Monitoring individual cell voltages

ESK8 Electronics
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Anyone got any experience with one of these?

￡87.26 17%OFF | 300A 8S 12S 24S Cell Lithium Battery Protection Board Smart Display Balance BMS Coulomb Meter lifepo4 Lipo li-ion APP Bluetooth

My build is 12s 12ah 50c max discharge - 2 x 6s lipo - dual maytech 6374s sealed with focbox unity - and wondered if this is going to be suitable? Rated higher than I need but price difference is negligible so may as well over-spec.

Any disadvantages or is this the ideal solution for charging and battery protection in my case?

Extremely grateful for any advice! :slight_smile:

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Thanks @deucesdown for the additional information. Very useful! I added some bits to the original post. Will do more updates later when I have more time.

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I’ll definitely make the FW available. Note though that this won’t be an additional functionality to the DAVEga. It only has a single UART port so you can either hook it up to a VESC or to a Smart BMS, but not both. Also even if I somehow figured it out, there’s not enough flash memory for combining the two firmwares.

You could make an enclosure for dual DAVEga though. :wink: The next obvious evelution step then is the DAVEga Unity! :smiley:

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It looks huge and well over powered for our needs but if that doesn’t bother you I guess it’s fine

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The guys at lithiumbatterypcb.com will customize the series count and settings for you, within limits of hardware (up to 15s)

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Found this external 12s bms too in case it’s useful to anyone…

￡83.63 | free shipping 300A BMS 2S - 16S LiPo LiFe Battery Management System TFT LCD Display Smart Lithium lifepo4 Li-ion Chargery BMS16

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the post is great. well done @janpom

Personally your 1.3 solution looks great. If only we could hook this up to VESC and get the data through metr same as DieBieMS.

I believe the UNITY has spare serial ports accessible inside via headers, they are there for future modules like the BT module that’s included. I believe they were planning on releasing the spec for these modules.

Hooking charge only smart BMS directly to unity would be ideal :+1:

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external or internal? its 3 x 4 inches in size, supports regenerative breaking. you could see that display from the deck no problem :sunglasses:

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External in the sense it has its own housing, but yeah I guess could be mounted internally too…

EDIT: doesn’t have a balance function, oddly - so it’s a bust

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Option #1.2 (LLT Power Smart BMS + bluetooth module) looks like the most builder & budget friendly option. Has anyone else used this BMS with success? I’m curious to know how many builders are using this product.

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https://www.analog.com/en/products/ltc6801.html#product-overview

In my feeble mind this one looks pretty simple?

Ah nevermind, the output is just safe/no-safe indicator. But, things learned: there’s probably an IC that does what we want, and this guy uses a MUX too. And, the boolean output is on a clock signal, so you can tell if it crashed/froze.

Clicking around on analog.com, found this video, didn’t watch yet, but the title is nice

https://www.analog.com/en/education/education-library/videos/5849886030001.html

Oh, and this (15s, cell voltages, error less than 2.2mV, SPI). And it has balancing? But the diagrams look more complicated. $19 for the chip at arrow. Looks tiny!

Oh hey this is looking interesing now. Demo board:

https://www.digikey.com/product-detail/en/linear-technology-analog-devices/LTC6812ILWE-1-3ZZPBF/LTC6812ILWE-1-3ZZPBF-ND/9806657

Aaah there’s a demo board but $150-200

https://www.digikey.com/catalog/en/partgroup/ltc6813-1-demonstration-board/75932

Did I mention I’m lazy? :slight_smile:

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The Chargery BMS16 that @Chrisjarram has linked looks pretty cool for use as an external BMS. Unfortunately, I haven’t been able to find any reviews. Does anyone have one?

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Chargery is considered quality stuff, from reading various threads at ES. but I couldn’t find much chatter about the brand!

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I want one! I guess it has 6s balance plug slots on side. ? I’ll be looking n likely ordering. Seems to have more features and bigger price than needed for off board balancing

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2x 8s, I guess. Was considering it but was put off at the time by the requirement to use relays for charge and discharge.

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Is it just that it uses relays instead of MOSFETs internally or do you need to provide external relays?

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Looks like the latter. OK, that’s indeed clunky. Better to stick with the LLT Smart BMS and make a nice case, display and beeper alarm for it.

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i am tempted to buy the LLT smart bms, but why is it so much smaller than a bestech BMS. My 80A 10s bestech is almost 2,7cm high. The llt only 1,5cm.

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Not my area of expertise, but I suppose it could have to do with the fact the LLT BMS is rated only 60A and that’s only if you get the aluminium housing (as @deucesdown pointed out here), which probably dissipates a lot of heat.

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I bought one of these , its WAY bigger than expected yet to setup and play with it but seems good value if you have the space

really like the amount of config

image

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