Another Ebike conversion kit death
- Thread starter AndyBike
- Start date
A 1s would need to have very good cells that are rated for 20 - 35a .
For £26 one isn't going get good high rate discharge cells , at most one might get about 500yds before voltage sag causes cut outs.
I built my own 2s 12p for £100 using quality 30a rated cells, that gives me some 24 miles or a little more towing a laden trailer
For £26 one isn't going get good high rate discharge cells , at most one might get about 500yds before voltage sag causes cut outs.
I built my own 2s 12p for £100 using quality 30a rated cells, that gives me some 24 miles or a little more towing a laden trailer
For a light weight bike with 1s how far do you want to ride ?
12 - 15 miles if you are lucky using a quality 21700 cell.
12 - 15 miles if you are lucky using a quality 21700 cell.
12 to 15 miles would be good enough for a lot of the stuff I do, mainly shopping on a lightweight Brompton, mostly within 4-5 miles. Could have bigger 2P batteries for longer stuff.
The non-converted Brompton weighs around 8.4Kg.
Post a link to the AliExp battery.
I doubt though it woul dbe a good buy even at £26 for your usage.
I doubt though it woul dbe a good buy even at £26 for your usage.
Wow that's light! Their lightest weighs 7.45kg. Is yours a fixie? I hope you'll post pics of your bike and conversion.
Not a fixie, a 2 speed, but no mudguards or rear rack, so the same features as the 7.45Kg T-Line but with 2 gears and at around half the price. However, so popular is the Brompton that there are mods for just about everything and someone does make a 3 speed rear cog set that will fit on my standard rear Brompton wheel.
One of the biggest weight savings was to get rid of the 3 speed rear Sturmey hub gear and swap for a standard 2 speed rear wheel, a saving of 600g.
2 Speed is enough on an electric Brompton, for my use pattern, and I rarely change gear on the current 3 speed Swytch one anyway.
I will write it up, although its rideable at the mo I am waiting for the carbon handle bars (costing £12 and a weight saving of 132g) which will be a starting point for a conversion thread.
Yep, thats the type.
There is a simular one that has 30000mAhr printed in big letters on the battery. I guess its a printing error though, and the m ought to be a u, 30000uAhr looks a more likely capacity.
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Any of those you will be a numbskull to even consider buying and a retard if you think any one will work safely on an ebike.
Both examples will likely use very poor cells or dangerous ones.
A seller who claims 30000mah can't be trusted if they can't even get the spec right and 4400mah 18650 simply don't exist.
We saw what can happen with the E-rider episode and the 30ah £90 battery, it simply failed in short time with poor duff cells.
A decent 1s pack will be a min of £50 /£60 using decent cells, a decent cell for a 1s will need to be at least 20a rated .
The cells will be something like those aweful Ultrafires that will guarantee a fire with an ebike and which have proved to be very low quality with less then 1000mah per cell.
Both examples will likely use very poor cells or dangerous ones.
A seller who claims 30000mah can't be trusted if they can't even get the spec right and 4400mah 18650 simply don't exist.
We saw what can happen with the E-rider episode and the 30ah £90 battery, it simply failed in short time with poor duff cells.
A decent 1s pack will be a min of £50 /£60 using decent cells, a decent cell for a 1s will need to be at least 20a rated .
The cells will be something like those aweful Ultrafires that will guarantee a fire with an ebike and which have proved to be very low quality with less then 1000mah per cell.
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Indeed so.
I was tempted for a microsecond or so to buy one just to see haw bad they really were, but could not thing of a safe way to try one in an eBike, even if you were in a quarry with nothing flamable around, you could still set fire to the bike.
But I bet people are buying and using them, if only for a short while, after all they are a bargain.................
Does that even have a BMS? Looks like plain shrink wrapped cells.
In my very early days of messing about with ebikes, I made a 10S 1P pack from cells I had lying around while I was waiting for the pack I'd ordered to arrive. I dutifully put a BMS on it and connected it up the the bike. It worked perfectly for less than 100 m, then the BMS cut in as the voltage sagged below 30V. I was not very happy and I removed the BMS and connected it directly. I did about another 100m before smoke started coming off of some of the cells. I quickly cut the power and stood well back. It cooled down, but the shrink warp on several of the cells had melted and peeled off. If hadn't spotted the issue, it could have been nasty.
So that's what will happen with a badly constructed 10S 1P pack with cells that are poorly matched and not designed for 15 A current draw. If there is a BMS and it does it's job, you won't get far. No BMS or a faulty BMS and you are likely to end up with a bike fire.
Good call, the Samsung 21700 40T is 4Ahr and has a very high discharge current capability. Might be a way to go, 10S1P for light weight and local, 10S2P for long distance mode.
My guess is what they have done is use 3000mAh cells, then there are 10 of them, so they came to the conclusion it must be 30000mAh
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I could get one similar to the UK, £14 plus £6 shipping:Ships to
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This is the claimed spec:
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Amazing.
Someone could buy 10, put them in parallel, paying £140 for a '30Ahr' battery or is it 300Ahr ?
(I recommend you dont try this).
The listings are different for the 4.4Ah and the 3Ah models, hence the difference in price, but yes, someone might try and put a lot of these in parallel, <£140 (as they do a bulk discount) would still be cheap for a 30Ah pack. Probably would need 10 Schottky diodes though to ensure some level of safety!
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