Charging rate on NiMH batteries.

Discussion in 'Beyond the Basics' started by Pure, Jan 14, 2010.

  1. Pure
    Offline

    Pure New Member

    Joined:
    Oct 22, 2008
    Messages:
    416
    Likes Received:
    0
    Trophy Points:
    0
    Gallery:
    Ratings:
    +0 / 0
    My Photos Are NOT OK to Edit
    So I finally got around to buying a decent battery charger, the Maha C-9000.

    On the instructions, it states to charge above .3C and but below 1.0C, C being total capacity. I assume this means if you have lets say 2500mAh batteries to charge them at a rate above 750mAh and below a rate of 2500mAh. Is this correct?

    However, I've heard of the .1C rule, meaning charge at a rate of 1/10 the battery's capacity.

    Also when discharging, what is the proper rate? I can't seem to find any hard answers for this stuff.
    Last edited: Jan 14, 2010
  2. Phranquey
    Offline

    Phranquey New Member

    Joined:
    Feb 16, 2008
    Messages:
    1,528
    Likes Received:
    11
    Trophy Points:
    0
    Location:
    Dayton, OH
    Gallery:
    Ratings:
    +11 / 0
    My Photos Are NOT OK to Edit
    You are correct on your proportions, except 1C is 2500 mAh....the capacity of your cell (unless you have 2700's & you typo'd).

    You can disregard a portion of those instructions... down to .3C. If you are doing a normal, everyday charge, .3C to .5C (two to three hours) is a good place to be. If you are in a hurry, I would recommend going no higher than 1C (1 hour), and if you want to do a conditioning (top off, full discharge, and then recharge) I would do it at .1C. It will take a log time for conditioning at .1C, but I recommend doing that roughly every 20 to 30 charge cycles.
    Last edited: Jan 14, 2010
  3. Pure
    Offline

    Pure New Member

    Joined:
    Oct 22, 2008
    Messages:
    416
    Likes Received:
    0
    Trophy Points:
    0
    Gallery:
    Ratings:
    +0 / 0
    My Photos Are NOT OK to Edit
    I was using 2500mAh as a nice average number. The cells I have are 2700mAh.

    I have them charging at 500mAh for a charge/discharge/charge cycle so I can measure their capacity.

    So a fair charge rate could be anywhere from 500 to 900mAh? Basically I want a nice middle ground thats not too slow that its a pain, but not too fast that it'll kill my batteries. .3C of my 2700mAh is just over 800mAh. 800mAh would be about a 3.5hr charge.


    Discharge rate anybody?
  4. Derrel
    Online

    Derrel Mr. Rain Cloud

    Joined:
    Jul 23, 2009
    Messages:
    29,064
    Likes Received:
    10,096
    Trophy Points:
    113
    Location:
    USA
    Gallery:
    Ratings:
    +10,366 / 1
    My Photos Are OK to Edit
    You know, my wife and I bought some rather slow 13-hour chargers a number of years ago, and those doggone things were used with some early Radio Shack brand NiCad and NiMh batteries, with the original sets of batteries lasting almost 10 years!!!! Literally, ten full years, with hundreds and hundreds of charge/discharge cycles, but a long, slow 13 hour typical charge time, and they were used mostly in Sony Discman CD players and various small cassette tape players for daily audio books on cassette tapes. Simply incredible duty cycles on 1200 then later 1600 and 1700 milliampere hour Radio Shack batteries.

    Later, as we moved into 7 hour chargers, we noticed a sharp and pronounced decrease in battery duty cycle (meaning shorter overall lifespan), even with batteries that had significantly higher capacity numbers, like 2000 then 2200 then 2400 and 2500 milliampere-hour ratings.

    So, I guess slow and steady wins the race...
  5. Phranquey
    Offline

    Phranquey New Member

    Joined:
    Feb 16, 2008
    Messages:
    1,528
    Likes Received:
    11
    Trophy Points:
    0
    Location:
    Dayton, OH
    Gallery:
    Ratings:
    +11 / 0
    My Photos Are NOT OK to Edit
    You'll be very safe at 500 to 800mAh charge rate. You can go to 1300mAh (.5C) for normal charging and not worry about doing too much. When you start generating a lot of heat above 1C is when you really start doing damage.

