How to find out mAH of a battery

CDN_Stalker · June 29th, 2006, 22:45

Quote:

Originally Posted by Greylocks

Pooh to you too. No Beer For You!

Cheers man. ASC will be safe since I'm going camping all weekend.

Me too................... at Rawdon for Quick Pass 2!!!! Muhuuuuaaawwawawaw!!!!

GraveTech · June 30th, 2006, 12:11

Yeah sorry for that, long day at work

As for actually finding the capacity of battery the retail test equipment looks expensive. You may want to try a few hobby stores around and see if they have any testing services available (they may do it for free, I would but I don't work in a hobby store:P ). Good luck finding something

thephenom · June 30th, 2006, 12:36

Quote:

Originally Posted by GraveTech

Yeah sorry for that, long day at work

As for actually finding the capacity of battery the retail test equipment looks expensive. You may want to try a few hobby stores around and see if they have any testing services available (they may do it for free, I would but I don't work in a hobby store:P ). Good luck finding something

No offence taking, it was funny though.

Yeah, I'll swing by a hobby store that's nearby my houes and see if they have any.

Thanks again!

Kos-Mos · June 30th, 2006, 23:49

Quite simple!

Find someone who as a good charger (I mean, your's is not that bad, but still) such as at least a Piranha Digital Peak, or even better a Intellipeak ICE, a Electrifly Triton, or any other good charger out there with an display screen that can cycle your pack..

Then have the pack cycled 2-3 times in a row at "Auto" rating, and your done!

Mafioso_Grande · July 10th, 2006, 00:15

I'm a crazy guy who races RC cars and plays airsoft, so maybe I can help you out. I've been through a bunch of chargers and have a decent understanding of batteries. The following explanation covers 2 things: my guess at what the numbers on your charger mean, and how to actually find out the capacity of your batteries. Just keep in mind this explanation of your charger is being put together from pictures of your charger and online info, I don’t have any first hand experience with this charger.

I've looked into your charger online (TLP 4000C IntelliCharger), and every article/sales site I can find of it says it has peak detection, so it should be able to auto detect when you batteries are charged, then switch from fast charge to trickle charge mode. Just wait for the charger to beep.

So now your probably wondering what the different mAh (milliamp-hours) ratings on the knob are for… I have never seen that on any charger before in my life (airsoft is really funky when it comes to batteries), so here’s my (somewhat

) educated guess:

Almost all peak chargers can adjust the input current into the batteries they’re charging, most range from 0.5 A to about 7 A. This is done to decrease charge times, because sitting around while batteries charge sucks. The problem is that you can’t charge small capacity batteries at really high rates, the cells of the battery will overheat and you’ll toast your battery pack, so you need an idea of the capacity of the battery pack in order to determine the MAXIMUM charge rate for that pack (you can always charge packs at a rate lower than the maximum).

Now look at the knob on your charger, it has 2 sets of numbers. There’s a 1, 1.5, 2, 2.5, 3, 3.5, 4, I’m confident this first set of numbers is the charge rate (current, in Amps). The second set is under the first and is a bunch of mAh capacity values. It seems the second set of numbers are the smallest battery capacity recommended for charging at the above rate, so if you want to charge a 1700 mAh = 1.7 Ah battery, the people that made this charger don’t recommend you charge it at a rate higher than 3.5 Amps.

Since you’re unsure of the capacity of your batteries, just charge them at a low rate, maybe 1A, and you should be safe. NOTE: since your dealing with smaller batteries made of 2/3A and AA cells, I suggest you charge them at really low rates. These cells are far less rugged than the sub C cells used in large battery packs. I wouldn’t advise going above 2 A, regardless of what capacity we determine your batteries to be.

Okay, now we can determine the capacity of your batteries. The best we can do is get an estimate, but since you’re only interested in capacity for charging purposes, an estimate should be good enough. If you believe what I just typed about charge rate, all you need to do is time how long it takes for your battery to charge (in hours) at a known rate (in amps). You then multiply the time it took for the battery to charge by the charge rate to get the battery’s capacity. So we have:

Capacity (Amp-hours) = Charge rate (Amps) x Charge time(Hours)

Lets say you charge a battery at 1A, and it takes 35 minutes (or 0.58 hours). The capacity of this battery is

1A x 0.58 hours = 0.58 Ah = 580 mAh, this could be a standard NiCd small battery.

I hope this clears things up. There are other more accurate methods of determining a battery’s capacity, but this should be good enough. Just beware of false peaks coming from your charger (these happen every so often with peak chargers). To avoid these you can try to re-peak the batteries shortly after their first peak, but I’m not sure if this is a good idea given the cell types in your batteries.

thephenom · July 10th, 2006, 00:58

Mafioso_Grande, thanks for your help.

I'll give your method a try.

THANKS!

foxtail · July 10th, 2006, 09:23

I know my charger has a display that shows the mah on a battery. when you go to a game as any players if they have a charger with a display and if they mind if you run a battery through it.

I know guys ask me to use my charger all the time.

Mafioso_Grande · July 10th, 2006, 10:19

Chargers just calculate the capacity from the equation I gave above. Its more accuarate because its all done internally with better time measurements and input current is known exactly since the dial's used on low priced chargers just give an estimate of input current. The math is the exact same though.

Gryphon · July 10th, 2006, 13:06

The only way to find the true mAh rating of a battery is to look at the cell and see what it says, or cross-reference any numbers to manufacturer specs. Any other way is speculation because the mAh rating is just that - a rating. Most cells take more current than they're rated for so going by what your charger tells you is not always accurate.

