Voltmeter for A123 cells
 

Does anyone know where to get some A123 volt meters? They differ in regular volt meters in that they show you the % life left on the pack rather than the voltage (which is useless since A123 have a 6.6v norminal voltage). I have seen them before but I forgot who makes them.

RE: Voltmeter for A123 cells
 

Not sure what you are talking about. How is a volt meter going to tell you the percent left in a cell? A123s have a very flat then abrupt discharge curve-in that they will hold 3.3 volts untill they are almost fully discharged then rapidly drop off the scale. Unlike a Nicd or Nimh that have a gradual discharge curve from 1.2 down to 1 volt. There is no way any volt meter is going to be of any use with a A123 cell. If the meter uses a recording amp meter ( like the Kodiak switch from Fromeco) that would be of use, but a volt meter is really of no use for 123s.

RE: Voltmeter for A123 cells
 

Here Ya GO !!! Thanks, by the way for asking this question...It made me curious so I Googled the hell out of it and finally found this product from Fromeco. I knew about the Kodiak (which is a meter and switch in one package) but I didn't know about this cool little meter. I think I'm gonna get some too!!

These meter the Mah USED (not volts remaining), so its easy to tell what's left if U just reset the meter after charging.........

http://www.fromeco.org/Products/05FRCWEASD/Default.aspx (Deans in/out)
http://www.fromeco.org/Products/05FRCWEAS/Default.aspx (Futaba and JR in/out)

RE: Voltmeter for A123 cells
 

I remember seeing a post on the forums from some guy over in the UK that was talking about such a meter. It was available over in the UK somewhere. I'll see if I can find it.

Jim

RE: Voltmeter for A123 cells
 

Maybe this is what you are talking about:

http://alshobbies.com/shop/lookupsto...pc=35017&Desc=

Whether or not it will actually measure the remaining capacity of an A123, I don't know............

Jim

RE: Voltmeter for A123 cells
 

The only thing that I have seen that get "pretty close" is the CellPro 4S charger. When you plug in a battery to charge, it tells you APPROXIMATELY how much energy is still in the pack. Still, I would NOT use this indicator as a reliable fly/no-fly indicator.

The best way (right now) to determine how many flight you can get is simply to fly for three flights, charge your A123 cells with a charger that will tell you how many Mah it has put back in, and then divide that number by three. Do this a few times and establish a good average Mah per flight. Then, simply divide the Mah per flight in to 1900. Since the cells are 2300, I feel 1900 is a good safe cut-off that will allow for a few flights with increased Mah draw.

RE: Voltmeter for A123 cells
 

The above post is exactly what i have done with my A123 converted jets. I can get 6 flights per charge but always top off after 3 and fly the rest of the day. The rx pack will last all day, its the jetcat pump pack that uses up the juice (approx 250-300ma) per flight so the rx onboard meter is really of no value to us jet guys unless it can be spliced into the pump pack which i doubt would be a good idea.
V..

RE: Voltmeter for A123 cells
 

I just don't see the point. You can hit these packs at 10 amps if need be and a fully discharged 2300mah pack would be charged in like 10-15 minutes. If you let the battery get to that point you probably would have lost the plane anyway. Best thing is to do what others have said. Get a baseline on per flight usage and leave a nice cushion to be safe.

Marty

RE: Voltmeter for A123 cells
 

Marty,
Since these packs always have the same consistant power after each charge its a no brainer to figure it out yourself.
V..

RE: Voltmeter for A123 cells
 

Yeah, I have to agree with Marty, Chad and Vincent. - one of the best things about the A123 chemistry is being able to super fast charge them and always have a boat load of life in the pack without the down time of a typical charge. When in doubt, charge it while chatting or listening to an Ipod tune, then go fly. It's a very quick charge and cheap insurance to always operate close to full capacity.

RE: Voltmeter for A123 cells
 

This is exactly what I was talking about but now that I look at it, it might be too big for my liking. I want to mount this into my fuse so it has to be comparable to the traditional onboard volt meters.

RE: Voltmeter for A123 cells
 

Is anyone charging their A123's with the Orbit PocketCharger ?
I just got one, with the latest firmware capable of doing A123's, but the manual is an older version and no info whatsoever in there.

Nicolas.

RE: Voltmeter for A123 cells
 

Nicolas, I know Bob at JetCat uses a pocketloader for their A123's. I think it is pretty much plug and play.

RE: Voltmeter for A123 cells
 

I am. Just set it to LIFE charge at whatever amp setting you want(I use 5 amp setting) and charge away. Works good.

RE: Voltmeter for A123 cells
 

The only downside (if you want to call it that) is that the pocketloader does not balance charge. Granted, while the A123's are NOT balance "critical" like lipos, it can afford you up to a few extra hunder Mah if they are out of balance. If you don't have another balancing charger, you may want to look at something like a blinky-balancer or other similar product. Just make sure it is A123 compatible.

Enjoy those batteries, there's nothing better out (right now).

RE: Voltmeter for A123 cells
 

You can`t go wrong with the cellpro4 especially at this price.
V..

http://www.fmadirect.com/products.htm?cat=45&nid=4

RE: Voltmeter for A123 cells
 

I agree 100%

RE: Voltmeter for A123 cells
 

That's a bit what I am afraid of. I like to know and fully understand with confidence how things work. Just plug and play is not good enough, would be great if I would have a manual for the V2.24 version.... [:o]