Whites XL Pro rechargable conversion question

[dward51]

Ok, I have a question for you guru's out there...

After seeing the idea of converting the 8 "AA" cell drop in battery pack to a rechargable on this website:

http://66.51.97.78/jb/battery.html

I decided to convert mine. I did not have a Whites charger on hand however and ended up trying to find a suitable NiMh auto charger with the help of our friend Google. Since the Whites model was for a NiCd pack, it made sense to me to look for a model that was made for NiMh assuming there was some difference in the charging methods. I found a manufacturer who will sell single pieces direct and promptly ordered one (Powerstream in Utah).

http://www.powerstream.com/NiMHWMm.htm

I initially ordered their 12v battery pack model, but they recommended I change to the next size down when I told them what type of battery pack I was going to charge. Their PST-5830-8 is what they recommended. So this is where it gets a little confusing to me.

All the NiMh automatic chargers I found said their 12v models were for 10 battery cells, and generally start charging at around 14 volts. Now as I understand it, the AA size NiMh is actually a 1.2v cell and not a true 1.5v. I'm using the popular Everready 2500mAh NiMh's in my two battery packs.

The charger manufacturer recommended I go with a 8 cell charger model and not the 10 cell 12v model. The 8 cell is actually a 9.6v charger. So my question is, will the 8 cell charger be the correct one? I guess since we think of a 8 "AA" battery pack as being a 12v pack that is what is causing me to wonder. Of course doing the simple math of 8 NiMh cells at 1.2v each = 9.6v but again, the detector is marketed as using a 12v drop in pack. See why it's confusing?

So I thought I would throw this out and see what Monte, Mr Bill or any of the others who know a lot more about this sort of think thought.

Thanks....

David W.

 

[Digger]

I am not Monte or Mr. Bill, but think I understand what you are asking. NiMH cells are only designed to provide 1.2 volts each no matter how many of them you can fit into the charger. Some of them will actually charge to a bit more. But for the sake of discussion, lets call it 1.2 volts each. What we need to be concerned with is how much voltage we are providing to the XL Pro. And the answer to that question can be found scattered around on pages 4 and 5 of the Instruction Manual. It says a couple things that help address the issue of providing voltage to the unit. It tells us that 6000 XL Pro has a voltage regulated system that is designed to maximize instrument performance as well as battery life beyond what most battery manufacturers recommend. It tells us that new standard AA batteries will provide 12 volts and peg the scale. Toward the end of their useful life, batteries may check as low as 50 on the meters 0 - 100 scale (50 = 6 volts). It goes on to say that the 6000 XL Pro may not respond to metals when operating at voltages under 6 volts. And, it tells us that if rechargeable cells are used in the standard battery holder, they will need to be removed from the standard battery holder to be recharged by an aftermarket charging system. (My thought is that if someone couldn't figured that out, they need to be using alkalines! LOL)

So, although Whites would like you to buy their #802-5211 battery pack, and their #509-0022 charger, NiMH cells will provide ample voltage to operate the XL Pro.

To address the question on number of mA..... simply put.... for detectors, the larger the number the longer the batteries will last. In the electronic world, E = I multiplied by R. Voltage is represented by the letter E, and represents electrical pressure. Current is represented by the letter I and means the flow of electons. The resistance to that current flow is the electronic circuitry of the detector. So, in this case, the voltage of the batteries has to put out enough power to send a sufficient amount of electrons through the circuitry of the XL Pro. AND, we want it to do that for the longest period of time that we can!

So, if the power supply and voltage regulator of the XL Pro allows it to operate on as little as 6 volts, and if your eight fully NiMH cells provide 9.6 volts, you will be fine. If you are using the 2500 mA cells, and they are fully charged, you are providing 9.6 volts of electrical pressure to push how ever many electrons that the XL Pro requires to operate, through it's circuitry. Since the resistance is constant, you will keep providing however many electrons that it needs, for as long as there is enough voltage to push them through! Once the voltage drops to a point that it is no longer able to provide a sufficient number of electrons for the detector to operate, (6 volts), you will need to recharge them. And, as you probably figured out by now, the more mA your cells are capable of providing to begin with, the longer you can hunt between charges. JMHO

HH Randy

 

[Mike in Tn]

Hey dward51, Digger is exactly right. I use regular single AA NIMH batteries in all of my machines that use AA batteries. I always get the 2500mAH batteries and they will actually last longer for me than alkalines. And my packs will usually charge up to close to 12 volts. So, I would be very careful about adding the extra battery to the pack. I would much rather have a pack at 10 volts or so that one with 13 volts or more which could fry your XL Pro. Now the rechargeable packs you get from White's also have 1.2 volt cells. They do not make 1.5 volt rechargeables. So, by putting the single cells in a regular pack. You are getting the same voltage as from a factory rechargeable pack. And, the White's pack is not nearly 2500mAh of useage time. Now, some people will tell you not to use a higher mAh pack than recommended because they think it will damage the machine. But, as long as the voltage is right. They will work fine whether higher or lower mAh. The only difference is just like Digger said. The higher the mAh, the longer you battery life. The mAh measurement has absolutely no other purpose but, to tell you how long the batteries will last at a particular drain level. Hope this helps you out!!

