Earthmate GPS PN-20 Battery Performance Analysis

[Kurt]

Earthmate GPS PN-20 Battery Performance Analysis

Based on power consumption tests conducted here at DeLorme, and using the average selling price for each power option shown, we recommend the following battery types when factoring cost per hour. Of course, any AA battery type will work and this information is provided to give you a baseline of information.

DeLorme Travel Power Kit

Rechargeable CR-V3 Li-Ion supplied by DeLorme: 500 charges, 11 hours per charge, average cost of .0010/hour. (Average full charging time in the cradle or in the device: 5 hours.)

AA Battery Types

AA Energizer Max: 14 hours, at an average cost of .12/hour
AA Energizer e2-Lithium: 22.50 hours, at an average cost of .22/hour

[DavidLibby]

AA Energizer e2-Lithium: 22.50 hours, at an average cost of .22/hour

Just a quick side note. It may seem the 22 cents an hour is a bit pricey but there are a few reasons to use them.

1. They are the lightest batteries on the market. If you are backpacking and need batteries you will have to pack less (Long run times) and those you pack will be lighter.
2. Cold weather they have an operating range from -40° F to 140° F, other batteries suffer in cold weather and will give diminished run times.
3. Overall power is fantastic as you can see we got 22.5 hours of continuous use out of the batteries.
4. 10 year shelf life. These things are great even if they are not your primary power source (I use rechargeable batteries) I keep an emergency set with me so If I get into low power I can just pop them in and away I go.
I go.


Dave.

[rowen]

Rechargeable CR-V3 Li-Ion supplied by DeLorme: 500 charges, 11 hours per charge, average cost of .0010/hour. (Average full charging time in the cradle or in the device: 5 hours.)

By implication, the DeLorme battery costs $5.50? Where can you buy that? Cheapest R-CRV3's I've found are around $8.95.

Since DeLorme only sells this battery in the travel kit for $40 bundled or $50+$7 shipping separate, an hour's run-time cost is, respectively, 7 and 10 times your quote of $0.0010. But at 400 8-hour charges, the hourly run cost is 12 to 18 times your quote. Compare those 400 x 8 hours with $0.0986 per hour from Best Buy's Energizer Max 16-pack (at your quoted 14 hours per set), and the AA's are costing 7.9 to 5.5 times as much.

If you think in terms of how many full days you'll use this GPS, you can see from the table that at about 75 it's a toss-up whether to buy the unbundled kit; for the bundled kit, that's at the 50 days mark.

# of
8Hr---Bundled--AA---------Unb'led--AA--------AA
Uses-$40-------Diff--------$57-------Diff-------Cost
400- $0.0125 $275.520 $0.0178 $258.52 $315.52
200- $0.0250 $117.760 $0.0356 $100.76 $157.76
100- $0.0500 $38.8800 $0.0713 $21.880 $78.88
050- $0.1000 -$0.5600 $0.1425 -$17.560 $39.44
025- $0.2000 -$20.280 $0.2850 -$37.280 $19.72

Given that the rechargeables don't seem to really fit without promising to eventually damage the PN-20 or themselves, that no one has ever heard of Moyoto batteries before, that some forum users have reported terrible experiences with them, and that one might doubt that DeLorme could really guarantee them for 300 charges, how can you tell if the travel kit is really a great deal?

[CowboySlim]

You might want to run your amortizations again.
I've hit end-of-life on three Rechargeable CR-V3 Li-Ion batteries.
About 5 recharges (1st), most likley 2 or 3 (2nd) and definitely 2 (3rd).
That is the PN-20 did not boot up after the second charge, or first recharge (in my possession) of the third battery.

Now I realize that my three are not a statistically significant sample.

It is just my professional practice to take a conservative, worst case path as prudent risk management.

Consequently, I am looking forward to a lifetime of NiMHs.

Slim

[Fullcampy]

I have been looking at all of the threads about battery issues, as my brand new unit came with the travel kit and the included battery just stopped working. Also, the included corded AC adapter that plugs into the charger itself did not function. Now I am wondering if the AC adapter was bad after all, or if maybe the battery had issues.

Delorme is sending me a replacement AC corded adapter, but now realizing I have the same QC issue others have had regarding the travel kit.

I suspect that Delorme may have gotten a good price on the battery package, but that there must be a QC issue at the manufacturer that may have been driving that pricing. Just like buying wine that is after its time, you may get some good ones in the batch, but you have to assume there will be plenty of bad ones in there as well.

