a123 or lipo.... and other ?s

[MetalMan]

Originally Posted by BrianG

The only bad thing about the lipodaptor is that it stops the charge as soon as it sees the 3.6v/cell peak, which would be the very end of the CC phase of charging. You'll lose whatever the CV stage would put into the battery. It's not much by comparison, but if you're using 1p A123s with fairly low 2.3Ah runtime, it could make a difference...

Personally, I'd do the manual CC mode thing MetalMan suggested. It just involves you to watch it carefully and make quick adjustments quite often. Also, this assumes your charger will let you adjust the charging current on the fly...

The CV phase on these LiFePO4 cells is rather short. At the end of the charge (3.50-3.60v) the slope of the voltage increases (thanks to the ICE I can see this). If you didn't stop them at 3.6v, you'd notice that the slope of the voltage continues to become greater.

Originally Posted by Scoob

Got it. So the CV mode doesn't kick in untill 4.1v. It would be a lot of trouble to keep the V constant on two packs at once. I was going to run them in series for a M-truck. I'll just have to stick to lipo. Thanks.

What sort of voltage are you wanting to run? I'm charging 5s (16.5v) A123 on my ICE right now (18v fully charged).

Originally Posted by t-maxxracer32

so if i just bought a lipo dapter my ice would charge them automatically liek it does with a normal batt? how long would the charge time be?

Yep, the LipoDapter doesn't do anything until a certain voltage is reached.
Charge time depends on number of cells used and the current you charge at.

[Scoob]

[QUOTE=MetalMan]

What sort of voltage are you wanting to run? I'm charging 5s (16.5v) A123 on my ICE right now (18v fully charged).



/QUOTE]

I was thinking of running two 3s1p packs in series for 6s or 19.8V. Runtime wouldn't be very long, but with the quick recharge time, it wouldn't be bad. With such high V on a conservative setup, current draw wouldn't be so bad. I love lipo but the "run it till it dumps" and "15-minute charge" is very nice on these cells.

I'm just thinking of options for the E-Revo that I have been considering for about a year now:eek:.

[starscream]

Originally Posted by MetalMan

I agree that the SPTs are great to use, and if I had some extra cash I might have gotten them. But for me, soldering works and I know that the joints between the cells are very strong, and so now the weak links are the tabs that are welded to the cells (I soldered to these tabs instead of directly to the tabs).

However, my soldering setup offers something that the SPTs cannot offer - I can have a 2p setup where there are groups of 2 cells in parallel that are then connected in series. With the SPTs, you would have to have two groups of cells in series that are then put in parallel, which IMO, is not as good of a way to do a 2p setup. Of course if you aren't doing a 2p setup like I am (and I know you are doing a 1p setup, starscream), then SPTs would work perfectly.

As for balancing, my packs are built for this. I had read that A123 packs would come into balance better after the first few cycles are completed, and at this point my packs seem to have done that.
You would be able to balance your SPT'd A123 packs, but it would still require soldering. You would cut slits out of the plastic tubes for each cell, and then you would use aluminum flux to solder wires onto the cells.

What is the advantage of running 2P in series as opposed to 2S in Parrellel?

With my 7S setup, I am able to get 15 minutes on the track at my LHS. Given the track is small, the runtime is great for only 2.3Ah. I am considering the Xtrema charger for my A123's so I can get that extra 5-10% charge that the LipoDapter can not provide. I am still considering my options for balancing but will likely balance them one at a time every 10-15 cycles or so.

[t-maxxracer32]

so many confuysing terms.

i would be running 3s1p 2300mah in my bl rusty so how long should i take to charge it?

[starscream]

Originally Posted by t-maxxracer32

so many confuysing terms.

i would be running 3s1p 2300mah in my bl rusty so how long should i take to charge it?

It depends on the charge method and amps. If you charge in series (1P) then the CCCV method will take 15 minutes at 10 AMPS. If you charge in parrallel (2P) then the charge will take twice as long (30 min) It will take 3 times as long using 3P & 4 times at 4P and so on.

[t-maxxracer32]

well id be using the ice and i think thats maxed out at 8 amps (or i think someone said that im probably wrong though) and i will be doing it in 1p

and what if i do the lipodapter way? how long will that take?

[MetalMan]

Originally Posted by starscream

What is the advantage of running 2P in series as opposed to 2S in Parrellel?

With my 7S setup, I am able to get 15 minutes on the track at my LHS. Given the track is small, the runtime is great for only 2.3Ah. I am considering the Xtrema charger for my A123's so I can get that extra 5-10% charge that the LipoDapter can not provide. I am still considering my options for balancing but will likely balance them one at a time every 10-15 cycles or so.

Having a 2p setup versus two packs in parallel allows for easier balancing due to half as many cells to actually balance (two cells in parallel will act like one cell).