Battery replacement for Volt Savile - options/ideas?

[tampano]

Ciao everyone,

while using very happily my Brompton (non electric) for commuting home-train-office, I decided to use again for some leisure the Volt Savile I was neglecting since some time.

I charged the battery, unused for months and months, maybe a year, and yesterday it went down, shutting completely down my controller, after few minutes. Having it charged only for a couple hours or less I thought that was the issue. I charged it again overnight, green light on the charger, this time the bike doesn't even turn on.

Tried with a tester, and it gives me really weird values, usually a low voltage, let say 10v but with decimals going up constantly until eventually it also reaches 36v. I plug it back into the bike. No result. Just to be clear, when I do these measurements with the tester the battery is NOT in charge.

Can I safely assume my battery is dead? It's almost eight years old now, and even if I didn't use it that much I think there's an age depleting factor, right?

On a replacement point of view, Volt website offers a £330 for 400Wh and a £590 for a 630Wh. I've never been extremely fascinated by the company after the purchase, so let's say that giving them money is not my primary instinct.

What's your experience on battery replacements? Can I find a fitting one? Alternatives?

I'm tempted by the self-building with 18650 batteries and connections (spot welder or terminal connectors?)...but if there are interesting alternatives already made I am totally ok with that.

Any idea is more than welcome...thanks in advance

T.

 

[Nealh]

Building your own is more expensive as you need to factor in the the spot welder, BMS, cells, wire, nickel, insulators and Kapton tape. If it is to satisfy your curiosity then and money isn't really an issue then self build gives more insight in how they are constructed, wired up.

Two scenarios I can see for your battery failure , one or more of the pouch cell/s have failed puffed /swelled up or more probable a cell pouch has discharged below the lvc of about 3.2v so BMS will not allow any charge to occur. In any case being li - po chemistry time to go over to 18650 or 21700.

Your cheapest option for new cells is Jimmy @ ebikebatteries.co.uk to recell your battery case with nice new better 10a rated cells. He will organise collection and return all for a good price.

The battery is a silver fish cased one so you can in fact buy one off ebay as long as it is 36v, ah/wh wise you can use any capacity that takes your fancy as capacity is only a measure of potential range available. A new battery will come with anew charger and carrier docking fitment.
Check the measurements if you buy.

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Difference between ebay cheapo and a Jimmy re -cell is Jimmy will use very good cells and not poor/ mediocre ones.

Or if you wish you can abandon the behind the seat fitment and opt to fit a down tube battery if you wish.

 

[tampano]

Thanks for the answer...I'll totally study all options here.

One side question...I'd like to be sure it IS the battery before buying a new one. Of course it's the most probable option but I'd like to investigate...and, forgive my ignorance in terms of electrical measure units...would it be possible to connect my battery charger (36v 2A) directly to the bike contacts just to see if the bike responds properly? Or those Amps would be good only to make the display turn on but not good enough for the motor? Does it make sense?

 

[Nealh]

It won't work ,battery charger doesn't supply the watts/demand required.

Undo you battery end and slide out the li -po pack, via the multi connector test each f the 10 pouch voltages. Any that are < 3.3v then you will have found your problem.

 

[tampano]

They seem to be square cells filling the whole space, fitted with some foamy double sided tape. How safe is it to push/pull them out? Still Li-Po cells

 

[Nealh]

They had to be pushed in to be fitted so should come out, what ever if li - po swell then they will tight in the space. Thye will have a BMS attached any wiring should have enough to be able to with draw the pack.
Show some pics.

 

[tampano]

Here it is

 

[Nealh]

Yep standard li - po pack slid in, under the blue heat shrink will be 10 pouch cells laid to face to face, BMS likley on the other end as don't see it or the thin sense wires.
Does the other end come off ?

 

[tampano]

Yep, these are pics from both ends

 

[Nealh]

O.k , it should slide/push out probably from opposite end to where the Red and Black wires exit.