Repurposing li- ion (18650S - 2500mAh) batteries?

Nealh

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Under 7ah is surprising when looking at the battery graphs, they suggest 8 - 8.5 ah for a pair. One will have to do a real world test to see.
 
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peterjd

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  • OK @Nealh , thanks for that very useful backstory to your BMS experiences.
Thank you Nealh and Bikes4two for that very interesting discussion about the potential problems with a bms. I think I understand the issues a little better now. I also found this Youtube video very helpful. Peter

PS It looks as though it's a BX100 low voltage alarm which I need if I want to follow the route of managing my own balance charging and low voltage detection.
 
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I893469365902345609348566

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Which BMSs are the most accurate and reliable? It doesn't help that when trying to search this forum for "BMS", this happens:

50547

But when you search this website using Google, there are tags for "BMS", but no recent discussions are listed:

50548

Why are searches for "BMS" not allowed? This is an ebike forum where people are highly likely to search for the term "BMS".
 

Bikes4two

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Under 7ah is surprising when looking at the battery graphs, they suggest 8 - 8.5 ah for a pair. One will have to do a real world test to see.
  • Hi Neal, I looked back to the discharge curves for the LG M50LT (care off Mooch) and I agree with your comment that capacity should be around the 8Ah
  • So I popped down to the bike shed to look at my record sheet and durgh........ I'd recorded/measured 8.6Ah capacity NOT 6.8Ah as I initially posted (and can't now edit) on the two discharge tests I'd done.
  • Double DURGH!
  • I've yet to use it on the bike as I need to temporarily connect my power meter to get a real world measurement and looking at the forecast for the coming days, I'll likely not be going out much.
  • 50555
 
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Nealh

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That sounds much better, glad you got to the bottom of the figures.
 
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Nealh

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In the past I have had no issue with 7, 10 or 13s BMS from Ann power shop on AliExp.
Only reason I changed BMS seller was for the need for a 12S BMS.
As mentioned don't other with the Daly type, very unreliable.

Most 12s BMS are for Lifpo4/Lfp , 12s lion isn;t very common but can be found .
 
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Bikes4two

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An update on my 10s 2p battery pack build using 21700 LG M50LT cells:
  • I built this pack to supplement my main battery, a 10Ah 36v bottle type - this in anticipation of wanting to ride beyond the range it gives me (in excess of 45 miles on the ECO setting - TSDZ2 250W)
  • I've mounted the battery pack in a small handlebar bag on my straight handlebars (see the marketing pic below showing drop handlebars) and have temporarily led the lead back to my saddle bag were I can manually swap power back to the bottle battery if needed.
  • In the last week I've done 3 longish test rides to see how many miles I can get from the M50 pack - two rides of 45 miles was taking the voltage down to around 34v off load, so some power still in reserve. Today I did 52 miles before the power was obviously backing off and selecting higher than ECO mode had no effect. At home the pack was measuring 30.9v off load so clearly the LVC point was cutting in under higher power demands/voltage sag.
So well pleased with that - now bring on the summer to enjoy those longer rides I mentioned :cool:

50923
 
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guerney

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So well pleased with that - now bring on the summer to enjoy those longer rides I mentioned :cool:

View attachment 50923

The trouble with bags like that, at least on my bike, is that they crush front cables, which is why this handlebar looked interesting, but I've read reports that they're too stiff:




There's a cake carrier (or biscuit) accessory for it:



These wouldn't be as stiff, but are a lot more expensive:


 
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AndyBike

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If you like Alpkit stuff, they've an outlet on ebay with reduced prices.

Or USE(Ultimate Sports Engineering) a company long in existence and very popular in the retro world. They're the ones who make Exposure lights.

Really are bargains on the USE site. carbon risers -£20. Straight carbon bars - £15 These are heavily reduced prices obviously.

Some reasonable savings on their Exposure lights - Im currently trying to decide on whether I'm buying a Maxx D or a Six pack to add to the Toro I currently have.
The Toro is pretty bright, but mostly gets used in flash mode, which drops the output considerably. Adding a super power main, light up the road, light to it would certainly make me visible. Probably from space lol
 
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guerney

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If you like Alpkit stuff, they've an outlet on ebay with reduced prices.
Thanks! When I found myself looking at those hoop handlebars, was the first I'd heard of them. Good prices in their outlet.


Really are bargains on the USE site. carbon risers -£20. Straight carbon bars - £15 These are heavily reduced prices obviously.
https://www.exposure-use.com/Brands/Ultimate-USE/Outlet-Store/ATOM-Rise-Carbon-MTB-Bar-ATOMR
I bet those get snapped up before I've decided how quickly I'd end up destroying carbon by overtightening lights, cameras and action. Bargains! I need oodles more space for more switches and gadgets, hence my interest in hoopiness. But very very tempting...


Some reasonable savings on their Exposure lights - Im currently trying to decide on whether I'm buying a Maxx D or a Six pack to add to the Toro I currently have.
Both of those look very bright in reviews - are replacement LEDs available? I've noticed one of my 1800LM headlights lowering in brightness after a year's continuous use, yellowing a bit too.
 
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Nealh

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planetx sell them as well.
 

guerney

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Bikes4two

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The trouble with bags like that, at least on my bike, is that they crush front cables, ............................................
I agree that that can be an issue in some configurations (of handlebars and cables) but I'd seen the bag I've got on a mate's bike and took a punt and it works fine for me.

The zippered opening is at the front and getting the 10s/2p battery pack in is fine and I lead the power cable out through a hole I punched in a rear seam.

As an aside, the wireless Cateye bike computer stops working when I draw power from the battery pack. I've tried the computer in several different positions but to no avail so clearly the magnetic field (or maybe RF interference) is disrupting the signal from the front fork sender.

The signal disruption is clearly seen on the computer - under no pedalling/power conditions the computer 'signal received' indicator flashes but stops as soon as you start pedalling under power (in my case ECO mode so only around 3-5 amps).

I've a good old fashioned wired computer on order!
50956
 
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guerney

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As an aside, the wireless Cateye bike computer stops working when I draw power from the battery pack. I've tried the computer in several different positions but to no avail so clearly the magnetic field (or maybe RF interference) is disrupting the signal from the front fork sender.
I tried a carbon handlebar extension... it was marvelously lightweight, but there was a limit to how much it could be tightened, before risking cracking the bar and/or causing asymmetrical deformation with the force of tightening the clasp gripping the carbon, the end caps popped off and couldn't fit back in.

Then, after a long 4 hour ride in heavy rain, it and the cellphone holder it was holding swivelled down, wouldn't stay up no matter how much I tightened it. Mind you, everything else held by clasps and bolts swivelled around downwards or slipped down, including hilariously, my steatpost and seat. But there'd be less RF interference.

I bought a Minoura aluminium extension bar recently, which appears to have a beefier clamp to the handlebar, but from what I've read, I'm unsure whether that will stay in position after being exposed to long periods of heavy rain either, but I think it's unlikely if something like a phone or tablet plus a light is clamped to it. Which furthers my interest in handlebars with welded hoops.
 
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