Jam2 Not Switching On - Battery BMS or Charger?

[andydurrant]

Hey all,

Got an issue with a 2019 Jam2 not powering on, either with tec pack or without.

Lots of forum research suggests either battery dead or possibly issues with charger....

Summary:

• Jam2 not powering on, occasional glow of the switch but other than that dead
• Came with a 4.5A charger
• Charger works fine on tec pack but plugged into bike it does the green blink and red lights many other users report
• Stripped the batt out, belled off all wires to check circuits sound, appear all good
• All connections sound, no dirt, grime or water ingress
• Stripped case off internal battery, again all sound, no signs of leaks or cracking or corrosion.
• With batt case off (so can get visual on pcb), plugged in, upon button press get a flashing blue light at the 60% marker on the pcb, and then no change on the second press.
• All the time on the pcb on the internal battery have a tiny green blinking led

That's about where I'm up to. Any advice would be massively welcome, and also any pointers in whether it could be a charger issue and finally if anyone is local to Cheshire and has a 4A charger could borrow for hour to check it!

I'm trying to avoid just dropping 600 for a new battery and finding it's something else!!

Cheers

Andy

 

[Mikerb]

I do not know the set up on your bike so this may be of no use to you!!

If the charger works OK well one battery but not another it suggests the charger is OK
So the problem lies with either the internal battery or the connection from the internal battery to the charging point on the bike.
Does the internal battery have a charging point on the battery itself? If so does the charger work when plugged into that?
If it has that facility, and that works OK, that rules out a fault in the battery
If not, there is probably no way to narrow the fault down to either the battery or the battery connection to the charging point, other than trying another battery borrowed from another Jam owner or a LBS, just for the test.

Given the part of the circuit subject to most use is the charging point I would be inclined to focus on that initially. Maybe remove it from the bike so it can be used to plug the charger in but be easier to check for a poor connection.

 

[steve_sordy]

This is a long shot as you have probably tried this already, but worth a mention.

My 2019 Focus Jam2 would not switch on. The trail head was very close to a bike shop so I took it there. The tech guy had never even seen a Jam2 before, but he did what he called a "hard start" that he had seen work on other e-bikes. He pressed the start button and held it for what seemed like ages but was probably less than 15 seconds (I wasn't counting). The bike came on and I have never had a repeat of this problem.

 

[Mikerb]

This is a long shot as you have probably tried this already, but worth a mention.

My 2019 Focus Jam2 would not switch on. The trail head was very close to a bike shop so I took it there. The tech guy had never even seen a Jam2 before, but he did what he called a "hard start" that he had seen work on other e-bikes. He pressed the start button and held it for what seemed like ages but was probably less than 15 seconds (I wasn't counting). The bike came on and I have never had a repeat of this problem.

I would think that is a reset procedure for your particular bike rather than a "hard start". Worth a try!!

 

[steve_sordy]

I would think that is a reset procedure for your particular bike rather than a "hard start". Worth a try!!

It may by chance be the reset procedure. But it wasn't in the Shimano manual I have and the tech guy was just chancing his arm as he had seen it done on another e-bike (probably another Shimano motor, now I come to think about it).

 

[andydurrant]

Tried the hard restart thing after seeing it on here in previous threads. Still no luck.