Why FM dischage BMS doesn't receive any love?

Help Desk
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1

After seeing Surfdao’s video “the BMS dilemma” I wonder why almost everyone I see online goes for “charge only” when talking about FM BMS and pretty stock XR?
Not sure if anything has changed recently, I’ve read several times that if the BMS doesn’t talk to the FM controller, it shuts off within x minutes.

I guess if that were the case, Surfdado or anyone would NOT recommend it.

I just ordered a VESC controller, so I’ll be joining the club as soon as arrives.
One of my main reasons to go VESC is safety. Not Using safety as anti repair tactic, real safety!

In my case, a stock XR battery,I don’t see as a good idea to go blindly around with potentially damaged cells, Be unaware of having a fire hazard only to save myself from some cut off if the FM BMS worns me of a battery problem.

I plan to use OWIE to be monitoring via wifi the cells, and how they behave with the new controller and being pushed more than FM ever allowed them to. This board has his age, so does it’s battery. Sounds a good Idea to not be trusting it very much and be cautious, till it’s the moment I go fully VESC with a new BMS + higher voltage. or return to FM since would be reversible and I have a unicorn: 4209 that doesnt double down as a vibrator.

“I don’t know what I do’t know”

What are the things I’m not aware of that should make “discharge only” a better, safer option?
What would I be loosing if I keep the Stock FM BMS as discharge?
Will I lose much torque considering it is Stock 15s2p battery with 2k on it?
-Why charge+discharge is so unpopular?

Lastly, any schematics to what changes will I have to make to the UBOX switch if I end up using discharge BMS? Most things I’ve found up to now are RE charge only BMS.

2

Because a discharge BMS is prioritizing board/component protection over the rider.
Just look at how many people had spills with the floatwheel because of the BMS detected something, especially below 30% battery capacity.

3

I’m talking FM BMS specifically. I don’t ride under 30% battery, If I do I know to not demand a lot from the board. Low battery cut off vs damaging cells without knowing, I’d have battery protection all day.

If the trade-off is that board can shut at low battery to protect cells, that is much better than riding thinking everything is fine, then have maybe the board on fire when you’re sleeping.

I’d assume there is more to the picture than this, otherwise everyone would/should go this route.
FM BMS and stock battery at least

4

It is not incompatible. If you have a smart BMS in your board, but charging only, you can always check the health of each cell and ride safely. You just need to adjust the values of low voltage in the VESC tool, and that’s it. It takes 2 seconds to check your cell voltage with an Ennoid for instance, no need for a discharge BMS that can throw you off your board, don’t forget those components are binary and will shut off the board at any misinterpretation.