Mark 1 Battery Question

[Happy_Hour]

What is the proper way to re-charge batteries for the Mark 1...Take them out and charge or leave them in and charge. With the charger attached, do all the batteries get an even charge with only one port to charge all the batteries...I read a post where someone stated that the Mark and the 9500 use a certain type charger only...

 

[duggr]

The Mark 1's external wallwart charger with the teknetics logo was for standard nicad battery's.
If you want to charge NiMh or lithium batteries on board you will have to have an appropriate charge made
to do this...

 

[JB(MS)]

Posted by George Payne on 9/4/2006, 8:27 pm

Teknetics 9000B, 8500B and Mark 1 Charger:

Input: 120 V 60HZ 8W, Output: 10V AC @ 1.4 VA

All these detectors required a AC charger. The reason has to do with the circuit used in those detectors. In the original design a 6 cell and 8 cell battery pack is connected in series. One of the charger wires is connected to the connection point of the two battery packs. The other charger wire is connected to two diodes that alternately charge one then the other battery pack as the line frequency changes polarity. Therefore, if you connected a DC charger to one of these detectors only one battery pack would charge. The other battery pack would never receive any charging current. As I said, the original system used two packs. One pack supplied 9.6 volts the other 12 volts. The original AC charger output voltage was specifically designed to charge a 8-cell (12v/cell) pack. Therefore, a resistor is used in series with the 6-cell pack to limit the charging current in that pack.

 

[Arthur-Canada]

I'm in the battery business so I can safely say you can use NiMH cell in the Mark 1. The only thing is that when the Mark 1 was made you had NiCd cell with only about 500 or 600 mAh capacity and the charging circuit was designed for an over-night 15hr charge. Now you put NiMH cells in there with 2,500 mAh capacity and you are looking at over 48 hrs to charge them up fully!

 

[Cyber Rosco]

If you have the heavy duty battery clips you might be better off taking the batteries out and charging them. Those clips are very durable. The batteries will charge much quicker that way.

If you have the original battery clips, then taking the batteries out and back in repeatedly will surely cause a clip or two to break eventually -- so charging them in the Mark 1 might be the better choice.

I had the heavy duty clips installed in mine & I use Alkalines from the Dollar Store and they work fine and last longer than the rechargeables.

Also, you'll want to swap the "A" batteries with the "B" batteries and viceversa to balance the discharge of the batteries. I usually swap them after about 4 to 5 hours of use. That will give me an extra hour or so of detecting time.

CR