Subject:
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Re: Best (disposable) battery for the RCX?
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 26 Jul 1999 04:06:59 GMT
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Viewed:
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646 times
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I use Ray-o-Vac Renewals (rechargeable alkalines), and am quite pleased
with them. For best performance they should be recharged very often -
even if only partially drained. I just get in the habit of swapping out a
set of batteries before starting any project and having one extra set
around always fully charged.
NiCad is a bad choice because the nominal cell voltage is pretty low
(1.2V) compared to alkaline (1.5V). This means that even when fully
charged they aren't delivering the same power as an alkaline. Memory
effect (depending on the cell itself) can also be troublesome.
I haven't tried NiMH myself. It should perform better than NiCad, but
leakage current in NiMH cells is pretty bad, meaning they will drain
annoyingly fast if just sitting on a shelf for days or weeks. Under
contant use, however, the leakage current isn't a big deal. Its been a
long time since I looked at battery chemistries, but if memory serves,
NiMH can support higher currents than alkaline. Given the power
requirements of the Mindstorms motors, I doubt this is a big deal.
However, if you wanted to power three or four of the old Technic 9V
motors, then this higher current might be necessary. This is what makes
NiMH a good choice for things like digital cameras with built in flashes.
(keep in mind I'm going from memory here - can anyone verify that NiMH has
a lower internal resistance than alkaline, thus can support higher
currents?)
Dave
In article <379BCE14.68ED7A28@midnightbeach.com>, jon@midnightbeach.com wrote:
> I've been using Duracell alkalines and they don't seem to last very long
> at all. Has anyone found a brand that works better?
>
> (I've avoided the Duracell "Extra" (or whatever their premium
> supermarket battery is) because the package seems to imply that its
> optimized for elctronics, and I figured it might offer no great
> advantage driving the Mindstorm's motors.)
>
> I searched the archives, and the consensus seemed to be that NiMH is
> much better than NiCad, but also that few people seemed to be using any
> sort of rechargable in their RCX. Has that changed?
--
reply to: dbaum at enteract dot com
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Message is in Reply To:
 | | Best (disposable) battery for the RCX?
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| I've been using Duracell alkalines and they don't seem to last very long at all. Has anyone found a brand that works better? (I've avoided the Duracell "Extra" (or whatever their premium supermarket battery is) because the package seems to imply (...) (25 years ago, 26-Jul-99, to lugnet.robotics)
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