problem with my Excal powering up/charging

[syko]

I charged this thing up the initial 16-17 hours it recommends.
I then installed the battery and tried to power up, nothing happens.
I checked the output on the wall charger, it says it outputs 14.3v ....put the meter on the leads of charger
shows about 8.18v.
The battery after all this time is barely showing about 5.5volts.

What is the deal? Can anybody tell me what you get on the charger lead output?
I think this pack should be a 9.6v...it looks like it's not fully charged up, but it has been charging long enough.
Does anyone know what a freshly charged battery has once you pull it from the charger?

This is irritating, but I just hope it's the plug or battery pack that's bad, I need this replaced since this thing is brand new.

 

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[erikk]

I get about 13.76 on all of mine but then again I am not using the Minelab charger.. I use the Sun-Ray SR-12

 

[Sandman]

I've heard this from others. I never have tested my charger as it is the older Minelab charger and does the job welll on my older Excal. I use a 1600 amh NIMH pack from Sunray and it is going on it's fifth year.

I would try another charger.

 

[Buried Crap NJ]

I am a bit confused. The one line reads 14.3v on the wall wart. Then another say 8.18v? The battery is 5.5v
Ok I checked my output on the wall wart the silly one that Minelab sends with the unit. I have 18.35v at the two pins.
If you know any RC plane guy that fly's electrics have him use one of his good chargers to see if its battery or the charger.
Hope this helps. steve

 

[Michigan Badger]

Hum, I bought my Excalibur 1000 back in 05 and the charger always worked great. I just charge overnight and never have had a dead battery.

 

[syko]

the wall wart has 14.3 v written on it.
After 17 hours the battery only has about 5.5v in it, the plug from the charger is outputting about 8 volts.
This is not enough for the machine to make one little beep.
Nothing happens.
It looks like at this rate it would take twice as long to charge it.
Unless I have a bad battery and charger,sure hope its not the Excal.

I called Minelab and was told they would call me back in about 24 hours. This is not good, the machine is brand new.

Im not looking at it but I remember seeing the charger saying nicad I know this is supposed to be NIMH battery.

Did they put an old charger in?

 

[syko]

I shouldnt have to buy a new charger but who has a link to this sunray charger, I have a quick charger used for 7.2 but dont want to take a chance and damage this batt pack cause it charges too fast . Does anyone know the rate it charges at (mAh?)

 

[TexasDigger1]

Don't know if a nicad charger will charge nimh batteries, I'd like to know myself....HH

 

[erikk]

Sun-Ray SR-12 no longer in production To bad

 

[syko]

Found this info out
Remember my Minelab charger says nicad not nimh, but my batteries are NIMH.
My charger is NICAD model 119 .. output 14.3 volts 60 mA.
What model do you all have? Thanks for your help...I'm pulling my hair here.

edit*** this is a pic from Minelabs website of what is the mains charger..mine does not look like that or
put out 100mAh.

http://www.greenbatteries.com/bachfa.html#NiCD charger for NiMH batteries

Can I use an older NiCd battery charger to charge NiMH batteries?



The answer to this question depends on the type of NiCd charger. Depending on the type of NiCd charger you have, the older NiCd charger may undercharge NiMH batteries (most likely), it may overcharge them (less likely), or it may charge NiMH batteries properly (but it's not likely to do so automatically and could take a very long time). Let's take a look at the three cases.



Many of the older NiCd chargers are the simple timed type charger which will charge batteries for a fixed amount of time and then shut off. Unfortunately, since NiCd batteries have a much lower capacity than NiMH batteries, the timer is likely to shut off long before the NiMH batteries are fully charged. This won't harm the batteries, but the NiMH batteries won't be fully charged since the timer will have stopped the charge cycle too soon.



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 found above.



The final possibility is that the older NiCd charger is a rapid charger that will charge NiMH batteries but will not have the necessary circuitry to stop the charge cycle once the NiMH batteries are fully charged. If the NiCd charger is designed to charge batteries in less than two hours it may be this type. In this case the risk is that the older charger will overcharge NiMH batteries. This will be apparent if the batteries get very hot during the charge cycle. (It is normal for NiMH batteries to get warm as they become fully charged, especially in a rapid charger). If the NiMH batteries get too hot to handle and stay that way for more than 20 or 30 minutes, then the NiCd charger is most likely overcharging the NiMH batteries and may shorten their life. You would be most likely to encounter this type of charger if the charger was designed for rapid charging radio control (RC) vehicle batteries. We would recommend that you not use an NiCD rapid charger to charge NiMH batteries.

 

[syko]

This is what my battery looks like when you look at it head on. Is that what you guys have also?
I checked it again after being on longer and it shows around 6.12 v.
This charger must be the problem unless battery is defective.
I emailed Minelab and received a call asking me for pics of charger and battery. Said it was late
their time but will get a call from a tech tomorrow. I got the call minutes after my email
and was asked to send pics and was apologetic. That sounds like good customer service and am just waiting
for a fix and everything will be okay. I know Minelab is a great company, but once in a while there could be something
missed. I don't think the detector is bad...something going on in the batt or charger.

Will keep ya posted.

 

[billinstuart]

Defective charger. Had the same problem..connected another charger and problem went away.

 

[Madmans Legend]

I suspect your rechargable battery pack is shot. The reason you are seeing such a low voltage across the battery pack terminals is the internal resistance of the battery pack increased from multiple overcharging of the battery pack. Sometimes the battery pack can be rejuvinated if you fully discharge discharge it and recharge it to its nearly full capacity by using a slow charge. It is safer to charge a NiMH or NiCAD pack at 10 percent of a battery packs charge capacity. That means that if you have a 2000mAh pack you want to make sure to charge it at 200mA of current for no more than 16 hours. Try to build a discharge circuit that I have provided and do a full discharge on the pack. In reallity you should do a full discharge of the battery pack after every use.

 

[Madmans Legend]

Also make sure the charger you are using outputs about 0.5 - 1 Volts higher than the batter pack voltage and the current output on the charger is between 10-40 percent of your packs current capacity (mAh).

 

[syko]

Thanks Madman for that circuit, but I don't see how it happened from multiple overcharging
because I only charged it that one time, unless ML overcharged it at some point.
I will not mess with it because I contacted Minelab and am confident they will take care of the problem,
so I will leave it alone for now.
I still think the charger was the problem but ended up possibly damaging my batt and won't feel confident
on the battery lasting the full amount it's supposed to.

But I do appreciate the advice from everyone and if I had a different charger I would have tried that right away.

 

[Madmans Legend]

When you overcharge a NiHM pack what happens is the internal plates inside the cells start producing a gas that causes the pack to heat up very quickly and causes the plates to " Sulphate " preventing the pack from reaching its full charge. But in your case you say you charged up the pack only once it sounds like the charger isnt properly matched to the battery pack. The charger should produce around 16-18Vdc when the charger output isnt connected to the pack and should drop to around 12.5-14.5 when you connect the battery pack. The battery should be charged with about 100mA and the power supply should be close to that current rating as well (100mA). Thats why I have a Spectrum XLT with a NiHM pack that has over 7 years and still using it. The pack dropped its total capacity from 100% to about 88% but i fully discharge the pack after every use with the circuit I provided above before I slow charge it.

 

[syko]

Well I got a new charger sent to me by Minelab. It was the problem.. luckily it was not the detector that was bad.
Will probably get one of the chargers others use later on. Now I need a good scoop and I can hit the beach.