FlexiBMS Lite - Flexible Configuration BMS w/ CAN-bus

These sound like great enhancements! :+1:

BTW, I had the MOSFET on my Flexi replaced and that seems to have fixed the problem. I haven’t yet thoroughly checked it but I no longer get 12V reported on the charger port.

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:clap::clap::clap:

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Came acros this @SimosMCmuffin thought it might case some issues with your BMS

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That is a yzpower charger to be precise. 12s 4A in plastic case. Flashes red/green as soon as mains power is interrupted

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Mine doesn’t do it. I believe it’s the exact same charger.

Maybe a bad piece?

Mine even trips for heavy machinery starting at work, sometimes even my hairdryer at home on the same socket trips it starting. I’ll try to demonstrate on a video tomorrow

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New test panels came in yesterday


As mentioned before, these are not electrically functional boards, as they’re only 2-layers and the actual working boards are 4-layers, but these are test boards on actual panelizing and break tab design testing. There are slight variations in the break tab designs (hole amount, distance offset) to see which combination leaves the cleanest and least sanding needed after snapping them with edge cutters.

Then I also got the USB-PD testing board and the new audio DSP board, shown also is the old DSP board that suffered from the incurable low buzz.

I believe I’ll get the new TVS diodes in the Digi-key shipment today, so I can get waiting webshop orders sent tomorrow.

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Just had a big order come in for the Lite units and they are now out-of-stock as of this moment. Placed order will be fulfilled.

Sorry, you’re gonna have to wait for the next batch, but if you want to talk then PM me.

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Maybe I missed something, but

whats this :wink:

I like building and developing all kinds of portable devices and see the USB-C connector and the possibility of using USB Power Delivery as a valuable feature to be able to support. That also synergizes with the simpler and cheaper BMS (3S-6S) meant for integrating into portable devices.

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Here’s proof.
Video is like 100mb so won’t upload here unfortunately.
https://linksharing.samsungcloud.com/zPYtOaZuO8rl
Valid for 24h

So, are you using a FlexiBMS and you have trouble starting your charging, if you first connect the charger to the battery pack and then to the wall, or was this just a demonstration of the behavior you described in the Noob question thread! 2020_Summer - #14003 by Athrx ??

The behavior on the video looks like the primary side (wall-power) of the charger doesn’t want to power up, as the secondary side is already reporting available voltage.

This though shouldn’t happen with the Lite, as the charger port is not connected to the battery, until voltage is detected on it after which the charging is started and that opens up the connection between the charger and battery side.

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Sorry mate, no flexy bms. Was just reporting that some chargers really don’t like higher potential power coming the other way around and it got ported as a question here. I’m using a ltt bms with common charge/discharge wires

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For some more anecdotal evidence, I sometimes use a 42V 10S (li-ion) charger to charge 12S LiFePO4 boards (43.8V)

disclaimer: don’t try this at home

and if the LiFePO4 battery is already above 43V when the 42V charger is plugged in, it flashes red and freaks out like that also.

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So this feature allows to wire the CAN cable without the 5V pin leaving only CANH and CANL?

Yes.

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Ok.

According to your measurements, how much current does the bms draw and how much will it change with this feature enabled?

I’m asking because I’m running a small battery atm (6S 4Ah).

Is there any info on how to use the can bus features? I have it wired up to my ESC but I’m not seeing any data in my VESC Tool or my DAVEGAX tho I’m not exactly sure what I’m supposed to be looking for.

Try setting $32=1.

Also, the latest (stable) firmware has options for visualizing the CAN communication by LED flashing on the FlexiBMS. That’s a good thing to have to assert that it actually communicates on CAN.

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I enabled those config params, but still not seeing any can bus activity. Tried re-flashing the firmware, to ensure it’s the latest, and with/without the opt-enable pin. But nothing seems to work. Is there a esc-bms wiring diagram anywhere?

:grimacing:

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