Shimano BTE8035 Battery

jonrobo

Member
Dec 11, 2019
9
3
Lemon Tree Passage
Hi, can anyone tell me if the newer BTE 8035 Shimano battery uses a better quality cell?
As the Shimano battery, I have had in my e bike in the last year has dropped percentages very rapidly.
I have compared it to the same size battery which I believe uses Panasonic cells in Giant ebikes the percentage drop rate is very minimal and they get a lot more Kilometers with the same weight rider and eco setting.
 

Growmac

Well-known member
Dec 4, 2020
384
450
Wilts, UK
I have one bought in January 2020 and one in January 2021. The newer is following exactly the same drop as the older.
 

jonrobo

Member
Dec 11, 2019
9
3
Lemon Tree Passage
Thanks, I will hold back was about to purchase another, it's a shame Shimano won't allow you to repack their batteries there are far better cells on the market eg Samsung, LG, Panasonic the BMS stops you from doing this, or maybe someone out there knows how to reprogram the BMS?
 

jimbob

Active member
Aug 3, 2020
520
432
East UK
Thanks, I will hold back was about to purchase another, it's a shame Shimano won't allow you to repack their batteries there are far better cells on the market eg Samsung, LG, Panasonic the BMS stops you from doing this, or maybe someone out there knows how to reprogram the BMS?
Do you know for a fact you can't re-pack the cells, or is that just an assumption?

When I had a quick look inside the battery it didn't look too difficult to repack from a physical point of view, and was something I was planning to do once the battery is knackered.
 

jimbob

Active member
Aug 3, 2020
520
432
East UK
Thats a great shame. What are the symptoms? Does it just refuse to turn the FETs on, or does it refuse to charge as well?
 

jonrobo

Member
Dec 11, 2019
9
3
Lemon Tree Passage
Battery light flashes yellow not green when plugged into charger and battery error comes on bike when installed...packing was done by a proffessional and we have rang shimano they have made there system to talk to each other battery..to . motor same with bosch and all of the larger part manufacturers.
Apparently illegal says most battery repackers but big money to take them to court
You will prob find some company's over in Europe or Usa even New Zealand that can repack Shimano batteries and some of the smaller bike companys have Shimano motors with there own batteries they must have program to marry there batteries with Shimano motors.
 

jimbob

Active member
Aug 3, 2020
520
432
East UK
Thanks. What a great shame.

I'm amazed that they went to the effort of designing a system to stop you re-celling them. I just can't imagine that many people would want to do so.

I'm guessing that's the first shimano battery they tried if it didn't work at the end?
 

Spiff

Active member
Feb 27, 2019
448
262
Earth
It is not known if the problem is low quality cells or bad design of the BMS. It could be that BMS is doing something wrong during battery charge and cell balancing, and it is damaging the cells, independently of their quality.

As FW can not be upgraded in Shimano battery, then the problem might be forever.

It is a pity that instead of fixing the issue in newer versions of the battery, Shimano is wasting efforts in denying warranty claims, removing battery diagnostic in etube, doing EP8 FW upgrades that "change" the battery health % reported by the battery to a better % health . All this to "hide" the issue instead of fixing it.
 
Last edited:

1oldfart

Active member
Oct 6, 2019
684
321
Outdoors
It is a no brainer, they want captive clients.
Let say Norco or some other make a frame for Shimano they are stuck, cannot change.
All the in frame batteries is a way to limit users from shopping around.
From all i read no Shimano for me until they change.
 

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