Whats up with Batteries?

Disco Mon Dec 21, 2009 8:37 pm

Disclaimer- I DO NOT CLAIM TO AN EXPERT ON BATTERIES THIS IS A PERSONAL LEARNING EXPERIENCE DONE FOR MYSELF AND MAY HELP YALL OUT TOO. ANY INPUT OR CORRECTIONS WOULD BE APPRECIATED.

Ok so ive been hearing a few people saying that they cant get any kind of life out of their batteries and they stop taking a charge after maybe 10-20 charges. I am writing this to try and help some people out that may not be using their batteries properly. I am not in any way claiming to be an expert on batteries but i do have a bit of experience with them. I raced remote controlled cars for years most of which were battery powered. I ran nitro powered cars in the beginning but quickly realized that electric cars were not only easier but faster in the right hands.

In competitive electric racing batteries were a make or break part of the racing equation. If you had a great set up on your car, perfect tires, and a hot motor you wouldnt get in the show running sub standard battery packs. By sub standard I mean anything that cost less than $80 for a 6 cell matched pack. When I came into racing ni-cads were on their way out and NMH were the new hot ticket, which was about seven or eight years ago. Since I was new to the sport I bought up every ones old junk Ni-cads for cheap and learned how to make them work. Then once I got more competitive I moved into NMH's and then lastly Lipos.

A good NMH was priced anywhere from $80 to $120 for a 6 cell pack that would set the track on fire. These packs were great since they required almost no maintenance. Ive had some of these packs for two and three years charging them 3 to 4 times a day every weekend. You do the math, that''s a lot of charges.

I just acquired 9 1500 ni-cad packs with all the rental guns from Jason the owner of southern command airsoft. After playing one game day with these batteries I noticed a serious problem with the available play time of these packs and the lack of voltage on packs that id charged on the "smart" charger on my truck battery. So I went home did a little freshening up on ni-cad care and use via the internet. After reading for a while on the net I remembered a system that I used to use when I ran ni-cad batteries back in the day. Ni-cads need to be discharged, and from what im reading, stored discharged and equalized. We're not going to get into equalizing ni-cads since I never equalized my batteries back when I raced. All I did was discharge them on a set of lights that has an automatic low voltage shut off built into them. You plug the battery into the lights, press a button and the lights come on and slowly dim until the battery pack reaches a certain voltage and the lights shut off.

So I discharged every 1500 ni-cad battery pack I have here. Some of them were still charged quite a bit and some weren't even able to light up the bulbs. (the bulbs are 10 turn signal bulbs soldered onto a coat hangar with a shut off switch built in line. Its very simple) After discharging them I charged them all on two of my old RC car chargers which are very safe and very advanced compared to most "smart chargers" I see airsofters using. The batteries were all charged in exactly the same manner in the same temperature using a fan to keep them cool. The battery packs took charges ranging from only taking in 280mah, which is pitiful, all the way up to 1410mah which is to be expected for battery packs that are at least a year old and have been very poorly maintained.

I took the worst pack of the bunch that not only accepted the least amount of charge but the connector is no god either so i'm using it as my guinea pig. I discharged it and charged it. The pack only took 280mah on the first initial charge. I discharged it and recharged again exactly the same and it got up to 325mah I kept repeating the steps with this pack and got similar results. 480mah 692mah 792mah 963mah i expect to see the same results for a few more charges, the pack should stabilize somewhere near its full 1500 capacity. Ill update more as I get more results. The charging and discharging process takes hours and hours of monitoring and cataloging is quite boring. If you wish to be able to do this yourself and save tons of money in the future here are the parts im using to perform my experiment. There are chargers that will do all the cycling for you, like my indi 16X8v6 charger, but I wanted to do this the old fasion way to keep the process simple.

The charger is nothing special in the rc world but its a solid workhorse of a charger its called the "Reedy Quasar Pro". Its an ac/dc charger which is important to me since I don't like the use of external desktop power supplies.

http://www.modelsport.co.uk/?CallFunction=ShowSpecification&ItemID=13490

I cant find the light set i'm using to discharge the packs online. I don't think anyone still uses them since ni-cads are totally obsolete in today's racing world. I was astonished to see how widely they are used in the airsoft world. We airsofters must be getting all the left overs that never sold back in their hay day.

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part 2
Ok so I put the test battery back on charge after leaving it sitting over night. It actually took justa touch less mah than on the last charge the night before, it kinda took me by surprise but im guessing its the internal heat that builds up in the battery that helps bring it back to life. I read something elsewhere online that said in order to bring the battery back to life some minimal heat needs to be built up in the cells to get them to knock the bad crystals off the plates inside the battery. So I discharged it and recharged it and she showed more progress. From the last mentioned 963mah to 1085 to 1166 to1285. I could most likely push this battery even harder but I think its safe to stop here and just put the battery to normal use. I will be keeping track of this one battery and its overall lifespan. I will update on its progress in the future.