Wisper Is my Wisper 575Wh battery toast?

[Ghost1951]

What's involved is not sliding the dead battery off the rack mount & sliding the replacement battery in its place. This is what I want to do. I don't want to fit a new rack & have to re-wire the bike.

Instead of ignorant replies that don't acknowledge what is involved can you point me to an affordable replacement battery?

This shows a very poor attitude Nigel. You seem to forget that you are asking this guy for help.

You have been offered a variety of options, none of which you have even considered. Early on, Saneagle mentioned that the batteries might just be out of balance, but you do not seem to have even noticed that, or thought about how you might investigate that, or do something about it. Then you suggest he gave you an ignorant reply.

I'd say there is a damned good chance those batteries could be brought back to life - especially the three year old one. I have a battery which is more than three years old and I can still get forty miles out of it. It is nothing special, branded Sanyo cells put together by a one man band in his little workshop. That one went well out of balance about two years ago after the winter when it was not used for six months and it would only take me about one or two miles before shutting down. Once I sorted out the balance issue, I took it forty miles up hill and down dale and it did forty miles without re-charging this week, two years later.

Of course now you have described saneagle as 'ignorant', I doubt that he will be that keen to tell you how to fix your bikes at no cost.

 

[nigelbb]

I already told you. If you want a Wisper battery, buy one. You asked for alternative solutions, but you don't want an alternative solution. Why did you ask? It seems to me that you just want to moan about it and drown in your sorrow instead of sorting it out.

Thanks for your suggestions but I didn't ask for an alternative solution. I first asked if the battery could be revived. I then asked where I could get a battery for the bike for £300. I just want a replacement battery. I don't want to replace the rack & have to rewire the bike.

I have just ordered a Wisper 375wH battery for £255 from Winstanley's which should be here in a few days & will simply slide onto the rack after I remove the dead battery. It seems the best solution as the price is acceptable & capacity should fine as we have never exhausted the batteries on any of our rides which have been up to 30 miles. We have the torque sensor models so battery life should be better.

 

[nigelbb]

This shows a very poor attitude Nigel.

You have been offered a variety of options, none of which you have even considered. Early on, Saneagle mentioned that the batteries might just be out of balance, but you do not seem to have even noticed that, or thought about how you might investigate that, or do something about it. Then you suggest he gave you an ignorant reply.

I'd say there is a damned good chance those batteries could be brought back to life - especially the three year old one. I have a battery which is more than three years old and I can still get forty miles out of it. It is nothing special, branded Sanyo cells put together by a one man band in his little workshop. That one went well out of balance about two years ago after the winter when it was not used for six months and it would only take me about one or two miles before shutting down. Once I sported out the balance issue, I took it forty miles up hill and down dale.

Of course now you have described saneagle as ignorant, I doubt that he will be that keen to tell you how to fix your bikes at no cost.

I just used the same word that he used in replying to me. What's sauce for the goose...

I asked for a way of reviving the batteries & I appreciated the response. I tried leaving the battery charging for 24 hours but it made no difference as it still died again after 50m. I then mentioned the other battery that is utterly dead even though it was working last week. I tried charging that one for 24 hours too but it's still completely dead.

As you think that there is a damned good chance those batteries could be brought back to life perhaps could you could tell me what you think I need to do to revive these batteries?

 

[saneagle]

I just used the same word that he used in replying to me. What's sauce for the goose...

I asked for a way of reviving the batteries & I appreciated the response. I tried leaving the battery charging for 24 hours but it made no difference as it still died again after 50m. I then mentioned the other battery that is utterly dead even though it was working last week. I tried charging that one for 24 hours too but it's still completely dead.

As you think that there is a damned good chance those batteries could be brought back to life perhaps could you could tell me what you think I need to do to revive these batteries?

They've most likely gone out of balance. To solve that, you have to open them and measure the cell voltages on the multi-pin connector joined to the BMS. Once you've established those cell voltages, you normally know what's wrong with the battery.

 

[Ghost1951]

There is another current thread in which NealS is advising how to do this.

