I haven't had any luck trying to reach Tom but yao was kind enough to help me further but now it's Tom's move again to help me getting a new BMS as it could be the problem.
The cells can't be faulty if the fully charged voltage stays the same even when there's a range decrease or capacity decrease.
So the only part of my ebike that hasn't been damaged and repaired was the bms and yao thought the fets were worn out or something like that, com'n Tom help us.
Sincerely Hardcore
My SLA's were rated to do 300 cycles at 100% discharge. Except I only used 50% on my rides so they were rated at 600 cycles at 50% dod..
I got 6 mths out of my SLA's because I ride a lot.
How old are your batteries hardcore?
http://electricbicycleconversionkits.net/2010/02/battery-comparison-lithiummanganese-oxide-limn2o4-lithiumnickel-oxide-linio2/"
In the last blog we compared LFP and LCO batteries based on some basic specifications. Here in this blog, we will compare Lithium-manganese oxide (LMO) and Lithium-nickel oxide (LNO) batteries according to the same specifications.
Even though LMO battery has somewhat lesser power and weight density, they have low operating cost in the long run. On the other hand, LNO will cost you more. In other words, LMO is more economical than the LNO battery. But when the operating temperature rises beyond 50 degree Celsius, LMO battery starts decaying and that too at extreme rate. Even though LNO battery has some disadvantages associated with it, it will work smoothly in temperatures ranging between -20 to 55 degree Celsius!"
Everything I find is that the LiMn2O4 has a cycle life of 500 cycles at max dod.
There could be something different happening with your batter. GM's specs on the site maybe exaggerated as there is no mention to what level these packs packs are rated at, if you don't discharge to max they may last 800 cycles.
Maybe GM should not have put a 1 year warranty on these packs. I know the LiMn2O4 would be lucky to last me 8mths tops, if that. So really for me expect this chemistry could last me a year would be a big ask.
You maybe different with you riding habits. I just ask people to consider how much use and how hot there packs could of been at any time. Maybe GM should re assess the rating on the GM battery.
Maybe they need to advertise better specs. Like, 1 year warranty or 800 cycles at 75% or 500 cycles at 100% dod.
I'm thinking I will give the GM packs a miss to be frank and build my own pack from A123 batteries.
http://cgi.ebay.com.au/8-A123-systems-NEW-2009-26650-Lifepo4-battery-cell-2300-/190422048004?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item2c5609dd04100% New A123 3.3V 2300 Li-Ion ANR26650M1A Battery
Nominal Capacity: 2.3AH/PC
Nominal Voltage: 3.3V
Internal Impendence: 8 m? typical
Recommended Charge : 3A to 3.6V CCCV 45min
Recommended Fast Charge: 10A to 3.6V CCCV 15min
Max Continuous Discharge: 70A
Max Peak Discharge: 120A
Cycle Life at 10C discharge: 1000+
Weight: 70 grams
OMG lil lifepo cell giving up 70A continuous. If you want quality LiFePo4 cells, you pay through the nose. GM cells are cheap and priced this way.
I start to purchase 8 pcs at $78AU a week from today, maybe 6X8 cells welded into 18.4ah 3.3v blocks a month. so its going to take me 3 month, I hoping 2 months.
The total price will be $1248 for a 18.4 ah pack. This will not include the battery box and
BMS.
Is GM selling a bad pack, I think not. It cost me $440 for SLA's that last less than a GM pack and I get no battery box with the SLA pack.
I will say that these packs are not LifePo and not like the A123 cell that costs you up 4x the cost of the GM cells. The GM packs are good for light average use.
For me the GM pack is not going to be good enough and I find myself looking at the better cells when I calculate what I want from my pack.
