yxan
Veteran
I was curious if anyone here has bought or assembled for use as a starter battery?
I was thinking that this would be the ultimate low maintenance battery option and wicked weight savings, prolly 1/3 of a Yuasa ytz7s battery.
I was thinking that this would be the ultimate low maintenance battery option and wicked weight savings, prolly 1/3 of a Yuasa ytz7s battery.
Northernboy
Pro
It would be alot lighter, would have to be quite a few cells and the charging system would have to be modified. I special charger would have to be designed. I have some experience with them in RC planes and they sure are powerful & light, the other problem is they don't like the cold. Usually freeze batteries to keep them from self discharging.
IFlyEm
Expert
I am pretty sure that the A123's have an extremely low self discharge rate. I know the LiIon and Lipo's will only lose about 2%-3% over a year if left untouched after being fully charged. The benefit of the A123 is that they can support a huge draw as well as a huge charge rate.
NyTrOMaNIaC
TY 4 Stroke Master
yxan said:
Well the 7s is already extremely light @ 4lbs, and there's guys who have run into problems with these running down in extreme cold, so personally, I wouldn't push it anymore. I run the 7s myself and haven't had any problems with starting my sled, but I don't leave my sled outside in cold either.
yxan
Veteran
NyTrOMaNIaC said:
I have used the 7s many years on my motorcycle, but I am willing to bet that lead acid technology has nothing on LI Ion. Like people have mentioned they dont loose any juice over time of sitting and if you build up a 4S2P that would give you a 4600 mAH at 13.2 volts or just keep adding parallel loops until you have mega capacity.
I know 4 lbs is light but loosing another 3 is even nicer
from what some motorcycle dudes who are deep in this stuff are stating is that you dont need to use special chargers on the a123 battery, when you set it up as a 12 volt system you can use regular car chargers, not that you ever would need to use one, unless you let your sled sit for a long long time.
twiz28
Expert
- Joined
- Nov 8, 2004
- Messages
- 236
- Age
- 54
- Location
- New Brunswick, CAN
- Country
- Canada
- Snowmobile
- 2017 Sidewinder BTX 1.75 Backcountry
2017 Sidewinder XTX 137
7s
I can attest to the downfall of the 7s, if it is colder than -20 celcius it can't turn her fast enough to start, warmer than that you are fine. I carry a small set of jumper cables to be safe.
I can attest to the downfall of the 7s, if it is colder than -20 celcius it can't turn her fast enough to start, warmer than that you are fine. I carry a small set of jumper cables to be safe.
Northernboy
Pro
I know for a fact that the charger I use for my RC A123 cells charge completely different, it will charger at a high rate until a voltage is reached and then go into a balancing mode to balance the cells. I regular charger could probably be used but the cells may not charge to thier full capacity and/or will not last long. Nomimal voltage of the cells are 3.6 volts so the system would be 14.4volts. I know there is a drag bike that runs on these cells alone, not sure what charging system they would use but it must be big. I think A123 has it on its website. Also temperature effects the output of the cells. I agree the self discharge of these cells are really low.
yxan
Veteran
Northernboy said:
you are correct for models, but no-one that has built these batteries has set them up to take digital chargers with balance ports. everyone that builds these batteries says not to use modeling chargers. I have a hyperion charger that does a123 and I emailed a builder of these batteries and he said not to use it. not really sure why they dont build them up like modeling packs with a balance charging option?
yxan
Veteran
all right thanks to some member help from this forum i got in touch with the guy at the ktm talk forum and ordered a battery into the sled it goes, I will write up a report once i get some days with it.
Northernboy
Pro
Yes please report back on they work for you. I just checked the specs on the cells and operating range is -30 to +60 Deg C, but the discharge performance drops quite a bit at -20 Deg C. If I had a couple of extra cells I would make a pack and see if it would work but I only have two free cells.
I see they have a new cell available for hybrid cars, I wonder what the specs on it is. Nothing for specs on the website but I'll do some seaching.
I see they have a new cell available for hybrid cars, I wonder what the specs on it is. Nothing for specs on the website but I'll do some seaching.
yxan
Veteran
putting a quick layer of insulation and it being behind covers and close to motor will definitely help on the low end of that temp gauge. granted ive rarely seen such cold days when i ride.
