Tesoro 9v battery upgrade = 100 hour run-time for $1.25

Afro

Tenderfoot
Nov 14, 2011
6
1
Primary Interest:
Metal Detecting
The new Sanyo eneloop AA NiMH rechargeables came out in November 2011. They are 1900 mAh capacity and hold 90% charge for 12 months, rated for 1800 recharges and have low internal resistance for extended runtimes. These are the batts I want to feed my Tesoro.

I want to make an external battery pack that will run much longer than a normal 9v alkaline (500mAh) or regular 9.6v NiMH (200mAh) rechargeable.
Nominally 8xAA NiMH = 8 x 1,2v = 9,6v @ 1900mAh. This should not cause any problems at all because some "9v NiMH rechargeables" are already putting out 9,6v and it will have a 4 times run-time of the 9v alkaline.

My local supermarket sells a 9v alkaline for R50 but I can get a six pack of AA alkalines (2700mAh) for R40 and they have 5x the capacity (or up to 100 hours run-time) compared to the little 9v. This seems to be a no-brainer, getting 5x the run-time at 80% of the price of one 9v alkaline. Harbor Freight has 24xAA alkalines for $4.99.

The one thing I haven't figured out is a fool proof solution to handle 6xAA alkaline = 9v and 8xAA NiMH = 9,6v. Some 'Muppet' is going to refill the 8xAA battery holder (meant for the 1,2v NiMHs) with 1,5v alkalines and blast the Tesoro with a full 12v.
 

N2CU

Full Member
Feb 13, 2011
136
7
Orchard Park, Western NY
Detector(s) used
Minelab Equinox 800, Fisher F70, Pro-Pointer
Primary Interest:
All Treasure Hunting
Take two dead AA batteries and solder a shorting strap from their positive to negative contacts. Put these in the battery holder when using alkalines, take them out when using NiMH's. Get a label made up and stick it near the battery holder with instructions.
 

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