Garmin GPS V & Battery Life

[madone]

Hello all. I got my GPS V about a month ago and really love it....but I have a battery life question.

 

I bought some of these : http://www.thomas-distributing.com/mh-4aa180.htm, The Maha 1800mAh NiMH rechargeable batteries.

 

I did the proper cycling with them, but I cannot get more then 7-8 hours use out of them, nowhere near the claimed 25 hours of use. This is with WAAS disabled and barely any backlight usage.

 

Does anyone else use these batteries in there V? How many hours are you getting?

 

Thanks!

--Mark

[+apersson850]

Haven't checked for the GPS V, but at least for the Vista, the claimed battery lifetime is with the unit in battery saver mode, which means that updating of the position is only every 3-4 seconds, not every second. In a Vista, you get about 75% of the time in Normal mode, compared to battery save mode.

 

Anders

[+Centaur]

6 to 7 hours is what I get with my NoMem 1800's but I run WAAS on and in non-battery saver mode, but with backlight off. Thats why I keep my V plugged in to the car power while driving to the cache, otherwise ill be empty by the time im in the woods. I have yet to try WAAS off and battery saver mode.

-Centaur

[+worldtraveler]

If you want an honest 30+ hrs of use from a set of batteries, change to lithiums. I've used two sets so far in my Garmin V and exceeded 30 hrs with each set. WAAS was ON most of the time with the first set, and OFF for nearly all of the second set's life. Battery saver/indoor mode was on for ~ 1/2 the time with the first set and less than that for the second set. I stopped using WAAS about the same time I stopped trying to operate most of the time in battery saver mode, so maybe that's why the times balanced out.

 

Lithiums are lighter and are also the only batteries that will give useful service at extreme temperatures (from -40F to hotter than you will ever find me caching); that's a real plus if you cache in the winter.

 

At $10 US for a set of 4 batteries, the operational cost is about $0.30 per hour. For that price and the other benefits, it's not worth it for me to bother with rechargeables.

 

Worldtraveler

[Alphawolf]

quote:

---

At $10 US for a set of 4 batteries, the operational cost is about $0.30 per hour.

---

 

NiMH rechargeables cost about $3.00 each. Assuming 8 hours on a set of 4 and a recharge life of at least 500 cycles(4000 hours worth), thats only.003 cents per hour (at the most). I would use lithiums if my life depended on my GPSR, but that would be the only time...

 

"Never take a sunset for granted. Stop what you are doing and enjoy it. You never know when it may be your last"

[+apersson850]

When I measure the current drawn by my Vista, I can see that having WAAS on or off doesn't make any real difference. It isn't really noticable.

 

But using WAAS implies using normal mode, not battery save, and that does make a difference.

 

Anders

[+Gliderguy]

You must not be getting a full charge. On regular Energizer 1850 Mah batts available from Wal-Mart I get 11-12 hours continuous use with WAAS enabled and an external antenna connected (the antenna draws an extra 7ma). With battery saver on, WAAS disabled, and the stock antenna, I get 18 hours and a few minutes. Disable the battery saver and I get about 16 hours. All of these tests done indoors making the unit work pretty hard to maintain a lock. Minimal screen backlighting used...

 

If you did this test from the very first charge the batteries have ever had, Nimh batteries take a few cycles to reach full capacity. I notice on the first cycle of my batteries they only lasted about 2/3 their final life.

 

In general, I find the V to use just over 100 ma, so that the 1850 mah batteries give more than 16 hours of continuous use, but less than 18.5. The other question is did the batteries sit for any lenght of time (several days to weeks) before you used them, some self discharging could have happened.

[+apersson850]

Just calculating 1850 mAh divided by 100 mA doesn't give you 18.5 hours. It's also a question about how the voltage varies during the discharge of the batteries vs. the cut-off voltage for the receiver. If the last 300 mAh can only be discharged at a voltage below when the GPS turns off, they are of no use to you.

 

Besides, at least my Vista runs on almost constant power, which means that the current drawn increases at the end of the discharge cycle, to compensate for the lower voltage.

 

Anders

[+bigeddy]

quote:

---

Originally posted by worldtraveler:

If you want an honest 30+ hrs of use from a set of batteries, change to lithiums.

---

I was first introduced to lithium batteries for headlamps around 1980 and have been a fan ever since. The long operating life, long shelf life, dependability, and convenience are well worth the extra cost. I can use a set for months on the GPSr or in a small digital camera.

 

I've tried Ni-MH rechargeables but dislike the constant fussing around with recharging and changing the batteries. It's also necessary to lug extra batteries around, something I can typically forego with lithiums until the power bars starts to dip.

 

Rechargeable Lithium Ion batteries have taken over heavy duty uses like computers, phones and digital cameras. I keep waiting for a type suitable for the GPSr but haven't seen one yet. Until then the disposables will have to do.

[+Gliderguy]

Iknow it isn't technically that easy, but Nimh batteries hold at a constant 1.2 to 1.25 V for probably 80 percent of their entire charge. Once they drop much below 1.2 they are going down pretty quickly. I think the initial time above 1.2 and the last gasp below 1.2 are pretty equal lengthwise, giving a near approximation of 100 ma. I remember somewhere that either the III+ or the V would run on 4 volts before shutting off, and I don't think the Nimh batteries capacity are rated below that cutoff voltage.

 

I do appreciate and understand the concept of the unit running on constant power rather than constant current.

[+GOT GPS?]

Use NiMh Energizers with a high quality charger(wont allow the batts to overheat).

 

Turn off the Interface: Goto SETUP Menu, then select the Interface menu, then select None. Wont be sending data to the serial port needlessly. Remember to set it back to Garmin, when hooking up to a computer.

 

Turn off WAAS.

 

Reduce Map detail.

 

Set backlight to 15 seconds or not at all.

 

Turn off Lock-On-Road if not needed(may help slightly).

 

Select battery save mode, except when you have poor visability of the satellites, then turn off battery save mode.

 

Having features turned on, make the software in the GPS work harder, using up batteries.

 

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