A123 batteries

[dadnjesse]

Are 4 cell A123 batteries at 3.3 volts the same as a 3 cell Lipo.
I'm looking to run these on a VXL stampede

[_paralyzed_]

lipos are 3.7v/cell nominal, 4.2v/cell fully charged, so a 3s pack is 11.1v at rest and 12.6v fully charged

A123 as you know has a nominal voltage of 3.3v/cell, and 3.6v/cell fully charged, so a 4s pack is 13.2v at rest and 14.4v fully charged.

The esc may handle the additional voltage, in my opinion it's not worth the risk. The motor is already at it's limits on 3s lipo, and any additional voltage (more rpm) will probably kill it.

I would not run 4s a123 on a vxl system. Run 3s and just gear up for the same overall speed.

[dadnjesse]

Thanks I did try 4 cell but the esc would not run, Do I run the A123's in Lipo mode?

[x-y]

in the actually use a123 cells is not a good idea ......... exist lipos cheaper, with more cycles life, more discharte/charge, extremely more powerfull, more lighter etc etc

I recommend buy nanotech lipos ......are better in all than the a123 ...... 3s lipo have more power than 4s a123 ........

[snellemin]

I tend to disagree with the raw power of the A123 vs Lipo or nanotech.

My old drag racing GTP ran just as hard on 4s2p A123 vs my competitors that ran 6s 5000mah lipo. To safe some weight, I also ran 6s1p to make up for the voltage drop and still beat those that ran 6s lipo.

Pro's of A123:
A123 will outlast lipo.
A123 will put out all the amps your need.
A123 can handle heat and cold way better vs any lipo.
A123 can be charged in 5 minutes.

cons of A123:
Weight
Package format

[dadnjesse]

Well I have a 36 volt dewalt cordless drill and one of the batteries stopped working. I took it apart and found 9 out of ten cell where good so they where free to me.
Anyway Im still trying to find out should I run the speed controll on NIMH or Lipo

[_paralyzed_]

well, I'd start on lipo. If it behaves oddly, like starting and stopping it may be because you are hitting the low voltage cutoff circuits limit. then switch it to nimh.

If it runs fine in lipo leave it.

[dadnjesse]

That's exactlly what happened, It went to low voltage cutoff very quickly, and ran fine on NIMH, I was just worried about over discharging them.

[snellemin]

You'll know when to stop with A123. Once the car starts to slow down, you know you are near depletion of the pack.

[zeropointbug]

Well said Snell.

x-y, with all due respect, but posting not so good english on something that just isn't true, makes me think you have agenda for someone, or something, HK?

A123's are in my opinion just as good as lipo's, if not, better. The only down side compared to today's lipo chemistry is the power difference, or more specifically, punch. A123's have toughness, life, safety, awesome discharge curve, super fast end-dump, and like Snell said, can handle cold and heat MUCH better than lipo.

[x-y]

Originally Posted by zeropointbug

Well said Snell.

x-y, with all due respect, but posting not so good english on something that just isn't true, makes me think you have agenda for someone, or something, HK?

A123's are in my opinion just as good as lipo's, if not, better. The only down side compared to today's lipo chemistry is the power difference, or more specifically, punch. A123's have toughness, life, safety, awesome discharge curve, super fast end-dump, and like Snell said, can handle cold and heat MUCH better than lipo.

I had +40 a123cells ..... and I used many years in my rc cars ..... If I explain the nanotech are much better in all aspects is simply because is my experience with this batterys .......

¿why you think I sold all my a123 cells/packs after test the nanotechs few months? ....... simply because are MUCH better ....... more powerful, more lighter, cheaper, and have the same life than the nanotech lipos ....

[pinkpanda3310]

I have had similar experience to snell. I have run 2p A123 on old cells and they took an absolute beating and came back for more.

[x-y]

for the a123 is recommendable use a cutoff of 2.5-2.6v/cell ........ without cutoff you shorten the life of the cells .......

[zeropointbug]

....and. You can run A123's to 100% DOD everytime buddy, no exceptions. You do not need to use a cut-off, you simply stop running when you notice pack dumping, which happens pretty quick. I was the FIRST person on this forum to run A123 cells in a large 1/6th scale RC back in 2006, and whaaaa, those cells are still working?! yup. 90+% of original capacity, and 100% of original performance.