Battery Chargers

It drives me nuts not to have a charger or a way to determine if my Xcal is charged. I noticed yesterday i have a fishing knife and the car and house charger fits perfectly. The AC one reads 9VDC at 1A while the ML charger reads 14.3 VDC at 60 MA. What kind of issue can i run into here? Id love to be able to use the car charger. I dont want to grab my detector and find out it takes even longer than the ML charges does. Ive seen some posts where people did some mods to charge these pods in less than 15 mins. but they dont appear to be cheap to do.

Dew

Same with me I would always try to keep track of the hours and fortunately never ran out of juice. I can't get myself to spend $150 plus on a spare. Back in the summer the thought occured to me if I had to recharge it next time I was down in Florida there would be down time as I'm pretty sure that battery takes over 12hrs to recharge (pls correct if wrong). I ended up just getting the alkaline pod and that was still around $80., but its worth the peace of mind.

I also most bought one of the alkaline as well.... then i read they were NOT water proof only resistant. That defeated the purpose for me. Everything to do with a ML is expensive. I do have to say the Pods seems to last very well.

Dew

I know nothing about the excalibur's battery pack construction, but it appears it can be dismantled in some way to allow replacement of the cells. A manufacturer of aftermarket battery packs here in the UK, Strikalite, list two packs as suitable. The NiMH is much higher capacity, I imagine it would probably take 2 days to fully charge using the existing (trickle?) charger, but would give much greater run-time. Website address is strikalite (dot) co (dot) uk. Hope this helps.

Dew,

There is TOO much of a delta/differential between your fishing knife charger..... vs ...... the ML charger. Your fishing knife charger is 1000mA and your ML charger is 60mA. I do NOT recommend 'trying' it. Besides......... the voltage difference is also in great error.

I would STRONGLY recommend the regular AA battery pod...... as a absolute 'emergency' backup. If you are traveling a great distance from home.... and should need to use the non-rechargable battery 'emergency' pod............ you could RTV coat the pod....... knowing this would be temporary...... but only IF you thought you may enter the water.

Thanks Tom..... better safe than sorry. But it just ticks me off they didnt at least put a pair of dummy lights showing it had completely charged the battery. We pay big bucks for these units as well as for a replacement Pod should this one die and they give us a China charger. Thats just wrong.

Dew

I have the exact same issue with my AquaStar-II..... and will ALWAYS carry an extra set of (very expenisve) batteries.

Well.....
The pod being only water resistant is news to me, oh well.
Glad to know before I go in the salt water.
Thanks Dew

I don't know how it could be just water resistant... it's virtually identical to the rechargeable pod. Just put some silicone grease on the washers as you close it back up and call it done. You're not diving for the Titanic.

If you're really concerned, you can build a quick charger fairly easily, but not cheaply. Google is your friend.



Edited 1 time(s). Last edit at 10/25/2011 02:28AM by Shambler.

On page 15 of the Xcal manual...... and i quote: The alkaline pack is water resistant but not water proof so is suitable for land and beach shallow-wading ONLY. This pack is NOT sealed and MUST be opened to replace the batteries.

Believe it or not it goes on to say rechargeable NiNH batteries CANNOT be used in the Alkaline pack, as they do NOT provide sufficient voltage. I suspect thats why they are half the price. If you have your unit chest mounted thou you can still hunt in the water.... just dont dunk it for a prolonged time or use the water hose with pressure to clean it. Its not a big deal if you remember you have it in and intend to wet/dry/shallow water hunt. Of course this may be a disclaimer and we all know we can MOD anything that isnt cost affective for the manufacture.

Ive have a friend that sent me a HOW TO on the unit.... or should i say units since it requires two devices an example of it can be seen at: [metaldetectingforum.com] The guys i know swears by it. But for the price it might be just as cheap to get a second pod.

Dew

"The alkaline pack is water resistant but not water proof so is suitable for land and beach shallow-wading ONLY."

I only do shallow-wading anyway, and the machine is never more that 2ft below surface,,,,,soooo, according the above statement I should be safe.

