Who using A123 batteries?

[hybris]

Please post any comments or experience. I am interested in unregulated use on both receiver/servos and ignition.

[madmax]

watching attentively. Very interested in this as well.

[felker14]

Where can the packs be purchased?

[klhoard]

The best place for A123's is to get on eBay and purchase a DeWalt 36V pack. You will get 10 cells and then you can make up your own flight packs.

I have (2) 2-cell and (2) 3-cell packs. I use them in an RC car and in a Mini-Inspire. The EagleTree data logger shows me pulling 30-40 amps for the whole flight and the cells don't even get warm. The also hold their voltage very well thru the discharge cycle. Many car guys discharge them at these levels, then immediately charge them back up in 5-10 minutes (15-20 amps). These cells take that abuse over and over and show very little, if any, performance degradation.

I think they will be just fine running as many servos as you can hook up to them. . .

The only down side is that they are a little heavier than an equivilant LiPo, and you need a special charger (3.6V / cell). Other than that, they are GREAT batteries.

If anyone is interested, I can e-mail or post the discharge curves from the Eagle Tree logger for these batteries when I get home.

[yooki]

How much heavier are these things than an equivalently sized lipo?

[klhoard]

Gentlemen,

Since I'll be out in the garage this afternoon spending some quality time with my Lite Stick, I'll take some photos and get y'all some numbers. . .

[klhoard]

OK guys,

Here are some weights for A123 vs. LiPo's. I don't have any 2400 Mah 2S Lipos, but I weighed two that are close - a 2-cell 2000 Mah, and a 3-cell 2400 Mah.

2S-2400Mah A123 - 169g
2S-2000Mah LiPo - 126g
3S - 2350Mah LiPo - 169g

[klhoard]

I use these batteries to power my Duratrax "Goose Chaser". . . this pack has sat under my workbench for about 2 months awaiting a goose foolish enough to wander into our yard. It took less than 4 minutes to top it off from "self discharge".

[klhoard]

I put the freshly charged pack on the West Radio CBA and set the discharge rate at 4 amps. You can see how well the pack holds voltage under load.
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That is the only other "disadvantage" to using these cells for a receiver pack. You can't tell when the pack is getting close to discharge until it falls off the cliff.
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[klhoard]

Here's the 10 amp continuous discharge curve. The pack temp started out at 79 F and ended at 105 F.

As you can see, that pack held a little more than 6 volts with a continuous 10 amp draw. Also remember that I've been beating the snot out of this pack with full power runs in my electric buggy chasing geese out of my yard for the last few months.

[klhoard]

Allright. . . Just for S & G, I gave this pack a 15 amp run. . . starting temp was 83F and finished at 116F. I took a screen shot half way thru the test and you can see that the pack was putting out 88 Watts at 5.9 volts.
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Another thing, look at the final measured capacity of the three test runs of 4, 10, and 15 amps. Every run shows 2.09 AmpHours +/- a smidgen. Of all the LiPo's I've tested, the measured capacity goes down as the current draw of the run goes up.
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[Surly_Schmidt]

when comparing A123s to lipo you need to be aware that A123 can be 100% discharged, lipos ~80%

Therefore; 2300 A123= 2900Mah lipo, but their voltage is less So ....

[bodywerks]

	Quote: Originally Posted by yooki
	How much heavier are these things than an equivalently sized lipo?

Unless you like to fly 35 flights in between charges and need 10,000mah to do so, you can't compare A123's capacity for capacity. A single 2300 can put out about eight times the amps of a 5200 li-ion.
The main reason people using li-ion's use such high capacity is simply to be able to deliver the required amps of their system, and most people will never use more that 1/2 the battery's capacty on a given day of flying.
Therefor, it is more sensible to compare a 2300 A123 to a 5200 li-ion. The Li-ion/regulator weighs about 8 ounces and is good for about 8 amps continuous. Two of those and a 2600/reg for ignition weighs about 21 ounces. The A123 2300 weighs about 6 ounces and is good for about 60 amps continuous and can easily power a 100cc bird by itself. Still, for a fair comparison, two of those and one A123 1100mah (found in the B&D VPX battery packs) weighs about 15 ounces.

[cjcyclesrc]

I am setting up my 88" EF Yak on one A123 2300 pack for the receiver. I haven't had any capacity problems flying a 87" EF yak on 3 Thunder Power 1320Mah LiPo's (2 Receiver, 1 Ignition). After 6 15min. flights both receiver batteries will use about 600 Mah each and the ignition about 500 Mah. I'm not comfortable using a single mechanical switch, so I called fromeco and had a pin flag badger switch built with 16ga w/ Deans in and dual receiver leads out.

A123=simplicity=no regs=

Charles

[RCRobb]

I am using a single A123 to power my receiver and ignition in my EF yak 74" powered by a ZDZ40 F3A engine. The battery is connected through a Fromeco badger switch with Deans in and JR leads out. One lead to receiver and the other to the ignition. I recharge after 30 min. of flying in less that 5 min.
I am using (5) Hitec 5955 servos and the battery is an A123 Racing. I saved about 6oz by taking out the 6 volt ignition battery & switch.