I am making the switch to A123 for my JetCat ECUs. Probably sending the units down to Bob tomorrow for modification.

I will be making up the 3 cell A123 battery packs myself and I plan to use a balance lead.

The question/request...

Can someone post the schematic for the balance lead for a 3 cell A123? Or give me a reason to go without a balance lead?

Thanks,
Bob

Here ya go:
www.scriptasylum.com/rc_speed/_lipo.html

The site is for Lipo's but balance leads don't know what the battery chemistry is.

It is recommended for optimal performance to balance 2 or more A123's. I use the CellPro Chargers. If you use 3 batts in series like for JC ECU, you will need a CellPro 4 prong plug. You can get pigtails with this plug from FMA or Andy Low at Electrodynamics. If you use other type charger, you will need an appropriate 4 prong or more plug.

Let's see. How can I put this tactfully? Oh ya...

I love you, Harley!

You, too, Tom!

Thanks to you both.

Things pretty lonely up there in Alaska, Bob?

LMAOWBLAH!!!

Take a look here...


[link=http://www.rcgroups.com/forums/showthread.php?t=599316]A123 pack construction with balance tap[/link]

I have been running A123's on ECU's and rx's for about 2 1/2 years now. The only time i bother balance charging them, is at the beginning of the flying day. When i first started using them, i always balance charged them, but the voltage never varied more than .1 to .15 volts per cell. If your batteries are fairly easy to get to, theirs no reason not to balance charge really.

Ditto to Thomas, I don't ballance charge unless I am in the workshop, on the field I just top them up every third flight or so, some people top up whilst re-filling the tank on every flight as another alternative, but as Thomas said above they do not seem to be too bothered by being ballanced or not.

Anyone who has not ballanced charged a pack of A123's at any time, can they test the capacity and voltage of these packs and let us know? It would be very interesting.

Mike

It is great that you are making 123's . Are going to give them to some one that actually fly's ? LOL GO 49ERS Dan

It obviously lost something in translation??????????????

Mike

Dan is making fun of me because I don't bring a jet with me when I travel on the airlines (or on my motorcycle) to attend jet events.

This is the only video I have of me flying my F-16, Dan. It is just one pass and only a few seconds long so I hope you won't be bored.

The start of the video shows the back of my beautiful head.

http://www.youtube.com/watch?v=pUfbZIugAVM

It's also hard to fly in the dark. What do you have up there this time of year Bob.....maybe 5 hours of "daylight"?

In Anchorage it gets down to about 5 hours right around Christmas, Craig. Did I mention that it gets cold, also? LMAOWFMAO!

The further north, of course, the shorter the daylight in the winter.

Summers are really great, though. In June we have about 20 hours of daylight at approximately room temperature.

Bob, dont let anyone talk you out of balancing wires on A123s. They are great batteries..

General Knowledge:
When they do get out of balance, it can happen fast. I lost my first plane with A123 cell failure before we really knew about its characteristics under light loads.. when they get slightly damaged from overcharge, they will lie to you. If I had a tap on them, it would have never happened. I immediately pulled all them out of everything and put taps on them, and found that several were out of balance.. that was a few years ago in the early days of flying them with Fromeco.. Kurt did a lot of research on them under light loads.. bottom line, they need balancing. Its really easy for a two wire to overcharge one cell after 5 or so charges. the lighter the load, the worse the tendency to go out of balance.. the FMA celpro is also my preferred charger. I am impressed with their sensitivity to balancing the 123's.. with the flat discharge curve, its needed. I think its safe to field charge a bit without it, but not much... my opinion from testing about 60 different packs.. for what its worth..

Hi Bob,
I have been using 123 batts for several years. Get yourself a cellpro 4s and buy the batts from electrodynamics. He has the matching charge leads and will make things easy for you.Once you set the cellpro to A123 batt its automatic and idiot proof. It will tell everything about the charge and how much voltage is in each cell. After one flight you can recharge and see how many mah are put back in the batts, this will tell you how many flights before recharging.
Vin...