Aaron..... that was so Shambler understood where i got that information. I also got this from another site: "If I understand the post correct. The 9vdc will not charge past say 9 volts. The Excal battery is dead long before 9 volts! So it would do nothing but trickle your battery. The batteries are fully charged at around 14.3vdc they drop down pretty quickly to around 12.6vdc and will run with reduced depth till around 11.3vdc then the threshold will raise till you can't hear targets. I ran some test with Minelab back in 2010 to trouble shoot a Excalibur battery issue! Not sure this was the answer." Is that how it works? You have to have a charger that produces 14 plus VDC to fully charge the battery? If so how does one increase how fast it charges..... by the MA out put? The site i showed a 13.8V being used.... so is it the GWS thats fast charging it and is it being fully charged? I believe i read that the ML Explorer adjusts the power to ensure the coil receives sufficient coil voltage through out its use. I can say on my DFX you could notice after half use of the battery you lost depth. Havent seen that with the SE or Xcal..... maybe its happening and im not noticing or im not getting to that point after 6 hours of hunting. I do realize setting, headphones, and targets will reduce the battery life.

Dew

The reason given as to why NiMH cells should not be used in the dry cell pack is correct. The small difference (1.25V vs. 1.5V) adds up when there is 8 (?) cells in series. The proper sealed Nicad/NiMH packs will have 1 extra cell in them to give the correct voltage. It's a similar thing to those PP3 9-Volt block batteries - crack open an alkaline one, there's 6 cells in series, open a NiMH, there's 7 cells.

It's water "resistant" because they know you're taking it apart and putting it back together. They don't want to be liable for your carelessness. Just use silicone grease and call it done. Too much thought into this. I use rechargeables and haven't had a single problem.

Shambler Wrote:
-------------------------------------------------------
> It's water "resistant" because they know you're
> taking it apart and putting it back together.

Thats exactly what I thought!

There should be zero depth/performance loss on today's modern metal detectors....... as the battery voltage drops during it's normal life-cycle. A
voltage regulator' built in the detector creates/regulates a constant voltage to the electronics....... so as to prevent any performance loss as the batteries deplete.

Voltage should be kept at a 'constant' of 14.3VDC. If you want the batteries to charge at a faster rate..... then keep the voltage the same..... but increase the current. Beware...... too much current can be detrimental to the batteries.

With All due respect, in order to charge a battery of any given DC voltage, one must increase the charger voltage in order to increase the charge current rate, this is true of all DC batteries, It is simply a vector a voltage working against another voltage, one cannot increase the speed at which a battery charges without increasing voltage , once the charging voltage meets "equals" the battery voltage , current no longer runs into the battery , and the charging voltage is met, satisfied. Agreed all Dc batteries suffer short life spans doing the quick charge. Please note if you are simply stating that a charger rated at a smaller current output vs. a charger of equal voltage yet larger current output then yes, I agree, time is the only factor involved, slower is better for lengthening the lifespan of the battery.

Tri.... did you take a look at the detector forum i put up? They are using a 13.8 V charger.... is the other device doing the quick charge? Next question is ... is it being under charged because of the 13.8 V charger? Let me get this straight.... if i use a charger of equal V as the factory one BUT it produces more MA then its charging quicker and a second device wouldnt be needed? Thank guys im getting smarter.... i think? Does make sense to get a battery to a certain V you have to produce that much voltage and it wouldnt over charge..... kind of like having your air compressor set for 20 lbs trying to fill a tire to 80 lbs.

Tom..... as far as depth loss i know i dont see any with the Explorer so i was pretty certain there was some sort of regulator.

Dew

There are several strategies used to charge NiMH batteries, but the most common is to limit the current, and allow the battery voltage to settle at its own level. To trickle-charge, this is all you need to do, choosing the current such that a full charge takes typically 12 hours. This is sufficiently slow that overcharging causes very little harm. Quick- charging (5 hours or less) needs some control, as overcharging will cause damage, long-term. Commonly, battery voltage is measured, looking for voltage-peaking or rapid-rises, but temperature of the battery is also often monitored.
Charging a 14 volt battery from a 12 volt vehicle supply introduces the additional problem of needing some kind of 'voltage step-up' circuit, to turn 12 into 'more-than-14'. Such things are available ready-built, from online retailers, such as this one:
[www.ebay.co.uk]
There are many similar types available. Set this to 16 Volt output, and use a suitably-chosen power resistor to limit the current so the battery pack charges in a modest 1 to 2 hours. Use a stopwatch/wristwatch etc to judge the charge time. It's a bit cheap-and-dirty, but these cells are reasonably robust, and with common sense, this will work fine.
If anyone fancies pursuing this, say so, I'll come up with more solid details.



