RM

"Rob Mills"

02/02/2006 11:14 PM

18 volt Battery/Hold charge?

I'm curious as to how long your 18 volt batteries hold a charge just sitting
un-used after a full charge.
I have a 2 yr old Ryobi drill that is just casually used and the batteries
which have never been run low drop to an un-useable low (12 to 15 volts)
within a week of being charged. I also have a 8 - 10 year old Ryobi 12 volt
drill with original batteries that is still quite hot a month or two after
being charged.
I'm tying to decide if I should shell out $39 for a new pair of 18 volt
batteries or throw in the towel. The 18 volt drill has seen very little use
as has the 12 volt drill. RM~

PS, The 18 volt batteries show a reading of over 20 volts just after being
charged.




This topic has 7 replies

Lr

"Leon"

in reply to "Rob Mills" on 02/02/2006 11:14 PM

03/02/2006 5:18 PM


"Rob Mills" <[email protected]> wrote in message
news:IEBEf.338569$0l5.172573@dukeread06...
> I'm curious as to how long your 18 volt batteries hold a charge just
> sitting
> un-used after a full charge.
> I have a 2 yr old Ryobi drill that is just casually used and the batteries
> which have never been run low drop to an un-useable low (12 to 15 volts)
> within a week of being charged. I also have a 8 - 10 year old Ryobi 12
> volt
> drill with original batteries that is still quite hot a month or two after
> being charged.
> I'm tying to decide if I should shell out $39 for a new pair of 18 volt
> batteries or throw in the towel. The 18 volt drill has seen very little
> use
> as has the 12 volt drill. RM~
>
> PS, The 18 volt batteries show a reading of over 20 volts just after being
> charged.

All cells will have a surface charge and read a bit higher right after
recharging. Run the tool a little bit and the voltage will come down.

That said, I mentioned this to Renata in another post.
Keep in mind also that larger voltage batteries have more cells packed
inside the battery case and heat is an enemy to these cells. Because there
are many more cells in an 18 volt battery vs. a 9.6 or 12 volt battery you
have more cells insulating the inner cells during heavy use and recharging.
It is an inherent fact that the more cells a battery has and the way they
are packaged in the battery pack the shorter life span they will have when
compared to the lesser voltage ones. Basically, what you gain in longer run
times and power you loose in life expectancy with all things being equal.









RM

"Rob Mills"

in reply to "Rob Mills" on 02/02/2006 11:14 PM

03/02/2006 7:53 PM


"Leon" <[email protected]> wrote in message
news:[email protected]...


>>> Run the tool a little bit and the voltage will come down.<<<

I sort of expected that but was surprised at the rate of discharge when it
was un-used. I charged one last night and it read a little over 20 volts on
a very good digital meter (Simpson), tonight it had dropped to just a bit
over 17 volts without ever being installed in the drill.
I've been using a lot NMH's for smaller applications, police scanners, photo
gear and etc, guess they have me spoiled.
Guess I'll just live with these, maybe go back to my old B&D corded.

Thanks to both of you for your thoughts, Rob Mills


RM

"Rob Mills"

in reply to "Rob Mills" on 02/02/2006 11:14 PM

03/02/2006 8:07 PM


"Fred Toewe" <[email protected]> wrote in message
news:[email protected]...
> That said, does it matter? In your use of the tool is it important that
> it hold the charge for weeks or months, or do you/can you/ simply recharge
> the tool when you need to use it for more than a short duration?

Doesn't really matter but even in use after charging it doesn't really match
my old 12 volt Ryobi in power while using or ability of holding a charge. I
can charge that 12 volt one, walk off and leave it, come back 2 months later
and it can still get up and go. I wouldn't have even bought the 18 volt one
but I loaned the old one to a neighbor and they ran one battery too low and
it never would take a charge after that.
Thanks for your reply, Guess I was expecting some reliability similar to the
old Ryobi. RM~

FT

"Fred Toewe"

in reply to "Rob Mills" on 02/02/2006 11:14 PM

04/02/2006 1:22 AM


"Rob Mills" <[email protected]> wrote in message
news:IEBEf.338569$0l5.172573@dukeread06...
> I'm curious as to how long your 18 volt batteries hold a charge just
> sitting
> un-used after a full charge.
> I have a 2 yr old Ryobi drill that is just casually used and the batteries
> which have never been run low drop to an un-useable low (12 to 15 volts)
> within a week of being charged. I also have a 8 - 10 year old Ryobi 12
> volt
> drill with original batteries that is still quite hot a month or two after
> being charged.
> I'm tying to decide if I should shell out $39 for a new pair of 18 volt
> batteries or throw in the towel. The 18 volt drill has seen very little
> use
> as has the 12 volt drill. RM~
>
> PS, The 18 volt batteries show a reading of over 20 volts just after being
> charged.
>
The loss of charge while sitting on the shelf is a very common 'feature' of
NiCad's, which those most likely to be. The best NiCad batteries will not
have this feature when they are new, but most will develop it with age
and/or use and/or abuse.

That said, does it matter? In your use of the tool is it important that it
hold the charge for weeks or months, or do you/can you/ simply recharge the
tool when you need to use it for more than a short duration?

I have had batteries with this feature and have continued to use them for
years. It just doesn't matter to me. Perhaps you also have two batteries
and thus can recharge one while using the other as I do. Fred

MB

Mike Berger

in reply to "Rob Mills" on 02/02/2006 11:14 PM

03/02/2006 10:35 AM

What's the battery technology? Nickel cadmium will stay charged
on the shelf a lot longer than nickel metal hydride.


Rob Mills wrote:
> I'm curious as to how long your 18 volt batteries hold a charge just sitting
> un-used after a full charge.
> I have a 2 yr old Ryobi drill that is just casually used and the batteries
> which have never been run low drop to an un-useable low (12 to 15 volts)
> within a week of being charged. I also have a 8 - 10 year old Ryobi 12 volt
> drill with original batteries that is still quite hot a month or two after
> being charged.

RM

"Rob Mills"

in reply to "Rob Mills" on 02/02/2006 11:14 PM

03/02/2006 7:32 PM


"Mike Berger" <[email protected]> wrote in message
news:[email protected]...
> What's the battery technology? Nickel cadmium will stay charged
> on the shelf a lot longer than nickel metal hydride.

It doesn't say on the battery but I'm fairly certain they are Ni Cad's,
doubt Ryobi could (or would) sell a pair of NMH's for $39. RM~

RM

"Rob Mills"

in reply to "Rob Mills" on 02/02/2006 11:14 PM

03/02/2006 8:18 PM


"Leon" <[email protected]> wrote in message
news:[email protected]...

>>> That said, I mentioned this to Renata in another post.<<<

I just totally missed that thread until after I posted back to you.
Later, RM~


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