Rechargeable batteries for Excalibur

[crs]

Hi my friends,
My Excalibur rechargeable batteries became weaker .
As I noticed 8 pieces Ni- MH rechargeable batteries will fit the original waterproof pack. The only problem is, the AA Ni-MH batteries are only 1.2volts. So 8 in series will be 9.6 Volts.
Do you think the Excalibur will work at only 9.6Volt? The original batteries are 12 volts.
What will be the best rechargeable batteries to replace the original ones?

Many thanks,
Crs

 

[Farmercal]

you have little choice. The Excalibur as you indicated needs 12 volts to operate. Someone mentioned a company that put 10 short batteries in a person's personnel rechargeable pod and sent back to them. I can't remember what the cost was but it wasn't that bad. Unless you can modify a pod to hold 10 NiMh batteries.

 

[crs]

Many thanks,

In case somebody might be in the same situation. I found a 2/3 AA size battery. The same size in the original pack. 1.2volt, 1200mA Ni-Mh. So no more memory, plus 200mA extra power. A 10 pieces pack will make exactly 12volt. It will fit perfectly in the original waterproof pack and ready to go. http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=138

 

[GraveDiggerMax-VaBch-Va]

n/t

 

[pb-to-au]

Another of Minelabs engineering triumphs! The batteries get so hot during a recharge they overheat the plastic case which shrinks around the batteries and makes it tough to remove from pod. I just got a new one from Minelab, took the cap off to release the heat and they still got so hot the pod shrunk around them. So if you get a new battery pack from minelab REMOVE THE WHOLE BLUE BATTERY from the pod before you recharge the FIRST TIME!! All that heat can't be good for the NiMh batteries either so your new battery pack should last longer. These Batteries don't last more than a couple of years anyway. I have 3 pods, two of which are for alkaline batteries. The battery holders for those are Radio Shack stock items.

 

[GraveDiggerMax-VaBch-Va]

n/t

 

[Farmercal]

n/t

 

[bdahunter]

[attachment 40351 P9190018-2.JPG]

This baby makes recharging properly effortless. The stock charger for the Excal is a great way to fry your battery.

BDA

 

[pb-to-au]

Well, mine do. Maybe I have a bad cahrger, but they also get mega hot when I use The 12 volt car charger overnight (6-8 hrs.) am I just jinxed?

 

[Farmercal]

My batteries and pod are only a month old. So it might just be that they improved the technology over time.

 

[pb-to-au]

I notice that the charger you feature is 750 Ma. output while the Minelab Charger is 400. I would suspect this thing senses when the battery reaches capacity and then shuts down or goes to a low Ma. trickle charge? I was actually going to go to Radio Shack and get a low Ma 12 volt charger to see what difference it made, say 150 to 200 Ma. instead of the stock 400 Ma.

<p> I got a new pod from Minelab, took off the end cap to let out any heat, plugged it in and the next morning the damn thing had got so hot it had shrunk the plastic in the pod so I had to tap the battery on a table edge to get out the blue pack. New pod, fresh first charge, fried battery. I am going to try the batteries listed elsewhere in this thread just for giggles, cheap enough!

 

[Art (NWOH)]

You say your Minelab charger is 400 ma??
The charger for my 2a ni-cd is 60 ma and the one for the GT is 100 ma.

Where did you get that hot charger? You sure can't charge for the time specified in the manual with that thing.
No wonder you are burning your batteries.

HH

 

[pb-to-au]

Well, maybe I am reading the info wrong.I have had the pod get VERY hot using the 12 volt auto charger (minelab, not aftermarket) with overnight charges. I will have to look at the info on that charger as far as output to see if it is close to the 110V charger. Funny it would happen with both! I was making a comment about the other charger (aftermarket) listed in this thread being nearly 50% higher output than mine, and if I am wrong in my recollection about the output on my chargers then the one posted is 100 to 150 % higher output and why would that not fry the NiMh pods, is there some sensor or other electronic "gate" if you will that senses a full charge and switches the unit off? Now that I have the bug in my ear I will check the Ma. output on BOTH chargers to see if they match

 

[Art (NWOH)]

You need to seriously look at what you have for chargers.
You should have a 60 ma wall charger.
Your car charger should also have some kind of spec and operating instruction.

Minelab tells me they don't have 400ma chargers. That would be nearly 8 times too much current.

The charger BDA has is not made for what he is doing, but does not seem to have caused him any trouble yet. It's a "smart" charger that knows when to quit. Would charge his pack in about an hour I would think.

I have a couple 1 hr chargers for AA bats, and they get the batts hotter than I like.

You have a serious problem of some kind.

HH

 

[bdahunter]

Va.Beach Ron hooked me up with an aftermarket NiMh battery pack and the Battery Tender Jr. to charge the pack. The battery pack barely gets warm because of the smart charge feature of the B.T. Jr., whereas the stock charger from Minelab used to get my NiCad pack smoking hot and the charge life started to fade after only 4 months.
No such problem with the B.T. Jr. and the NiMh holds a charge for weeks, the NiCad is flat after just sitting for 4 days.
When the NiCad gets too weak to make it worthwhile to charge it I will strip out the pack and use the battery case as a retrofit for another NiMh.
VaBeach Ron has been using his B.T. Jr. charger for a lot longer and there are no problems with it that I am aware of.

Cheers,

BDA

 

[Art (NWOH)]

How long does your nicad run your excal after a full charge????
Does the pack start getting hot right away during recharge, or does it take a couple hours to start cooking??

