Reading about various kinds of leakage right now, and it’s way more complicated than I would have thought.
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This is a concern for me, i only have one oack connected to a ubox but its a 12s9p… looks like ill be adding a loop key to that enclosure.
Ltt +stormcore, no drain.
My flexibms has a little drain that will bring me from 3.8v to 3.5 in 2 months on a 12s3p p42a, but as a responsible board owner I check it occasionally.
No loop keys
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Sure that’s why we used over 200 ones both on boards and for diy. And so far 1 reported problem and was caused of 1 bad connected phase wire due to being soldered wrong by user. It’s the best and most problem free esc I ever used, and we used 200 unitys also and I can’t say the same about them.
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So your saying skill issue then?
not a serious reply
I mean it’s also the LLT BMS, it drains faster than one would like. so bit of a gray area there. there’s empirical data from years of use calling that out too. for example.
unlikely to be a major factor on the kalys though with such a large battery.
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Uboxes do have a significant idle current draw, and the current itself varies from sample to sample.
The presence of both the 5v and 12v buck converters on the Ubox is one of the things that lead to it having a higher than average idle draw, and from the few boards I’ve had through the shop with Uboxes in them, what’s become apparent is that their manufacturing quality varies enough to also lead to variance in idle draw.
Whether that’s due to the PCB assemblies themselves, or the variation in component tolerances, I don’t know.
My experience with Uboxes has been fairly suboptimal, and I have indeed seen them lead to fully drained packs that need replacement, including in boards with no other accessories connected, or particularly power hungry BMS units.
For context, I have had 9 boards in the shop with Uboxes in them. 3 of them were due to idle drain sapping the battery to flat dead, of those 3, 2 had no other accessories connected, and used standard hardware Daly BMSs, which I can’t say I’ve ever known to be power hungry, over the 90ish of them I’ve installed into packs.
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Can’t someone hook up most common vescs to a power supply and measure the draw over a week?
Definitive proof would solve all those random guesses as to what might drain or not.
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I can do it.
Send me all the vescs.
Pm for adress
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If you want us to help you troubleshoot this, post some pictures and details of how you have things set up, and describe in detail how much voltage the pack is losing in a day / week / month.
LLT BMS’s are quite good, and it would be rare if that was what is draining your pack.
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I’ll try that next week, there’s a Ubox sitting in a dead board I have to tear open.
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It’s not draining fast enough that I’m concerned about it, just faster than I would expect from self discharging. I use it for a 48v, 3kw inverter when the power goes out, and I just keep it at 46v. I’ll have to monitor it more closely to produce any figures.
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The problem is your BMS
This particular model has a higher then normal idle drain aswell. I would replace the BMS
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Ahh, thought you were using it in an esk8. Yeah, disregard what I said above.
@Skyart has seen more LLTs than most/any of us - time to pick up a different LLT or another brand of BMS.
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I’m also hearing from someone that in the Kaly XLR there is a buck converter direct from battery powering the servos for the stability control system. and that they tested this and think it’s the source of the vampire drain.
If someone could verify those tests, with some current numbers, that’d be nice to know.
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are some LLT better than others?
or you’re saying all LLT bms have higher draw than other brands?
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Surely Ernesto put this buck converter after the BMS so that it wouldn’t kill the pack, surely…
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The buck converter is on the discharge output of the bms
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So either the low voltage cut off failed or something else is draining the pack
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Is the buck converter in the Kaly always on?
The lacroix sentinel board only powers on the buck converter when it detects 5v (or 3v?) from the stormcore UART port.
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