As someone who was thrown from their board because of BMS cutout I can say I will never ride a board that’s not wired with bypass. I don’t wish to repeat my mistake.
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What do you think of buying a smart BMS and bypassing the discharge? Maybe add a low voltage alarm for piece of mind?
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Stay off my boards then 
. When did the BMS cut off power at yours board?
i’d be down with that.
but if you pre-balance your cells and they all have the same capacity before you build your pack the odds of having a bad p-group on a well constructed pack are extremely low.
I guess im just a little paranoid because I had my 10s4p VTC6 pack go out of balance right before a huge group ride.
Or, buy a smart BMS that has been designed as charge only in the first place.
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If I paid right now when would I get it in my hands?
bypassing discharge protection won’t keep your pack from going out of balance. Packs go out of balance because of 1) a terrible BMS that can’t balance charge even as little as they normally do or 2) variance in pgroup capacity. Variance in capacity is a result of one or more bad cells or bad welds. Bad cells must be cutout like cancer, and beyond a certain cycle count the whole pack should be replaced because of them.
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Yes I understand. My question is; Would it be wise to buy a smart BMS with a low discharge rating (30A?) and bypass the discharge? How do these smart BMS’s react to having the discharge bypassed?
you’d be just as well buying this $17 BMS and only connecting its charge leads to the battery.
https://litechpower.com/product-detail/HCX-D503V1LI12S15A_01.html
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Is this what you would put on a build with a BOM of >$2k?
That’s a solid BMS for charge only applications. If you don’t need Bluetooth or settings adjustments fine tuning its perfect. There’s no reason to spend more money than that for a charge only BMS unless you just hate money or want to constantly fiddle with things. The price of the final board is irrelevant.
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I hate the ESC,BMS and motor options in esk8
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Does anyone test and build equal Ah 1S packs for esk8?
haven’t heard people talk about it
yeah we need better shit for real.
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you talking about chainable block packs? Somebody else here said they were going to, I’ve been talking about doing it for years and just haven’t yet. There’s really no reason we can’t, just need the right connectors.
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Been riding for weeks fine. One day I turned up the vesc power a little weight thinking about it.
Went out for a ride, hit the go button and leaned forward into the acceleration.
At around 20mph the current got to much and the 80A bestech BMS went into it’s overcurrent protection, cutting power to the board. I was to committed so went straight over the front and into a full streetface.
No way to check what the BMS was doing or why. No way to verify that it wouldn’t happen again.
Now I use LLT power smart BMS with bypass. I don’t look at it often but when I do is very useful to be able to see that it’s doing it’s job properly and check that the pack is healthy without having to open my board.
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no lol I’m talking about testing cells in an attempt to perfectly match Ah in 1S parallel pack when making batteries . This requires and excess of cells and time building batteries which most of us do not have.
It would be cool to see numbers on cell life degradation in esk8, and if this makes for unbalanced packs.
oh no what happened to me
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That BMS has no balancing function? Isn’t the D140 the smallest bestech with balancing?
It’s not an issue. But these are like $35 devices. Very close to “cheap junk”, unlike the TinyBMS @moon linked.
Downsides to the smart bms:
- kinda bulky
- cheap so kind of worried about random failures
- some passive drain especially with BT module installed. Enough to need at least a monthly check (don’t store over winter at storage voltage with BMS connected)
- some hardware/firmware/software revisions happening, no change logs, no firmware update procedures, mysterious
If we fix this everything costs 5x and/or performs like Boosted? I think we’re the hotrodders of LEV… There are high $$ good options for esc and bms, but maybe not motors.
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