I want to buy a rechargeable glow plug igniter. I currently own a glow plug igniter that connects to a heavy duty battery. I'm worrying because i know with rechargeable batteries when you recharge them you have to drain the battery fully so you can keep the batteries life. So when i recharge my starter box battery I let my starter box run until the batteries are completely drained.

So when the rechargeable glow igniter can't start your car anymore how do you drain the rest of the batterie or can you just stick it in the charger with out draining the rest of the igniter???

If you run LiPo batteries then you don't want to fully discharge them, it will cause damage. If niMh then just charge them if they won't cause the plug to glow.
Even if the plug glows you will want to make sure the igniter battery doesn't go flat part way through the day so if going to a club or race meet then make sure its charged.
As long as you discharge the niMh here & there then it should be fine for a fair while.

So if it is the day before you are going to the track and you are using a nimh battery and you glow igniter is half charged. How will you drain the battery in the glow igniter so you can have a fully charged glow plug at the track

No need to discharge unless its been along time since you used it last. Just keep puttin a charge in it.

Just charge it, thats all I do & the battery is fine. You could hook up a small light globe or put battery in a torch to flatten it completely if you wanted, it may help it last longer.

Most modern changers, ie of the lipo era, there is normally a discharge function. I set discharge for my NiMH to 0.9V.

Well then if it is half charged how long will i know to charge it for

charge it with a peak charger ,it will stop itself

dude, your knowledge amazes me once again....

youre just jealous you slacker

Ye but can you charge it from when it is half charged

Attually if it is the day before the track and my glow igniter is half charged do I have to discharge to charge it up fully so wil have a fully charged glow igniter or can I just put it in the charger from half charged

just put it on charge

Do I charge it for the full time or half time

as houston said if you have a peak charger it will stop charging when the battery is full. what sort of charger do you have.