Or perhaps I'll call it 2wd FATMON (any of these names taken yet?
) -It's the mongoose steel fatbike I've been working on and this will be the build thread.
In the meantime I have a question before I put the boards pack in their cases and reattach etc etc, hopefully completing the new battery setup, including controller mod.
The old 12s spun the 29" dia tires way too fast (44mph), and the battery was sagging like crazy anyway on takeoff.
So I went with 9s 30c 15ah zippys, and removed controller LVC jumpers from pcbs for now. I knew there would be less wattage/power on 9s (without shunt mods) but figured the lower gearing would make it a wash, at worst. (I will link all the threads pertaining to this build which includes one on modifying with a trim pot or the proper resistor for custom LVC on non-programmable cheapo controllers.)
Anyway, 9s does 33mph HOC WOT and 29mph-ish WOT when discharged. Here's how I've been testing the battery: Medics hot glued together with neo magnets on back.
It works great to see the cell levels as I flounce this thing and 'get used' to being the 'bms' for the new pack via total pack voltage Led.
SOo0o, I went from 4.10 avg to 3.85v resting - ~3.75v WOT with brakes on at maybe 10mph quite a bit and nothing got noticeably hot. And although NET I have more torque now than w/12s, that means the front tire breaks loose first when thrashing a hill, alot quicker than before.
With everything staying super cool while pounding on it (. . . what she said?), I figured permanently increasing amperage to the rear motor would make sense on multiple fronts.
So finally, here's my question:
I have tentatively wrapped 8 strands around the 3 shunts which should easily lower resistance by 33%, guessing visually by the volume of the copper VS the shunts. So I assumed that should give me about 1/3 more amps?
Results of the testing the mod(read: thrashing, lol):
Battery depletion and sag as noted above, thrashing WOT (even with brakes) the whole time . . . .
90F Rear hub
87F Front hub
Short <1ft runs of thin-ass phase wire: 72F.
Seems like I should keep adding copper? Or start adding solder?
But I don't wanna blow anything up. I notice a little increase in torque and better balance rear VS front, but judging from less than a 10% temp increase (3 deg F on maybe 10ah of 'testing'!) for the modded controller , it really didn't do that much.
Maybe I should mod both front and rear??? Hubs can survive fine up past 200deg iirc, so even @ 100F ambient I wouldn't expect the current setup to get much over 140F while thrashing it thru nearly a whole 'tank' of electrons?
I'd like the rear to still have more power VS the front, so IYO (in your opinion?) what should I do and are there any things 'not to do' that this bonehead might stumble upon lol?? Thanks!