[Oeva-list] Help with BMS selection

Dima Kukushkin dimakukushkin at gmail.com
Wed Aug 8 20:59:44 PDT 2018


Yes, have to admit that Hobby Chargers are quite a configurable and
powerfull BMS for charging.
But was hoping to find more of a purpose built solution, like this
https://m.ebay.com/itm/4S-30A-BMS-Protection-PCB-Board-For-Li-ion-Lithium-18650-Battery-Pack-Balance/263718963926?hash=item3d66e00ad6%3Ag%3AU-AAAOSwtItbYtPZ&_nkw=4s+bms&_from=R40&rt=nc

But with controllable upper/lower limits.
I use such in my upgraded 27v lawnmower, and similar for roomba. But
neither are configurable.  Otherwise price and specs are perfect

Dima

On Wed, Aug 8, 2018 at 15:53 Travis Gintz <frodus17 at gmail.com> wrote:

> For that, use a low voltage alarm, also a hobbyist device.
>
> https://hobbyking.com/en_us/batteries-chargers/battery-accessories/voltage-indicaters.html
>
> For 12V system, it's really not worth having an expensive BMS that costs
> hundreds of dollars. I'm currently using a Zeva BMS. And like the Orion Jr,
> it's overkill for a 12V pack.
>
> On Wed, Aug 8, 2018 at 3:44 PM Datta, Sham M <sham.m.datta at intel.com>
> wrote:
>
>> You can, but that would only take care of charging part of taking care of
>> Lithium cells.. if Dima wants to also control discharge part (going below
>> 2.6v or whatever the spec says) and force controller to limp mode (or
>> warning light whatever) – then you need a legit BMS.
>>
>> Sham
>>
>>
>>
>> *From:* oeva-list-bounces at oeva.org [mailto:oeva-list-bounces at oeva.org] *On
>> Behalf Of *Travis Gintz
>> *Sent:* Wednesday, August 08, 2018 3:32 PM
>> *To:* Dima Kukushkin <dimakukushkin at gmail.com>
>> *Cc:* OEVA <oeva-list at oeva.org>
>> *Subject:* Re: [Oeva-list] Help with BMS selection
>>
>>
>>
>> Couldn't you use a Hobby charger? I have a Venom Pro Duo, that can
>> balance 6s on each channel. You really only need one channel, and balancing
>> for 4s, but there's chargers out there.
>>
>>
>> I set it for 40,000Ah for my Saft cells and it balance charges them.
>>
>>
>>
>> On Wed, Aug 8, 2018 at 10:30 AM Dima Kukushkin <dimakukushkin at gmail.com>
>> wrote:
>>
>> Hello dear DIYers!
>>
>>
>>
>> This topic been around for years, so hoping some one has hands on
>> experience and can advise.
>>
>>
>>
>> I have 4 cells from Nissan Leaf that i'd like to reuse for my project of
>> battery-assisted kayak.  Need reliable BMS that keeps battery happy, and
>> away from red  zone voltage.
>>
>>
>>
>> From experience with cheapo BMS (used on for Roomba upgrade) - formal
>> presense of balancing is not in reality doing the balancing work - board
>> instead charges cells to 4.4 volts and then discharges top cells to 4.2
>>
>> But since current is not  reduced by board at the top of the charge -
>> once power removed - all cells drop below 4.2, and i'm seeing 0.2-0.4v
>> disbalance.  As well as seeing battery above 4.2 for some periods of time.
>>
>>
>>
>> For Leaf cells - i'd like to configure BMS to keep voltage below 4.1 at
>> all times, while balancing cells.
>>
>>
>>
>> If this project rings a bell for any one - please give me a helping hand
>> with BMS selection.
>>
>>
>>
>>
>> Thanks!
>>
>> _______________________________________________
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>> Oeva-list at oeva.org
>> http://www.rdrop.com/mailman/listinfo/oeva-list
>>
>>
>>
>>
>> --
>>
>> Travis Gintz
>>
>
>
> --
> Travis Gintz
>
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