Search found 589 matches

by kdog
Oct 22 2019 5:55am
Forum: Battery Technology
Topic: Aluminum-Air Battery
Replies: 2
Views: 55

Re: Aluminum-Air Battery

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) ...
by kdog
Oct 15 2019 3:27am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 223
Views: 38807

Re: Spot Welding Copper Strips to 18650 Battery Cells

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...
by kdog
Sep 10 2019 11:11am
Forum: Battery Technology
Topic: Fuse Questions
Replies: 23
Views: 544

Re: Fuse Questions

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...
by kdog
Sep 09 2019 5:04am
Forum: Battery Technology
Topic: Fuse Questions
Replies: 23
Views: 544

Re: Fuse Questions

And remember, its not the bms's job.
by kdog
Sep 09 2019 5:03am
Forum: Battery Technology
Topic: Fuse Questions
Replies: 23
Views: 544

Re: Fuse Questions

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...
by kdog
Sep 08 2019 9:23am
Forum: Battery Technology
Topic: Motor Controller cut out during riding
Replies: 16
Views: 338

Re: Motor Controller cut out during riding

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.....
by kdog
Sep 08 2019 5:26am
Forum: Battery Technology
Topic: Fuse Questions
Replies: 23
Views: 544

Re: Fuse Questions

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.
by kdog
Sep 07 2019 4:52pm
Forum: E-Bike Build Threads / Photos & Video
Topic: Super fast tommm's bike build.
Replies: 6
Views: 568

Re: 1st Build. Black Enduro 72v 3kw 50-65mph (fast)

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.
by kdog
Sep 06 2019 6:27pm
Forum: E-Bike Technical
Topic: KT controller MOSFET replacement question
Replies: 5
Views: 249

Re: KT controller MOSFET replacement question

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.
by kdog
Sep 06 2019 6:15pm
Forum: E-Bike Technical
Topic: KT controller MOSFET replacement question
Replies: 5
Views: 249

Re: KT controller MOSFET replacement question

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 ...
by kdog
Sep 06 2019 5:11pm
Forum: Battery Technology
Topic: Motor Controller cut out during riding
Replies: 16
Views: 338

Re: Controller cut out when throttling from a dead stop

Not the voltage you are concerned about here, but the amps . What are the amp ratings on both the controller and bms?
by kdog
Sep 03 2019 11:06pm
Forum: Stand-up E-scooters and E-skateboards
Topic: Which is better 48v with bms or 4x 12v with bms each connected in series ?
Replies: 3
Views: 253

Re: Which is better 48v with bms or 4x 12v with bms each connected in series ?

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...
by kdog
Sep 03 2019 8:41am
Forum: Stand-up E-scooters and E-skateboards
Topic: Which is better 48v with bms or 4x 12v with bms each connected in series ?
Replies: 3
Views: 253

Re: Which is better 48v with bms or 4x 12v with bms each connected in series ?

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...
by kdog
Sep 03 2019 6:49am
Forum: EV Business World
Topic: EV-power Australia Ltd
Replies: 5
Views: 366

Re: EV-power Australia Ltd

Bought several batches of batteries from ev power over the years, and same with bms's. Always been good transactions.
by kdog
Aug 31 2019 5:54am
Forum: E-Bike General Discussion
Topic: dynamo on a bike
Replies: 29
Views: 1050

Re: dynamo on a bike

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...
by kdog
Aug 30 2019 6:34am
Forum: Battery Technology
Topic: DIY spot-welder, transformers from microwave ovens?
Replies: 54
Views: 10402

Re: DIY spot-welder, transformers from microwave ovens?

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...
by kdog
Aug 30 2019 6:26am
Forum: Battery Technology
Topic: DIY spot-welder, transformers from microwave ovens?
Replies: 54
Views: 10402

Re: DIY spot-welder, transformers from microwave ovens?

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...
by kdog
Aug 29 2019 11:42pm
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 5284
Views: 211840

Re: Wind and Solar vs Coal, Gasoline, Nuclear

Australia's governmental review into nuclear power has effectively dismissed large scale nuclear as 4-5 times more expensive than renewables. Small modular reactors are expected to be 50%more costly than large nuclear. Build times are in the 15-20year time frame. I'm sure that for the 10s of billion...
by kdog
Aug 29 2019 11:17pm
Forum: Battery Technology
Topic: DIY spot-welder, transformers from microwave ovens?
Replies: 54
Views: 10402

Re: DIY spot-welder, transformers from microwave ovens?

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?
by kdog
Aug 28 2019 5:00am
Forum: Motor Technology
Topic: In need of a motor & motor controller
Replies: 6
Views: 292

Re: In need of a motor & motor controller

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?
by kdog
Aug 27 2019 5:58am
Forum: Motor Technology
Topic: In need of a motor & motor controller
Replies: 6
Views: 292

Re: In need of a motor & motor controller

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...
by kdog
Aug 25 2019 8:56am
Forum: Motor Technology
Topic: In need of a motor & motor controller
Replies: 6
Views: 292

Re: In need of a motor & motor controller

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...
by kdog
Aug 24 2019 3:45am
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 257
Views: 39638

Re: Common pack design mistakes, how to avoid?

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.
by kdog
Aug 23 2019 7:57am
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 257
Views: 39638

Re: Common pack design mistakes, how to avoid?

Power leads like so:
IMG_20190823_40991.jpg
IMG_20190823_40991.jpg (95 KiB) Viewed 220 times
by kdog
Aug 23 2019 7:49am
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 257
Views: 39638

Re: Common pack design mistakes, how to avoid?

Pwd, that layout has many problems Complexity, very poor current sharing, insufficient area for series connects. Something like this would be better : IMG_20190823_33441.jpg Then add as many series connects as possible, one for each cell is ideal.. In you previous version several groups had only 3 s...