Rigid 24v li-ion self-discharging?
For xmas my wife got me a set of Rigid 24v LI-ion tools. It came with 2 batteries. Used all the tools pretty regularly for a few weeks, then the sheetrockers showed up and tools went into the van. Three weeks later, I pull them out and both batteries are dead. I know I put them into the van with something in them.
I’m not used to this. My NiMH Makita would hang onto what charge it had for quite a while, it seemed like.
I’m pretty much OK with the tools, but this is one strike against them. Guess I gotta leave them on the charger, or at least ONE of them on the charger. <sigh>
Anyone got a similar experience or other comment?
Replies
From what I understand, LiIon batteries can't take the cold too well. Has it been cold your way?
"I am the master of my fate, I am the captain of my soul." Invictus, by Henley.
No idea whose cells Rigid uses, but as a class li-ion self discharge is only a few percent a month, less then NiMH.
However, if you used the li-ion for a lot of cycles and ran them all the way down to dead every time, you did considerable damage to the cells. li-ion (or almost any cell for that matter), does not like to be fully discharged, any discharge to below 3.6V/cell is bad news. . For long life a 40% depth of charge is advisable (keep it above 3.6 V/cell) - which means either monitoring cell voltage or developing a keen ear for motor speed and voltage relationship.
Something is a bad state for a battery to be left in.
BTW: have never looked at a rigid li-ion batt pack - is there a charge indicator on the pack with a lit led or some such? it could be discharging thru it's own monitoring circuit.
Edited 4/7/2007 7:48 am ET by junkhound
Regarding complete discharge: I was told by the guy at the store that these cells are basiclly 100% and then go until they quit, no tapering off. I found this to be true. Drill one hole, and the next hole, nothing. He said there were so-many times you could recharge, like 2000 or something, but every recharge, little or big, counted as ONE, so your best bet was to use 'em until the quit and then put 'em on the charger.
We did get some weather down in the mid 30's at night lately, back up to mid 40's in the day. Not super cold by any means.
They have a button you can push to monitor the charge, but it's not on all the time, just when you push the button.
I'll charge them both to 100% and keep an eye on them.