What to do: Repair-Recell-replace battery, new kit or what?

Pendragon

1 mW
Joined
Feb 26, 2021
Messages
10
Hello,

I am new here (living in the UK), this forum seems to have quite a long history and I hope you guys will be able to advise me on what's best to do in my circumstances!

So first of all, a link to the ebike I've got:
https://www.e-bikesdirect.co.uk/electric-bikes/step-over-frames/greenedge-cs2--electric-mountain-bike

Link to the battery:

https://www.e-bikesdirect.co.uk/electric-bike-batteries/greenedge-cs2-battery/greenedge-cs2-battery-lithium-ion-36v-9ah--5-pin-(new-style)

Aside from the complete rip off price, they don't even have it in stock apparently.

What happened:
Last week the battery suddenly died during a ride. I say "died" but if I turn it off and wait for a while, when I try to turn it on again and press the button to check how much charge is left on it, 4 lights out of 5 will show as green, and a few seconds later it will turn off again. Assuming it can't be the fuse (if only life was so easy), I am not really sure if it's worth trying to get the battery repaired/recell it, as I have no idea about how much that could cost.

Desired max speed on level ground:

Don't really care much. The original setup is locked at 15.5mph as that's the limit by law here in the UK, I don't really need more than that, although a bit of extra power and torque would be appreciated if the price difference is negligible.

Desired max range at what cruising speed:

30 Miles at the above mentioned 15.5mph would do, again anything more is appreciated if the price difference is negligible

Preferred bike wheel size, or wheel size of bike you want to convert. Most common kits are for 26" wheels:

The bike has 26" wheels

Brake type of motor wheel. Disc or not:

Disc

Rider weight.

155Lbs

Terrain. Exp:

mostly flat, some short hills under 20% grade

Budget: Depends. If I am just going to repair/replace the battery, I'd like to go for the cheapest option. I am considering (and that's why I need advice), about whether it would be convenient to just buy a whole new kit for a different bike I have instead of wasting money on the one I have (I seem to understand that when replacing the battery I would probably need to buy a new controller and other parts?)

Where to shop? Most of the websites seem to be Chinese, with shipping/custom fees that cost almost as much as the actual batteries.

Any suggestions? :)

Thanks!
 
What you describe is usually a no longer usable battery. But try this first. Put it on charge, charge it full. Then wait 30 min. Try to ride it around the block, or run the motor with the wheel off the ground 5 min. Then charge full again.

Repeat at least 5 times. If no improvement, the battery likely has dead cells in it, generally unrepairable by ordinary people. If at that point the battery can be opened up, look for small disconnected wires. that could also be the problem. What this process does is try to force the bms and battery to charge the emptiest cells. The half hour wait is for the bms to lower the charge on the fullest cells. Then the ride discharges a bit more to get the bms to let the battery try again to charge full.
 
Thanks for the advice.

I've tried but I am afraid it proved to be impossible since the beginning. The charger supposedly turns "red" while charging, and green when fully charged/nothing plugged.

Plugging the charger into the battery doesn't switch the light to red anymore, I've just noticed this. I ain't got anything else that I could plug on that charger to ensure the charger isn't faulty as well, but from the look of it, I think there's no way to reproduce the steps you've suggested.

Might be a loose cable/connector, but opening the battery is proving to be quite a challenge. Some of the screws were already chipped/stripped and I just can't manage to unscrew them. It doesn't help that those screw are also deep inside the plastic/rubber of the battery and the hole entrance is way too narrow for a cordless drill.

Giving for granted that the battery is no longer salvageable though, what would be my best option/course of action?
 
Pendragon said:
Last week the battery suddenly died during a ride. I say "died" but if I turn it off and wait for a while, when I try to turn it on again and press the button to check how much charge is left on it, 4 lights out of 5 will show as green, and a few seconds later it will turn off again. Assuming it can't be the fuse (if only life was so easy), I am not really sure if it's worth trying to get the battery repaired/recell it, as I have no idea about how much that could cost.
If the battery worked perfectly normally up to this point, and suddenly failed with no previous symptoms and absolutely nothing different happened to it or the bike (no bumps, drops, rain, etc) than before, it is very likely that it is simply a poor connection within the battery.

