Question For any Vintage Teknetics users!

[MarkCZ]

Okay, I have a Tekentics 8500/B hip mount (not that that matters) and I'm wondering about the onboard charging ability and the newer Nickle Metal batteries.
Here is where I'm at with this right now,

First, I already had a set of nickle metal batteries in the detector, that were ran down far enough that the detector would power up but not operate right.

Next, I wanted to test the charging circuit to see if it would do anything, so I put the detector on charge for about an hour. I know that's not NEAR enough time to put a charge in any battery, but I thought if it was working at all it might bump the batteries up enough for the detector to respond right if just for a couple of minutes. BINGO! the detector fired right up and seemed fine. The charger and the circuits are at lest working.

Okay, I know that the charging system was designed for the older Nickle Cadium batteries and not for the higher ma Nickle Metal ones. So I left it on charge for about four hours and checked the battery temperature to make sure nothing was going crazy, they were cold! (good) I left them on charge over night and checked the batteries again come morning, kind-a cool. Then after 24 hours I checked them and they felt just a little below skin temperature, maybe 80 degree's or so.

My question is,
What can I expect from the Teknetics onboard charging system and the new nickle metal batteries? (right now the batteries show CHARGED in the detector but I know because of them being rechargable that that doesn't mean they are FULL charged.
Reading the manual it states that it takes 14 hours to fully charge the factory installed nickle cadium batteries. Will the charger EVER fully charge the nickle metal batteries or is it nothing more than a trickle charge?

Mark

 

[wvrick]

I am not a Teknetics user BUT.... I have used NiCd and NiMH for over 35 yrs.

Also common among older NiCd chargers are the so called "overnight" chargers which charge batteries at a low rate as long as the charger is plugged in. This type of charger can fully charge NiMH batteries, but it might take a very long time to do so. It's possible that an old NiCd charger could take as long as 48 hours to fully charge new high capacity NiMH batteries! This type of charger is not likely to damage NiMH batteries unless the batteries are left in the charger for weeks at a time, but it may not be very convenient to use. If you have this type of charger you can get an idea of how long you'll need to charge your batteries by using the calculator.

It's pretty easy to estimate how long it will take. Simply divide the capacity of the battery by the charge rate of the charger, then increase the amount of time by about 20% to allow for a certain amount of inefficiency. As an example, a battery with a capacity of 1600 mAh will require about 4 hours to be fully charged by a charger with a charge rate of 500 mA. (1600 mAh/500 mA x120%). Incidentally, this example would apply to a standard AA NiMH battery and a typical "rapid charger". Keep in mind that a battery that is only partially discharged will be recharged in less time.

 

[straker]

I bought (14) new 1.2V 800 mAh NiMh rechargeable batteries and modified a new 12VAC output wall adapter to charge them. Full charge is gained in 12 hours according to George Payne who helped me with the parameters. I charged them once after the first time out with the detector first using Alkaline's and never used the unit since. I used the detector once outdoors for 9 hours and I found quite a bit of silver in one day in the one time out.