breadbin

I must have left my battery go completely dead and now it won't charge at all. It is, I think just out of warranty and has not many miles on it. I forgot to charge it over the winter and it is dead as a dodo. I read somewhere I can trickle a charge into it and it might wake it up a bit, enough to charge it with the charger but has anyone any experience with this or any other tricks? I can see the shop telling me to buy a new one if I go in there and they can be quite expensive if I recall. It is a Carerra Impel bike.

2old

They've discussed this in endless sphere thread(s); you might check there. From what I've read, you're on the right track; trickle charge until the voltage is high enough to use the regular charger.

sande005

Depends on how the Battery Management System inside the battery was designed. Some shut everything down to prevent damage, and then can be reset to again allow charging. Contact the manufacturer for advice. If it was allowed to go totally dead, and kept in that condition for any length of time (hours/days), odds are very high it is permanently damaged. One might wake it up enough to accept a charge, but it likely will have no capacity. Also unknown as to the chemistry of the battery. Some "flavors" of lithium batteries are notorious for almost unstoppable fires if damaged and then forced to take a charge. Others (LiFePO4) will not have that issue, but just won't ever be as "good" as they were.

Be safe, and do your attempts at revival outside, away from anything you care about that might burn down....

breadbin

Thanks for the advice, I will ring the shop I bought if from and ask them but I bet they will just expect me to buy a new battery. I don't blame them really, if it is dangerous and not guaranteed then why would they try and fix it? I was thinking of opening it and seeing what cells are inside. If they are 18650 I could get replacements and charge them maybe? Not sure. Maybe even find someone else more qualified to repair it. Expensive mistake.

sande005

I'm half a world away, and so can't give much specific advice - but try contacting Carrera directly. Your local shop will rightly only want to sell you a new battery - for ease of solution, if nothing else. But, they may be able to give you contact information for tech support from the manufacturer. Here in the States, there are a few legit places that build/rebuild batteries for bikes. My daughter had to go that route when the maker of her Dutch cargo bike no longer imported to the States and her battery wore out . Your shop might be able to recommend one. There are a lot of guys who are unqualified working out of their garden sheds though...so it can be a challenge to find the good ones.

timtak

The charger may not attempt to charge if the voltage is too low. So connect up some other charger or batter very briefly to try and increase the voltage to a level that your charger will recognise. I have used a 12 car battery charger on 8v drill battery packs to achieve this.

The idea was from this video

Watch the ampage and only connect briefly. Batteries may explode but the reasons why they do so are fairly primitive and predictable -- the battery gets hot, gas is created, the gas has nowhere to go... And they have a fail safe mechanism which (usually) allows the gas to escape and prevents the battery from ever being charged again.

The shop, warranty, or a new battery is the safer option but may be expensive.

Unfortunately I see that your bike has a 42 volt battery. You'd need 4 car batteries in series to get to a voltage sufficient to give it a boos, depending on whether the terminals of the battery allow you to access a smaller subset (e.g. half) of cells.

Tim

blacknbluebikes 

Please don't make a more expensive mistake, sometimes the fire department takes a while to arrive.

breadbin

Thanks for the advice, I did try one car battery and it didn't do anything so I guess it probably would take 4 which I don't have and which I won't even try. I am guessing that there might be 18650 cells in it, if so I can try and get fresh ones and replace the ones inside. I haven't been able to get to the bike shop because the car is out of action, that's actually why I was trying to charge the electric bike!

timtak

I think you are right that it will probably be 18650s inside. And I think that they will be okay if charged.So if you can dismantle the battery and put the individual 18650s in a 18650 charger then you should be able to charge them up and put them back in the pack without having to purchase new cells.


One issue may be that individual cells are usually welded together with nickel strip. I have recently purchased a welder and nickel strip from China very cheaply for precisely this purpose but I have not tried it yet. It is said to run off one car battery. Details below this photo with link to aliexpress

Battery Welder by Timothy Takemoto, on Flickr


But cutting apart your battery, charging the cells individually, and then welding the cells back together sounds very time consuming.


As mentioned above, I guess that there is more than two battery terminals but Googling the battery, it seems that only two of the terminals are made for charging so you are going to need more volts or get a new battery.

The batteries for the Carerra Impel 1 (there is also a Carerra Impel 2 ) are 36v cost 200UKP from ebay.
https://www.ebay.co.uk/itm/394509832421

There are videos on YouTube of people trying to get 18650 batteries to explode and or catch fire. They succeed but it is clearly not all that easy -- e.g. a fully charged batter, a hammer and a spike -- to get them to explode / catch fire.

So I dismantle laptop battery packs with a screwdriver watching the sparks without much fear. I have about 40 18650 cells harvested in this way.

Good luck

breadbin

Thanks again, I actually looked online again. I found somewhere on a facebook page about holding the button on the battery for 30-35 seconds to reset it. I tried it, not hoping for anything but it seems to be charging now! Whether it is working again or not only time will tell. I don't hold out much hope but maybe it wasn't too dead for too long. I did use the bike over the winter, just never charged it.

About the welder, it looks great. I actually wanted one of these before to make a custom battery for an old laptop. I have a Toshiba 460CDT from the 90's. I didn't buy it in the 90's, it would have cost about €5000? Madness but the cmos and resume batteries are cells welded together. No way to get them now but make up my own with individual new cells. I foolishly thought I could solder them together but seems I need to weld them They are only tiny coin batteries in series to fit a specific shape in the laptop. Might have a look at the welder you got. It might do the job too. And if the battery doesn't charge now I might go that route. I didn't go into the bike shop yet, the car was supposed to be fixed today but he has to order a shock mount which he didn't realise he needed! I messaged the guy on ebay will he ship to my address, he might not and it is looking like the best part of €250 for replacement.

sande005

Ah, so there was a way to reset! Great! That also means that the BMS has a protection mode that prevents damage from discharging too much. You should be ready to roll as soon as the charger lets you!

timtak

I think they will be okay. Good luck.

Good luck with the car too.
I will let you know if I try out my welder.