R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Thread Tools Search this Thread
Old 03-31-2006, 12:10 PM   #1
Tech Addict
Iceracer's Avatar
Join Date: Feb 2006
Location: Canada
Posts: 656
Trader Rating: 1 (100%+)
Default Battery capacity

When a battery is rated at 3300 mah, what should I see as the charge mah going in on a digital peak detection charger (I'm using a Reedy Quasar Pro set to 5mv/cell)? What should I see for output when I measure it at 15 or 20 amps discharge rate?

None of my nimh batteries seem to be taking anywhere close to 3300 mah charges, and they sure aren't outputting 3300 mah when discharged at 15 amp rate to 0.9 volts per cell. These are only 3 month old batteries. What am I doing wrong, or what is normal?

Last edited by Iceracer; 04-01-2006 at 12:44 PM.
Iceracer is offline   Reply With Quote
Old 03-31-2006, 02:42 PM   #2
Tech Elite
imprsme's Avatar
Join Date: Feb 2004
Location: Va.
Posts: 3,563
Trader Rating: 70 (99%+)

MAH input is going to depend on if you are discharging them all the way down or re-charging them while they have a partial charge still in them.

If you discharge them all the way down to .05 then take them down on a tray to zero then when you charge them you should see a MAH number in the 3400-3600 range.

If you are not fully discharging them you will not see numbers that high since the cell is still partially charged at the time you charge them.

As for you MAH output at discharge the 15amp. with a .06 cut off is a very odd discharge. Most matchers recommend at least a 30 amp rate with a .05 cut off.

So again your numbers will be low because at the .06 you are not fully discharging the cell...
eXpress Motorsports
imprsme is offline   Reply With Quote
Old 03-31-2006, 05:31 PM   #3
Tech Addict
TL_XXX-S_racer's Avatar
Join Date: Jun 2004
Location: Florida
Posts: 577
Send a message via AIM to TL_XXX-S_racer

The MaH could also change with what amperage youre charging your batteries at. The higher the amperage the less MaH you will have (or run-time) but you'll have more power. It could also be false charging as well. But yes, try what imprsm said by putting your batteries on an equalizer before your charge, on a discharge after and equalize them after as well. That will help tremendously too. Also keeps your batteries in tip top shape

Hope this helps,
"Nobody does it better"

Team Corally

Superior Hobbies
"Supplying all your r/c racing needs"
TL_XXX-S_racer is offline   Reply With Quote
Old 03-31-2006, 09:47 PM   #4
Tech Addict
Iceracer's Avatar
Join Date: Feb 2006
Location: Canada
Posts: 656
Trader Rating: 1 (100%+)

I don't know what I was thinking. The Reedy charger discharges them to 0.9 volts per cell at up to 20 amps rate. So the 0.9 v/cell is what is probably holding them from dumping all their capacity? I guess I need an equalizer tray that takes them down further.
Iceracer is offline   Reply With Quote
Old 04-01-2006, 09:17 AM   #5
Tech Master
akuhon's Avatar
Join Date: Feb 2006
Posts: 1,155

On the contrary,
My 3 months-old-unused match (SMC GP3300 old-30-amps discharge) performs out of my IB3800 matched cells.. I'm using LRP Pulsar Comp at 6.0, peak detect at 45mv

Check the pics. Any comment ?
Attached Thumbnails
Battery capacity-bat1.jpg   Battery capacity-bat2.jpg  
akuhon is offline   Reply With Quote

Similar Threads
Thread Thread Starter Forum Replies Last Post
Battery charging capacity T35 RKeasler Electric On-Road 0 01-09-2008 11:42 AM
NEED A HIGH CAPACITY BATTERY ihor14 R/C Items: For Sale/Trade 2 11-08-2007 07:35 PM
need a high capacity 7.2v battery ihor14 R/C Items: Wanted to Buy 13 10-13-2007 06:03 PM
Battery capacity, doing the math? Mabuchi540 Electric On-Road 5 02-27-2007 12:38 AM
new battery capacity b-man777 Electric On-Road 2 12-09-2005 12:37 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

All times are GMT -7. It is currently 04:25 PM.

Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net

SEO by vBSEO 3.5.0