Battery just suddenly Died

[FrodoBaggins]

Hi Everyone

I have just bought my first ebike, a Oxygen City Ebike with 36V 15.5ah battery.
The bike was second hand on Ebay but the seller had acquired around 12 of them from a hire business that never took off. Whilst the bikes maybe a year or so old they had never or hardly been used and you can tell because they all had knobbly bits on the tyres and every other part was clean.

I have done about 100 miles on it so far and without issue and was able to get around 40 miles on a single charge in a very hilly area, so I was quite happy with that and it was about expected.

Anyway tonight I was doing a quick 8 mile round trip, up a big hill (12% gradient) and back down again.
All was fine and I got to the top and still had 3/4 battery showing even using assist level 4/5

On the way down I decided to stop and take in the views.
For some reason I also decided to remove the battery from the bike, just to see how heavy it would be to carry around with me. When I put the battery back on there was nothing. No power. No lights Nothing!

I thought it might be the connectors, so tried re-seating it, and tried all the turning it off and on again and still nothing. Luckily the way home was all downhill so I got back and then plugged it into the charger. The charger fired up and went orange but still nothing on the battery.

Previously I could press the power button on the battery and it would show lights 1-3 usually 3 to show fully charged but all of sudden I get nothing, not even the first red one. Its been on charge now a few hours and I still get nothing.

It was perfectly dry and nothing untoward happened other than me taking it out of its battery holder.

Any ideas what this could be or what I can do?

As I bought it on Ebay I cant take it back anywhere, but the fact that last week it did 40 miles on one charge makes me feel the battery is still fine.

Thanks

Frodo

 

[Deleted member 4366]

Could be the fuse. Did you check that? My guess is that you reconnected it when the battery was switched on, so the inrush into the controller's capacitor over-loaded the fuse.

I know about those bikes and the seller's story is true, except that it was a bit longer than what he said. I helped the business in Snowdonia assemble them three years ago. They were going to hire them, but they ended up in a dispute with the staff, so it never happened. I bet whoever bought them got a bargain.

 

[FrodoBaggins]

Hi d8veh.

Thanks so much for your response
I need to get a new fuse and try it as everything you said adds up.
Yes the business was in Snowdonia and I think a mate of his bought them off him in Cheshire to help with cash flow.

I am sure there is more to the story but ultimately when I went there he had 8 what looked like brand new bikes and let me take my pick. The fact most of them had the wrong pedals on suggested they cant have gone far on them.

After I peeled off all of the "bike hire" branding there was nice white Oxygen paint work underneath.

Hopefully it is just a fuse like you say and I have got a bargain.

I will source a fuse a report back here my results

 

[Deleted member 4366]

How much did you pay?

 

[FrodoBaggins]

I paid about £770, with a load of other stuff chucked in.
Helmet, lock rack etc.
It seemed to have good reviews and the Whoosh and Halfords ones were a fair bit more, albeit new.
Ideally I would have loved to get the Whyte Coniston but sadly that is new and also over £2k.

It seems good so far in fairness.
The fuse in the battery says 40amp 250V is this an easily sourced fuse. I dont have a multimeter so cant test it yet.

 

[Deleted member 4366]

it seems very high for a 15 amp controller. i was expecting it to be 20 amps

 

[FrodoBaggins]

I am no expert on electrics but based on the system being 36V and 250W am I correct in thinking that 250/36 (x125%) would work out at 8.7amp. So anything higher than this should be OK.

Or am I totally missing the point and like you say the controller is 15amp so 20 should be fine.
40amp fuses are not that common on ebay but 20amp are very common.

 

[Woosh]

The fuse in the battery says 40amp 250V is this an easily sourced fuse. I dont have a multimeter so cant test it yet.

you can see if the fuse is burned out in the middle.

 

[FrodoBaggins]

The fuse looks fine which I was hoping it didnt for a simple fix.

 

[Woosh]

check the output voltage. If it's less than 31V and more than 5V, you will need a new BMS.

 

[Deleted member 4366]

Did you look at the contacts on the base of the battery?

 

[Danidl]

I am no expert on electrics but based on the system being 36V and 250W am I correct in thinking that 250/36 (x125%) would work out at 8.7amp. So anything higher than this should be OK.

Or am I totally missing the point and like you say the controller is 15amp so 20 should be fine.
40amp fuses are not that common on ebay but 20amp are very common.

Your calculation is correct, but the rationale not so. When the device is switched on there will be a very large inrush current, charging internal capacitors in the controller. This current peaks at maybe 100 amp. And is limited only by the series resistance of the wiring from battery to controller. But this only lasts a fraction of a second, and the fuse, depending on its thermal capacity should not blow. When the controller is operating it may well draw 15 to 20 amps, under adverse conditions .. low speed travel, going uphill. This is not to say that the motor is generating 36 X 20 watts of mechanical power. But it could be drawing 700 w of power from the battery.
A slo blo 20amp fuse might do the trick.

 

[Danidl]

The fuse looks fine which I was hoping it didnt for a simple fix.

The only way to test it is with a meter or a battery and bulb...

