Here is the inside of the focus jam2 battery , may be of interest to some people. Some corrosion starting in the last picture.

ottoshape

Well-known member
Dec 19, 2018
149
58
Right Here
Ride
???
Kinda looks more like dirt/trail munge than corrosion when compared to the color of the foreign material on the plastic connector. How far has this battery traveled?
 
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Russ

Newbie
Feb 10, 2019
26
3
Perhshire
Ride
Focus jam 2
No it's corrosion, like the green verdigris you see on copper pipe,
Maybe due to flux residue , but the case was distinctly damp inside, case very well sealed, and very difficult to get apart!.
There are 41 volts sitting in those cells but the faulty battery management systems won't let them out!
The battery has done 136 miles
Russ
 

Mabman

E*POWAH Elite
Feb 28, 2018
276
223
Oregon USA
"but the case was distinctly damp inside, case very well sealed,"

Simple condensation issue due to atmospheric conditions. When the battery heats up during use and then cools down some moisture will occur, albeit a relatively small amount, that will build up inside the casing over time especially if the case is very well sealed and no way for any escape via air flow.

Notice that the new Haibike flyon has an actual air duct built into the system. Not only to evacuate heat build up but also the effect your battery has.
 
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Russ

Newbie
Feb 10, 2019
26
3
Perhshire
Ride
Focus jam 2
"but the case was distinctly damp inside, case very well sealed,"

Simple condensation issue due to atmospheric conditions. When the battery heats up during use and then cools down some moisture will occur, albeit a relatively small amount, that will build up inside the casing over time especially if the case is very well sealed and no way for any escape via air flow.

Notice that the new Haibike flyon has an actual air duct built into the system. Not only to evacuate heat build up but also the effect your battery has.
Yes I agree it's probably condensation, still hardly an ideal situation for delicate electronics .
Russ.
 
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Eckythump

Well-known member
Founding Member
Jan 16, 2018
831
93
North Yorkshire
Were there any screws lurking under any stickers? I tried to take mine apart the other day when I had some issues after the bike had been washed upside down.
The battery case has cracks radiating from where the retaining bolts pass through it so I wanted to check for water ingress.
After taking out the 8 obvious screws I couldn’t tease it apart with the usual electrical casing tools.
 

Russ

Newbie
Feb 10, 2019
26
3
Perhshire
Ride
Focus jam 2
Were there any screws lurking under any stickers? I tried to take mine apart the other day when I had some issues after the bike had been washed upside down.
The battery case has cracks radiating from where the retaining bolts pass through it so I wanted to check for water ingress.
After taking out the 8 obvious screws I couldn’t tease it apart with the usual electrical casing tools.
There are only 8 screws, but inside the case there are 5 internal clips down each side
You will need a stout screwdriver to pry and twist at the same time, it's very difficult! You'll here cracking noise as clips separate.
Not really supposed to come apart I guess. My new battery now ordered 😀 two week wait though😞.
IMG_20190223_180800.jpg
 

shreddr

Member
Sep 21, 2019
4
13
NJ
Ride
Focus Bold2 GravEl,
Is there any way to hot rod this battery, can you swap out cells to get longer life, or could you wire in extra cells outside the case?
 

sdcoffeeroaster

Well-known member
Jul 22, 2018
118
78
San Diego, CA
Ride
Focus
Really great pics Russ. How about some showing the clip pairs and how they snap together. Also some detail about where they are exactly might be valuable, telling us which direction to pry to best get them apart since this is our one opportunity to see the battery up close. Do you think this battery could be rebuilt if the board is OK? Those LG cells are about $5. online and you would need a welder. I know there is a place up in LA that specializes in re-building ebike batteries.
 

towzer

Well-known member
Aug 31, 2018
18
53
Oxfordshire
Ride
Scott e-spark 710
Hi, can you take the battery out easily - ie currently have an external Shimano 8020 so battery lives in house and is charged in the house, so can you do that with the focus and if so how much hassle is it, ta
 
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Peaky Rider

E*POWAH Master
Feb 9, 2019
417
193
Derbyshire Dales
Ride
Spectral On 6
Hi, can you take the battery out easily - ie currently have an external Shimano 8020 so battery lives in house and is charged in the house, so can you do that with the focus and if so how much hassle is it, ta

No, you have to take the motor out to remove the battery. Not a particularly onerous task but certainly not quick and easy.
 
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towzer

Well-known member
Aug 31, 2018
18
53
Oxfordshire
Ride
Scott e-spark 710
No, you have to take the motor out to remove the battery. Not a particularly onerous task but certainly not quick and easy.
Daggnabit, really like the lightness of them but I also really like being able to remove the battery(house, hotel, motorhome charging), I see the later Bosch ones appear to be removable but you loose the weight advantage ............ ho hum
 

Russ

Newbie
Feb 10, 2019
26
3
Perhshire
Ride
Focus jam 2
Am I the most unlucky focus jam owner ever?
After my original battery failure at 136 miles new battery ordered and all going well until yesterday.
Guess what, new battery has went tits up at 525 miles!! Same symptoms as before, bike will not switch on or charge, charger fine and all wiring fine.
Am not taking this one appart , hopefully get a warranty claim.
Interesting this battery has developed stress cracks around various casing screw holes.
Talk about a love hate relationship!! ( Hate bike at the moment).
 
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sdcoffeeroaster

Well-known member
Jul 22, 2018
118
78
San Diego, CA
Ride
Focus
Am I the most unlucky focus jam owner ever?
After my original battery failure at 136 miles new battery ordered and all going well until yesterday.
Guess what, new battery has went tits up at 525 miles!! Same symptoms as before, bike will not switch on or charge, charger fine and all wiring fine.
Am not taking this one appart , hopefully get a warranty claim.
Interesting this battery has developed stress cracks around various casing screw holes.
Talk about a love hate relationship!! ( Hate bike at the moment).
So sorry to hear about your luck with the batteries. Not sure what could be going on here. I'm assuming the wheels all turn freely and you're getting a decent amount of mileage out of the battery initially, which would indicate normal current draw. Could the fault lie with the charger? If not then that either means some bad batteries are out there or there's some issue with the motor overloading the battery (should show up in reduced range I would think).

On another subject my dealer just received my warranty carbon frame from Focus. The decals all "checked" and look terrible. The frame is complete with rear stay and all bearings all installed so the main issue will be battery and motor removal and wiring routing. I'm doing this myself since I trust "me" to get it done right and dealer wanted to charge me $240. I would have done it myself since I don't see it being that difficult except for those two items above and the wiring. Are there any "pointers" you would care to share? Thanks.
 

Russ

Newbie
Feb 10, 2019
26
3
Perhshire
Ride
Focus jam 2
Bad battery agian , everything else is as it should be.
Am dying to take this one apart but resisting as under warranty.
Not impressed with the cracks in the casing radiating from the screw holes,
Clearly been overtightened at factory, god knows how much water has potentially found its way in .
15758770398881578202376.jpg
 
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mtbphysics

Newbie
Mar 13, 2019
8
1
Georgia, USA
Ride
Focus Jam2 27.5+
I happen to have an extra integrated battery (out of an decommisioned Focus Jam2) that I would like to convert to use externally on my Focus, anyone have an idea on how to convert it to use externally? It would have to have a wire harness to mate with the bike and the charger obviously. I would carry it in my backpack to extend my rides. Is this even possible? Any thoughts would be appreciated.
 

Gspot

E*POWAH Master
Jul 28, 2019
53
118
NW
Ride
Cannondale Kinneto
Could someone post a pic of the battery label please
 

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