yet another noob question, batteries! (lock this up mods)

[wawa456]

can i charge my NiMH battery even if it hasnt fully discharged? i wanna have a full charge but not have to run through all those bbs just to do it, and i also dont have a smart charger (yes i know, i need a smart charger) so i cant discharge it that way

[Fluffy Boy 32]

[-EAF-]

Here goes a topic for ya to look at. I asked the same thing awhile back.

viewtopic.php?f=10&t=18867&hilit=Discharge

[wawa456]

ok, well that all seems way to complicated so ill just grab a smart charger and use that, thanks

[Fluffy Boy 32]

[Devildog]

I don't think you need to decharge NiMH, you only need to decharge NiCD batteries. I think, like 90% sure..

[Fluffy Boy 32]

[chrisw670]

NiMh batteries aren't as susceptable to developing memory as are NiCd's, but they can develope it over time. With NiCd batteries, it's best to discharge before recharging. NiMh batteries can be recharged at any point, but it's recommended to excercised them every few months, or so, by discharging them, then doing a slow full recharge. To safely discharge your batteries, buy a good discharger or a smart charger with discharge feature. Using just a light bulb, straight wired can over discharge your battery and actually shorten it's life.

[JayC]

For the love of god, don't discharge NiMh batteries.... The amount of bad information posted in this thread is just scary.

NiMh's will self discharge over time without you doing anything. Also, it's virtually impossible to create memory in airsoft gun batteries no matter the type of battery being used.

NiCd memory happens only in certain types of batteries which use sintered plate cells, which are rarely used in the types of batteries we're using in airsoft, and even in that type of battery, it's pretty hard to get the 'memory' effect in real world environments (memory happens when the battery is discharged to an exact point and recharged... over and over again - this is often only seen in lab equipment and things like battery power communications systems) So it's VERY unlikely you're going to have to worry about memory in any of the batteries you're using.

There is almost never a reason to completely discharge batteries as part of the recharging process, and in many ways you're doing more harm than good if you do.

So why do batteries go bad if it's not memory?

1 - Batteries have a limited life... The more times you charger and discharge the battery the less effective it becomes and at some point stops holding a charge... By discharging the battery you tend to make this happen quicker.

2 - 'Voltage Depression' - This for sure is an issue with NiCd's, and there seems to be some evidence that NiMh's can be effected by this as well... It doesn't impact the capacity of the battery much, but does cause the voltage to drop unusually quickly. Voltage depression can be fixed through individual cell discharging - but there are a number of big issues with doing this and it's very easy to run the battery pack if not done correctly.

3 - Reversing weak cells - This is a VERY common problem in the airsoft world... in the process of fully discharging a battery the weaker cells can become 'reversed' as they discharge first and then are 'backwards' charged by other cells in the pack. This will kill a battery pack really quick.

Most likely all the 'memory' effects you think you've seen over the years are one of the above issues and has nothing to do with battery memory.

The end result with NiMh batteries, don't discharge them as part of your recharging process... they will tend to last longer that way.

[wawa456]