 

[dward51]

Ok, thanks for the replies but I think I was not real clear on what I was asking.

I'm clear on how much power it takes to run the XL Pro and all about amp/hr ratings and using NiMh batteries in the 8 cell pack (been doing it since day one). I just got tired of taking them out of the pack to charge them so I'm adding the charging outlet like in the link posted in the first post of this thread.

My question was about a them recommending a 9.6v charger for an 8 cell pack (8 AA's is usually thought of as a 12v pack). I was getting pretty close to 1.5v out of my 2500mh batteries when I was taking them out of the 8 cell pack to charge them in my external charger. 8 batteries at 1.5v is 12v, not 9.6 hence my question. Not talking about adding 2 more cells to the pack, just the is a 8 AA NiMh a 12v pack or a 9.6v pack question.

After much web reading and even digging up a 2500mah Energizer box, they are all rated as AA 1.2v batteries (even says so on the box). And yes, the do in fact charge to a lot more than 1.2v in a Energizer NiMh charger.

Ok now to the new stuff.....

The 9.6v 8 cell NiMh Powerstream intelligent charger which Powerstream recommended arrived the other day (minus the adaptor plugs so I had a few days delay as they shipped me the proper adaptor plug to complete the unit. They very promptly shipped me the plugs after I called them).

As an FYI their 9.6 volt 8 cell charger (see original post for link) works fine with a whites 8 AA cell battery pack which has had a power adaptor outlet installed like in the original link. It will charge the whole thing as a pack to 11.4v in under 2 hours from an 8 volt starting level (not sure how long it really took as I pluged it in and it was charged when I next checked on it 2 hours later - the bulk charge rate is 1000mah so I suspect it was charged in well under 2 hours). It did drop back to a trickle charge at 35ma and will float there with any input on my part so this is indeed working as a smart charger. So if anyone is looking at doing the conversion to a AA whites 8 cell pack, this charger will work. The only thing I did different was use a size "N" outlet & plug instead of the size "M" in the original article/link (Radio Shack near me was out of size "M").

As I understand it, the White's NiCd charger is just a dumb charger and has a constant output but a selectable aHr rating (fast or slow charge rate). That's why I was interested in going with one of the intelligent chargers made for NiMh on the market instead of the factory Whites. Price was about the same if you were buying a new whites wall charger, so to get the automatic NiMh charger for the same price as a "dumb" chager seems like a good deal to me.

So now I just need to remember where I put the other power socket I bought so I can modify my 2nd battery pack as well (or make another trip to Radio Shack).

Thanks....

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[Mike in Tn]

Hey dward51, I understand what you were saying now. Sounds like you got it worked out. I might just have to try me one of those too. I got lots of packs but, it is a pain to have to remove the batteries and replace them every time. Pretty neat setup!!

 

[china-clipper]

Is the #802-5211 battery pack, and #509-0022 charger for Nicad or NiMH? Is there a process for building your own rechargable battery pack for NiMH?
Thanks, Rick

 

[Digger]

DFX

 

[china-clipper]

Thanks! I'm looking at some batteries on eBay (Duracell) with 2650 ma rating. I already have a few extra alkaline battery packs and all I need to do is get the plug and diode. Looks like a nice winter project!!

 

[Digger]

That would be a good project. I didn't convert my AA pack. I simply charge the NiMH cells in their intended charger and pop them into a spare AA pack instead of alkalines. Seems to work fine. HH

 

[PokerShark]

I do the same. High mA NiMH rechargeable AA batteries work fine for me. I shop for 2500 to 2600 when I am stocking up. They work just as well as the rechargeable NiMH pack that came with my V3i. The rechargeable AA batteries in the AA battery pack actually last longer than the rechargeable Whites NiMH battery pack. But converting the AA pack to a recharger seems like a great deal of effort to avoid loading it each time with AA batteries. Now I may consider converting a couple left over XLT NiCad packs to NiMH rechargeables in the future - if they will work in my V3i. That would depend on the physical characteristics of the pack more then the electrical properties after the conversion I have no doubt. One can never have too many fresh packs while in the field ya know!!

The Shark