View Full Version : 2500 mah AA charging questions


Outlaw 44
01-25-2007, 04:16 PM
Okay.

This Is my 1st post in the 1/18 scale section (I race 1/10). My question isn't exactly RC related, however some expertise coming from Micro RS4 racers running standard Nimh AA cells could help me.

I just purchased a Fujifilm A700 digital camera and can't figure out why I can't take more than 10 or 15 pics without my batteries letting me down. They ARE new mind you and were charged in a wall unit one or 2 days without use.

While I went back to the store to return it because it uses up so much juice in no time, the store clerk tells me I need to run at least 6 or 7 cycles on my batteries before they can perform to their peak. So what? I can take 100 pics instead of 15 with the same batteries after 7 cycles? Yeah right!!

First question. With 2500mah cells how many pics should an average camera be able to take on one charge?

Second, I want to put the store clerk's 6-7 charge cycle theory to the test. I got a GFX, so I can do all the charge and discharge cycles I want. Providing I let 2 hours rest time in between cycles, whats the recommended amp setting for charging, then how many amps do I discharge at, and with what kind of a cutoff voltage?

Denney
01-25-2007, 05:19 PM
For reference: 2500mah in my 3PK last ~6-7 hours (per the timer on the radio)

in my Canon digital camera I can get maybe 500 pics (varies a bit depending on how much you use the display - that's what uses a lot of the power)

I have seen maybe a 5% increase in the cells capacity after 3-4 cycles, anyone who suggests much more than that doesn't use rechargeables much...
Not sure about the GFX settings, but a lot of the newer "wall" chargers claim 1 hour charges, which would be ~2.5 amps. I don't charge mine higher than 1.5 amps though (or discharge much more than that either). As for voltage cutoff I would guess .03-.04 (based on a 4 cell pack), raise it if you get false peaks, otherwise watch the battery temps, as long as they don't go over 125-130 degrees you s/b ok - If they're not that hot their probably not fully charged.

p.s. just to make sure the camera isn't the problem, throw in a set of alkalines, I've seen ~200 pics with a set of those.

Denney

Outlaw 44
01-25-2007, 06:24 PM
Well Gee!

Alkalines is what I put in the last time because I doubted my rechargeables and still not more than 20 pics!

Thanks for the tip!

ScottH
01-29-2007, 12:09 AM
In my Dig CAm I use the lithium cells and they last forever!

I have not had good luck with rechargables in my dig cam. But I would still think you should get alot more than the few pics you are getting. Are you using alot of flash and the display?

okracer
01-29-2007, 07:12 PM
hey i was wondering if anyone thought about a four cell aa car with a big block and the new chassis with the batterys running longways instead of horrizoltal

tfelog
01-30-2007, 08:40 AM
Check this charger out for aa/aaa bateries.http://thomas-distributing.com/la_crosse_bc-900_battery_charger.php

Slider
01-30-2007, 09:03 AM
I use my gfx .voltage cutoff..03.to .04 charge at .9 amps. discharge at .5 amps.

Discharge first. then charge and note how many milliamps they take. I have decent success with AA's But it is hard to beat the lithium. Note I have many new batts being junk right out of the box.

ScottH
02-03-2007, 01:49 AM
The new chassis is just a little short to lay 4 AA's down like that. It was a tight fit on the VII chassis.