budchugger

My Feedback: (1)

I also have been running A123 bats for over two year with no regulator on all Hitec digital servos with not problems.

SinCityJets

I should probably clarify my statements.....everything I said about using A123's direct were reference real, genuine A123's, NOT LiFePO4 generic batteries. I have no experience with them, other than knowing that there are dozens of suppliers, and if they are anything like the dozens of LiPo suppliers, their quality can be significantly different.

I'm not saying they aren't any good, I just don't have any experience with them, or know their tolerance levels.

When in doubt, buy the real thing.

Chad

David Jackson

My Feedback: (15)

My mistake, the batteries are the A123 Racing 4600 mah pak. [8D]

ww2birds

My Feedback: (14)

Does anyone here know the typical failure mode of A123s? Short? Open? Something else?

I see people recommending the technique of plugging two A123s via two switches directly into the receiver on two different channels. A very simple scheme, and very well proven with NiCds and NiMh's. In the case of those packs, the typical failure mode is for a cell to short, so you have a 4c and a 5c pack in parallel, and the voltage difference is only 20%, and not much current flows, and you can survive the failure. I use that setup on a lot of planes.

If the typical failure mode of a A123 cell is to short, then you have a 6V pack in parallel with a 3V pack and that does not sound really good, especially when the output impedance of the A123 is so low .. seems like a really bad idea. Now, if the typical failure mode is an open cell then this is no problem at all.

For now, I am using dual A123s only with some sort of active battery management (e.g. SmartFly).

Can someone with more insight into A123 behavior comment?

Thanks
Dave McQ

SinCityJets

Dave,

I have not heard of a A123 failure yet. Any A123 that I have seen that had to be replaced was user induced by over-charging/discharging. During the assembly of packs, I have witnessed cells being shorted. Aside from melting a hole in the side of the cell, from the near 120A discharge, the pack still worked and functioned just fine. I would never use those cells for flight packs, but it gives you some insight to the resilience of this battery technology.

Chad

ww2birds

My Feedback: (14)

Chad,

Interesting comment. If that's true, then I guess there is no point in redundancy (2 packs) to improve reliability, just to increase the MaH capacity, in which case "hard paralleling" should be fine. If you parallel to gain reliability you do so with some idea of the failure mode. If there is none .. well that's cool :-)

Dave

bigbri

My Feedback: (287)

there is a failure mode for sure, Let me say I love 123's and use them often..but had a flameout with my p-80 not to long ago. ECU read "OC powerfail" which is often a low ECU battery...sure enough number 2 cell in a 3 cell pack was nearly dead (about 0.5 under a load. They were new batteries....The only real warning was when I charged them that cell was way under the others in voltage, but where it was a new pack I felt it just needed to be balance charged. Now the real question is how to tell if a pack is going to fail..WW2birds has a great question. anybody have the ancwer?

SinCityJets

I always run dual flight packs for the "what if" scenario. What if a cell goes dead, or I forgot to charge a pack, etc. While the technology is bulletproof, it may not be missile proof

Chad

hoser

i started this year using A123's on 2 on of my jets with a DX-7 no issues so far.

streetrodder

My Feedback: (4)

The other great thing is that these 2200 mah packs are $11 each.

Where are you getting 123"s for 11 bucks at??????

baam1211

i am going to use a smart fly in a 1/4 scale yak 1 2200 a123 on rec a 100 for ingnition is there a need for dual rec batt with the 123 i am new at these batt was a nmih man any ideas or imput would be appr.

baam1211

also i've never seen them for 11$

baam1211

1100 for ign. can't type today

David Jackson

My Feedback: (15)

You only need dual paks for a little added insurance. Just as Chad mentioned earlier, for those,"What if," situations. As a rule, I use dual battery paks (4600mah each) in all my plane (jets and props), whether A123's or LiIons. Might be overkill and may not prevent system failure, but its just a habit for me.[8D]

VF84sluggo

My Feedback: (55)

How would you recommend rigging two batteries with an AR7000 RX? In my Hellcat recently ditched my 4-cell NiMH battery for an A123 after concerns about getting too close to triggering a low voltage lockout. But, reading this thread has got me thinking: In an L-39 I'm building, I'm using two A123's (AR9100RX, but it's set up for two batteries). If I'm doing it with the L-39, why not in my Hellcat? But how?

