bluetooth BMS?

Batteries, Chargers, and Battery Management Systems.
Koontzy   1 µW

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Re: bluetooth BMS?

Post by Koontzy » Apr 29 2021 7:14am

flippy wrote:
Apr 29 2021 5:03am
Koontzy wrote:
Apr 28 2021 2:54pm
My BMS is doing the same thing. As soon has they start balancing, I practically lose any way to communicate with the BMS. When only charging (no balancing), I can connect fine. Android latest app on two different phone. Also when balancing they randomly ask for password after fews secs (5-7). When only charging without balancing or no charging at all, everything work fine.
Sometime I can connect when balancing but every is sluggish, I can barely read or write any configurations then eventually it just lose connection and crash
check the bms board. its probably a fake one.
The board have a big sticker from lithiumbatterypcb on it so it may be fake but I'll be surprised if it is ;)
bms.jpg
bms.jpg (455.48 KiB) Viewed 364 times

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agniusm   100 MW

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Re: bluetooth BMS?

Post by agniusm » May 08 2021 1:32am

I am having issues setting this bms up. My main issue is with balancing. I have 2 packs, 16S 60ah and 20s 21ah. I have left it on a charger for a week and it did not balance the pack. My upper voltage is set to 4.13 so now after a week the high cell is at 4.13 and the low is at 4.07.
What settings should i input for balancing, like start balancing?
Attached the week balancing difference on the 2 packs
Screenshot_20210503-120907.png
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Screenshot_20210503-120827.png
Screenshot_20210503-120827.png (1.87 MiB) Viewed 310 times
Screenshot_20210502-154414.png
Screenshot_20210502-154414.png (1.97 MiB) Viewed 310 times
Screenshot_20210502-154315.png
Screenshot_20210502-154315.png (1.87 MiB) Viewed 310 times
Perhaps this equates to fully balanced? My setting is to balance within 0.03V, i think default

john61ct   100 GW

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Re: bluetooth BMS?

Post by john61ct » May 08 2021 2:23am

Yes those are all within 0.03V aren't they

You can try for a lower delta but likely will hit the accuracy limits and just cause unnecessary wear to little benefit.

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flippy   100 MW

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Re: bluetooth BMS?

Post by flippy » May 08 2021 3:28am

dont go below 0.05V. below that they tend to start messing up. the black units with active balacing can go lower to 0.005 because they have better components.
The bitterness of low quality remains long after the sweetness of low price is forgotten

Thunder_blade   1 µW

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Re: bluetooth BMS?

Post by Thunder_blade » May 08 2021 10:14pm

Set balance voltage 4,051в precission 0.002v. Save settings and then turn Static balance..... and wait few days...... :wink:

john61ct   100 GW

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Re: bluetooth BMS?

Post by john61ct » May 09 2021 4:51am

Stupidly high precision, total waste of time and excessive wear on components.

And bad for cells to sit at high SoC% that long

Really best to forget top balancing completely, do it at the bottom, or mid point as they are delivered.

JoostR   1 µW

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Re: bluetooth BMS?

Post by JoostR » May 17 2021 9:25am

I am unsure whether I will use a 13S9P or a 14S8P 18650 pack for my electric (moped) scooter. I have decided to go for the JBD Smart BMS.

I am thinking about ordering a 14S JBD BMS, but I am not sure if it would be possible to change the 14S BMS to 13S afterwards? What I understand is that this should be possible for an ANT BMS. Is this something that is possible for JBD as well?

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thundercamel   1 kW

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Re: bluetooth BMS?

Post by thundercamel » May 17 2021 7:53pm

The PC app for the JBD boards let you change from 14s to 13s, but I've never tried it. From what I remember reading one of the balance wires (not sure which) becomes unused, and needs to be tied to a balance wire next to it (not sure which again).
My Ebike builds - Existing bikes, affordable motor kits, self built 14s6p batteries - Now with more recumbent!

JoostR   1 µW

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Re: bluetooth BMS?

Post by JoostR » May 18 2021 10:20am

Thanks thundercamel! JBD confirmed it is possible. Maybe someone else can elaborate the schematic?

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flippy   100 MW

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Re: bluetooth BMS?

Post by flippy » May 19 2021 4:15am

john61ct wrote:
May 09 2021 4:51am
Stupidly high precision, total waste of time and excessive wear on components.

And bad for cells to sit at high SoC% that long

Really best to forget top balancing completely, do it at the bottom, or mid point as they are delivered.
you actually would want more then triple digit accuracy on larger batteries, especially with lifepo4 that has a stupid flat discharge curve.

please stop giving advice about how to charge a battery. recommending a mid point balance "because that is how they are deliverd" is litteraly the most ignorant recommendation i have seen to make as of yet.
The bitterness of low quality remains long after the sweetness of low price is forgotten

john61ct   100 GW

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Re: bluetooth BMS?

Post by john61ct » May 19 2021 9:07am

Actually it is the ideal, especially for large banks.

But of course nothing to do with using a BMS.

I know dozens of packs that have not needed **any** rebalancing **at all**, well past 7-10 years of often daily cycling.

And hundreds more that only need rebalancing every couple years, or 200 cycles, or whatever the owner decides, based on a realistic delta spec.

Doing it according to some theory the closer is better is just a waste of time and exacerbates the problem especially if using top balancing anywhere near the datasheet max voltage.

Please stop giving advice as if every use case is close to your limited scope of experience.

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flippy   100 MW

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Re: bluetooth BMS?

Post by flippy » May 19 2021 9:46am

john61ct wrote:
May 19 2021 9:07am
I know dozens of packs that have not needed **any** rebalancing **at all**, well past 7-10 years of often daily cycling
i never crashed my car in in the past 20 years so seatbelts, airbags and insurance are bullshit imho.

you have proven time and time again you dont know the basics of (lithium) charging, so please stop commenting as if you speak as certainty or authority.
john61ct wrote:
May 19 2021 9:07am
Please stop giving advice as if every use case is close to your limited scope of experience.
https://en.wikipedia.org/wiki/Psychological_projection


i domt mind if me or someone else is wrong, its a moment to teach and/or learn. but you need to be willing to accept you dont know what you are actually saying/recommening in the first place, especially if leads to dangerous situations.
The bitterness of low quality remains long after the sweetness of low price is forgotten

Wanda   1 µW

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Re: bluetooth BMS?

Post by Wanda » May 19 2021 10:15pm

The BMS of JBD is good in china.
Very stable, good balance effect.

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