 

[FrodoBaggins]

So many thanks to everyone for all of your advice and help, I have to say this i great forum and today I solved (although not necessarily fixed) the problem:

here were my steps:

1. tested the fuse and that was fine, it is a 40amp fuse that is in the battery for future reference.
2. Put the battery on charge and the lights went from red to amber to eventually green ( 1 hour or so) on the charger suggesting that the battery was in good condition and no issues with the charger
3. I tested the voltage on a multimeter and it was reading a constant 39.7V as per Woosh's advice
4. I then cleaned the contacts to make sure that wasnt the issue either

It was at this point I thought I was getting into the BMS etc, but then noticed something interesting with the barrel and the key in that occasionally if I held the key in a certain position the battery would light up with 3 lights, but then wiggle it around and it would go again.

So I took the top off the battery and had a look at the barrel and switching mechanism.
I cant say i did anything major other than remove all the bits I could remove and jiggle it about again, before fitting it back together.
And hey presto, one Oxygen Ebike back in the game!

Personally I still think there is a minor fault with the switch/ ignition mechanism but at least now I know how to get it going again if stranded miles from home.

Would anyone know where I could get a new barrel and key/ switch fitted? I suppose its the same scenario as someone losing their key but at least I have the key to get the battery off.

Many thanks

 

[Danidl]

So many thanks to everyone for all of your advice and help, I have to say this i great forum and today I solved (although not necessarily fixed) the problem:

here were my steps:

1. tested the fuse and that was fine, it is a 40amp fuse that is in the battery for future reference.
2. Put the battery on charge and the lights went from red to amber to eventually green ( 1 hour or so) on the charger suggesting that the battery was in good condition and no issues with the charger
3. I tested the voltage on a multimeter and it was reading a constant 39.7V as per Woosh's advice
4. I then cleaned the contacts to make sure that wasnt the issue either

It was at this point I thought I was getting into the BMS etc, but then noticed something interesting with the barrel and the key in that occasionally if I held the key in a certain position the battery would light up with 3 lights, but then wiggle it around and it would go again.

So I took the top off the battery and had a look at the barrel and switching mechanism.
I cant say i did anything major other than remove all the bits I could remove and jiggle it about again, before fitting it back together.
And hey presto, one Oxygen Ebike back in the game!

Personally I still think there is a minor fault with the switch/ ignition mechanism but at least now I know how to get it going again if stranded miles from home.

Would anyone know where I could get a new barrel and key/ switch fitted? I suppose its the same scenario as someone losing their key but at least I have the key to get the battery off.

Many thanks

.. you could just put a high power toggle switch, available from Halfords in series with the battery and just use the barrel key switch for physically holding the battery pack in place. Just bypass the electrical contacts on the barrell.drill through the shell of the battery case. Halfords have these switches in up to 20, 30, 40 amp rating. A cheap reliable 3£ solution. It would also confuse potential robbers.

 

[Woosh]

the lock has a peg that turns a mechanical switch at the bottom of the lock.
Humidity gets through the lock and corrodes the contacts inside the switch.
Sometime it's enough to detach the switch from the lock and squirt a bit of WD40 to clean the contact and it'll work again. You can turn the switch with a flat blade screwdriver and leave it on if you need to ride before getting a replacement.
post a picture. Some members may have a spare.

 

[Deleted member 4366]

I've fixed a few solder joints on those key-locks. Our Chinese friends are not very good at soldering big joints like that. If it plays up again, try resoldering them. use plenty of heat and allow time for the solder to fuse properly. I've never heard of the switch itself being faulty, though I have seen one of the cheaper type fail. This type:
http://www.ebay.co.uk/itm/E-bike-Scooter-ATV-Electric-Motorcycle-Bicycle-Ignition-Switch-Lock-/361386491279?hash=item5424503d8f:g:9~8AAOSwq~tZNkG2

 

[FrodoBaggins]

OK a week or so on, here is an update in case it helps anyone else out and also to say thanks to everyone who helped.

I thought I had solved the problem as per my previous post, but first ride back it all re-appeared midway up a hill.

It was 100% related to the switching mechanism and sadly the easy fix of spraying WD40 in made no difference.

The solder for the 2 wires controlling the switch looked good, but I noticed the mechanism itself was quite squashed into the controller part of the battery, this was pressing on the wires pretty heavily so I released this.

This time I took the whole barrel out and then apart. By using a flat head screw driver I could get the switch working 100%. So I then set about rebuilding the whole lock.

This seems to have done the trick, possibly the little spring or the plastic bit around it wasnt quite in place and this was stopping the barrel turning the plastic bit completely. So once all reconstructed the switch turned freely
Fingers crossed this is it and the Oxygen is back in the game.

Just as an aside, I am new to ebiking and today I went out around the Yorkshire Dales on my normal thin wheeled road bike. I saw a guy (must have been about 65 years old min) on either a Wisper or Oxygen bike that looked like mine in front of me. The plan was to catch him up and have a chat with him, however every time we got near a hill he left me for dead and I never did manage to see what he had.Pretty impressive for a guy who is at least 30 years older than me and a great advert for ebikes

So there is proof that ebikes really do work and you can easily keep up with the hardcore bikers (not that I am one of them )

 

[D C]

(must have been about 65 years old min)

A lot of us on here would like to be only 65
Nice to get feedback.
Dave.