One BMS with multiple parallel packs?

[FlexiRex]

I have been floating around this forum for a while and there appears to be a number of battery experts on here which is exactly what I need!

I have built 18650 battery packs before but I have a project that is a little different and I think I have the solution.

I need a 6S pack with high capacity. A single 6S6P BMS protected pack would be ideal, BUT it needs to be travel friendly, so it cannot be over 100Wh.

My plan is:

• Build 6 x 6S1P unprotected packs with balance leads. Each pack will be under 100Wh.
• Once the packs have arrived at their destination, connect them in full parallel (discharge and balance leads) inside a purpose built enclosure with a single BMS to look after protection and charging.
• The packs can then be unplugged again for travel.

Will this work?

 

[eMark]

https://www.amazon.com/dp/B0971HZVH9/ref=sspa_dk_detail_0?psc=1&pd_rd_i=B0971HZVH9&pd_rd_w=qnPzT&content-id=amzn1.sym.88097cb9-5064-44ef-891b-abfacbc1c44b&pf_rd_p=88097cb9-5064-44ef-891b-abfacbc1c44b&pf_rd_r=TS78KNFS45T5JNDAQHZ1&pd_rd_wg=BC5h3&pd_rd_r=504c859f-1874-484a-b939-6fde91638122&s=toys-and-games&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFZM05QTlNDODNXU1cmZW5jcnlwdGVkSWQ9QTAxNzg0NjhQMkkxVldISU8wVDQmZW5jcnlwdGVkQWRJZD1BMDg1NTg5MTE1U0Q5TE1NOUQzQksmd2lkZ2V0TmFtZT1zcF9kZXRhaWwmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

Amazon.com

Amazon.com: Parallel (6X) JST-XH Balance Adapter 4S : Electronics

Buy Parallel (6X) JST-XH Balance Adapter 4S: Power Converters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

(bottom one is 6S)

 

[DogDipstick]

It will work but not ideal. You will have a rats nest of wiring to deal with in the future. Clean plan and it can work.
Many have used BMS on many-brick lipo retail packs in the past. This is no diifferent.

 

[DogDipstick]

https://www.amazon.com/dp/B0971HZVH9/ref=sspa_dk_detail_0?psc=1&pd_rd_i=B0971HZVH9&pd_rd_w=qnPzT&content-id=amzn1.sym.88097cb9-5064-44ef-891b-abfacbc1c44b&pf_rd_p=88097cb9-5064-44ef-891b-abfacbc1c44b&pf_rd_r=TS78KNFS45T5JNDAQHZ1&pd_rd_wg=BC5h3&pd_rd_r=504c859f-1874-484a-b939-6fde91638122&s=toys-and-games&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFZM05QTlNDODNXU1cmZW5jcnlwdGVkSWQ9QTAxNzg0NjhQMkkxVldISU8wVDQmZW5jcnlwdGVkQWRJZD1BMDg1NTg5MTE1U0Q5TE1NOUQzQksmd2lkZ2V0TmFtZT1zcF9kZXRhaWwmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

NEVER go over the rating ( or even close ) with those Parallel boards. That is not even a "SAFE PARALLEL" board ( they make them with fuses on every line, Progressive RC SAFE balance parralel board polyfuse EVERY line).. you linked a " Danger Ranger Parallel board"...

They will burn at constant duty > 25A.

I have three burned ones here.

Here is a PRogressive RC SAFE board ( fused). MUCH MUCH MUCH MUCH SAFER.

Safe Parallel Board for JST-XH & EC5

Easily and safely charge and balance up to four batteries in parallel

www.progressiverc.com

 

[eMark]

delete - double post

 

[eMark]

Multi-Port Safe Parallel Board for JST-XH & XT60

Charge and balance up to six LiPos in parallel, with fuses on every connection and additional ports for 1S packs, RX and TX batteries - daisy chain multiple boards together to charge even more batteries!

www.progressiverc.com

That's for charging six 6S1P ... he wants to attach a single (protection) BMS to the 6S6P ... assume he ALSO wants to discharge as a 6S6P ??

I need a 6S pack with high capacity. A single 6S6P BMS protected pack would be ideal, BUT it needs to be travel friendly, so it cannot be over 100Wh.

My plan is:

• Build 6 x 6S1P unprotected packs with balance leads. Each pack will be under 100Wh.
• Once the packs have arrived at their destination, connect them in full parallel (discharge and balance leads) inside a purpose built enclosure with a single BMS to look after protection and charging.
• The packs can then be unplugged again for travel.

Will this work?

 

[FlexiRex]

That's for charging six 6S1P ... he wants to attach a single BMS to the 6S6P ... what if he wants to discharge as a 6S6P ??

It will be charged and discharged as a 6S6P.

It will work but not ideal. You will have a rats nest of wiring to deal with in the future. Clean plan and it can work.
Many have used BMS on many-brick lipo retail packs in the past. This is no diifferent.

For the wiring I'm thinking build a "parallel board" but with wires (and fuses) and pot it all in the enclosure when complete. The BMS can be wired to this permanently. Then I just plug in the separate packs discharge and balance leads and I'm good to go.

I just wanted to make sure I'm not missing something obvious.

 

[lnanek]

Reminds me of the modular battery system Grin made:

LiGo Batteries - Grin Products - Product Info

The LiGo battery is a modular 36V pack designed and manufactured at Grin that is just under the 100 Wh limit allowed for passenger air travel. This allows you to bring multiple small batteries with you in your carry-on baggage, and then hook the packs together to behave as a single large battery...

ebikes.ca