Using my Bluetooth-linked GPS unit with my iPAQ 2210 Pocket PC has the serious downside that the 1000 mAH lithium-ion battery runs out after3 hours or so, nowhere near long enough for a day's walking/hiking.
I'm considering buying a higher capacity battery (3300 mAH) but that has the disadvantage that the 2210 would no longer fit its leather case. So an alternative I'd like to explore is using conventional (alkaline or NiMH) batteries. The lithium-ion battery is apparently3.7V. The DC power unit plug that fits the cradle I use when at home reads 5.28V on my meter. So a 6V set of 4 AA or C or D cells are candidates, possibly with a diode in series. Has anyone tried this please? I'm assuming there's protective circuitry to maintain the appropriate voltage anyway. Presumably the lithium ion battery in place would get charged simultaneously? Safely?