The first most likely problem is a sense / balance wire from the BMS to one of the cell groups has broken off or has a bad crimp to the connector that plugs into the BMS. The BMS can't read that cell group anymore, so it shuts the pack down to prevent possible damage to something it can't monitor. (this prevents both charge and discharge)

The second most likely problem is the BMS "crashed"; quite a few newer BMSs are "smart" so they have an MCU chip that runs firmware designed to monitor things, and like any computer and programs there can be bugs that cause crashes. Rebooting them is sometimes hard, and sometimes easy. If it has a reset button on the board, or two pads that can be shorted (often marked as RESET or RST) then it's easy. Otherwise it usually requires disconnecting the board from the cells, waiting a bit, then reconnecting to reboot it.

The third most likely is the BMS just failed. It would need to be replaced in that case.

There are ways to open a case whose screws are stripped, but it may take more than one person to do. I'll type up a basic explanation if you are interested in trying it. (even if you ahve it open, you may not be able to fix that battery without buying parts).


If you don't want to open up the battery (or cant'), then replacing the whole battery, case and all, is your next option. What you have now is called a "bottle battery", and using "bottle battery ebike" in google will find a lot of similar ones. Many of them will have the same connector to drop right into the cradle on your bike, but not all will, so you must verify at least via pictures from the seller that the new one will fit before you get it, or you will have to open up the old battery and transplant parts over.... :/

Optionally, you can replace the whole cradle and battery, with whatever will fit in the same place (shark, hailong, etc) that also has the right voltage (36v) for your system, and enough Ah to run your bike for the range you want. Most likely the cradle of yours uses the water bottle mounts to screw down to, and so you just have to get a new battery and cradle that can do the same thing, or that cna mount in an alternate way to your frame. I recommend keeping it in the triangle as it is the best handling that way.


Assuming that you need to replace the battery, then:
30 Miles at the above mentioned 15.5mph would do, again anything more is appreciated if the price difference is negligible
Rider weight.
155Lbs
Terrain. Exp:
mostly flat, some short hills under 20% grade
means that for hte most part you will use less than 20wh/mile (probably a lot less). That means that for 30 miles, you need only around 600wh. (20 x 30). Since your system is 36v, then 600wh / 36v = 16.7Ah. So a 36v 16.7Ah battery would get you at least 30 miles, and probably significantly more, depending on how much you pedal, wind, traffic stops/starts, etc.

Getting a bigger battery than you need is good because it means that as it ages, you'll still have at least as much as you need. Also if you run into bad weather (headwinds all the way) or have a big detour, you still have range to get where you want.

If this is the path you want to go down, we can try ot help you find the right one to do what you're after, within your budget and capabilities of installing on your bike.


(I seem to understand that when replacing the battery I would probably need to buy a new controller and other parts?)
Only if you choose to get a different voltage system. If you stay with 36v (which is fine for your speed/etc needs), and the bike did do what you wanted other than the battery failure, then all you need is a new battery. (if you don't/can't fix the one you have).
 
Hmm. does the charger work? Stuck on red sounds weird. I'd look at the charger plug, with a voltmeter, and see what is going on. FWIW, broken plug on chargers usually shows a green light. Never turns red when you start a charge.

Tried charging overnight? It might be in a default slow charge mode, because of low pack voltage.

Next thing I'd try is leave it on charge overnight, hopefully charging at very low amps. unplug, then try charging overnight again.

Oh,, and lastly, outside. Don't charge a suspect battery inside.
 
Charging overnight, next to you while your sleeping or out in the middle of a field, or in a bbq.
If you live in an apartment building or condo, then charge while your sleeping next to it but you'd need to put it in a metal bucket or metal cage/basket for easy "chuckage" out the balcony/patio door.

dogman dan said:
Hmm. does the charger work? Stuck on red sounds weird. I'd look at the charger plug, with a voltmeter, and see what is going on. FWIW, broken plug on chargers usually shows a green light. Never turns red when you start a charge.

Tried charging overnight? It might be in a default slow charge mode, because of low pack voltage.

Next thing I'd try is leave it on charge overnight, hopefully charging at very low amps. unplug, then try charging overnight again.

Oh,, and lastly, outside. Don't charge a suspect battery inside.
 
Thank you all for the replies.

Regarding the battery, I tried your suggestions, it just doesn't seem to charge, the charger light stays green at all times. Whether it is plugged to the battery or not, it never turns red.
The battery keeps showing as charged when I press the button as soon as I switch it on, but after a few seconds it seems to lose all the charge. I leave it untouched for a while, detached from the charger, and when I try to switch it on again and press the button to check the charge amount, it will display as charged for a few seconds again before seemingly losing power all at once.
It does make me feel like it might simply be a displaced wire, but I sure wouldn't know where to look, the ones leading to what I presume is the BMS seem fine.

