Removing and repacking Focus Jam/Sam2 battery

[Danijel]

Hey Guys,

I was wondering if any of you have ever removed the internal battery of a Focus Jam2?

I would be interested i knowing if would be possible to repack the battery in the future.

Greetings,

Danijel

 

[Injidup]

It requires removal of the motor, so it will take some time, but it is possible.
You could also add the T.E.C pack.
What does repacking involve?

 

[Danijel]

Yeah i figured that out. I even removed the motor (which is surprisingly easy). But when is saw the battery including all the wires in there i decided to not remove it.

Repacking a battery means replacing all the cells in the pack with new ones. This could save a lot of money because you won't need to buy a completely new pack from the manufacturer.

At a cost of around 4 euro per cell i could rebuild the pack for around 140 euro with LG 3600 mah cells. Focus wont probably sell me a new pack for that price. I do wonder what the price for a replacement pack would cost. Can't find that information anywhere.

 

[Injidup]

Yes, very difficult to find that sort of information. I can’t even find a price for a replacement charger. I was considering keeping one at work for when I commute, but I don’t need it as I have plenty of battery left.
Apparently you should get over 1000 charges before the battery starts to lose power. I’m charging 2 to 3 times a week, so that equals around 300-500 weeks!

 

[bissona]

Removing the battery is a 2-3 min job once you have the engine off, but it can be a bugger to get back in due to the wiring loom. The battery does have a really annoying habit of catching the frame on the way out, requires a fair amount of jiggling sometimes.

We had a dead battery recently (child/sea water incident....) and the cost of replacement from Focus was around €450, so take care of them!

We also tried to break open the old battery (an electrical engineer did, at least) but it was so well caulked together than it didn't want to budge. We didn't want to destroy the case, so left as it as it was and just replaced it.

 

[OldBean]

I love my Focus Jam but this overall problem rather bugs me. Battery accessibility is my only worry especially when away from home and needing a charge.
My next EMTB will have easily removable battery...never mind the weight... ~And a gearbox
Meantime I intend to HAVE FUN.

 

[bissona]

Battery accessibility is my only worry especially when away from home and needing a charge. My next EMTB will have easily removable battery...never mind the weight...

We bought the T.E.C. packs and they work great for this scenario. Will be taking them to Spain in April to see how far they take us in a full day in the mountains.

 

[Danijel]

Removing the battery is a 2-3 min job once you have the engine off, but it can be a bugger to get back in due to the wiring loom. The battery does have a really annoying habit of catching the frame on the way out, requires a fair amount of jiggling sometimes.

We had a dead battery recently (child/sea water incident....) and the cost of replacement from Focus was around €450, so take care of them!

We also tried to break open the old battery (an electrical engineer did, at least) but it was so well caulked together than it didn't want to budge. We didn't want to destroy the case, so left as it as it was and just replaced it.

Thank you for this information. This everything i needed to know.

And 450 seems reasonable. Specialized asks around 850 for the Turbo Levo

 

[S D]

Would anyone happen to have any pics of the motor removal procedure?
Even some of how to remove the cover to check for muck ingress etc would be useful.

 

[Epic_drifter]

Would anyone happen to have any pics of the motor removal procedure?
Even some of how to remove the cover to check for muck ingress etc would be useful.

I too would like to have some detailed info about battery removal. My Jam2 9.6 carbon frame is making annoying creaking noise during driving which disappears when I loosen those 2 big battery screws a bit. I would like to take battery out check what needs to be oiled etc. to get rid of the noise...

 

[MartinW148]

Removing the battery is a 2-3 min job once you have the engine off, but it can be a bugger to get back in due to the wiring loom. The battery does have a really annoying habit of catching the frame on the way out, requires a fair amount of jiggling sometimes.

We had a dead battery recently (child/sea water incident....) and the cost of replacement from Focus was around €450, so take care of them!

We also tried to break open the old battery (an electrical engineer did, at least) but it was so well caulked together than it didn't want to budge. We didn't want to destroy the case, so left as it as it was and just replaced it.

Do you know what size cells are in the battery?

Thinking if you can rebuild with bigger cells for more capacity (same size cells).

 

[steve_sordy]

We bought the T.E.C. packs and they work great for this scenario. Will be taking them to Spain in April to see how far they take us in a full day in the mountains.

I hope that you are driving there. Batteries of this size are not allowed on the aeroplanes.

