Go Back  R/C Tech Forums > General Forums > Radio and Electronics
Charging brand new NiMh receiver packs>? >

Charging brand new NiMh receiver packs>?

Charging brand new NiMh receiver packs>?

Old 06-30-2010, 08:24 AM
  #1  
Tech Apprentice
Thread Starter
iTrader: (9)
 
Join Date: Jun 2010
Location: LONGMONT,CO
Posts: 66
Trader Rating: 9 (100%+)
Default Charging brand new NiMh receiver packs>?

Just trying to get back into nitro offroad and have a few questions on charging receiver packs.
1. I have a brand new Mugen 6v 2300 mah NiMH pack, do I need to cycle this battery to start with or just charge it?

2. If I do cycle it what amp rate do I charge it with and what voltage should it come up to? When discharging what amps do you discharge at and what voltage should it drop to? And how many times do I do this?

3. When doing a normal charge after this what amp rate should I use and what voltage should it come up to? Will the charger show it coming up to the 2300mah its rated at or less? And does it go passed the rated 6V?

Just trying to get the best life out of this pack and some of the technology has passed me by.
By the way I will be using a Racers-Edge SC2000 charger. Thanks for any help up front!
BMXNBULLDOG is offline  
Old 06-30-2010, 10:10 AM
  #2  
Tech Lord
iTrader: (21)
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

New NiMhs will show some increase in capacity over the 1st 10 -12 cycles, but I don't see a need for cycling since the initial capacity will still be enough to run with so I'd just charge it. I don't 'breakin" NiMh unless I'm told to by the cell manufacturer and this has just been with the bigger cells, sub c sized cells.

NiMh should be discharged to 0.9v/cell so a 5 cell pac you'd disch to 4.5v. I discharge mine every 4 to 6 times I use it to help balance voltage of the cells inside. Your pac is AA type cell based and these cells are sensitive to heat and if you overheat them by charging at too high of a rate, you'll reduce their life. Fast charge for rcvr pac/AAs is 1amp, slow charge is 0.5amp. I try to use the slow charge as much as possible and only fast charge when I'm in a real rush. I would try a peak sensitivity of 3 -5 mv/cell as a peak setting. This should get the cells hot, but the shouldn't get so hot you can't hold one. NiMh peaks at 120-125F so they should be hot.

Voltage should get upwards of 1.45v/cell so I wouldn't be too surprised to see 8.6-8.8v. The charger will read higher than this since it has to force the current intpo the pac - this is the input voltage, not the pac voltage. These cells have relatively high internal resistance and the charger has to over come that resistance and stay at a higher voltage than the pac to keep current going into the pac. The charger can't put 2300mah into the pac since it will never be truly 'empty'. I use 1600mah sub c cell type hump pacs and I see 1150-1200mah going back on charge.

The downside to a pac this size is going to be charge time. It will be a few hours at a fast charge and longer at a slow charge rate.
Duster_360 is offline  
Old 01-13-2011, 02:12 AM
  #3  
Tech Regular
iTrader: (5)
 
Nickmind's Avatar
 
Join Date: Jan 2006
Location: San Diego
Posts: 388
Trader Rating: 5 (100%+)
Questions?? What Amp Rate to discharge NIMH Receiver Pack at?

Originally Posted by BMXNBULLDOG
When discharging what amps do you discharge at
Really, what Amp Rate do you all discharge your Receiver NIMH Packs at?

You would think that this question was asked 1000 times, and have been answered 1500 times. But after some "mastergy google searching" I haven't seen a good answer yet. And if I did, i havn't seen the same answer any where twice. So when you discharge your NIMH Receiver Packs, what amp rate do you choose?

Now I know from the past, I didn't always discharge my RX packs every time i go to charge the pack, like we did with Sub 'c' cells. But being out from the hobby for a few years, i need to see what packs are good, and which ones are not. My guess would be to match the highest amp draw from what your average Servos + Receiver are drawing. But i don't know these numbers, or how to get them. Plus, I could be wrong, but i can't imagine that amp draw being to high.

Thanks all for your time and help,
Nick
Nickmind is offline  
Old 01-13-2011, 05:58 PM
  #4  
Tech Lord
iTrader: (21)
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

The guideline that I see consistently from knowledgeable sources is to not discharge at a rate that causes the cells to overheat and get hotter than you can comfortabley hold. This is usually stated as 125-130f.

I've always discharged at 1amp regardless of how big the rcvr pack is.
Duster_360 is offline  
Old 06-22-2015, 06:09 PM
  #5  
Tech Rookie
 
Join Date: Jun 2015
Posts: 2
Default Discharge

The best way to discharge is low amps as the cells need slow discharge so they can all equalize slow and deep i say and dont hammer them when charging,and they wont need discharging as often.
dunk8888 is offline  

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.