I have 2 Fromeco A123 packs connected to 2 switches, which in turn are connected to my Power Expander, but only one of the "Smart-Sense" LEDs light up. Each LED lights on individually when I turn on the switch, but they do not light up at the same time. I connected a pair of LI-ION batteries and both LEDs turned on at the same time. Any ideas on why this is happening?

Anyone??? Sounds like a good question to me. Bob Ritchey at Smart Fly may have an answer.

Are these the "similar" to A123 cell batteries from Fromeco, or the actually labeled A123 "Extreme" packs? If the Smart-Fly PE works with Li-ion, then it should work with A123. I just converted my 38% CA Extra from duel Smart-Fly HD switches, Turbo Regulator, and 4400 Fromeco Li-ions, to duel A123 packs. I removed the switches and installed the Fail-Safe pin-n-flag switch, removed the turbo regulator, and plugged the batteries directly into the Power Expander.

Flew and worked flawlessly this Sunday. My thinking is that you have a battery problem or one is intermittent, possibly.
Thanks,
Jim

Originally Posted by Dr. Yankem

Anyone??? Sounds like a good question to me. Bob Ritchey at Smart Fly may have an answer.

Since this post is in the SmartFly support forum, I am sure he will reply when he checks in. I will be curious to see if it has anything to do with the charge state of the two batteries.

I am using a smart fly power expander with A123’s and when I first powered the system up only one side would light up as you experienced. It was the charge state of the batteries. If they are off by more than 1/10 (I think) of a volt then the power expander would assume one of the batteries was weak and it would use only one side. I ran each battery for a bit and then recharged and balanced. With a cycle or two on the battery they came right inline and worked great with both powering up as expected.

That is correct. if the batteries aren't within like .1 to .2 volts, then the "smart-sense" only draws off of the higher of the two voltages. Once the voltage gets back in range, it will draw off of both.

I should add that I used the FMA charger, which has a specific "balance/charge" lead that is used for its namesake. The FMA unit charges close to capacity, then balances the pack each charge cycle.
Thanks,
Jim

thanks guys. What you guys have said was confirmed by Smart-Fly. I was being a little paranoid.

Hi All,
The Smart-Sense inputs look at the two input voltages and if they are different by more than about 50 milli-volts the higher one will be chosen. If they are within this then the Smart-Sense will turn both inputs on. The two sides are completely independent circuits if you were wondering. Each side looks at the source and drain of the P-FETs and makes the decision. Let me know if you need any more information.

Hello All,

I just bought a Power expander 14MZ. Will be using it with a JR R1221 receiver and two A123 Fromeco batteries. I need a help on the following questions:

1. Do I need one or two switches?
2. I wont be using regulators. What will happen with the servo speed if on the first couple of flights the battery voltage will be higher than the voltage of the batteries at tthe end of the flying day. Having no regulators, the voltage will be lower at the end than at the beginning. Do you thing it will be perceptable this speed change?

Thanks,

i'm presently using a power expander eq-10 with jr 10x rig and it works great. i am considering replacing the 10x with jr 9303 2.4. can i drop in the 2.4 receiver in the eq-10? thanks, paul byrum.

Paul I just put 2.4 in two planes, no change was nessary. I use the smart fly eq. with two a123 battery packs, no voltage regulator.

Izubiria I find if I use the switch that smartfly sells that plugs into the expander to turn it on or off that it will bleed off voltage over night in one of the batteries. I unplug the batteries from the expander after use for the day. My advise would be to put a switch between the batteries and the expander.

thanks, alan. should have asked you on the phone. paul.