Excal Battery Question

[Tin Fin]

Hello everyone,

I have been using the Sovereign GT and Excal for about six or seven months - best detectors IMHO. A couple weeks ago when I was detecting, I met someone in the field that had some questions for me. Unbeknown to me, I ended up putting the Excal into the car, without turning it off. It was a couple days before I noticed this. I'm using the NiMH battery pack, and it can be replaced - but, when I measured the Voltage of the batteries, it's down to 1 Volt. I have other batteries that I can use, that's not the problem.

When I plug the charger into the battery pack - I'm using the Powerizer, Universal Smart Ni-MH & Ni-Cd charger - the light on the charger comes on, flashes red, then green, then turns off. With other batteries, it does the same, but then the red light comes on and stays on until the battery is charged.

So, my question is; Did I over-discharge this battery pack too far to be able to salvage it? Or is there a way for me to save them? If I need to, I can replace the cells with a new set from Onlybatteries.

I have had this on the charger overnight, and beyond, and the Voltage reading does not change in that time. I have not been able to find in my research online whether they cells have gone into a "reverse charge" state or not; I don't know if that's possible with NiMH's or not.

Either way, I sure learned my lesson on this one.

Any help is very much appreciated.

 

[dewcon4414]

Dont sound good does it. Have you tried using the original factory charger? It sounds like the charger you are using checks the bettery first .... much like the newer chargers on drill batteries.

Dew

 

[Tin Fin]

Nope Dew, I haven't tried that - but I will. I hadn't thought about that part of things. I do have the original charger, so I will go plug that into it and see if it changes anything.

Thanks,

 

[Tin Fin]

Dew,

Thank you. I put the battery pack on the original charger for just over an hour. When I measured the Voltage right after disconnecting the charger, it showed nearly 14V. I put the "smart" charger back on it, and the lights flashed the way they are supposed to, and then the red light came on and stayed on to show that it is charging correctly. Once that goes green, I will measure the voltage again. I will update this to see if the normal battery life is as long, or shorter than, normal.

Thanks very much - Don't know if I would have thought to put the original charger on it or not.

Findmall is the best!

 

[Ron from Michigan]

Thanks Ron

 

[hershey1]

Dew. HH

 

[John(Tx)]

Glad you got it working, I've got the same charger. From time to time I will discharge my Excal's batteries but not below 8 volts....HH

 

[dewcon4414]

Glad it worked..... that sure saved you a bundle for a new pod. Sounds like that charger thought your battery was gone when it tested. I have pretty good luck with ML batteries and chargers. I dont like there isnt a light on the things to tell you its full. Ive had my SE since they came out and rarely use any thing but there rechargable. Now same with the Xcal..... I really put them thru it. In 9 months ive got close to 1000 hours on the Xcal.

Dew

 

[Critterhunter]

The battery is just fine. I drained mine completely dead two or three times a year to fully excercise them by hitching them up to a car tail light buld. After the light goes out I'll let it sit on it for another hour or so to make sure all the cells are dead. It puts the pack back in balance too because some cells can be ahead of others in terms of charging and thus the charger shuts off thinking the pack is charged when a few cells are still lagging behind. Just don't let them sit around drained dead like that for weeks or they risk reversing polarity.

The problem you had was not the battery but rather the charger. I've seen many chargers over the years refuse to recognize a completely dead pack. Drill battery chargers and so on. A good charger like the Accucel 6 (Hobby King) has recovered these drill battery and other packs for friends and such when their chargers just wouldn't recognize the pack. By putting it on the stock charger (which is in reality just a wall transformer) you are in effect force feeding a trickle charge to the pack until it's raised it's voltage enough for the other charger to recognize it.