Swapped out my 190kv Polar motors for @Kaly’s 230kv (210 actual) and now I go up to 38 mph @_@
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Do you wanna sell the polar motors? If they are sealed version Id be interested if the price is right.
Theyre not sealed, they are similar to torqueboards motors. $60 + shipping each. They have VESC compatible sensor already installed, and 5.5mm bullets. Might have a buyer though
Cool, I’m looking g for more of the sealed ones for a hybrid off-road board. Thanks tho.
Did you ever measure the KV on the Polar motors?, I’m guessing they are 170KV actual.
How much torque did you loose with the increase of KV, is it noticeable?, top speed sounds pretty scary
Yea it’s in my realistic kvs thread, but they’re about 170kv. Torque is actually pretty comparable. KV doesn’t directly affect torque, copper content does
If torque is pretty comparable then you must be extremely happy with Kaly motors.
38 mph is no joke
What pullies, battery and wheel diameter are you runing?
10s 16/36 97mm
Small update:
Found out my BMS doesn’t actually balance my pack, but only provides overcharge protection. I thought my cells were going out of balance as my voltages were all over the place. Discovered that a bunch of cell fuses broke (could be vibration, could’ve just blown, my guess is vibration). So I repaired all the fuses with double fusing now since it’s so much of a headache to re-fuse the modules.
At least what I’ve learned from this is how to measure individual cell voltage in a parallel pack. When I measured voltage from the fuse wire, I got similar readings throughout each cell in each pack. This was my ultimate mistake. While the cells seem to be the same voltage, I should have probed on the actually contact terminal of the cell to get the individual cells voltage. Straying too far from the cell terminal will instead get me a reading of the parallel pack voltage.
Now that all fuses have been repaired, just have to wait for my Bestech BMS, then I’ll most likely have to repair even more fuses in the future… In hindsight, I should’ve just soldered the buss bar straight to the cells.
What charger are you using, what’s your cutoff voltage?
How many amps does your charger pushes?
I always slow charge at 42v 2a, cut off is 4.25v. Definitely not blowing while I’m charging if that’s what you’re thinking.
@jinra Concerning cell level fusing with fuse wire…
Two things: 1) I love the professionalism of that build, looks great. 2) Please don’t take the following as the rather grumpy message people often try to send on forums to disrespect others, I’m genuinely likely to copy your battery design very closely, so just questioning for my own peace of mind, not in an attempt to rubbish your design!!
The fuse wire… My understanding of fuse wire from uni is that it melts at a given Amperage and that is normally within or related to the ambient temperature. The temperature gain is not necessarily linear, i.e. if 0 degrees above ambient at 0A and T degrees above ambient at 25A, (where T is melting temp, say 400 degrees), then the wire will not get to 200 at 12.5A, or 300 at 18.75A, that would be a linear behavior and unusable!
However, they DO go up in temperature as they approach the current limit, and when they do blow the molten metal can splatter about a bit and is still conductive. The higher temp when near the current limit and the splattering of liquid conducting material on breakdown are why fuses are ideally contained in things, like translucent plastic (cars) or little glass tubes (domestic plugs).
- have you ever measured the temp under load of those fuse wires?
- Have you checked their conductivity (/resistance) at nominal temps?
Both of these may be published by the manufacturer, electrical components are rarely supplied these days without details. I’m sure you’ve had them in play for some time so now trust them…
- have you ever had one tested, i.e. had a cell fail and the wire blow?
Thanks dannyboy, that means a lot.
To answer your questions, I have no measured temperature. I don’t have an IR temperature reader and the setup is in an enclosure for which I cannot hastily get access to see the cells. I have no tested resistance
The fuses that have blown always blow dry. There’s no spattering of anything, it just simply breaks, which likely means that it’s not getting “molten metal” hot. However, I’m slowly, but surely replacing all the fuses with double the fusing and non of those have broken yet.
I have not had a cell thermally runaway and fail, but then again I’m not 100% sure since I dont’ have a temperature reader. I imagine my double fusing would blow as well in thise case anyway.
To be honest I decided to go this route as an alternative to spot welding my pack since I dont’ have access to a welder. My soldering station does get hot enough to easily fuse these cells, however.
If I had to do the pack over again, I’d probably go with 20awg wire instead.
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Just to avoid spot welding? (lack of a welder is definitely a good reason for that! I’m going completely nuts and making my own for fun out an unnecessary amount of components and effort!) Or are you sticking to thin wire because that gauge is known to fail at 20/25/30A or whatever your chosen max current is and effectively give you per-cell fusing?
I guess the losses will be very low because they are very short runs (1.5cm?, so x10 x4 = 60cm in total for your pack there?) at 20A that would be 8W total, so utterly negligible as compared to the 720W your board would be pulling at 20A.
Yea I originally thought my wire would be able to take 25a continuous. Since thats obviously not the case, I think 20awg wire would be a better choice (at least from my provider). My battery max is set to 20a per cell so you’re right on the money. Each wire is about 2-2.5 cm
simply amazing… hi5ber is awesome i love their boards! how did you mount to the carbon fiber just drill in =)
yea takes a little time with the drill bit, but just use a high rpm you’ll eventually go straight through
That looks like a deck with a built in enclosure? Not sure what your question is.
How did they sink in? Maybe you overtightened
If the screw head can go into the hole, using a washer won’t work. The washer is too weak to hold the trucks together with that force. Plus the screws are countersunk and will be above the hole.