Finding out your battery's ACTUAL capacity is relatively simple although it involves using a charger that has a display and tells you what's happening, and those are expensive. The Intellipeak ICE will do that and is what I use. See if you can find a hobby shop that has one in operation and ask if they can cycle your pack for you, or better yet a battery shop. Failing that, mail me the pack and I can do it for you.

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June 30th, 2006, 12:11	#17
GraveTech Trader rating Join Date: Sep 2005 Location: Kitchener, Ontario	Yeah sorry for that, long day at work As for actually finding the capacity of battery the retail test equipment looks expensive. You may want to try a few hobby stores around and see if they have any testing services available (they may do it for free, I would but I don't work in a hobby store:P ). Good luck finding something

June 30th, 2006, 23:49	#19
Kos-Mos Trader rating Join Date: Nov 2005 Location: Lévis (QC)	Quite simple! Find someone who as a good charger (I mean, your's is not that bad, but still) such as at least a Piranha Digital Peak, or even better a Intellipeak ICE, a Electrifly Triton, or any other good charger out there with an display screen that can cycle your pack.. Then have the pack cycled 2-3 times in a row at "Auto" rating, and your done!

July 10th, 2006, 00:15	#20
Mafioso_Grande Trader rating Join Date: Dec 2001 Location: Vancouver, BC	I'm a crazy guy who races RC cars and plays airsoft, so maybe I can help you out. I've been through a bunch of chargers and have a decent understanding of batteries. The following explanation covers 2 things: my guess at what the numbers on your charger mean, and how to actually find out the capacity of your batteries. Just keep in mind this explanation of your charger is being put together from pictures of your charger and online info, I don’t have any first hand experience with this charger. I've looked into your charger online (TLP 4000C IntelliCharger), and every article/sales site I can find of it says it has peak detection, so it should be able to auto detect when you batteries are charged, then switch from fast charge to trickle charge mode. Just wait for the charger to beep. So now your probably wondering what the different mAh (milliamp-hours) ratings on the knob are for… I have never seen that on any charger before in my life (airsoft is really funky when it comes to batteries), so here’s my (somewhat ) educated guess: Almost all peak chargers can adjust the input current into the batteries they’re charging, most range from 0.5 A to about 7 A. This is done to decrease charge times, because sitting around while batteries charge sucks. The problem is that you can’t charge small capacity batteries at really high rates, the cells of the battery will overheat and you’ll toast your battery pack, so you need an idea of the capacity of the battery pack in order to determine the MAXIMUM charge rate for that pack (you can always charge packs at a rate lower than the maximum). Now look at the knob on your charger, it has 2 sets of numbers. There’s a 1, 1.5, 2, 2.5, 3, 3.5, 4, I’m confident this first set of numbers is the charge rate (current, in Amps). The second set is under the first and is a bunch of mAh capacity values. It seems the second set of numbers are the smallest battery capacity recommended for charging at the above rate, so if you want to charge a 1700 mAh = 1.7 Ah battery, the people that made this charger don’t recommend you charge it at a rate higher than 3.5 Amps. Since you’re unsure of the capacity of your batteries, just charge them at a low rate, maybe 1A, and you should be safe. NOTE: since your dealing with smaller batteries made of 2/3A and AA cells, I suggest you charge them at really low rates. These cells are far less rugged than the sub C cells used in large battery packs. I wouldn’t advise going above 2 A, regardless of what capacity we determine your batteries to be. Okay, now we can determine the capacity of your batteries. The best we can do is get an estimate, but since you’re only interested in capacity for charging purposes, an estimate should be good enough. If you believe what I just typed about charge rate, all you need to do is time how long it takes for your battery to charge (in hours) at a known rate (in amps). You then multiply the time it took for the battery to charge by the charge rate to get the battery’s capacity. So we have: Capacity (Amp-hours) = Charge rate (Amps) x Charge time(Hours) Lets say you charge a battery at 1A, and it takes 35 minutes (or 0.58 hours). The capacity of this battery is 1A x 0.58 hours = 0.58 Ah = 580 mAh, this could be a standard NiCd small battery. I hope this clears things up. There are other more accurate methods of determining a battery’s capacity, but this should be good enough. Just beware of false peaks coming from your charger (these happen every so often with peak chargers). To avoid these you can try to re-peak the batteries shortly after their first peak, but I’m not sure if this is a good idea given the cell types in your batteries.

July 10th, 2006, 00:58	#21
thephenom Trader rating Join Date: Jan 2006 Location: Toronto	Mafioso_Grande, thanks for your help. I'll give your method a try. THANKS!

July 10th, 2006, 10:19	#23
Mafioso_Grande Trader rating Join Date: Dec 2001 Location: Vancouver, BC	Chargers just calculate the capacity from the equation I gave above. Its more accuarate because its all done internally with better time measurements and input current is known exactly since the dial's used on low priced chargers just give an estimate of input current. The math is the exact same though.

July 10th, 2006, 13:06	#24
Gryphon Trader rating Join Date: Mar 2005 Location: MB	The only way to find the true mAh rating of a battery is to look at the cell and see what it says, or cross-reference any numbers to manufacturer specs. Any other way is speculation because the mAh rating is just that - a rating. Most cells take more current than they're rated for so going by what your charger tells you is not always accurate. Finding out your battery's ACTUAL capacity is relatively simple although it involves using a charger that has a display and tells you what's happening, and those are expensive. The Intellipeak ICE will do that and is what I use. See if you can find a hobby shop that has one in operation and ask if they can cycle your pack for you, or better yet a battery shop. Failing that, mail me the pack and I can do it for you.

How to find out mAH of a battery

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