Crank

Yes will do,my battery has 4 blue lights so should i continue past the max 4 blue lights while on charge The lights on the battery are pretty useless. Go by the charger.

www.pedelecs.co.uk

Read that and the subsequent post.

 

[nigelbb]

Thanks for the pointers. I haven't got time to take the batteries apart this evening so will report back tomorrow. I did fish out my digital multimeter & can confirm that the two chargers are both delivering 42V. For the battery that dies after 50m it's 39.8V on the charge port & for the one that's totally dead it's 34.5V on the charge port.

 

[Nealh]

Thanks for the pointers. I haven't got time to take the batteries apart this evening so will report back tomorrow. I did fish out my digital multimeter & can confirm that the two chargers are both delivering 42V. For the battery that dies after 50m it's 39.8V on the charge port & for the one that's totally dead it's 34.5V on the charge port.

39.8v and not going far before cutting out suggests possibly a very unbalanced cell group that is very low to LVC.
The 34.5v battery suggests at least one very low cell group below LVC or even a dead cell group.
Opening up and checking group voltages is the only way one will know for sure.

 

[Az.]

I think it is a good time to introduce some changes to your battery maintenance routine. After all you don't want history to repeat itself in few years.

 

[nigelbb]

After charging for 24 hours the battery that dies after rising 50m now died after travelling 400m. I put I back on charge & after about five minutes the red light went out & the green light came on. Voltage at the terminals is 41.1V.

I have cracked open the battery that is completely dead & measured the voltage of most groups as 4.13V but there was one group of 3.79V & the highlighted group with a red & a white wire at just 0.111V What can I do to fix this?

 

[Nealh]

0.111v is scrap /dead as I suspected . If it were at 2.5v then it might have been salvageable.
If you have the means ( arduino spot welder) and 4 x cells one could try replacing them, though one could use likely any 2500mah cell of 5 - 10a rating if one can get some
The 2500mah cells look like no name china ones, the green sleeve is indicative of pannasonic wraps though but they sure aren't panny cells.

A replacement cell that would suffice would be an Eve 25p , Sinowatt 25sp or BAK 18650cnp , one is looking at about £4.25 - £4.75 per cell.
Or if one is capable of replacing all the cells one can get them for less then £2+ vat a piece so aboput £94 all in.

This battery is 360wh one could via self build upgrade it to 432wh or 500wh.

 

[Nealh]

The first battery is either unbalanced and has a weak cell group or the cells are knackered . At 41.1v one would expect 25 - 30mile son low power .
I suspect the latter with only a few hundred metres capable.

What power level are you using for it to only manage 400m ?

 

[saneagle]

After charging for 24 hours the battery that dies after rising 50m now died after travelling 400m. I put I back on charge & after about five minutes the red light went out & the green light came on. Voltage at the terminals is 41.1V.

I have cracked open the battery that is completely dead & measured the voltage of most groups as 4.13V but there was one group of 3.79V & the highlighted group with a red & a white wire at just 0.111V What can I do to fix this?

View attachment 58930

You can probably get that battery working again, but it probably won't have full capacity. It's worth a try. You can use any single cell charger (4.2v output), and if you don't have one, then any USB charger (5v output). If you have a few, choose the one with the lowest charge rate. Anything more than 2A is too high. 0.5 amps would be ideal. If you use a USB one, you must watch the voltage very carefully. It should take a few hours to get to 4.13v, but then it'll rise quite quickly, so you have to watch it more at that time. In the beginning, keep feeling the cells to make sure they're not getting warm. It's probably best to do it outside away from anything in case of problems. I don't believe there's any chance of anything going wrong, but always better to be safe.

When cells go below 2v, their performance normally drops off afterwards, but it's not an exact rule. Sometimes they''re OK, but mostly not.

Once those two groups are charged up to 4.13v, you can use the normal charger. Check to see whether the recovered one goes to the same level (around 4.2v) as the others. If it stays low, or when you try to charge it to 4.13v, it doesn't reach it, the battery is scrap.

 

[Nealh]

From 0 .111v to 3v the voltage rise will be quite rapid, it is between 3v - 4v one needs to keep an eye on it.