Jam2 internal battery woes

[simono]

I have a 2019 Focus Jam2 with suspected internal battery failure. I want to test the charger and the external TEC battery to check are working 100%, but when I place multimeter probes on main 2 terminals of either the charger or the TEC, I get 0 volts. The TEC has 5 bars, but charger works ok briefly when I plug it in to the TEC, before cutting off due to being fully charged.
Am assuming they need to be "triggered" by BMS on battery before showing volts?
BTW, I,ve opened up internal battery, & tried to reset with no luck. I do get 36v+ on cells, but around 2v on battery outlet, after BMS. What a crap design!
I have also opened the charger, & get 42v briefly on cable outlet when plugging into TEC (before it cuts out as battery is already at 100%) , but nothing when plugged into internal battery.
Thanks

 

[steve_sordy]

51 views and no responses! But it has been just over 12 hours. I'd give it until after the weekend, at least.

 

[simono]

Its looking like I might have had a good outcome with this. Basically, I bought the bike in February this year from a independent bike shop , & it has a years warranty.
I contacted the owner, thinking he would say the battery is not included, especially as I paid 1200€, including TEC pack.
Am waiting to confirm today, but he has said if I contribute 200€, he will get a new battery sent to me direct from Focus.
Pretty great customer service!

 

[Fangs2k]

The battery has probably developed an internal short by the sounds of it, so the BMS has put it into protection mode.

A new battery is the best solution, better safe than sorry etc.

 

[Shorty4]

I have a 2018 Carbon Jam2 with the same problem, it's actually happened twice now and fortunately both times focus here in Australia have repalced the battery under warranty as it's a known problem.
The first time when the bike was about two years old I had to return the faulty battery but the second time I got to keep the faulty battery so like you I cut it open and tested all cells which were fully charged so then went looking and found that there was corrosion on the charging socket and battery connection on the bike with very small tracks between conductors.
I cleaned them all with contact cleaner and clean cloth and then checked the battery connections and they too showed signs of corrosion. After cleaning them I then pushed the reset button on the BMS and it flashed a few times, so I then refitted the battery to the bike and it works!
It's a pity the battery reset button isn't accessible without wrecking the battery case as it would appear the corrosion between terminals caused the bms to shut it down as it should but then the battery is bricked for the sake of not being able to reset it externally.
I've had similar happen to a friends bosch powered bike and after cleaning contacts we could reset the battery and it was good to go.
The second time it happened on mine I was in the middle of a months trip to rise rail trails aroudn the contry so wasn't happy as I suspected what the problem was but without the tools to disassemble the battery.

 

[simono]

So, got my new battery, fitted it and bike is all back to normal (kind of) , now the TEC pack no longer works.
Worked fine before and is like new, 100% charge etc, but when I connect it to bike, can't power bike on.
I spoke to the dealer before I bought new battery , as had read a bit about this issue, and was told to not believe everything you read.
Now , he is saying I need to take it to Focus dealer for them to check software, all seems like poor product design/execution.
Thinking maybe should sell it and upgrade to something bit newer, maybe a Bosch gen4.

 

[Shorty4]

Mine did that initially when the new battery was fitted , check the contacts on both the short connecting cable and the socket on the frame on the bike. If the little ones are dirty it can't "see" the TEC battery.

 

[simono]

Mine did that initially when the new battery was fitted , check the contacts on both the short connecting cable and the socket on the frame on the bike. If the little ones are dirty it can't "see" the TEC battery.

Thanks, I did look at them and cleaned them with contact spray, but will check again

 

[steve_sordy]

This sorry saga, informs me that no matter how much I love my bike and want to keep it, I must keep my eye on spares availability for the battery and motor. I do not want to end up with an unusable bike just because I can't get a battery or a motor for it.

 

[Shorty4]

Steve I agree completely, I still use my Jam, it's now 7 years old and still working well but yes the battery situation is the biggest threat to it being parked permanently. My wife and I also have a Focus Thron2 each which we use for road, bike and rail trail rides and they have Bosch motors with easily detached bosch batteries which are common across most bike manufacturers as I have been told that Bosch will only supply motors with their batteries.
My early Jam has a Shimano motor and a battery which is made by Focus specifically for that bike which isn't a great idea.

 

[steve_sordy]

Steve I agree completely, I still use my Jam, it's now 7 years old and still working well but yes the battery situation is the biggest threat to it being parked permanently. My wife and I also have a Focus Thron2 each which we use for road, bike and rail trail rides and they have Bosch motors with easily detached bosch batteries which are common across most bike manufacturers as I have been told that Bosch will only supply motors with their batteries.
My early Jam has a Shimano motor and a battery which is made by Focus specifically for that bike which isn't a great idea.

I had a Focus Jam2 9.6 NINE. It was my first ebike and I bought it new in Jan'19. I sold it in Jul'21 with 3100 miles on it. It was the pandemic and I got a great price for it. I also sold the guy the TEC pack for a good price too. The guy wanted to use it for commuting in London. I had two tyres suitable for road that I could have sold him, but I didn't want to put him off. I had already told him that existing tyres were grippy and for MTB. I loved that bike and I would have kept it, but I needed the money to buy my next bike the Merida eOne Sixty 9000. Still got that after 4 years. Must check motor and battery availability!!

 

[Shorty4]

I forgot to add that my Jam now has just under 10,000km of mostly cross contry single track use, the wife's Thron just over 3.000km and my Thron just over 9,000km.