Searching for GP45EVLF Cells

5 posts / 0 new
Last post
Heavendenied
Offline
Last seen: 11 months 2 weeks ago
Joined: Sunday, February 1, 2015 - 08:12
Points: 89
Searching for GP45EVLF Cells

I now use my "new" Vectrix VX-1 Li+ now for about 7 weeks and drove about 800kms in this time. I bought it used and knew that there is any problem with the cells. After charging i allways have a cell drift between 20 and 100 mV, i think about 60mV in average. I have a range of 70 (at -3°C, batteries completly empty) and 80kms (at 5-15°C and 2 bars left).

But on this last ride i recognized, that only one cell is weaker than all the others (2.96V after riding, all others had about 3.16V). After charging this cell is one of the midfield (not the lowest but also not the highest voltage).

So i decided to to make this thread for searching one or maybe more "new" GP45EVLF cells. I searched the internet but i can't find these cells. I know that they are not very wide common but maybe one of you has some of these cells for sale...

I know the best would be to change all cells to better Winston cells or something like this, but as the range of my vectrix is more than enough for me and the costs for new cells and new BMS would be very high i think i should try to change this weak cell...

So please, if you have these cells or can tell me how to get one or more please tell me!

P.S.:
I'm from germany...

vectrixparts
Offline
Last seen: 7 months 2 weeks ago
Joined: Monday, March 30, 2015 - 01:11
Points: 25
Re: Searching for GP45EVLF Cells

Heavendenied

There is nothing wrong with your battery sofar. All LiFePO4 batteries, GP in particular (unfortunately), go down to 3.360 - 3.450V after charging is completed and current switched off.
When riding there always will be cell with lowest capacity / highest internal resistance / highest selfdischarge ratio - which will limit capacity of entire battery.
If you are getting 70-80km range @ temperatures around 0C - you are very lucky owner of one of the best GP batteries I've seen.
Make sure you are completing EQ on each charge and enjoy your bike.
If you have an CANBus / USB cable (it looks like you have - since you know which cell is lowest, and how it rise up in charging) - download from our website newest firmware for your bike.

If you will face any issues with battery in the future - we sell single cells and rework batteries. We are based in Wroclaw, Poland

Regards
Piotr Stec
vectrixparts.com

vectrixparts.com

Heavendenied
Offline
Last seen: 11 months 2 weeks ago
Joined: Sunday, February 1, 2015 - 08:12
Points: 89
Re: Searching for GP45EVLF Cells

Hi Piotr,
thanks for your comment. The fact that the cells are a little different after charge is the thing i don't care too much, but the weak cells while driving is the one i'm a little bit uncertain. Espacialy because it is only one cell which always has a much lower voltage after driving while after loading it is ok. The thing with the different internal restistance is one thing i already read very often, but i hoped to find a few cells with "better" internal resistance.
The lowest range i had so far was 69km and on this ride i got the battery warning and the vectrix lost the last 3 bars and stopped at neraly exact 69kms. After this i didn't drive to the last bars to prevent my batteries from damage.
What i already did after this was to buy the CANBus Cable and flashed the newest firmware (which you already send me when we wrote about my main stand order, my real name is Jürgen Edelmann) and changed the max current to 135A. I think this should help to not stress the cells too much in the future. Last time i got 80kms range with two bars left (in VectrixDiag i got 20% remaining capacity, but the lowest cell was 2.96V and dropped below 2.5v while driving, i drove with the Live Data Dash mode to see this).

If you think this "bad cell" does not do any damage to the others i think i will leave it as it is and maybe change the complete batterie pack when the range drops too much. At the moment the range is much more than i expected...

But as i need the cargo panel (i already wrote you eMail about that) if you have the GP45EVLF maybe it would be wise to order some spare cells just to be sure...

vectrixparts
Offline
Last seen: 7 months 2 weeks ago
Joined: Monday, March 30, 2015 - 01:11
Points: 25
Re: Searching for GP45EVLF Cells

Hi Jurgen
You can adjust the actual battery capacity via dashboard - to make the estimated range and battery bars accurate (I would even set one Ah less then battery gives - to be on safe side).
There is a pdf file on our website with instruction how to do it.

I assume the 69km happened also with low temperature. In the better weather you should get more juice out of the same battery.
Lower max current will help to get more from the weakest cells as well.
Even very bad / weak cell will not affect the other 39 in you pack - it will affect usable capacity (range) of whole pack, but not other cell directly.
Make full EQ as often as possible, don't leave bike with very low battery in storage, if possible charge battery in temperature no lower than 10C and the pack should be OK (at least based on what you wrote).
Selling parts including cells makes my living, so if you order cells I'll ship you, but the subject of "weak" cell/s is quite complicated.

We have spent with Matteo 2 years trying to fix the GP cells issue and the internal resistance is only one of many factors. There are variance of capacity between the cells, variance of self-discharge ratio, spread of aging speed, high current response differences etc. In last months of Vectrix we were re-matching packs based on 3 variables and these packs work well till now. It was possible because we had a pool of few thousand cells available to pick and marry together. GP cells unlike most of other on the market are build from single cells (40S1P) - most of other manufacturers put inside the can few (4-50) cells in parallel. Single cell solution in theory should be more reliable / safe but reacquires highest quality control on the production floor and precise sorting / matching. Many GP cells are simply contaminated at birth and have internal micro shortages which gets worse with aging. We are selling now batteries build from Valence cells (which supplies many major OEM - electric and hybrid buses, Smith, Segway etc) and still we decided to cycle 100% cells and rematch before assembling. We built before few packs on A123 cells and also had to rematch them. Looks like LiFePO4 is just more demanding then LiMn, LiCo, NMC etc (popularly called Li-ion) but is very safe and has much longer life. Kind of trade off.

Just after Eastern I'll do inventory of painted parts - so I should find cargo panel in your color.
Best
Piotr

vectrixparts.com

Heavendenied
Offline
Last seen: 11 months 2 weeks ago
Joined: Sunday, February 1, 2015 - 08:12
Points: 89
Re: Searching for GP45EVLF Cells

Hi Piotr,
thanks you very much for your reply and explanation! Again i have to say, that it is very good to know there still is someone who helps my and all the other Vectrix to stay on the road!
So I'll stay with these cells as long as i can and than (hopefully for me not the next years) i will change the whole pack...

Just one more question about the adjusting of battery capacity:
As i wrote the last time i drove the batteries nearly empty (2 bars left, battery warning appeared about 500m before i were at home, 20% remaining if i can believe what was shown in VectrixDiag) i downloaded the riding history and had 35,77 AmpHrs drawn from the battery. After charging there was something around 36,xx AmpHrs charged.
So do you think i should set the capacity to 36 AmpHrs or should i first do another test ride and drive until all bars disappear? (Unfurtunatly i live up on a hill, so i can't do this testride here...)

Thanks!

Log in or register to post comments


Who's online

There are currently 0 users online.

Who's new

  • Naadu_b@
  • SolarRichT
  • victoria098
  • PtheDude
  • Gilles

Customize This