Jamie... You should probably note, that the cells I am using, and have been using all along, are the green sleeved ones, all premium grade A123 cells... Ie even those have measurable vairances, and the main reason I match them up is that I'm a bit ****...

The second reason is that it helps avoid the problem you had with one cell going dead if you run the pack down to dead flat... That cell was most likely the weak one and the other cells kept pumping juice through it once it was dead, reversing the cell polarity, and presto! Dead cell...

 

Actually uchi, they are a bit larger than AA cells... Closer to C cells in width but longer... Actually if you are a smoker, a good reference is a standard BIC lighter... It's about that long and roughly the same width as the widest part, but round...

It's been discussed... But you get the short version...

Ther are NOT remotely the same as the one's in your cell phone... But there are some similarities...

As long as you charge them in the bike, they will never start to "fade" (within their lifetime 2000+ cycles)... But involve a charger and they will fade pretty quick... Chargers try to be smart, and since they don't understand this type of cell, they just outsmart themselfes and damage the cell...

And the dumbest thing anyone can do to one of these is to try to use a "Battery Tender"... That really screws them up... Hence why I recommend to unplug them...

If your bike isn't drawing any juice while off (no watch, or whatever) than by all means leave it plugged in... If the bike is sitting a week or month in the summer, and you have no watch, leaving it in is fine...

But slowly discharging the battery over a month or two with a small draw is stupid, when it takes 30 seconds to pop open the seat and disconnect that Anderson connector...

Also in my winter garage it can get down to low temps, and if you store this battery at room temp it doesn't self discharge (below freezing it does), so when I started my bike for the first time this spring, I just took the battery out of my lid (hanging in my hall closet) where I left it last fall, plugged it in and pressed the starter... No charging first...

A lead battery needs tending, this needs you to leave it alone... Opposite principle...

Same applies for R/R failure... A lead battery boils over if the R/R overvolts it, and keeps going a while if given undervoltage... The LiFePo cells "dies" and needs recharging pretty quick with undervoltage, and copes with a decent amount of overvoltage before they complain... And if you look at a recent thread from 99forde, you might think the LiFePo is more violent, but they are actually less violent than a lead battery once they do go "poof"... But yeah, abuse them enough and they do, like all batteries...

I have been riding almost daily for two summers, some 1900 miles with my pack... And it's like new... My best guess is that it will at minimum last the same as a good Yuasa battery and at best keep going 2-3 times that...

 

uchi... Size reference... One AAA, one AA, a LiFePo4 cell and one BIC...

 

I understand it if you do more than one pack for yourself. But shipping costs from OMG are for free what makes some difference, and the rest is reasonable extra fee for quality of cells, I don´t plan to buy more.

 

Ah, my apologies. For some reason I thought you were using the white ones. Considering what I did (it was an accident) to my pack I'm not even sure the green ones would have survived! It was left with a small drain on it for three months straight. Oops. Oh well, it's working again and seems fine. That said, I still moved it over to a less-demanding CBR600RR application.

 

thanks for the clear write up and pics tweety. had i known about this before my last battery died i would have gone this route. being that its a yuasa its bound to explode mid season again so ill get a hold of you for one of those im sure, lol

 

I hope that I have not given anyone the impression or misinformation that the Lipo4 batteries explode or are unsafe. I thought that I had actually tried to promote and prove the exact opposite in my long discourse. Having viewed failures of each, the Lipo4 battery tends to make a lot of smoke and melt, whereas the Lead Acid battery will blow the entire top off, effectively covering anything within range with acid.
I don't know if anyone has been following the updates I added at the end of that thread, but a likely (since I do not know for sure) cause of that battery failure could actually have been assembly. Shorai used thin spacers between the layers of media in the small case size. It was actually possible during assembly to damage this thin spacer enough that the layers could actually touch, or, with a little heat touch. Since the Lipo4 batteries do not take overcharging well, a marginally operating thyristor R/R, with fatigue high resistance and slow cycle times could easily have allowed an overcharge condition that could have either caused or greatly contributed to that battery failure. Shorai is implementing changes in production right now to cure this issue. See the other post for more information on thyristor vs. MOSFET regulation,additional Lipo4 trivia, as well as for information from David at Shrorai itself. Not only is Shorai improving the battery structure, but they are also integrating overvoltage protection that will prevent overcharge concerns.

