Garmin GPS III Pilot battery questions.

[Rupert S]

Does anyone know what the average battery life on one of these GPS units is?

Also, can I use rechargeable batteries?

[Genghis the Engineer]

Not sure about (a), but rechargeables are generally hopeless in GPS units due to the slightly lower voltage.

But, if you buy one of those gadgets that recharge normal batteries, those work very well, since a GPS normally only takes a battery down to about 60% charge before declaring it flat.

G

[Lowtimer]

While I hesitate to contradict an engineer of GtE's experience, I must report the opposite. I have used a variety of Uniross NiMH rechargeables in both my GPS-12 and my GPS-Pilot III and never had any problem with them at all. These are the ones you can get at Tesco. I have various sets of 4, which I keep segregated in packs through their charging and discharging lives in various appliances. They come in various nominal capacities, the cheaper ones are now 1300 mAh, there are some others a bit more expensive at 1850mAh. The GPS-12 gets used on and off over a period of about two weeks in various vehicles, with and without the backlight, and usually manages around 7-8 hours mixed use on the 1850 mAh cells. The GPS III I use differently: I always use a faully charged set (no more than a couple of days old) when I start a day's flying, and discharge them before recharging. Under these circumstances, normally without use of the backlight, I get a consistent 13-14 hours on normal mode. Both GPS sets have an intermittent "battery saver" mode but I've never used it.

If you want to use Nicad or NiMH batteries a lot it is worth investing in a decent charger / discharger (you want to run them down to a consistent voltage per cell, not completely flat, before recharging), and bear in mind also than most rechargeable batteries don't deliver their full performance until they have been "run in" with a few charge / discharge cycles. The people who know most about the capabilities of these calls are those involved in flying electric-powered radio-controlled models: running them in a low-current device like a GPS is a piece of cake compared to what model flyers put them through.

There are plenty of reputable on-line suppliers for this kind of gear in the UK, I shan't name any here to prevent upsetting the PPRUNE "no advertising" ethos.

I have no idea what if anything I've been doing differently from Ghenghis, but I'm very happy with these Uniross cells.

[--o-o-0-o-o--]

Rupert S,

I use GPS111 regularly and have found re-chargeable batteries work fine. I asked at shop for 'longest life' batteries.....they (Dixons) suggested VARTA AA and Varta re-charger.

I have never had any trouble (touch wood), and have found the batteries remain charged for well in excess of 12 hrs. Personally i have never needed to use it for more than this. I just charge them up at night then they're ready for the morning's bumble around in the old 'petrol pigeon'.

:)

[Genghis the Engineer]

Contradict me all you like, I'm an aeronautical engineer - I don't really understand this electronics stuff, and a GPS is just a tool I use like anybody else.

And incidentally, I use a Magellan handheld, my second - I've not owned a handheld Garmin - we've got a panel mount GPS100 in the PA28 which is looking long in the tooth, but still continues to work well.

I'd still recommend one of those "recharges normal batteries" devices by the way, saves me a fortune.

G

[Snigs]

I have never had any trouble with my Pilot III and I use the Uniross NiMH rechargeable batteries.

Just remember that you should change the GPS battery setting default to the NiCad setting (I think, not got my GPS to hand), this might make the unit use the battery more efficiently.

[GroundBound]

I've replaced my Garmin PIlot III with another newer handheld. However, from memory, Duracell AAs lasted between 8 and 10 hours.

I also used NmHi rechargables (1400 milliamps comes to mind)which were slightly less powerful than standard AAs and ran out slightly more quickly (maye 6 - 8 hours?).

GB

[david viewing]

Genghis

I'd still recommend one of those "recharges normal batteries" devices by the way, saves me a fortune.

The only snag here is that these 'rechargers' can cause the cell electrolyte to leak with devastating consequences for the equipment, especially those where you cannot replace the contacts. It's a particular problem for aviators because of the altitude changes.

[140cherokee]

Assuming your aircraft has electrics, why not use the cigar lighter lead? I usually get through just one set of Duracells a year, where they're used as a backup for the cigar lighter (I change them when they show 50% remaining).

140

[Algirdas]

Rupert S,
for what it's worth, I use Uniross Ni-MH 1700mAh rechargeables in my Pilot III, and get a good day's flying out of them - the worst I have seen in 5 hours, but that was when I forgot to fully charge them the night before - I normally see at least 6-7 hours use per charge. I've never used disposables, so no idea how that stacks up against them - though I carry a spare 4 pack - so I may find out one day!