Bad Battery?

[crokett]

My 18V Ryobi cordless batteries are coming up faulted when I plug them into the charger. I am down to a single battery pack from 3 of them. Both come up as failed after leaving them overnight plugged into a switched on flashlight to drain them before charging. Are they actually bad? or is there too little charge in them to recharge? Is there something I can do to reset them so the charger will charge them?

[LCHIEN]

By the way, it's really bad to leave battery packs loaded to drain them. The flashlight is the worst, being more or less a dumb resistance, it will keep draining the batteries when some cells are depleted. Since cells don't always have the same exact capacity, the current flow out of the cells with more capacity will reverse charge the first depleted cells and irreparably damage them.

If you must drain your cells (and not everyone recommends this), the you must use a device which has a cutoff that will turn the device off when the first cells in the pack are emptied and the voltage starts to drop rapidly. Examples: computers, cell phones etc. with some power management. This protects the cells in the pack from reverse charging.

[TheRic]

You might be SOL.
I have seen trying to charge them in a cold environment be a problem. Try charging them at room temperature. Leave the battery time to come up to room temperature, not outside feel temp, but inside. Wait a day or so.

There is a solution / myth (take your pick) that by putting a battery in the freezer for 24 hrs, then letting it warm up for 24 hrs, then charging it. This method might take a couple of tries. Several people here have said they have had luck, success rate is said to be about 50%. I personally have had no luck.

Loring is correct on the draining of a battery. It's a big myth about them holding a memory (I assume that is why you had them draining with a flash light).

[crokett]

Thanks. sounds like I killed 'em then. Guess I know what to ask for for Christmas. So batteries having memory is a myth? You sure about that?

[LCHIEN]

You might be SOL.
...

There is a solution / myth (take your pick) that by putting a battery in the freezer for 24 hrs, then letting it warm up for 24 hrs, then charging it. This method might take a couple of tries. Several people here have said they have had luck, success rate is said to be about 50%. I personally have had no luck.

...

I personally don't have much faith/belief in this method, but what the heck have you to lose by Trying...

[JTimmons]

Thanks. sounds like I killed 'em then. Guess I know what to ask for for Christmas. So batteries having memory is a myth? You sure about that?

I don't know about battery memory being a myth. I used to work for a cellular phone provider on their tech team. I'd commonly run accross users that would let their batteries get half way discharged and then stick them on the charger over and over again, the run time would soon only be about 30 minutes to an hour, when they were new they would have 4 hours. Those were NiCd batteries too.
Then they introduced lithium ion batteries and one of the selling points was no memory.

I have read contridicting docuementation from DeWalt that says otherwise about letting batteries discharge completely and I belive these are NiCd battieries in my drill. http://support.dewalt.com/cgi-bin/de...i=&p_topview=1

At this point, I'll trust DeWalt and do as they say.

[JTimmons]

Oh yeah, forgot something too. I had a problem with my batteries not long ago. I'd put them on the charger and the charger would come back with the code to replace the pack. I noticed some corrosion on the terminals and cleaned it off, the charger seem to like that and they are taking charges again.

[Ken Massingale]

David,
All NiCad packs are basically the same inside the housing. This is from the B and D site pertaining to NiCad memory.

"Do I need to worry about the “memory effect” when I recharge Black & Decker NiCad batteries?"


"No. The NiCad batteries used in Black & Decker products do not contain memory cells and will not develop a memory.

Batteries provided by Black & Decker may be charged at any time and are not required to be fully discharged before charging. "

This is from the Dewalt site:

"You should re-charge the battery when you notice a significant decrease in tool performance.Battery packs should not be completely discharged before re-charging. Completely discharging a DEWALT battery pack may cause damage to the cells in the battery."

Check the Ryobi manual, they may have something about their recommendation, the Ryobi site does not.
HTH
Ken

[Ed62]

So batteries having memory is a myth? You sure about that?

I'm not an expert on this, but I think that was a concern years ago, and the presently used batteries do not have a memory issue.

Ed

[paulstenlund]

The freezing trick only seems to work on the older Ni-Cads I had a 50% recovery rate on 6 old Makita batteries I got from work. This got me excited so I went to my old rechargable battery/ keyless lock/lockless key storage drawer and tried it on cellphone - cordless phone - BD flashlight batteries (none Ni-Cad) with a 100% failure rate.

Paul

[crokett]

I will plan on new battery packs for the drill. LOML has been asking for gift ideas for me anyway It still works like a champ and it and I have built a lot of projects together.

[jerrye]

My .02

Ryobi literature that is included in new tools states that you should recharge batteries as soon as you notice a decrease in the tool's speed or performance. I now follow that advice and have four 18v batts that after use for a year or more seem to have the same life they had when new. I too have had the problem with batt charger giving me the red and yellow light (or yellow alone, can't remember which) that is supposed to indicate bad unit. Most of the time this happens because the batt is too warm. Charger doesn't like warm batts. At other times unplugging and replugging charger w/o batt seems to reset charger: when batt is thten placed into charger all is OK. HTH