Any thoughts on why i’m only getting 10mins on efoil? 11s3p
Try increasing your speed to 25-30 to see what happens.
Do you use Bms for the download?
What brand and type of cells were used in your battery? The problem seems to be low quality cells that were used in the battery build.
I think this is related to your battery. Nominal voltage 39.6V (11S), 15Ah (3P).
39.6x15=594Wh. Usable capacity ist aprox. 0.8x595=475Wh.
You should get a bit further but not much. Depending on your setup, weight, speed and number of takeoffs, 50 - 80 Wh/km is what you can expect (in flat water). Under 60Wh/km is good. Over 80 is inefficient or choppy condidtions.
What cells are in the battery? The capacity is also related to the discharge current, the higher the discharge current, the lower the capacity. As you mentioned it is from an eBike, the cells might not be high discharge current cell types.
To isolate the issue you‘d have to log, but you‘re using a flycolor not a vesc, so you would need additional equipment for logging.
Thanks for the replies.
Cells are 21700 Molicel P50B…
That should be capable cells. Discharge BMS? Or charge only?
Charge and discharge BMS
JBD-SP22S003A/B JIABAIDA JBD 6S-22S Smart BMS 40A-100A …
JBD- SP22S003
Settings below
Anyone any thoughts on overheating battery?
Thinking two directions…
- battery contact resistance leading to overheating and or
- propellor pitch causing requiring too much torque and therefore drawing too much currnent
Think next step is to try some alternative props
- have microhobby 2 blade prop
- trinity 3 blade prop
Might try to 3D print some alternatives.
Any suggestions for 11s 6384motor ?
We know the problem is in the battery if it is overheating at 80 amps. Could be a build issue with low quality nickel or fake cells. I would start by trying a different battery. Many people run all of those props without any issues on lower quality cells or less amp rating.
For a test you could run 2 lipo batteries in series just to see what the results are (6s and a 5s).
Thanks @s9tim for the response.
I dont have easy access to other batteries so might try running system in a water tank, monitoring current via BMS app, rpm via maytech remote and battery temp with IR thermometer and see if i can locate / confirm heat source.
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How did you make that you epoxy stayed between the magnets and did not flow out?
@petr see earlier post above. Printed a ring to fit and spread epoxy and microballoon mix inside. Note - check youbise the right epoxy, mine was too soft when cured and peels a bit.
I mean the complete inner part. Did you make the epoxy with the microbaloons that solid when you applied it, so that it is not floating at all, or how did you do that?
Sorry, yes, the epoxy mix was thick enough and quick setting so that it was like toothpaste. Pushed it between the magnets with a wooden lollipop stick !
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That bms is 100A - too low for my taste, if you use it for discharge. Maybe it overheats…
Consider for example esc like xcross - it is built with the most capable mosfets and still, without heatsink it can heat to more than 100c even in foil-assist use. Ok, the current on the motor is higher and it is pulsed, it is not exact comparison to battery current, but still…