Ron, 14.5V probably is just about right. You see, cheap transformers will output a higher voltage until the pack (load) is put on, but better ones wont sag as much, or will read the pack to see the # of cells and then raise the voltage to where it needs to be to charge it. Even if that charger don't sense the cell count, I bet 14.5V is fine. It probably won't sag under the load much and stay right around that, which is about perfect for a 10 cell nimh pack.
I think. Can't remember off hand but it's either a 8 cell or 10 cell nimh pack charger that should be around around 14.5V output while under load from the pack. The tricky thing is reading the voltage. If the pack is way dead if you throw a volt meter on the thing while it's charging, the voltage output might read say 8 or 9V perhaps, until the pack gets up there and raises as the charger raises.
Off hand here, by memory, and not reading/testing that much in the past since never saw a need to. I'm saying though that 14.5V is probably perfect for it, regardless of if it sags some under load, I bet it'll rise back up to that once the pace is near charged. You should be good.
The bigger deal is knowing the output current of that charger. Divide that into the capacity of a completely dead pack and that should give you roughly charge time, though overshoot that by about an hour to be sure. If the pack is say half dead then split the capacity by half of the pack, then divide the output of the charger into that. Off hand I think the GT draws around 50 to 70ma, so # of hours hunted times that = how much capacity was taken out of the pack. If the charger has 100ma output figure around half the charge time to charge the pack as the # of hours you hunted, but I would overshoot that by about an hour due to the inefficiency of the charging process.
Also, a car charger won't necessarily take longer to charge the pack. All depends on it's output current. Read the output of it in mill amps, then compare to the stock wall transformer for the pack. I know some car cell phone chargers are slower than wall outlet ones, but only because the one meant for the car has a lower output current.
I hate these simple wall transformers often given with detectors, or the same deal with cordless drills. With no way for it to know when the pack is peaked when it's fully charged, you are slowly destroying the life of the cells. If it's more than just luke warm for sure it's peaked, or is being charged too fast. When I used the stock GT pack I charged it via the main battery leads (you can't use that little charge plug) with a good charger so it would tell me when done. Plus I could charge in say 1 to 2 hours, and also could monitor capacity put back in via the display. If you know where to look a good computerized charger is around $20. Accucel 6 is the one I use, which will do numerous cell types, and has a computer display, though it requires reading on the net to set up right and know what you are doing. It does things chargers over $100 won't.
At least I encourage people to get a simple plug-n-charge nimh charger for the stock nimh GT pack. The pack is 1000ma, so I would find a charger that will do up to at least 10 cells (10 cells in the stock pack) in nihms, and also shoot for around 300 to 500ma output, which would be about 2 to 3 hours charge time on a near dead pack or so. Make sure it clearly indicates the charge being completed. If pushing it I will charge a 1000ma nimh pack at 1 amp, or even 1.5 amps here and there, but if it's getting hot then stop, as it's stressing the pack and will give shorter life. Feel the pack about halfway through the charge and near end too. Hot then never charge that fast again. Luke warm is normal, like a warm bath at the most, and even then that's getting sort of hot.
