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View Full Version : Lipos getting stronger and cheaper. Why A123?


aramsdell
12-29-2008, 04:18 PM
You may have noticed that prices on lipos are coming down. This begs the question 'Why use A123 cells?'
I haven't got long term data yet but I am really enjoying my new Zippy 'Rhino' 6S 4900 pack. It seems to hold voltage better than most and barely gets warm during a hard run. Capacity seems to be more than 4900 , according to my charger.
5 to 6 minutes of fairly hard flying on Swift with 600 + motor and 530mm blades.

So what does 12 or 14 A123 cells cost all built up? The 6S4900 is $111.00 plus shipping. That's 1/2 or less than the same size pack elsewhere. Is this making the 123's less worthwhile???
This Rhino 6S4900 is the best performing pack I have had.

nguyen
12-29-2008, 09:44 PM
A123 is more safe to handle than the Lipo.

JustPlaneChris
12-29-2008, 10:08 PM
Is this making the 123's less worthwhile???Not to me. A123s do not have to be partially discharged for storage. They can be charged VERY quickly, without a cool-down period before charging. You can drop a pack without damaging it.

Sure, they are heavier than lipos. Yes, they still cost around $15 per cell (new). But I still like them. :)

aramsdell
12-30-2008, 04:57 PM
JPChris. How many cells do you use? 10 X $ 15 = $150. a bit more than my, much lighter, 6S4900.
I did try to get some cheap 1100 mah cells at the B&Decker outlet. Seems they had been selling those little 2 cell packs for $1 ! Ran out of course. They must be discontinuing that line of tools.
I use FMA BalancePro HD 6S charger. It's good for 10Amps and will charge at 2C if I WANT to. It will charge warm batteries. It charges each cell individually. It isn't one of those with a discharger on each cell while charging so there isn't the large risk of overcharging any cell.
So far I haven't had a cell go bad from anything short of ABUSE. Overdischarging in the heli. Never had a problem on charging with an FMA charger, also have the 4 cell Cellpro A123 compatible charger. Thunder Power mini charger, my first charger, and the passive balancer, did kill a couple of packs way back when because it isn't a smart charger.
Again you could have 2 6S4900 packs for short money and get longer flights and better performance.
JMHO. Al

JustPlaneChris
12-30-2008, 06:18 PM
I use 10 cells in my Swift, so yes the current pack price would be near $150. I bought mine from eBay for ~$100 each.

My entire power system is configured for high voltage, so I couldn't just swap to 6S lipo. 8S would be more appropriate for my kv and gearing, and I have considered it. However, careful analysis of the weight of 8S 3500 or 4000 Zippy packs shows a net weight gain compared to my A123 packs (775g) so I haven't been motivated to try it just to gain some flight time. 5.5 to 6 minutes is fine for me, especially considering the 20 minute recharge times.

GyroAl
01-01-2009, 12:41 PM
Initially, one of my flying buddies configured his Swift with the 10 x A123 packs. But after seeing how mine performed with relatively light 6S/3700 packs he has regeared his for them. We found that it got better overall flight performance due to the much lighter weight, and endurance due to the higher mah relationship.

If memory serves me correctly he saved 6 or 7 oz. of weight. On a heli this size, that is a worthy sum.

And as you said armsdell - at the current costing of these packs now. He figured it was well worth it.

JustPlaneChris
01-01-2009, 01:31 PM
You guys are being enablers. Quit it! ;) :lol:

Actually, I will likely have to go lipo on my Swift anyway if I buy that Approach Cobra kit for it. I doubt the A123 packs will fit.