 30A BMS (no balancing or bluetooth) named Super Power 30A
My usage would be with a BBSHD rated 30A and I read that its better to use a BMS rated a little higher (obviously if my cells can handle it which they can) so not to stress the BMS and also if you ever want to use a higher rated motor.

My questions are:
1) do you know any good quality 40A BMS that could fit the reention dp-9 case? (Ideally with bluetooth and auto balancing), or in the worst case a 30A BMS with those fubctions.
2) or do you think it is just fine with the 30A BMS?

The seller is Jenny from Aijiu Power (recommended in several forums).

Thank you very much!
 
Balancing can be done with other devices, if / when needed.

Just make sure you have access to the balance wires from outside the pack, as well as the power pair.

In fact you can ask the pack be delivered that way without the BMS installed, so you can easily remove / replace it as needed.

________
HVC and LVC and maybe OCP and overtemp are the functions offered by the protective BMS.

Some functions can also be provided by other, more reliable devices.

Or done without.

Some just trust HVC to their charger, use balancing Hobby chargers, or just monitoring cell level voltages manually.

Some program their controller or CAv3 to LVC well before the BMS would, and/or monitoring cell level voltages manually.

OCP can be often be handled better with fuses.

CAv3 or other circuits can handle overtemp, but many just check by touch.

All this up to you and your use case.
 
Thank you for your reply!
As I wouldnt know how to do that/ want to do it without knowledge, I prefer just using a BMS that do that for me. So my two questions remain the same, if you would advise against using a 30A bms for my use (30A bbshd) or if you know any good bms (40A ideally or 30A) with bluetooth and balancing functions that fit in reention dp-9 case.
 
Dunno, but I still advise you instruct the builder to give you access to the balance wires from outside the pack.

The BMS is likely to need removing for testing / replacing anyway before long

So you could just tell them to use whichever they like (probably cheap) and then if needed later on, replace it with a better one,

if not inside the case, then devise a way to mount separately nearby.
 
franciscogalaz said:
Thank you for your reply!
As I wouldnt know how to do that/ want to do it without knowledge, I prefer just using a BMS that do that for me. So my two questions remain the same, if you would advise against using a 30A bms for my use (30A bbshd) or if you know any good bms (40A ideally or 30A) with bluetooth and balancing functions that fit in reention dp-9 case.

One question, not two. You already said the 30A doesn't support balancing.
 
franciscogalaz said:
True, you told me to better not have a BMS if it doesnt have autobalancing.

In your particular case. Your battery has more than enough output that it won't be damaged before the motor melts down; so you don't need overcurrent protection. The stock BBSHD has something like a 41V LVC, so you don't necessarily need the battery LVC protection. So that leaves balancing, which the 30A you described doesn't have. Therefore, the 30A BMS is not really doing anything for you but taking up space. You may be able to use an active balancer instead of a BMS, if one can fit in the space.
 
Thank you! Now I understand. Then ideally I should find a reliable BMS with balancing otherwise is not "necessary".
If anyone knows a bms with balancing that can fit inside dp-9 reention case (along with 91 cells) I would really appreciate it.
 
Thinking outside the box ... or more appropriately "outside the case" ...
when I rebuilt my shark battery, I did not have room inside for the dally BMS.
So I cut a slot in the case and ran the balance connector and power leads outside the case.

I am not recommending that drastic approach, but it can be done :wink:

Sharp Rebuild  clip.JPG
 
This is the BMS you wanted? Nice. You could mount it outside.

https://www.amazon.com/DALY-Protection-Balance-Programmable-Configurable/dp/B08PYKCP1M/ref=sr_1_4?dchild=1&keywords=Daly+13S+BMS+40A&qid=1631975053&s=electronics&sr=1-4
 
LewTwo said:
Thinking outside the box ... or more appropriately "outside the case" ...
when I rebuilt my shark battery, I did not have room inside for the dally BMS.
So I cut a slot in the case and ran the balance connector and power leads outside the case.

I am not recommending that drastic approach, but it can be done :wink:

Sharp Rebuild clip.JPG

That looks very cool. Good idea!
Thank you
 
docw009 said:
This is the BMS you wanted? Nice. You could mount it outside.

https://www.amazon.com/DALY-Protection-Balance-Programmable-Configurable/dp/B08PYKCP1M/ref=sr_1_4?dchild=1&keywords=Daly+13S+BMS+40A&qid=1631975053&s=electronics&sr=1-4

Yeah that type of bms I wanted, i will figure it out! Thank you!
 
To use commonly available balancing hobby chargers, split your high voltage pack into sub packs.

e.g. 7S *2 to get 14S

There are some few chargers on the market at 10S or higher, but fewer every year.

6-8S are most common, will be available forever and at good value pricing.
 
john61ct said:
To use commonly available balancing hobby chargers, split your high voltage pack into sub packs.

e.g. 7S *2 to get 14S

There are some few chargers on the market at 10S or higher, but fewer every year.

6-8S are most common, will be available forever and at good value pricing.

Good to know! Thank you!
 
Back
Top