Battery Woes

[jedd]

Hi.
I've recently been given by a good friend a very nice Ebike that I'm enjoying immensely.
It came with two batteries,The original and a replacement.The original would not charge from new so the company sent a replacement and never asked for the faulty one back.
The issue with it is that when plugged in to charge,the charger light would go straight into green.
When I received it the first thing I tried was this battery and after a few attempts I managed to get it to charge by just simply plugging/unplugging the connector and switching it on at the wall.
Ever since I've been having some great rides and a range that's more than enough for me.
It's still temperamental though.Sometimes it will charge first time and other times it takes a few attempts..
Yesterday the weather was quite nice and dry and as I'm on holiday I deciding to go out for a longish ride of 50 miles.
The temperament battery was fully charged and it returned a decent 43 miles before it got to around 20% to which I swapped it over.
Once home I went to pop it on charge but it was playing up again with the charger going straight to green.After a few attempts it eventually turned red.
This time though the charger only set about charging it for about 45 minutes before turning green (it normally takes about 4 to 5 hours). leaving it partially charged.
After trying to get it to charge again it now totally refuses to with it just going straight to green.
I'm a bit "gutted" by this as I have been making all kinds of plans for the holidays to travel far and wide.
Am I safe to keep trying, in attempting to get it to charge up ,or should I just leave it well alone now and either get replaced/repaired
Many Thanks
Jedd.

 

[saneagle]

It's almost impossible to give sensible advice unless you tell us what you have.

Assuming it's a normal Chinese ebike, there is a simple connection fault between the charger and the battery. In sequence, that could be:

• Burnt charge socket because charger was connected when switched off;
• Bad solder joint on the charge socket;
• Loose fuse;
• Bad solder on fuse;
• Bad solder on BMS.

 

[Nealh]

As the charger works ok with one battery and not so well with the other , then one can at least pindown the issue to the original battery.
Issue now is , the original battery needs opening and checking for the charge fault.
Areas to check;
Charge port for burning /pitting.
Both solder joints to charge port.
Fuse holder.

Solder joint to C + on battery pack.
Solder joint to C - on BMS.

BMS multipoint sense conneciton.
All individual sense wire solder joints to the cell pack.

For a dry joint , re wetting fully and applying a little more solder to each joint may help. If it is a dry joint then to pin it down re wet one joint at a time and test charging each time to see which is at fault.

The fault is likely a simple one but it is tracking down the culprit methodically.
A meter on beep test /continuity may help out in trying to find a dry joint.

 

[jedd]

Thanks for taking the time sharing your knowledge.
I'm not very good with electrics so I will have to get someone else who's got a better idea and more confidence than me to check it over.
In fact I have a good friend who works in the electronic industry who knows his onions about these kinds of things.
The only thing I can work on is common sense, to which I can rule out such things.
It can't be the battery charger because it charges the other battery up just fine.
It charges intermittently so I'm thinking it's got to be a loose connection somewhere.If the battery was unbalanced I'm working on the assumption it just wouldn't intermittently charge.
In fact as I type this I've got the battery now in the back garden well away from the house and it's taking a charge again.I plugged it in and worked first time.
As you rightly say it needs a proper check over,but by someone who knows what there doing.
I shall let you know how I get on and will give you any updates as they happen.
If any other members here have got some words of advice please feel free to share them
All the very best,
Jedd

 

[jedd]

EDIT..
Just thinking about this whilst having a coffee,but I think I've made a school book error judging when I thought or think the battery has hit 20% before I swapped it over for the fresh one.
There's 10 bars on the display screen and for some idiotic reason I was thinking 1 bar would equal 20%.
It doesn't it equals 10% .
I've done this twice to the battery now over the couple weeks and thinking on , both time's it been a pain in the back side to recharge.
Would I be right in saying I'm pushing the battery to far.If it was on a true 10% at resting plus the voltage sag when riding it,it maybe what's causing me the issues with recharging it up again.
If I manage to get it charged again for the next ride out I will swap it out at before it gets to low and see how it goes .
I'll will let you know how I get on with it.,,

 

[jedd]

I's just got to around 75% and it's turned green again

 

[saneagle]

Wiggle the connector when it's in to see if it makes contact.

You still haven't told or shown us anything about what you have! What's been said might be completely irrelevant. Instead of typing nonsense, give us what we need to help you.