New Battery Charging Questions.
Paul Rybarczyk
Hi. I just ordered some 1700 SCR NiCads from rcbatt.com. They
came with many different charging recommendations which I had
never heard before. I'm interested whether those in this forum
agree/disagree, based on your experience.
Of course there is the usual stuff about fully discharging and memory.
But they claim batteries will "last longer" ( I assume they mean number
of charges) if fully discharged each time. Agree?
They say always trickle charge a dead battery, especially new ones.
Does everyone else do this? What's the downside if you don't?
They say it will take 10 charge/discharge cycles before the batteries
are "broken in". Prior to that, they won't accept a full charge if using
a peak charger. Since the only moving parts in a NiCad are electrons,
I don't see why a break in is needed or what exactly breaks in.
Last, since these are "SCR" batteries (instead of the lower discharge
rate SC variety), they say a peak charger should have an "SCR setting"
to peak them properly. Anyone heard of that? My charger has no such
setting.
--
Thanks,
Paul.
Billy Bad Ass
--
...and also check the loose nut behind the wheel!
"Paul Rybarczyk" <pa...@REMOVETHIS.rybarczyk.net> wrote in message
news:3B0F1924...@REMOVETHIS.rybarczyk.net...
>
> Hi. I just ordered some 1700 SCR NiCads from rcbatt.com. They
> came with many different charging recommendations which I had
> never heard before. I'm interested whether those in this forum
> agree/disagree, based on your experience.
>
> Of course there is the usual stuff about fully discharging and memory.
> But they claim batteries will "last longer" ( I assume they mean number
> of charges) if fully discharged each time. Agree?
battery charger manufactures recommend that you discharge before charging >>> is simply
because their equipment is not sophisticated enough to tell when your battery is fully
charged. is a precationary measure to ensure that the battery won't overcharge.
BBA
Tom
>
> Hi. I just ordered some 1700 SCR NiCads from rcbatt.com. They
> came with many different charging recommendations which I had
> never heard before. I'm interested whether those in this forum
> agree/disagree, based on your experience.
>
> Of course there is the usual stuff about fully discharging and memory.
> But they claim batteries will "last longer" ( I assume they mean number
> of charges) if fully discharged each time. Agree?
>
The lifetime of your NiCads is determined partially (depending on how else
you abuse them) by how much charge goes through them. If you deep cycle
them on the bench, this is charge going through them that isn't making
your car go, so it's a waste in my eyes.
The only time you really should think about deep cycling your NiCads is
when preparing them for long-term (a month or more) storage.
More people have damaged their NiCads by discharging them (in order to
preserve them and avoid the mythical memory effect) than have preserved
them.
> They say always trickle charge a dead battery, especially new ones.
> Does everyone else do this? What's the downside if you don't?
>
If the battery has been sitting in an open circuit for any length of time
(like a day or more), I see no reason for this. If you are removing them
from storage (where every cell is shorted individually), then it is good
to let them come up to their rest potential before charging.
> They say it will take 10 charge/discharge cycles before the batteries
> are "broken in". Prior to that, they won't accept a full charge if using
> a peak charger. Since the only moving parts in a NiCad are electrons,
> I don't see why a break in is needed or what exactly breaks in.
The initial cycle for NiCads is unique, since the chemical reactions
haven't taken place before on the electrodes, and there is a great deal of
wasted charge energy that can never be recovered during a discharge.
However, they're all cycled before we get 'em anyway, so we don't need to
worry about this.
>
> Last, since these are "SCR" batteries (instead of the lower discharge
> rate SC variety), they say a peak charger should have an "SCR setting"
> to peak them properly. Anyone heard of that? My charger has no such
> setting.
In the days of yore, chargers had an "SCR" setting (meaning pulse charge)
and an "SCE" setting (meaning linear charge). It really doesn't make that
much of a difference, and the peak detection works identically.
___
TTTTT OO M M The sixth sick shiek's sixth sheep's sick. |~~~|
T O O MM MM @o o@
T O O M M M So if it is in it or if it is on it, it is *
T OO M M as it is, be it in it or on it. `-'
Paul Rybarczyk
Tom wrote:
>
> More people have damaged their NiCads by discharging them (in order to
> preserve them and avoid the mythical memory effect) than have preserved
> them.
I'm probably one of them. About fifteen years ago, I was reading
about nicad memory and how my old packs would work oh so much better
if I completely drained it. So I did.
After that it worked like crap. My pack's power output and
capacity dropped almost in half. I'll never do that again.
So is there a trick to avoid discharge damage and
actually get some benefit?
--
Thanks,
Paul.
Tom
(*SNIP!*)
> I'm probably one of them. About fifteen years ago, I was reading
> about nicad memory and how my old packs would work oh so much better
> if I completely drained it. So I did.
>
> After that it worked like crap. My pack's power output and
> capacity dropped almost in half. I'll never do that again.
>
> So is there a trick to avoid discharge damage and
> actually get some benefit?
Yep.
Don't worry about it.
Drive your car 'till the battery is dead (meaning your car slows down and
isn't fun to drive any more). Take it out. Let it cool completely before
you charge it again, be it that day or next week.
Don't read R/C car magazines too closely, because the authors of the
articles genearlly don't know what they're talking about.
Jonny Hodgson
> I'm probably one of them. About fifteen years ago, I was reading
> about nicad memory and how my old packs would work oh so much better
> if I completely drained it. So I did.
>
> After that it worked like crap. My pack's power output and
> capacity dropped almost in half. I'll never do that again.
>
> So is there a trick to avoid discharge damage and
> actually get some benefit?
If you do want to completely flatten nicads, discharge each *cell*
individually. Most of the problems are caused by flattening complete
packs, which invariably reverses at least one cell.
Jonny