    The "15 minute" chargers are what make me cringe...those are charging at 4C !! So, for a 2500mAh AA cell, you are cramming 10,000mAh (10 AMPS !!) into that little cell. Most portable car battery chargers run at 6 Amps.... think about that one.
  6. Garbz
    Offline

    Garbz New Member

    Joined:
    Oct 26, 2003
    Messages:
    9,712
    Likes Received:
    202
    Trophy Points:
    0
    Location:
    Brisbane, Australia
    Gallery:
    Ratings:
    +202 / 0
    My Photos Are NOT OK to Edit
    Charging time is inversely proportional to the battery life.

    Charge at the rate you need to but no more. If you got home, throw your batteries in overnight at the slowest rate. If you're out in the middle of a gig toss them on a quick charger. Batteries cost next to nothing compared to the rest of your camera gear so it's not really worth worrying dearly about it. Even if you use one of those 15min quick chargers your batteries should still last a few months.
  7. Brian L
    Offline

    Brian L New Member

    Joined:
    Nov 4, 2007
    Messages:
    374
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Michigan
    Gallery:
    Ratings:
    +0 / 0
    My Photos Are NOT OK to Edit
    I have a maha charger as well. Love it. I charge my cells around 500mah or so. Sometimes more if I need to charge them faster. Although the guy above me is right not saying your wrong....lol but that charging fast does generate more heat and cells and heat don't mix. Slow charging if you have the time is better. Believe it or not but charging at a higher mah rate will also not give you as much run time out of the batteries. I learned this from racing electric 1/10 on road cars. Charging a 3300mah nmhi at 5 amps got me bout 15mins of runtime with a mod motor. charging it at 3300 or lower got me 20 to 25 mins. Little more battery info there for you.

    Now you may ask why I was charging at 2 and half c's more well when charged at higher amps you actually get more burst our of the pack when acceleration is applied. So now that im off topic and brought back my days of racing im going to quick talking now. hahaha. Peace.
  8. Pure
    Offline

    Pure New Member

    Joined:
    Oct 22, 2008
    Messages:
    416
    Likes Received:
    0
    Trophy Points:
    0
    Gallery:
    Ratings:
    +0 / 0
    My Photos Are NOT OK to Edit
    I've discovered my 2700mAh cells hold a charge anywhere from 1900mAh to 2600mAh. I'm going to do a few slow slow slow charge/discharge cycles on them to see if I can get them past there. I've had these batteries for just over a year or so. We'll see what happens.
  9. Big Mike
    Offline

    Big Mike I am Big, I am Mike Staff Member

    Joined:
    Dec 16, 2003
    Messages:
    33,539
    Likes Received:
    1,731
    Trophy Points:
    113
    Location:
    Edmonton
    Gallery:
    Ratings:
    +1,740 / 0
    My Photos Are NOT OK to Edit
    That's fairly typical. Few batteries seem to actually be up to their rated capacity. I just tested a set of older 2700s and they came in between 2000 & 2300.

    You C-9000 has a 'break-in' mode, does it not?
    That is the mode that you can use to push that capacity back up.

Share This Page

Search tags for this page
battery aa charhing rate
,
best rate to charge nimh batteries
,
carging rates for nimh batteries
,
charge rate for 2000 ma nimh radio control battery
,

charge rate for nimh batteries

,
charging nimh 1c
,

charging rate for nimh batteries

,

charging rates for nimh batteries

,
how long will it take a 1700 mah ni mh to be full charge with 800mah charger?
,
ni-mh 2500mah aa sony battery first charging time
,
nimh battery basics
,

nimh battery charge rate

,
nimh battery charge rates
,

nimh charging rate

,
optimum charge discharge rate for 2500 nimh batteries
,
rules for nimh charging
,
safe charge rate for 1500mah nimh
,
safe charging nimh
,
safe charging rate nimh
,
what rate to chrge a nimh aa battery