All the rechargeable pack for the Sovereign use the 10 cells so it will have 12 volt operating voltage. I know a freshly charged pack may read over 13 with a multi meter, but this is not a load voltage you get with a multi meter and will read higher. The Sovereign does need 12 volts to work correctly,Some will work for a while before giving a low battery alert, some will not work correctly either and lose depth and not respond correctly too I feel. Just think the alkaline pack take 8 AA batteries that are 1.5 volts each which we all know will read over 1.5 volts each on a multi meter so the pack too will read over 13 volts and this is what Minelab uses for a alkaline pack.
Over the last 10 years with the Sovereigns we have seen many have different problems with the Sovereigns only to find out they were using 8 rechargeable Ni cad or nickle hydride in the alkaline pack and when they put in 8 of the alkaline the detector worked fine. Back a few years ago I remember someone doing some testing with using 8 of the rechargeable in the alkaline pack only to see it didn't have the depth and didn't respond right with the 9.6 volts instead of the 12 volts required. It was then tried with a extra cell so it had 13.5 volts and found that didn't increase the depth or performance as the Sovereign has a internal voltage regulator so the voltage is regulated to a certain voltage if too high, but can not bring a lower voltage higher then what it is to meet the required voltage.
In all the Sovereigns I have sold and bought new and used I have never seen one with a FET problem, but there is always the first time for anything.In all the detectors I have used in the last 34 years the Sovereigns have been the most trouble free detectors I have seen. I had one new one with a bad sensitivity control right out of the box and one used one someone tinkered with and shorted it out as they didn't know what they were doing, it was so bad Minelab was unable to repair it.
Good luck with your original Sovereign and if you have any problem or wonder on the Battery voltage give Minelab service dept and call and I bet they have seen problem of low voltage by those trying to run 8 rechargeable in the alkaline packs.
Now on the Explorers this can be done as the factory pack have only 8 rechargeable (9.6 volts) in them and the alkaline pack has 8 of the 1.5 volts (12 volts) but with the voltage reg it only uses the 9.6 volts it needs to run.
Rick