Interestingly enough, though, Shorai actually recommends storing the battery in the refrigerator during periods of inactivity. At low temps the charged Lipo4 batteries slow down, greatly accentuating the natural slow discharge rate of these batteries. Of course they stress, as has nearly everyone here, to keep parasitic loads to a minimum for extended periods of inactivity.


Oh, and I have no idea why I call them Lipo4 either....I am sure you all understand what I mean....

 

Bingo! That's exactly what happened to mine.

 

any idea if these are worthwhile.

Where are people sourcing the a123's lately?

any thoughts on these http://www.batteryspace.com/LiFePO4-...minum-Box.aspx

 

Found a couple sources that seem to provide some batteries, one of them is still omg battery as mentioned earlier. OMG seems to say that their batteries are no longer the true a123 product.....?

any thoughts on these?

A123 System High Power Nanophosphate LiFePO4 26650 Rechargeable Cell: 3.2V 2500 mAh, 120A Rate, 8.0Wh

High Power LiFePO4 26650 Rechargeable Cell: 3.2V 2500 mAh (40A Rate, 8.0Wh) --- UN38.3 Passed

A123 System High Power Nanophosphate LiFePO4 18650 Rechargeable Cell: 3.2V 1100 mAh, 30A Rate, 3.52Wh

8 Pcs High Power LiFePO4 26650 New Cell A123 26650 Replacement | eBay

8 Pcs New Arrival LiFePO4 Rechargeable A123 Systems Original 18650 Cells | eBay

 

It certainly would do the job. No way to know what's inside and how it's constructed. The aluminum case bothers me, but is most likely fine. There is a typo on one of the dimensions, 97mm is 3.8" not 2.8".

 

The price on the ebay 26650 cells is good and would make a very decent battery pack, if the cells are well made.
At that price I just might give them a try.

 

Exactly what modifications does this mean? A 12V Zener diode instead of the 11V?

 

Yep

 

Hi, I've upgraded my bike with several items. Two of them being the battery and R/R.
Fist attempt, 8 A123 26650 copies from KOK. Internally I wired with 12 AWG and single 10 AWG from main out to ground and start relay,
It pulled the starter but it was draging on, hesitating. I used it for few days but starting got more troublesome not less. Finally I took a closer look and found that the voltage whne cranking over, or trying to was way low. At that time the cells were probably already badly damaged. I had trouble getting it to cranc over when cold and voltage dropped all the way to 4V when trying to start. I did some research and found that starter currents can be over 200Amps at peak. Starter motors are typically rated to handle more than 300 amps peak at standstill. I rewired my battery pack but the damage was already to far gone.
As I discussed this with a couple of neighbors this weekend one of them said he had some light weight battery packs for emergency power to radio/television ground transmitters. I looked at then and got very curious: A123, 4.6 Ah, 12V LiIon was among the writing on the side. With permission and split one of them and they were packed with eight A123 26650 cells and a circuit board. He got loads of them and access to many more as these are replaced on a fixed schedule.
I got another pack, got some copper rails (used for connecting several circuit breakers in row) Connected 12 cells (6.9Ah) with the copper rails, and connected the mains to 16mm2 (6+ Awg) Battry cables. This time there were no doubt. When cranking over I got minimum 10V at the indication light (probablt 11V at the battry), fast cranking and immediate fire.
Lesson learned; read all posts and do your own research. Not every ting on the net is 100% correct.

 

I also had some troubles with real A123 cells i had a home made pack of 8 cells, exactly wired like all my old Nickel metal Hybrid packs but i may have put to much heat on 1 cell because after awhile with full draw off the lights and everything it would cut out.... it would start just fine and fast to, i now have 2 R/C cars zippy packs from Radio Control Planes, Helicopters, Cars, Boats, FPV and Quadcopters - Hobbyking and they dont have as much burst/peak power as the A123 but it does the job perfectly... balance leads alreadt attached, i get a minimal of 12,8 volt even on cold starts, but i also ditched the standard battery terminals for 8mm gold plugs