There has to be a reason for this.
Your nicads are shot right now. No doubt about it.

So let's look at a theory........
Let's say you have developed memory in the nicad that only lets it run for two hours due to improper care.
Considering the specs on minelab's nicad chargers and nicads, you recharge for the same length of time that you use the batteries.
So instead of recharging 2 hrs to replace the current that you used up before the pack died, you recharge 12-14 hrs as if the pack was good and had been run down to the "needs recharge" point.
That would constitute an over charge for about 10 hours.

Think that would get hot?

HH

 

[bdahunter]

A full charge with the standard charger (8 to 10 hrs) now yields 2 x 3 hour hunts. The battery would get hot with the standard charger after only a few hours, which was always the case and a cause for concern. Initially I was able to do 3 x 3 hr hunts but no longer.
With the new charger the NiCad only gets warm not hot and it still gives 2 x 3hr hunts but it hasn't gotten any worse since the change over to the new charger.
Left standing without any useage and the batteries drain away very quickly which is why I prefer the new NiMh pack which holds a charge for over a week without useage. As you probably already know as an Excal owner the NiCads have a bad reputation and let's face it, this is old battery technology that most cordless tool manufacturers abandoned a long time ago.
I would agree with your previous post if those were my conditions but I have been very cautious about the charging of the NiCad pack from the beginning as I knew about the problems other Excal users have experienced in the past. Therefore my NiCads have no memory build up to substantiate your theory.
A more probable hypothesis is that the very cheap charger provided with Excal has cooked the battery pack, this makes sense in that the charger is as old a technology as the NiCad pack that comes as standard equipment. If Minelab upgraded the battery/charger provided to something more modern this post wouldn't be necessary.
While they are at it they could change the stock shaft to a more ergonomic straight shaft, provide headphones with decent sound, a coil cover that fits properly and a camlock that doesn't strip out the first time you hand tighten it. Not so much to ask when you consider that the basic model is $1,200.00 and then you need to spend several hundred dollars more just to bring the machine to good working order.
Anyway, that's my theory.

BDA
Excal 1000

PS now that I have made the expensive adjustments my Excal works very well and I find my fair share of loot

 

[Rick(ND)]

That charger is putting out more than those Nickle Hydrides can handle I am sure. That charger looks like it is not made for dry cell battery and made for the lead plates car or motor cycle battery.
Looking at my list the charger for the Excalibur is the same as the Sovereign charger, so the 60 Mha is what is to be used on the Excalibur Ni cad battery. Now if you replace the batteries with the Nickle Hydrides than I would check with the manufacture of the battery what the max charging current can be. I find that some battery can be charged at a faster rate and will get warm, but if this battery can not handle this rate of charge they will get so hot you cant touch them.Also some batteries will get warm while charging and when they get fully charged they can get hot.
This is what was nice with the Sun Ray SR 12 Super charger as it would shut down to a pulse trickle charge so they can not be over charged plus this charger could also restore many Ni cads that were over or under charged so it built up a memory.
I have seen some of the Ni cad batteries use on the XS back in 1996 still working like new yet as they were charged and recycled a couple times a year on the SR 12 super charger. I believe the charging rate on that one was 150 Mha and the batteries would get warm while charging, now a 400 would cook them for sure.

 

[Art (NWOH)]

Something don't look right here......
The standard recharge time is 12-14 hrs, not 8-10. This would be a " short charge" that will cause memory effect and reduce your operating time. It would start to reduce the recharge time too. If you continue to "full charge " them, you will be overcharging.
Now you are up to 2 kinds of damage.
Getting them very hot......up to 3 kinds of damage.

One of the methods used in automatic chargers to determine when full charge is reached is a temperature sensor. When the batteries get hot enough, it turns off. There may already be some damage at this point. Would depend on what level the charger is set to shut down at, beginning temp of batts, and room air temp. Not very trustworthy, in my opinion.

With a "dumb" charger you have to calculate recharge times for ni-cd batts. You don't want to over or under charge them.
Unless there is something wrong with the pack or the charger, you can simply follow the easy method of giving a full recharge time when the pack has run down until the detector stops working.

There can be hidden problems ......
Lets say you have a bad cell in the pack, or the charger is putting out the wrong voltage. The battery pack will self-destruct over time because operating time and recharge time no longer line up right.

My poor old ni-cd in my 2a is almost 5 years old. It can sit unused for a month and still run 6 hrs. It will run for 12 hrs on a fresh charge. I don't have any problems, and I don't do anything to make problems for myself. It took a lot of years destroying ni-cd powered devices through my own ignorance before I got things figured out.

The way I see it, there is nothing wrong with ni-cds if you go to the extra bit of trouble to take good care of them. While it would be good if Minelab switched to ni-mh batts (eliminating memory effect) you would still have to worry about reverse charging, over charging, and over heating.

If you want Minelab to add in some "smart " chargers to prevent overcharg and over heating, you could also add in an increase in the price tag.

HH

 

[pb-to-au]

I went and looked last night at both chargers, 110 and auto chargers, and you
are right they are around 100 ma 12 to 16 volts.
Less than I thought. I am going to investigate something like that battery
minder thing but I don't see where 750 ma is ok, even for one hour, and would not the battery life be shortened by repeatedly "quick" charging at 750? I am going up to the N.H. lakes region this weekend to play in the water with the WOT coil and will start off with the NiMh packs to see how long they work, and will be bringing plenty of alkalines too.I will probably end up getting a set of the batteries mentioned elsewhere in this thread and a charger as well, so I will have more batteries than God himself!