IMG_20210301_185112.jpgIMG_20210301_185140.jpg

Could it have had something to do with having left the battery in the garage? It's been quite cold here in the UK.

I am also attaching pictures with details of the current system.

IMG_20210225_155932.jpgIMG_20210225_155950.jpgIMG_20210226_123644.jpgIMG_20210227_111501.jpg

I've been trying to open it up, but a couple of screw are so tipped/stuck, I just can't manage!
I even bought on purpose a screwdriver that barely fits in to get the maximum amount of grip, but only managed to take out a couple. Plus I can already see three more screws that I've got absolutely no idea how to get to aside from an offset screwdriver maybe, but if they are as stuck as these, I can't see how I'll manage to put enough strenght to move them at all.

I've got the feeling that all of those cables have some kind of connection pins and it wouldn't be a good idea to just cut the cables and somehow solder them instead, would it?

I feel like I am behind even the starting point, can't even unscrew the damn thing to properly assess the situation :mrgreen:

Any advice on how to deal with tipped/stuck screws please? :confused:
 
First, ask yourself this question: "Am I happy with this bike when it works?" If yes, then just move on to replacing the battery. You likely have one or more bad (not dead) cells that are producing a voltage high enough to prevent the charger from starting, but that collapses under any load - even just the startup load. If you really like the bike, get an 18-20AH, 36 volt battery that will drop in, as suggested. If you weren't thrilled with the bike, then it may be time to look for something better...
 
LeftieBiker said:
First, ask yourself this question: "Am I happy with this bike when it works?" If yes, then just move on to replacing the battery. You likely have one or more bad (not dead) cells that are producing a voltage high enough to prevent the charger from starting, but that collapses under any load - even just the startup load. If you really like the bike, get an 18-20AH, 36 volt battery that will drop in, as suggested. If you weren't thrilled with the bike, then it may be time to look for something better...
Thanks for the insight.

Well I wouldn't say that I am thrilled with it, but it has served me well so far.
I've got another shimano ebike that I would normally use instead, but recently I've managed to kind of get my partner into going for a bike ride and she would obviously pick the shimano when we go, therefore I have been using the green edge for those times and for when I want to go a bit off track as a backup ebike. I just find difficult to justify the purchase of a completely new bike at the minute because of the money aspect.

What is kind of preventing me from taking action right now, it's pretty much understanding what kind of DIY to expect even for something as simple as replacing the battery, as I was advised it would involve soldering stuff around which I am not really good at to be quite frank.

Ideal would have been to find the same exact battery, but I've only found that one (5 pins connector) on a chinise website with 100 pounds of shipping fees!

That's why first of all I would like to see how hard it would be to just replace the battery and its connector with a different one, potentially upgrading the setup in the process (maybe a 48volt battery?)
 
Something like this would work. You pull the old cradle off your bike. Find the two positive and negative wires that connect to two of those five pins. Install the new cradle and wire it right. You could even use two crimp-on connectors if you cannot solder to wire it.

This is a 36V10AH pack with a 1 year warranty, UK delivery. Is a 48V possible? You would have to look inside your controller and discuss handlebar controls.

https://www.ebay.co.uk/itm/36V-10Ah-250W-350W-Bottle-Lithium-Battery-Pack-E-bike-Electric-Bicycle-Scooter/174558814130?hash=item28a4841fb2:g:Uf4AAOSwC4Jf0yfD

uk_battery.jpg
 
I just don't know what to do anymore.

I can't get rid of the case where the controller and the cables are.

Any suggestions on how to crack the damn thing open? :mrgreen:
 
I tried, no success. Not sure if my drill/heads are just not good enough for the job but the only thing I managed to do was making the screws ever more tipped and to ruin the openings in the plastic/whatever the case is made of.

I am so frustrated I am starting to feel like just smashing the damn thing with a hammer until it's pulverized.

Do bottle battery normally come with their own controllers? Knowning the controller is inside that case is the only thing preventing me from extreme measures.
 
Pendragon said:
I tried, no success. Not sure if my drill/heads are just not good enough for the job but the only thing I managed to do was making the screws ever more tipped and to ruin the openings in the plastic/whatever the case is made of.
Well drilling the screws will damage them beyond repair; that is the goal.

Takes a certain skill and experience. Bit size selection, pressure, speed, etc.

What's your experience level?

How about trying left-handed drill bits? Often times, drilling screws with left-handed drill bit, the bit will "catch an edge" on the metal screw and unscrew the screw as it is drilling it.

