just use a buck
it’s mostly because of laws here in Norway. my board runs at 22KM/H with a 22V battery (which is the speed limit) but I wanna go faster, and with a 42V battery it can go around 36+ KM/H
What is a buck?
ahhhh ok, thank you very much
if u need to regularly switch between the different speed limit, just get a metr and setup the speed limit profile.
The reason I bring up speed is mostly just because I wanted a bigger battery too so i could go farther than 20 KM. and the speed was just a side effect. But for another question about the buck converter, could i just plug and unplig it depending on waht voltage i want`?
no, no question. i was not aware u tried to run 2 different voltage to power the esc, buck that can withstand high amp are big af, thick af and hot af.
u r better off having 2 loop key to disconnect the series connection between group5 and group6, then have discharge leads from the 2 sets of 5s and run that as 21v battery. technically u should also parallel the 2x 21v battery when using, so u putting less load on each cell. but this method is extremely dangerous, any wrong order of plugging and unpluging coud and will result in fireworks.
i really don’t understand why u trying to do this, with the same amount of cell count, if it doesn’t get u 20km, there is no rearragement with the same cell will get u that 20km
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It’s two different kinds of batteries, one is a scooter battery with 8s5p (I think, I’m not good with identifying these) 18650 cells and another with a 6s2p lithium pack
hell no, don’t ever do this. period.
ask any battery builder, they will tell u the same
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okok, but why? Both use a XT60 connector, if both batteries were 36V couldn’t both be used
100%
Genuine question so I can give a more appropriate answer: how much do you know about how batteries behave electrically?
Battery cells’ output varies a lot. Cells are the usually cylindrical metal bundles of chemicals, batteries are the fully assembled packs. The same size cells from the same manufacturer but different models hold different total amounts of energy, supply energy differently, and tolerate heat and stuff differently. If you run two batteries (presumably with their own BMSs) in parallel, any difference in how one performs relative to the other will end up passing current assways through one of the packs. It could likely overload one of the packs to the point of starting a fire. Running two different packs in series means all current flows directly through both, so if one can handle 30A at a given voltage and the other 20A, congrats they’re now both a fire hazard.
Do not do this, it is very very bad
Also as Poast said, 8s and 6s are not both 36V (in fact neither of them are). My message above is assuming you used packs of the same voltage. If you’re using two packs of different voltage, did you mean having a button that switches between just using the 8S and using the 8S + 6S? If so you wouldn’t get extra range because the 6S would just sit there unused as extra weight
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8s full charge ≠ full charge 6s
not to mention 5p willsee less load than 2p so it holds a hgher soc than the 2p
just cause it has the most common connector for hobbyist batteries doesn’t mean they’re compatible
if you’d like to charge your 6s pack to 5.6V per cell when you put your 8s pack to 4.2V per cell (full charge), by all means , but make sur you bring out the hotdogs n smores
What about the secret third option: charge your 6S to 4.2/cell and 8S to 3.15/cell? Checkmate atheists
I think I confused everyone, I am NOT usining them both at the same time. I would only use the scooter battery
Ok but then you’d have the weight and bulk of two batteries in the board, and only the capacity and power of one at a time? You’d also need to reprogram your ESC in between switching. It would be like having a petrol and diesel engine in the same car, and requiring you to reassemble the steering wheel to switch between them
Yes, but neither of the batteries you described are 36v. 8s is 28.8 nominal, and 6s is 21.6v nominal.
You can’t just wishful-thinking your batteries into a 36v configuration.
So just build a 6s (22v) battery with larger capacity, or put several smaller 6s batteries in parallel. More capacity = longer range. You don’t need to increase the voltage at all.
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that’s where i think i confused you again, I said the board would be faster with a 42V battery which would be true, but the scooter battery is a 36 V battery (and I have 3 of them, the only reason I didn’t want to build another battery, so I was hoping there was a way to make the 36V batteries function like a 22V. but I might just do what you said,)
Btw @TheBoardGarage was nice enough to give me the simplest solution ever: just use the custom MakerX firmware advertised on the website. Thanks for trying though
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Yeah I think this is a big part of why we were confused. 8s is not 36V. Pack voltages are specified as either max voltage when fully charged, or nominal voltage at mid charge. 10s is 42V fully charged (10x4.2) and 36V nominal (10x3.6)
Because the voltage is unclear (especially when the ebike crowd come in with their nonsense voltages), we don’t tend to use them to identify batteries that often unless the context would make it very clear. S count is much less ambiguous. So “36V” is assumed to mean “10S pack at nominal voltage”, because 36 doesn’t divide evenly by 4.2, and cannot refer to an 8S pack. It could possibly refer to a different chemistry while fully charged but that would be even more unusual. What did you mean by 36V? Did you measure the pack voltage and it’s currently at 36, or does a sticker on the pack say 36, or did it come as part of a product that called it 36V?
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