Adding an extra battery

[below2doe]

Hi Guys,
Have posted this on the v3i forum with no replys. As you can see in the first photo there has been another aa battery added to give the pack more lasting power. What i want to know is how to wire in the extra battery and have it so i can remove it like the other 8 so can be charged outside the pack as this is only a alkaline pack.

Regards Below2doe.

 

[Jeff In North Georgia]

I wouldn't add the extra battery but would change the type of battery you are using.

I have a Minelab Explorer, it is meant to use 8 1.5 conventional AA batteries or a 8 1.2 AA recharge able pack.

I been using 8 Powergenix NiZn 1.6V (yes I said 1.6V) batteries. Most days the battery meter never moves off full. I have a special charger that charges them in the pack holder so I don't have to take them in and out all of the time.

Jeff

 

[GoGoGopher]

The way the pack is currently made, your not going to be able to ADD the extra batery and keep the voltage the same...The batteries are wired in series, adding the voltage of each cell 1.5V to get 12V total...If you add the extra battery in series, you get 13.5V...this should be OK for the machine, as it has 1 or 2 regulators inside to bring the voltage down to I believe 6 or 9V...I cannot remember which...getting that one battery out from where you picture it is not gonna be easy no matter what you do...as stated above...I would go for better batteries...Powergenix, or PowerEx...they are true 1.6V rechargeables...

http://www.zbattery.com/Maha-AA-NiMH-2700mAh-Batteries-w-FREE-Carrying-Case

http://www.zbattery.com/

HH,

 

[Larry (IL)]

As stated on the V3i forum, Rob (IL) is on vacation and will be back today or tomorrow. BUT, that pack was made by him 4 or 5 years ago for the MXT that runs best at 10 volts or better. The extra cell brought the working voltage up from 9.6 to 10.8 with the added cell. That extra cell in not needed for the V3i. Since that pack was made, the new Ni Zn batteries have came out and have further eliminated the need. Rob only showed that configuration for those who wanted to "play" with their packs.

The batteries were not designed to come out, he modified the alkaline pack to be charged like a regular White's rechargeable pack by adding a charging jack as well.

 

[Rob (IL)]

Those are 2500 mah NIMH batteries. That pack was designed to take the batteries out and charge them on a separate charger. For the V31 I modified the pack to leave the batteries in the pack and added a thermistor so it is charged in the regular Whites V3i charger. The new pack gives me 12 volts, batteries stay in, and uses the Whites charger.

It is nothing to get the cells out of the pack, the 2 contacts covering the 9th battery just lift off. It doesn't take 10 seconds to get the 9th cell in and out.

The V regulates voltage to 8V and 14V is safe.
[attachment 208575 pack3.JPG]
[attachment 208576 pack4.jpg]
[attachment 208577 pack5.jpg]


ROB

 

[below2doe]

Hi Rob[il]

Thanks for the reply
, fantastic.

Regards Below2doe Down Under In Oz.

 

[gilfordberry]

I believe these new NiZn batteries are 2500mWH (milli-watt-hour) batteries, not mAH (milli-amp-hour)....assuming full voltage (1.6V) until battery death, that would make them equivalent to a 2083 mAH 1.2V battery. In any event I agree the easiest way to do this would be to simply purchase high capacity NiMH (2700mAH?) batteries and use them in the alkaline pack, removing them to do the recharge on a NIMH "AA" charger. You could, of course, adapt the pack to use the White's charger...but why bother? How long does it take to dump 'em out and put 'em into the charger?

 

[Rob (IL)]

This is an old post but it is so easy to put in the thermistor as I did later. Believe me it does last longer. After a day of hunting it still registers 11.3v which is what a pack reads right of the charger.

Is it necessary, no but this is a mod forum. And also who wants to use 2 chargers one for the mod pack and one for the Whites rechargeable packs.

 

[ivanll]

There is an easy way, as Jeff in Nort Georgia pointed out.

Search for NiZn Battery...............when the page opens take the 4Th choice down from the top (NiZn Battery)

Now select to your need...........they post free to Au.


ivanll

 

[Rob (IL)]

This was an old post and an old pack design.

Some of the reasons I didn't go with the NiZn cells as I said was I didn't want to use an extra charger. I also didn't want to keep putting them in and out of the case, I did that with the first pack I built. Also guys were complaining about a high failure rate on these cells. if you check the reviews on Amazon you will see.

When freshly charged, the NiZn terminal voltage is around 1.85V, which is dangerously high for most battery-operated appliances. These would still work in my Whites but if I am not mistaken Minelab says 13v is their limit.

According to technical data found on PowerGenix web site, the NiZn cell is only rated for 200 cycles at 100% deep discharge. Most NiMH cells are rated for 500-1000 deep discharge cycles.

NiZn cell does not pack more energy than eneloop NiMH cell, yet it suffers from lower cycle life and higher self-discharge rate.

[size=large]I say use what works for you.[/size]

 

[Critterhunter]

Adding an extra battery won't do a darn thing to increase performance as detectors have a regulator that only allows a fixed lower voltage to the circuit board. I assume the mod is being done to increase run times by keeping the voltage higher so it hits LVC (low voltage cutoff) later on in the discharge for more run time. If that's the case you'd be better off just sticking with 8 cells and using a higher capacity nimh cell. 2500ma or higher should give you more run time than a store bought non-rechargeable battery. At least it has for me in devices I've used them in.

 

[ivanll]

[size=large]I say use what works for you.[/size]

I'll agree............but it is nice to be aware of what is available.

eneloop cells are my favourite, have used them for years and not yet had a failure.

ivanll