 

[steve_sordy]

Be aware!
JE James replaced the battery on my Jam2 at the request of Focus. A month later, I got intermittent problems with the display not coming on and no power. Turned out to be that one of the electrical cables had been pinched during battery installation, damaging the wiring.

 

[bissona]

I hope that you are driving there. Batteries of this size are not allowed on the aeroplanes.

Yes, we drove! Have been down to southern France / north Spain three times with the bikes now, some great riding and cracking places to stay.

 

[bissona]

Do you know what size cells are in the battery?

Thinking if you can rebuild with bigger cells for more capacity (same size cells).

Pretty sure they’re 18650s, and they look pretty tightly packed in there.

 

[Doomanic]

At a cost of around 4 euro per cell i could rebuild the pack for around 140 euro with LG 3600 mah cells.

Where can you get those cells from?

 

[bissona]

I too would like to have some detailed info about battery removal. My Jam2 9.6 carbon frame is making annoying creaking noise during driving which disappears when I loosen those 2 big battery screws a bit. I would like to take battery out check what needs to be oiled etc. to get rid of the noise...

It’s very easy getting the battery out (20 mins careful work) but, as @steve_sordy points out, you do need to be careful with how the cables go back. The cables seem very long, and sometimes don’t want to stay in the right place when refitting the battery. A bike stand with a rotating head can help.

 

[MartinW148]

Pretty sure they’re 18650s, and they look pretty tightly packed in there.

A quick bit of Google and I can see you can get these anywhere from 2500mah to 3500 mah, with varying Amp ratings 10a to 30a. Still no idea what the standard ones are (and I am no expert) but I guess it must be technically possible to upgrade with denser cells?

 

[bissona]

A quick bit of Google and I can see you can get these anywhere from 2500mah to 3500 mah, with varying Amp ratings 10a to 30a. Still no idea what the standard ones are (and I am no expert) but I guess it must be technically possible to upgrade with denser cells?

I would probably want to speak to the designing engineer at Focus before swapping anything. I can imagine that higher rated cells have less room for expansion, and/or are designed for low loads than our bikes have. Ambient operating temperature ranges from 0C to 35C, for me at least, which would cause some concern if the wrong cells were used.

Personally, I am more interested in repacking once the cells start to die, so would like to ask the engineers what cells they would have used if price had not been an issue. These bikes will be 100% useless in the future without a viable power source, and my experience with 3rd party laptop batteries gives me the impression that this is a job best done ourselves!

 

[NickMc]

Hi, just wanting add my 2 cents because this was the only place I could find any info when I had to remove the battery from my Focus Jam2 - it and what’s here is a bit light on detail. To remove the battery, as people have mentioned, you need to remove the motor. But it doesn’t just pivot down. It looks like it should, but the motor mounts nearest the battery catch on the frame. So you have to take it right out. Good news is, it’s not too hard. You don’t have to take the cranks off and you don’t need special tools. I even left the chain on. Remove the plastic bash guard 4x torx). The 5 main hex bolts are easy but there’s a 6th which is stuck behind the chain guard so that needs to be loosened via 3 small hex bolts. If you turn it, you can just get it out without taking the guard right off. I did take the chain ring off - 4x the usual hex bolts. I also took the plastic covers off the motor but I don’t think it’s necessary, just gives the wires some play and allows you to completely unplug if you want to. With the motor free you can wrangle it around the dropper post cable and give yourself room to slide the battery out. This isn’t quite as easy as it should be. Once you’ve removed the two big hex bolts on the bottom of the downtube it should slide out but there’s a mess of wires in that tube just randomly floating around. In my case gravity wasn’t enough, it needed some coaxing. There really should be some tubing or something holding these wires to the side. And the battery would benefit from something to help you pull it out. I was tempted to make a little pull handle with tape in case I need to do this again. Anyway, my battery, like everyone else’s had a star crack around one bolt hole. It’s a design flaw. It looks bad but doesn’t seem to cause issues.
putting it back together is all the same stuff in reverse. And yes, due to those wires just randomly hanging out, you’ll need to be careful - 1) to avoid snagging, 2) not to run them along the top or bottom of the battery or they’ll be fouled by the downtube bolts, 3) you also need to remember, this is a mountain bike and if any of those wires end up in a place where they rub, one day they’ll wear through, the bike will report and error and it’ll take ages to figure out why. I didn’t have time, but maybe find yourself some cable management - those curly tubes you use to tidy wires at home or something.