Edited 2 time(s). Last edit at 10/26/2011 10:06PM by Pimento.

More detailed...... and more correct. Thanks for spending the time. Yes .... heat short-life's (kills) a battery .... so 'temperature' control is very important.

Dew I did look at your forum link and the GWS-MC2002 device is a step/up down integrated circuit device, it works using a range of DC voltages from 9VDC-15VDC and works by detecting what is connected to it to automatically adjust a charging (output) voltage.

Now the other device is simply a 13.8 VDC transformer . (rated at 8.5A ) that is connected to the input of the GWS-MC2002 and provides the power for it to do its thing.

In answer to your question, yes it IS the other device that is doing the quick charge. There is a knob that allows you to increase/decrease current output.

My above reply still holds true. To charge any battery to its rated DC voltage one must use a charger at least rated to that voltage. (ie using a 9VDC charger on a 12 VDC battery will only yield a battery charged to 9VDC.)

Pimento is also correct, gone are the days of just plain old battery charger without a built in IC controller chip.

If you are still scratching your head, think of voltage as water pressure and current as the water.....think of your batterie(s) as water containers...the larger they are the longer they will take to fill up.

Using a small, low current output charger is like filling a swimming pool with a squirt gun.

Make no mistake......doing these things will increase your knowledge....yet void your warranty.....those Minelabs are expensive to replace......proceed at your own risk.

Thanks...... its clicked now and i have a much better understanding of what would be required to not only charge the battery fully but at a quicker pace. I was curious since id seen the set up and it seemed expensive and wondered why 2 devices were needed. Ok..... now for my next question. Do they make a device you can plug the charger into that plugs into the wall with an idiot light showing its fully charged? Or.... on the Xcal there is a plug that goes into the detector that the charger plugs into like a cell phone. Is it possible to use that plug in .... and do some sort of inline lite? I know you are going to say..... just use a multi meter arent you? I still like to just look and see its charged before i run out the door to hunt. Ive really not found a need to super charge one since i can hunt all day and its stays charged and i plug it in when i get home.

Dew

I'm slightly confused. Dew, I thought you "would love a car charger", and you had a home trickle charger (the 60 mA one). As it's a trickle charger, you can't really over-charge the battery with it. So if you're unsure whether a battery is flat, part-flat or whatever, just put it on charge beforehand for 10 hours. No harm will come.
One possible issue you may have is this. The 60 mA figure written on the ML charger refers to the current limit that the output is restricted to. This rate is appropriate for 600 mAH capacity cells, and would charge these in 12 - 15 hours from flat. I assume the cells inside the battery pack are AA size. If so, 600 mAH is what NiCad cells used to be 20 years ago. Your battery is likely to be more modern, and could be up to 1200mAH NiCad, and double that if it's NiMH. Consequently your old charger will need 24 hours plus to fully charge the battery. You need to determine what your battery is and then maybe consider a better charging arrangement.
Another thing worth being aware of is the memory effect, if it's a NiCad pack. Performing a complete discharge on the battery every so often with a light load for a long time will keep the performance up.



Edited 1 time(s). Last edit at 10/27/2011 09:00PM by Pimento.

Sorry about the confusion. I was more interested in the QUICK CHARGER i showed in the web site. I was trying to figure out how they worked and see if i could reduce it to a single charger and still get a fast charge. Believe it or not ..... i met the guy yesterday while out on a hunt. He can put one together for me for under a $100. I think the 110 V trickle charger is the cheapest thing made for the Xcal..... like $10. For a $100 i might be better off buying a second pod and just keeping one on the charger all the time. Thanks again for making me battery smart..... knowledge is power lol.

Dew

Dew. It is possible to assemble something cheap out of stuff you could get cheap/free. One useful part you should be able to obtain is a laptop power supply. These are commonly 16 to 20 volt output, with a hefty current available, often 3+ Amps. This could be used to make a 'brisk' charger. Trying to make a really rapid charger is just making things expensive - high currents, the need for precise control to avoid overcharge damage, etc.
I often use these poor-mans charging arrangements - the front light on my bicycle is converted to a rechargeable pack, the charger for that is made from a cellphone charger. It takes 4 hours for a full charge, I have an idea how much charging it needs based on how much I've used it, and I can feel if it gets warm as a secondary 'fully-charged' indicator.