Controller inside battery not as common as separate componentry. Almost universally hated here on E-S because of the extra layer of difficulty for hacking/upgrading, and extra cost of failures (as you are experiencing). Proprietary vs. open source.
 
You do know I meant "drilling out" the screws, right?

As in, drilling right through them, yes destroying them on purpose in order to get the csse open without damaging the case body itself.

If you have decided you don't want to be a DIYer then you need to pay the extra money for others to do stuff for you.

Buying a proprietary ebike of the shelf may be the best way forward.

I do not mean this as an insult, accepting your own limitations is a big step toward achieving your goals
 
No offense taken, I always welcome any feedback or advice, that's what I am on a forum for, and I'd rather hear what people truly think rather than being given false hope.

I also have no problem accepting my own limitations if I feel like it's an unrealistic goal, but I think anybody can learn at least the basics if given the chance and proper directions, so before giving up I want to exhaust my possibilities.

I did understand what you meant for "drilling out the screws", I simply haven't managed yet and I am trying to figure out if that's because I've used the wrong tools for the job or I simply did it wrong.

So to understand first of all if my problem is the equipment not being good enough, how powerful does the driller needs to be?

This is what I've got, more of a toy than a drill for anyone into DIY, but back then it served its purpose and it was the cheap option (obviously).
IMG_20210304_130120.jpgIMG_20210304_130150.jpg
The heads are simply the all purpose ones that came with it, so I have no clue whether I need to buy specific ones for metal or not.

Goes without saying that I am more than happy to buy a new drill/heads that will be adequate for the job, I see it as an investment anyway.
I've always had the bad habit of buying cheap if I thought I wouldn't have much need for it in the future, but it more often than not pay off to invest a bit more into something of better quality/performance.

On the off chance the drill should have still been good enough for what I was trying to do, I'll simply give it another go.

Also, while researching on what to do about those screws, I read about these kind of damaged remover tools:
https://www.amazon.co.uk/Damaged-Remover-Extractor-Hardness-62-63hrc/dp/B01E9ZC2K2/ref=sr_1_9_mod_primary_lightning_deal?dchild=1&keywords=unscrewing+drill+head&qid=1614862028&sbo=Tc8eqSFhUl4VwMzbE4fw%2Fw%3D%3D&smid=A1PTC6EXHYYJWT&sr=8-9

Are they worth a try at all?

Thanks again for all the feedback.
 
If there is enough of the screw head left, or if the screw shafts are thick enough, screw extractors can be better than a drill bit. They are usually better than a dull, cheap drill bit. ;)
 
The only catch is that the screw extractor does need to be harder metal than the screw head, and I wouldn't guarantee that with the cheap ones. ;)

Generally a good brand (Dewalt, Craftsman, etc are usually good enough) Titanium Nitride drill bit will easily take the head off any common screw, as long as the drill being used has enough torque to let it grab the head and rip thru it. If it just grabs the head and turns the screw, it may force the screw to strip out the threads from the housing it's screwed into instead. :(

As noted previously in the thread, a reverse-twist drillbit will also work, and may allow extraction of the screw, as long as the plastic or metal the screwthreads are in is not stripped out (with cheap stuff it's acutally more common than stripped screwheads).
 
Your drill motor appears to be satisfactory for the current task. From what I could tell by the photos of the labels. The bits, we have no way to judge their quality via long-distance internet forum. :lol:

If they are not drilling the screw heads off, then buy new ones. Titanium nitride coated at the least, but cobalt is among the best commonly available.

I still recommend trying left-handed bits (heads you call them?).
 
bringing the pack to a local mechanic, or anyone with a drill press might be easier

yes those are "bits" heads are not a thing

and it's a drill, not a driller
 
Apologies about calling them "heads" :D As well as a total newbie with DIY I am also a foreigner so thanks for letting me know how to actually call them! :D

I'll start by buying new bits (titanium nitride as suggested) for the drill and give it another go, will let you know how it goes fingers crossed!

Thanks again for so much advice, I am learning a lot :thumb:

P.S:
LewTwo said:
OH and be gentle with those small bits.

I'll shamelessly admit that the first one I used on my first attempt snapped in two :D Surely due to my carelessness, but I got the feeling the bits that came with the drill are not exactly of the highest quality.
 
1/8" bits (and whatever the metric equivalent is) and smaller are easy to break even when fairly high quality. Steel has its limits.
 
bits are consumables, most don't even learn how to sharpen them

buy a bunch of cheapies to practice with

before starting with the pricey ones
 
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