Answered Focus Jam2 battery charging problem

[steve_sordy]

The bike is a Focus Jam2 2019, only had it a few weeks. Very recently I discovered that the battery needs to be run down until it goes into sleep mode before fully charging.

As per the manual I ran down the integrated battery today. I was on Trail and the range went to zero and a mile or so later, it changed into Eco and the display went to red. I kept going for about another mile and the battery switched itself off. The display was still functioning, but no pedal assist. I switched over to the spare battery from the TEC pack and carried on.

When I got home I removed the spare battery and then put the integrated battery on charge. As expected, the charging light flashed green on/off on a 2 second cycle. But after about 30 seconds it stopped flashing and went out, no charging lights at all.

According to the charger manual, If the battery has less than 25V, then the charging current starts with 500mA for half an hour. When the 25V s reached, the charger will switch to fast charge.

I have left the charger connected and switched on for two hours now. At intervals I have switched off the charger and back on again. The same cycle repeats, ie flashing on/off for a short while and then going dead, ie no lights at all. I removed the charger from the bike and switched on the bike as normal to see if it had been charging anyway, it hadn't.

Prior to this the battery charger had worked as normal. In fact I have just tried charging the spare battery and everything worked as normal.

Any suggestions as to what I can do to fix this. Or have I done something wrong by running the battery past the red until it switched itself off?

 

[SvenHelgason]

2018 JAM2 Factory Plus
4000km
4.0mA charger / 220v mains
Have installed lights which are were on (has been ok to charge with them on as they draw very little current)

got home on red battery indicator, plugged the bike in, left it there. Morning after it’s completely dead. My charger wall outlet had been turned off so no charging and the battery 100% drained.

now I am having a hell of a time getting the charging cycle started. It starts for about 15 seconds (4 full illuminations of the blue button) and then goes red on the charger.

any quick fix?

 

[steve_sordy]

You have made a donation to the National Grid.

Try bringing your charger indoors to get it to room temperature before trying again.
If that doesn't work, I'm out of ideas other than take it to your LBS.

 

[SvenHelgason]

You have made a donation to the National Grid.

Try bringing your charger indoors to get it to room temperature before trying again.
If that doesn't work, I'm out of ideas other than take it to your LBS.

Bike and charger always kept indoors when charging, 22°c Garage temp

I even tried to heat up the battery pack by blowing hot air from a heat gun to the bike frame downtube, with no luck.

 

[SvenHelgason]

Bike and charger always kept indoors when charging, 22°c Garage temp

I even tried to heat up the battery pack by blowing hot air from a heat gun to the bike frame downtube, with no luck.

I have tried to unplug and plug the charger multible times to try to trickle some volts into the battery, no go
I have tried to hold the button while plugging, still nothing
I have left it overnight on charge, but the same thing happens, starts to charge for about 15 seconds, then red light on charger.

Borrowed the external battery pack from a friend, my charger charges it so I can rule out my charger being faulty.

When connecting the external battery pack to the bike it will not even power on, and the external battery is fully charged.

Tells me there is something wrong with the internal battery (seems the bike will not turn on if its completely drained, even with the external pack connected) or there is a fuse/circuit board issue within the bike.

 

[steve_sordy]

How frustrating!
Sorry, but I have nothing to offer you except take it to your dealer.

 

[SvenHelgason]

How frustrating!
Sorry, but I have nothing to offer you except take it to your dealer.

Took it there this morning, Andy Schleck Cycles here in Luxembourg. Spoke to a very friendly technician, but I suspect they will want to change the battery

 

[steve_sordy]

Took it there this morning, Andy Schleck Cycles here in Luxembourg. Spoke to a very friendly technician, but I suspect they will want to change the battery

That seems to be the standard solution by Focus.

 

[SvenHelgason]

That seems to be the standard solution by Focus.

bike is ready,, picking it up later, don't know the cost yet, but since they didnt call with an estimate and it only took one day it cant be big

 

[SvenHelgason]

bike is ready,, picking it up later, don't know the cost yet, but since they didnt call with an estimate and it only took one day it cant be big

New battery... but I got a super deal

5000km, 3 years, every day use, probably 800-900 charging cycles seems to be the lifespan

 

[ENMTB]

One like this:

Battery charger for Shimano integrated batteries E-bike Battery and Charger, E-Bike Charger FOCUS

You may struggle to get an exact answer from anyone on this, knowledge is in short supply no matter where you look. We had a Focus factory electrical engineer on the phone swearing blind that you could ride the bike entirely without an internal battery, just with the TEC pack, but that was proven false when our friendly dealer tried exactly that. There are an additional two wires coming off the internal battery that we have deduced turn the motor on/off, and the section of the loom that goes to the TEC pack / charging point does not have these wires.

Given that you can still ride with the TEC pack, your BMS / bit-that-switches-on-the-motor must still be functioning in the internal battery, so it can't be completely dead. As you say, that would point to something stopping the charger from charging your internal cells from their very-low state.

There are five key components to the whole system;

1. Charger
2. Battery
3. Motor
4. Loom
5. Display (I'm not 100% sure any display is even required to run the system, but it does help to be able to see what's going on!)

If you can try swapping those for ones you know function (anyone close to you with another Focus?) then it shouldn't take long to find the culprit. Getting replacement parts, however, is another thing entirely, but Derby (who own Focus) are reliable if not very speedy. We have a spare loom we could send you, but doesn't sound like that's the issue here.

hi Bissona,
jam2 2018 not turning on, so I decided to take apart and now have NFI(no idea)

1. charger flashes green for 30 sec then goes into Red led( which says serious problem) ok i gathered that but is that a serious problem with the charger or ebike battery or motor
2. battery - i have taken battery out of tube and shows some light cracking, The battery has a health percentage blue light and it’s flashing 80% health, not 100% as it says on stunlocker
3.motor looks ok from outside but am curious on the inside
4. Loom this looks as normal, though havent tested
5. Display- worked fine then switched off and never turned on