Hey folks - Focus Jam2 battery issue (2018)

[Gonzo79]

Just wanted to say hello from Scotland.

Interested to know if there is any experience of rebuilding batteries or retrofitting a new battery and BMS into an existing housing?

I have a Focus Jam2 (2018) with a defective and totally dead battery and from what I can tell it is impossible to replace the cells in it as the BMS needs to remain powered (how this is ever built from scratch is a mystery then).

Any help / guidance is greatly appreciated.

 

[Paulquattro]

Hello
And welcome to the forum

 

[Trots55]

Just wanted to say hello from Scotland.

Interested to know if there is any experience of rebuilding batteries or retrofitting a new battery and BMS into an existing housing?

I have a Focus Jam2 (2018) with a defective and totally dead battery and from what I can tell it is impossible to replace the cells in it as the BMS needs to remain powered (how this is ever built from scratch is a mystery then).

Any help / guidance is greatly appreciated.

Need to replace my battery finally so I'd be very interested if there are any tips for doing this. I've read that it's getting the new battery in without trapping some of the wires that's the trick so any top tips would be very welcome!

 

[Peaky Rider]

Several recent threads on here about battery failure/replacement. It is fiddly rather than technically demanding and keeping the cables and hoses out of the way, especially when finally fitting the bottle bracket/clamp, is the tricky bit. Take note of where the cables run as you remove the old battery.
Best done with the bike upside down and the electrical connections plug in place and used as a grip.

 

[Trots55]

Several recent threads on here about battery failure/replacement. It is fiddly rather than technically demanding and keeping the cables and hoses out of the way, especially when finally fitting the bottle bracket/clamp, is the tricky bit. Take note of where the cables run as you remove the old battery.
Best done with the bike upside down and the electrical connections plug in place and used as a grip.

Thanks for that. Patience will be the order of the day I’m thinking… not always my strong point!

 

[Gonzo79]

Just to state that I have been able to get my old battery working again by cracking open the battery (carefully) and pressing a reset button on the PCB. The battery had gone into a protective mode and wouldn't charge until this was done.

 

[Peaky Rider]

Just to state that I have been able to get my old battery working again by cracking open the battery (carefully) and pressing a reset button on the PCB. The battery had gone into a protective mode and wouldn't charge until this was done.

That's good news. When my Focus battery threw a wobbly I tried the reset button but it didn't work for me.
You have to question why Focus make this operation so difficult and once you have 'cracked' the battery open it will be more vulnerable to water damage.
On my Trek Rail there is a small hole in the cover where you can reset the system by inserting a cocktail stick.

 

[Oly]

I have a 2017 Bold. Never had a problem until Christmas time and couldn't get it to power up. figured I lost the battery. Sent it to Ebike market place in vegas to be rebuilt but that was a bust without them having the bike there....wish they would have told me first. Thinking it is a bad BMS because all the cells were ok. However, my tec pack will power the bike up. I Hate to spend $900 on a 378whr battery here in the US. Really bums me out how quickly manufactures leave you behind these days. Just 5 years old and my bike feels like a relic with no one around who can work with the BMS without special software that no one has. There is another company who rebuilds batteries called FTH power in los angeles but they are stuck regarding the focus proprietary battery software as well. Anyone have any idea's to keep it on the road? Maybe I should try the reset button?

 

[Oly]

Several recent threads on here about battery failure/replacement. It is fiddly rather than technically demanding and keeping the cables and hoses out of the way, especially when finally fitting the bottle bracket/clamp, is the tricky bit. Take note of where the cables run as you remove the old battery.
Best done with the bike upside down and the electrical connections plug in place and used as a grip.

You still have your focus? I feel stuck with mine even though I really like it. My battery cells are good but won't power up thinkig bad bms. the cost here in California is about $900 and can't find anyone to rebuild with all the proprietary software needed. You think it is worth putting a new battery in at $1000 plus instalation or should I consider parting out and buying something new. Mine is a 2017 bold 29er hardtail.

 

[Peaky Rider]

Yes, I still have my Focus Jam 2, although it is no longer my main bike. It is still a great bike and it is only the size of the battery that limits it.
I bought my replacement battery from the local bike shop about a year ago and it cost £520, around $650. Unusual for stuff to be more expensive in the US than the UK.
Your Bold is no good without a battery, it just depends how much you want to ride it again.