David Jackson

My Feedback: (15)

On my Bearcat with a JR 955 receiver (72mhz), I use two A123 paks. One is plugged into the battery slot and the other into an unused channel on the receiver. So far no problems. On my larger prop driven planes and jets, I use the Smartfly EQ 10 which has the built in slots for dual batteries. [8D]

cavandish

http://www.sdshobby.com/2s1p-a123-66...ry-p-1151.html


http://www.cyclonetoy.com/

My packs have had 5 perfect cycles and about 15 top ups, all four take about 300 mah after 5 flights.
they are 'real' 123s.

Email Vivianne [email protected]

request an invoice inclusive of air postage (this is from china) tell her John from christchurch, New Zealand recomended cyclone.

I bought 4 packs I should of got 12 !

I have the 25 kg servos ($11) in two Giant scale planes with a couple of hundred flights between them, I would not trust them in a Jet though !

lots of other good stuff on there, Dl 222 is less than a grand.

VF84sluggo

My Feedback: (55)

Ok, thanks. My switching setup right now has the battery going to the switch/charge port on the fuselage side, then to the RX. Not sure how I'd hook two batts into that...not sure if putting two A123's on a 'Y' and then into the switch is prudent. Probably need the EQ10.

bcovish

My Feedback: (8)

Use a second switch and charge port then plug both into the RX

highhorse

My Feedback: (2)

That's a good setup in that u get switch redundancy as well, but with SOME switches there will be charging issues unless one batt is unplugged from the switch or rx first.

I'm having that problem on one setup now, though I don't remember what brand of switches they are. U need to use switches which have no common ground between charge and rx side.

BaldEagel

I use two A123 batteries into two Fromeco Kodiak switches into the Rx, the Kodiak switches have a digital display that tells you how many Mah you have used during your flight and are fail on, use Deans plugs, and are very pretty. LOL. if you have a Futaba 6014 then the use of an Orbit power jack will neaten the whole thing up as well.

Mike

VF84sluggo

My Feedback: (55)

Thanks guys!

Sluggo

gooseF22

Yes MANY times. no issues. have run that exact setup. No worries mate. My rookie is 2x A123's into the 9100 with hitecs.

Wire it direct., reg not needed

gooseF22

I have had a few A123 packs fail in testing, but every and I mean every failure was traced back to improper handling or charging or soldering. If you buy a welded pack from reputable folks, AND balance charge it, it will last forever. I have one pack that is on its 5th airplane. Currently in a rookie. It was one of my original test packs from Fromeco.

The failures are all related to allowing the pack to get out of balance and then subsequently overcharging accidently and failing the cell. If you allow a cell to pop or get above about 4.3 volts, it will die a slow death and then the other cell becomes vulnerable for overcharge. they will hold a small charge fooling you but if you use a blinky or balance charger, it will find that problem right now.

I have tested the A123's to the failure point. they are very durable and provide power when damaged pretty good. We drove a nail through one at 50 amps. It lost 4 amps but kept on providing power. It vented a bit too. If an A123 vents from overcharging, it have a /VERY pungent smell. I was able to get over 5 volts in the cell before it got hot enough to melt the tape around it. It still did not explode, just vented.

SO... what Im saying is the battery is very safe, but as a receiver pack, you must balance charge it often because the discharge curve is so flat, it will creep out of balance if you dont, and you will eventually overcharge one cell. so get the bal charger or blinky and you will have years of reliable service. None of my packs have failed from general usage, only mistakes or intentional testing.

gooseF22

+1