Endless Sphere

I know XTR is top end and all, but at 5kw through the cranks you are going to wear it out really fast, months maybe. Maybe use slx or xt for lower cost or do a LHS drive...or you can just spend heaps. XTR is gram saving xc gear and will wear quickly. If anything go saint bc weight is of no consequen...

Don't do that! Multiple shorts in that proposal. Look at it again and see the many short circuits created, loop after loop.

I learnt a hell of a lot from that thread.... One of the best here. I was glued to it. Probs 3-4 years ago now . Time flies (with the right winding).

Yeah I read an article about it in my news feed recently. Some random guy (possibly with some cred/education behind him) reckons that he's solved the electrolyte problem that has prevented al/air batteries going commercial. Did it in his shed, and it's so harmless you can drink it (the electrolyte) ...

Yeh the copper was 0.1mm, haven't tried the test again as I'm not currently building any high power batteries. I've got a feeling that you could use 0.15 without too much trouble cause it's more being fused by the nicked than welded with the amps. @artvk That pack I built is still cranking. I use it...

I've pulled apart lots of ebike batteries that have 'died' where the fuse has been so hot that all the surrounding plastic is heat affected, and the contacts are corroded out but the fuse is still patent. Long periods of just sub critical current. Must have been like a dim little light bulb in there...

And remember, its not the bms's job.

Pretty much any old controller is going to be way more accurate than a fuse. If they go over a predefined limit, then program the controller to limit a little lower. Not too hard to verify this with a big ass shunt popped (poor choice of word) into the battery input even for amp draws in the several...

Geeze so angry.... Not really warranted. Hard to telling it's bms or controller. Easy way to tell is to bypass bms (take pos and neg directly from the battery) and try. If problem goes away, it's bms, if not, controller. one other thing is to check all connections for corrosion etc esp phase wires.....

It's your controllers job to limit amps, not the bms except in a failure like a downstream short. Then it's faster than a fuse, and re-settable.

Controllers inside cases get hot and die(if thats it there at the top) if you've got the space maybe bolt it on outside for some cooling air flow.

I used these last time: Irbf3307zbf
Good for up to ~60v batteries, if you're only using 10s you might be able to get a better lower voltage choice of mosfet (lower RdS on) for similar price.

You need to match one with the same DS voltage rating, same gate polarity (n-channel), same enhancement mode, same package. Then choose the lowest rds on spec that your willing to pay for (but not higher than the current ones) Sounds like a difficult task but it's not at all. Go to an online seller ...

Not the voltage you are concerned about here, but the amps . What are the amp ratings on both the controller and bms?

Cheap Chinese bms's are sold by all the various online vendors so there's no way to say 'these ones' are good or not. Try ordering from: https://www.litechpower.com They have a large selection and quality seems to be good in my 2-3 purchases through them. But they are more expensive than say aliexpr...

Firstly if you series them up, it will be 48v still with a 10amps bms limit not 40a...not sure if this is a mistake or misunderstanding. Series connected bms's can fail if one shuts down and the sees full pack voltage not the 3s it was designed for. So you're better off reconfiguring to 12s with one...

Bought several batches of batteries from ev power over the years, and same with bms's. Always been good transactions.

When I was young, I (for the fun of it) built a chainless bike. I bought a perm mag alt and built it into the front triangle. I welded a 2nd bb in to the down tube and ran a 50:12 to 50:12 step up. The pma directly powered a crappy little 200w rear Currie style motor. Now even then i knew it would b...

But to answer your question, use thinner cable to generate less amps. Same number of wraps ~2-3. Crappy way of doing it though. You'll end up with little burn marks that sink heat into the surrounding area and give inconsistent weak welds. Lots of amps = melting metal, Short time = minimal heat disp...

OK I looked it up. I suspect that a mechanical switch (relay) is too slow to respond quickly enough. And the timer only goes down to 0.1sec which is already too long, and... The 0.1s increments are too big. This results in way too much power due to the long pulse (and a relay is likely to be inaccur...

Sounds like your pulse length is too long. Don't reduce the amps.... Shorten your pulse. Hot and short is the way you weld with minimal heat permeating the surroundings.
What sort-of timer are you using. How does it work and what pulse lengths can you achieve?

Hmm I was out in my guesstimate by 5+kw...and not in LL's favour... yeah fairings are the way to go for that speed. Do standard road motorbike fairings make much difference over an unfaired motorbike? Or are they mostly for looks?

Those shkitty unite motors are tin can pieces of crap. Forget them. They will last aprox 3secs at anything like the power you want. If you want a mid mount motor you are going to have to look at very high quality motors to fit in the space you have. They will be pricey. Qs make motors that many here...

Is this a motor bike or based on a bicycle? You'll need 7ish kw (ottomh) to reach 130kph (on a bicycle, if you wanted do that!) so you are never goings-on achieve this on a 1000w motor. It'll be more on a motorbike /scooter. Also your dimensions for a motor are pretty tight... Don't know if you'll f...

Can't really see the image clearly enough to make out all the bits and pieces. Can you make it a bit easier to view. The Yellow is really hard to see.