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John-Del[_2_] John-Del[_2_] is offline
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Default Rechargeable battery question

On Thursday, April 19, 2018 at 9:32:41 AM UTC-4, ~misfit~ wrote:
Once upon a time on usenet John-Del wrote:
On Saturday, April 14, 2018 at 9:57:51 PM UTC-4, mike wrote:
On 4/14/2018 1:42 PM, John-Del wrote:
I have this device which uses 14 AA rechageable batteries. It was
originally shipped from the factory with nicds and a charger.

The instructions show it has two recharge modes switchable from the
front panel; recharge and store. The store is a very low trickle
charge. Because it's from the early 80s, I'm assuming it's just a
current limited charger (dumb charge) as it takes 14 hours to
charge the entire group.

I would have like to install eneloops in it, but anecdotal evidence
suggests they don't like this type of charge, so I'm back at
looking at regular nicads for it.

So, is it true that Panasonic eneloop cells need a smart charger
and does anyone know if anyone is making a quality nicad battery
anymore? In the old days, I'd buy Sanyo nicads and although they'd
often advertise less mah per cell than others, they seemed to last
almost forever.

There are a LOT of variables here.
It would be helpful to know what it is.


Trying to avoid that It's a Teknetics 9000 metal detector. Back
when it was new, it was a high end detector. I don't know where I got
it or even when, but there it is in my collection. My brother lost
some keys last fall and has a pretty good idea where they are. He
was going to buy a detector but I told him I have one so that's what
prompted my inquiry.


Are the batteries in series, parallel, separate supplies?


Series, but in two different banks of 8 and 6. If I feed in a dc
supply on the 8 cell bank, the LCD display comes to life and the
controls affect the display. If I put a supply on the 6 cell bank,
it draws current but the LCD doesn't light. No, I haven't powered
both simultaneously. I will before I order any batteries to confirm
it's working.

Is the OFF power drain really zero?


I think so. There is a physical switch for power.


Is it gonna sit for a long time between uses?


Probably, although these are fun toys and I do have several acres of
uncleared woods on my property to explore. One of my best friends
has a house built in 1798 with an original rock wall and outhouse, so
there's that.


The best strategy is to charge the cells externally in a proper
charger and put 'em
back in when you're ready to use it.


I agree, but one of the banks of batteries had a leakage and several
of the very thin battery contacts have disintegrated away. If I
install batteries in it, it would be far more convenient to not have
to physically remove them for charging.

I may have to rebuild the battery box with new contacts and go with
external charging as you suggest. I was just looking for an easier
way out (which is my defining personality trait...)

Thanks everyone.


If it were mine I'd retro-fit a single battery made from lithium Ion cells
with two buck converters to give your two supplies.
--


The two supplies don't share a common ground.