Metro A2B rear battery

Richard_UK

Finding my (electric) wheels
May 16, 2014
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First of all apologies if this info is already on the site somewhere, I did spend a long time searching bit didn't find anything.

A friend of mine has a metro a2b with a (almost) dead battery, his bike didn't come with the frame battery just the rear one, he's not exactly well off and can't afford the £500 for a replacement battery pack. Is there a way to open the battery box and replace the pack of cells inside? Or would he be better to buy a bigger battery (more power) and strap it on the back? If he did go the route of buying a different battery how would we connect it to the bike?

Please note I am a total noob with electrics so would need any guidance explained in idiot proof style.
 

pdarnett

Esteemed Pedelecer
Jul 5, 2013
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You could open up the pack and have a go with the cells, it's tricky if you're not used to dealing with potentially dangerous lithium cells.

Another route would to be get a good rear rack battery from BMS like this http://www.bmsbattery.com/packs/657-36v-10ah-lithium-ion-alloy-shell-ebike-battery-pack.html and change the connector for about half the price.

This guy on Endless Sphere built his own battery http://endless-sphere.com/forums/viewtopic.php?f=14&t=25890&start=0

I've got the rear battery connector diagram somewhere if you need it. Don't bin the old battery though if he gets a new one. Let me know!
 

Richard_UK

Finding my (electric) wheels
May 16, 2014
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trex

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May 15, 2011
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can you post pictures of the inside of your battery?
 

Richard_UK

Finding my (electric) wheels
May 16, 2014
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Stourbridge
It's a friends bike, he's tried to open the box but can't, I haven't looked it at myself yet just spoke on the phone about it.
 

trex

Esteemed Pedelecer
May 15, 2011
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that's tricky.
pdarnett has one of those and he is good with batteries.
 

trex

Esteemed Pedelecer
May 15, 2011
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looks like an easy job for cwah and his spot welder.

 

Richard_UK

Finding my (electric) wheels
May 16, 2014
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Stourbridge
Paul, thanks for the pictures, I couldn't find anything anywhere after spending a long time searching, it definately looks beyond my capabilities so it looks like going with plan b unless one of you fine gents on here can fix it. My friend is based near me in the West Midlands.
 

pdarnett

Esteemed Pedelecer
Jul 5, 2013
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If you do go with plan B and want to offset some of the cost, I'd buy the old battery off you (just for the case alone!) and have a tinker at building a complete battery from scratch!
 

Richard_UK

Finding my (electric) wheels
May 16, 2014
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Stourbridge
Paul, I have spoken to my friend and he says if you're not due down this way he'll happily drive up to you if you think you can fix it?

I also forgot to mention, he bought the bike from a local Best Buy which was closing down, someone had stolen the battery off it and they replaced it with the battery from a different model, it looks the same but is a 9.5ah version.
 

pdarnett

Esteemed Pedelecer
Jul 5, 2013
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I should be able to test it at least and see where the problem lies and then what the best course of action is. This week's a bit mental for me but next week looks better.
 

Richard_UK

Finding my (electric) wheels
May 16, 2014
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I know it's difficult to say without seeing it but do you think it could be one or two cells down, and if so is this something you could fix while he waits? It's a very kind offer but it would be quite a journey to have it tested but not repaired.
 

pdarnett

Esteemed Pedelecer
Jul 5, 2013
599
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www.mybigdaydj.co.uk
It'd be finding out which cells are down, then sourcing replacement cells, there's no repair option for a dead cell apart from cut it out and replace it. I'm not sure which cells A2B use and you can't just replace them with whatever's handy. I've learned that lesson the hard way!
 

cwah

Esteemed Pedelecer
Jun 3, 2011
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I'm testing some NCR18650A cells (3100mAH) and probably will buy few of them. If you need some I can send them to you. I think I can get them for maybe £3/cell shipped. It's cheap but these are disassembled cells (but tested to capacity)

So you can replace the 48 cells with better cells for £150 shipped!

Tell me if interested.


ps: Paul, if you replace down cells, you need to have similar resistance and capacity for each cell string. Or you'll end up with unbalanced pack.

pps: I'm not sure but I think the A2B battery uses Sanyo UR18650ZT. Specs here:
http://www.panasonic.com/industrial/includes/pdf/UR18650ZT.pdf
 
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Richard_UK

Finding my (electric) wheels
May 16, 2014
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Stourbridge
Are there any West Mids based members on here who are capable of sorting this? It's just that it's a long way to travel if there's not much chance of it being sorted on the day. Either that or would it maybe be better for him to post the battery to you Paul? Obviously he would pay whoever sorts it for him for their time.

P.S. Thank you to everyone so far for your input, it's much appreciated.
 
D

Deleted member 4366

Guest
If you want to drop it off at my house in Telford, I'll have a look at it for you, but I don't know if I'd be able to fix it while you wait; however, I should be able to diagnose the problem with it. Send me a PM of you want that.
 
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Richard_UK

Finding my (electric) wheels
May 16, 2014
19
0
53
Stourbridge
That sounds great, I'm sure he'll be happy to drop it off at Telford and come back if/when you can fix it. He's chomping at the bit to get out on it with this weather we're having right now. I'll pm you for the details.

Paul thanks again for all your help with this, sorry if I've wasted your time.
 

cwah

Esteemed Pedelecer
Jun 3, 2011
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Yeah D8veh is one of the most knowledgeable member here. You could even maybe see how he's doing that so you'd be able to fix it yourself later on
 

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