[seakayak]

I've only had my unit 3-4 weeks.. But with the rechargable battery when I first used it, it didn't last a day. Ive recharged it twice now and every time I get MORE time. I can use it now for more than a day of caching. Haven't even used the pen lites yet. I've read a lot of the complaints about the battery pack and had concerns, but after my experience.. I like it..

[CowboySlim]

Well, as I mentioned three posts above, I've had three successive rechargeable battery packs go out on me within three recharges or three days, whichever came first.
I kind of got tired of the RMA business, which seemed pointless after 3 quick failures.

But, as FC mentions, some of those other peripherals seem a little cheezy.
Now the jinglebob that plugs into my cigarette lighter has split and I have together with a nylon wire tie.

Well, we have an off road trip this weekend so I'll wait until Monday and call tech support for an RMA jobbie.
I'll see if they'll deal with the 3rd failed battery pack in addition to the split 12V adapter/plug.

[Cabornay]

CowboySlim,

You should buy a RCRV3 pack from that place I did. www.all-battery.com
They are $9.95 and you do not need another charger, the Delorme charger will work fine. My packs are working great. I just tried a Energizer Titanium. Nothing to brag about on total time. Other than the rechargable's, that Energizer Lithium is tops.

Good Luck

[CowboySlim]

Thanks, Cabornay,

I bought the Delkin RCRV3 pack from Thomas several months ago and it works just fine.
Keeps charged in my Jeep using the cable from the DeLORME travel kit.
Never have to take the pack out of the PN-20.
That it has worked that long for me is evidence that it is not my fault that three OEM battery packs have failed after no more than 3 days each.

Now that the cigarette lighter receptacle adapter has split, I want to send it back.
It is currently bound circumferentially with a nylon wire tie, not pretty.
So if it goes back, the third failed battery pack may as well also.

[rowen]

Can you charge the Delkin batteries inside the PN-20 using the cable that comes with the PN-20? (Not the cable in the "travel kit."

[CowboySlim]

Rowen,

IIRC, I performed a bunch of cable - 12v source charging previously.
You might do a search and see if that comes up.

Regardless, I just ran a quick check.
I can charge the Delkin battery pack when it is in the PN-20 from a 12V source with either cable.

However, the travel kit instructions note that such charging can be affected with the PN-20 turned OFF or ON.
On the contrary, in GPSr charging with the other cable can only occur with the PN-20 ON.

[benjamin921]

Well, I picked up one of these. I charged it for just three hours that night and the next morning took it to work with me and turned it on and left it on. I placed it next to the window so it had a lock and turned the back light on to 50%. Through out the day I would mess around with it quite often and the charge lasted just over 8 hrs. The next time I charge it, I will leave it in the charger longer and see what happens. Taking the battery out is not quite as bad as the one DeLorme has supplied though.

It floats too

[Sanaghan]

I've got a pile of rechargeable AA's.....but the thought of always going out with a charged unit is just to nice to pass up. Dang, they are expensive, tho.

I went with the Moby as well. I didn't need another set of cables and charger floating around. The Moby, while it has a rather large plug head according to reviews, is a single charging unit.

[frischma]

I also purchased Delorme's rechargeable CR-V3-Li-ion battery. I find that charging this battery using the USB port is very inefficient and unusable. As an example, the PN-20 reported that the battery charge level was about 50%. With PN-20 powered on (as required), I left it charge overnight, over 9 hours. In the monring the battery was still not fully charged (only at 70%)! I then charged the battery with the wall charger and it took another 3 hours to reach full charge.

Does this battery appear to be defective or others having problems charging th CR-V3 Li-ion quickly and fully, using the USB power with PN-20? I am puzzled why Delorme designed the PN-20 to be powered on in order to charge the battery. Even with the GPS off, only part of the bus current is available for charging which only lengthens the time required to reach full charge.

Currently, I have decided to use NiMH cells which have a capacity of 2300mAh, much higher then the 1300mAh for the CR-V3 Li-ion. I can also charge these cells in 2 hours, using a the latest state-of-art charger.

[John Moran]

Most computer USB ports, even on desktops, just aren't going to put out enough power to run a GPS unit, plus charge a Li-ion battery as well. Besides, it may not be desirable to even risk frying a laptop motherboard with such adventures.

Some versions of Toshiba laptops have such rinky-dink power inlet connector jacks that they won't even reliably charge the laptop battery by itself.