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-   -   Charging A123 batteries in the plane? (http://www.rcuniverse.com/forum/batteries-chargers-84/10740007-charging-a123-batteries-plane.html)

ezflyr 09-29-2011 04:29 AM

Charging A123 batteries in the plane?
Hi All,

I'm about to replace an old NiMH flight pack battery with an A-123 battery. Until I started to do the installation, it didn't occur to me that there might be couple of problems with this new setup. First, I tend to use Maxx Products switches in my models. These switches have an integral charge jack built into them, so my charger plugs into the side of the airplane. This is really convenient for charging at the field (no need to disassemble the model!). Will these charge jacks handle the higher charge currents of the A-123 pack? The second problem I see is that the "balancing" port for the battery will now be buried deep inside the model. Probably not a problem for charging at home, but not convenient at the field. Is it permissible to charge an A-123 battery occasionally without balancing for the times I want to charge at the field?


aghost 09-29-2011 04:46 AM

RE: Charging A123 batteries in the plane?
I haven't seen a spec, but I understand the standard connectors like those on the MP switches are good for 3 amps. I use the MP switches with charge ports and regularly charge my A-123 batteries at 1 amp in the plane. My setup allows me to balance charge even at the field.

You might read through the Hangtime Hobbies setup guide for A-123 batteries. Good info and some methods related to what you are planning.


Capt Lou 09-29-2011 05:38 AM

RE: Charging A123 batteries in the plane?

I can't comment on your switch but I will tell you what I do for my A123 packs. I purchased from Hangtimes the Ultra II switch/charge jack and use them on all my giant scale planes. Hangtimes has a helpful wiring diagram that shows you how to set-up the Untra II with a balance plug so you can charge/balance A123 packs thru the switch jack. As you mentioned, this is convenient when you want to charge the pack at the field. The Ultra II is rated for a 4A charge rate which is also the maximum for my CellPro charger that I use for my A123 packs. I am aware that some flyers believe that 4A charge rate is too high but the Ultra II can handle it; however, to be safe I charge at 3.5 A.

I have used these packs in four giant scale planes using the baove charging technique and have never had an issue. I find these packs and charging system to be convenient and very reliable.

Capt Lou

dasintex 09-29-2011 06:31 AM

RE: Charging A123 batteries in the plane?
I charge/balance my A123 packs right in the Plane; two ways to accomplish this; you can get one of those Combo Charge Port /Switches from Maxx Products or the one from Electrodynamics called the Ultra Switch II; on either one, you need to cut the White Signal wire on the output side before it plugs into the receiver; Hangtimes Website http://www.hangtimes.com/ describes this in detail.

Or Electrodynamics sells a Modified version of their Ultra Switch II specifically for use with A123 Packs here it is http://www.electrodynam.com/store/product240.html

I use the FMA Cell Pro Charger and it utilizes JR/HITEC Connectors as does the Electrodynamics Ultra II A123 Switch, the wiring is simple, the Red is pack Positive, the Black is pack Negative and the White or Signal wire is NODE #1 Balancing.

So now all you do is plug your 3 wire balancing/charging lead into the integrated charge port on the switch, providing the wiring is as I described on both the Pack and Charger you use and it should work.

Again, go to Hangtimes and go to their A123 section and it describes it fully.


HunkaJunk 09-30-2011 12:47 AM

RE: Charging A123 batteries in the plane?
I charge mine right in the plane,  I use a separate charge and balance jack so I can charge at a higher rate, I originally used the wiring through the switch jack for charging and balancing but the wiring didn't hold up at its rated capacity.

nonstoprc 09-30-2011 01:39 AM

RE: Charging A123 batteries in the plane?
I have been used himax heavy duty switches with charge port on my giant scale planes with A123 packs.

Yes, it is possible to balance charge A123 through the charge port on the switch. The trick is to use the signal wire on switch for balance purpose. That is, connect the balance wire from the battery to the signal wire at the charge jacket of the switch harness, and connect the signal wire from the charging port on the switch to the balancer.

The signal wire from the switch to the receiver has to be disconnected (e.g., through a small cut on the signal wire in that section of the wires) to avoid shorting a cell through the receiver.

The heavy duty version of himax switch can take a couple amps of current. So fast charging through the switch is OK.

dasintex 09-30-2011 04:02 AM

RE: Charging A123 batteries in the plane?
When you refer to 'Hi-Max Heavy Duty Switches' are you referring to these from 'Maxx Products International'?



nonstoprc 09-30-2011 04:40 AM

RE: Charging A123 batteries in the plane?
1 Attachment(s)
Yes, I have been using "3170 - Futaba J switch".

Photo 1 below shows my charging harness that goes to a GP TRITON charger at one end, and to the charging socket on himax Futaba J switch on the other end. The wiring is as follows.

1. Black wire goes from the charger, to the black wire on the balancer, and to the black wire on the himax J switch;
2. Red wire goes from the charger, to the red wire on the balancer, and to the red wire on the himax J switch;
3. The signal wire goes from the himax J switch to the balance wire on the balancer.

In the airplane, connect the "middle"/balance wire, plus the black and red wires from the battery to the charging side of the switch. The "middle" wire of a 2-cell A123 and the black wire provide half of the voltage of the pack (~3.3v).

Photo 2 is the J switch with the signal wire cut at the receiver side.

Upnet 09-30-2011 06:01 AM

RE: Charging A123 batteries in the plane?


No NEED to cut the wire.

pilotpete2 09-30-2011 11:31 AM

RE: Charging A123 batteries in the plane?
No need to even have a separate balance connector. Radical R/C will make them wired with a 20AWG three wire servo lead for balance charging through the switch, plug and play[8D]. I charge at 2A to be on the safe side.

4*60 09-30-2011 09:40 PM

RE: Charging A123 batteries in the plane?
Don't fly giants but I've been using A123 flight packs for about a year(at least). I do not balance them. An expert on batteries(not me) suggested that if charging and discharging at only a few amps like when using packs as flight packs, there is no need for balance charging. Light duty means the cells don't get seriously out of balance.
A123's are seriously good cells for our purposes and I charge at 1C or so and discharge at about the same, in use.

cloudancer03 10-03-2011 08:29 AM

RE: Charging A123 batteries in the plane?
guess I best look at my switch as I have an mpI switch and am switching over to life batteries .no more nimh batteries ..have to say with my wildhare 30cc...al I do is unstrap the velcro remove the battery and charge it on my ICharger takes minutes not hours and I have a second battery that I can simply pop in as well.a123 is so darn simple..

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