 

[NickMc]

Motor not pivoting down - you can see the mounts hitting the bottom of the downtube. Not a biggie, just remove the bolts and take the whole thing out.

 

[NickMc]

See that last pesky bolt in the centre there? That’s hiding behind the chain guide mount so you need to loosen those little hex bolts and turn it - the bolt just gets past. Of course if you’re taking the cranks off and have the right tool to remove the lock ring, it’s not an issue. But if you want the battery out with the least work, and just basic tools, here’s how.

 

[rogers827]

View attachment 67618
See that last pesky bolt in the centre there? That’s hiding behind the chain guide mount so you need to loosen those little hex bolts and turn it - the bolt just gets past. Of course if you’re taking the cranks off and have the right tool to remove the lock ring, it’s not an issue. But if you want the battery out with the least work, and just basic tools, here’s how.

Hi Nick - many thanks for the comprehensive info on removing the battery. I have a friend that has the same bike & he has the dreaded E010 error. I have seen that this is often cured by cleaning the pins on the motor casing that connect to the battery. Can you say how the battery is connected to the motor on this bike? From what you say about all of the wires it sounds like there is some sort of specific plug which would be an improvment over the normal shimano steps motor/battery interface. I was hoping there may be some pins that if cleaned would cure the E010 issue. Any advice would be gratefully received? Regards Rog

 

[sdcoffeeroaster]

I would probably want to speak to the designing engineer at Focus before swapping anything. I can imagine that higher rated cells have less room for expansion, and/or are designed for low loads than our bikes have. Ambient operating temperature ranges from 0C to 35C, for me at least, which would cause some concern if the wrong cells were used.

Personally, I am more interested in repacking once the cells start to die, so would like to ask the engineers what cells they would have used if price had not been an issue. These bikes will be 100% useless in the future without a viable power source, and my experience with 3rd party laptop batteries gives me the impression that this is a job best done ourselves!

Since the Focus Jam2 just uses 3500 mah (highest rated 18650 cells) made my LG replacing with the same rating (10A) should not be an issue. Taking everything apart is the real issue. You can't use the 5000 mah Tesla 21700 cells because they just won't fit. They other issue I've heard is that the BMS needs to have voltage on it at all times or it will somehow need to be re-set or reinitialized in some way. I was thinking that if you could put another 36v source on the BMS during re-packing (re-welding etc.) that might get around this issue. 30 new cells would only cost about $150. USD. My 2018 battery is still pretty strong but someday I may either be trying to get a European company to sell me a new battery or re-packing it myself. I have made a few range extenders on my own so you really have to be very careful doing this or you'll get an intense fire. And if I keep this bike I'll need a new e8000 motor too (6k miles now). Lots to convert using the EP8 and besides there's that annoying motor rattle downhill that I could never tolerate. I rode a Fezzari with the EP8 and loved the smooth torque and mostly quiet motor but the rattle is a non-starter for me.

 

[NickMc]

Hi Nick - many thanks for the comprehensive info on removing the battery. I have a friend that has the same bike & he has the dreaded E010 error. I have seen that this is often cured by cleaning the pins on the motor casing that connect to the battery. Can you say how the battery is connected to the motor on this bike? From what you say about all of the wires it sounds like there is some sort of specific plug which would be an improvment over the normal shimano steps motor/battery interface. I was hoping there may be some pins that if cleaned would cure the E010 issue. Any advice would be gratefully received? Regards Rog

Hi Rog, yep, there's a plastic pin connector from memory - should've got a pic, but it's back together now and I can't remember the details. With the way the wires just sit loose in the downtube, they could easily get pinched, or worn so the wires short or break. The connector itself was sturdy from memory, but like any connector the pins could corrode etc. If you're getting an error and you can't work it out any other way, it could be worth pulling it all out. It wasn't that much of a chore, even without fancy tools. It would be pretty easy to see issues and come up with a bit of tubing or something to help shield the wires.

N

 

[2WheelsNot4]

I know this is about repacking but theres been a drop in replacement price of, well the 625wh anyway. For a while they were priced about £750-£770 but looking about now I see many selling at between £549-£599.
So it can only be a matter of time before that drops again, especially if the norm is for higher power - 750,800,900wh etc leaving hopefully the 400,500,625wh being least wanted and maybe therefore cheaper, maybe even as low as £300-£400 over the next 3 or 4 years.