760 'Low Battery' Question

Short answer - yes. By leaving the unit plugged in constantly the battery needs recalibration - or at least the charge indicator. If you do a search on battery here, you will come across several discussions about taking proper care of the battery in your unit,

Li-Ion batteries only need to be run down to recalibrate the gauge. In your case, if the gauge shows fully charged, I'd write it off to an idiosyncrasy as long as it corrects itself quickly and doesn't shut you down.

I thought I'd mention that the battery does need to actually be used about once a month (just let it run down to about 1/2 on the gauge) to keep the electrons moving. I had a laptop PC whose battery was ruined by having it on the AC charger all the time without ever using the battery. After about 1 year, the battery went into a state where it was very quick to recharge but only ran the PC for a few minutes. When a laptop is used in this manner (like on a desktop), the battery should either be removed or cycled periodically. Since you can't remove the nuvi's battery, your only other choice is to periodically cycle it.

Hi, my nuvi 765t has had a problem with the battery gage since new, i let it discharge completly and then recharge overnight if i press the screen while it is doing this it says[ charging battery ]
no matter how long it is plugged in, then when i remove it from the charger all the green icons are full then within a few mins of use it will lose 1 icon it will do this again within 1/2 an hour of use, also the gage will later show it as being emptey, but i can still get up to 40 mins use from it before it goes blank i am wondering if anyone else has had this problem with their unit

I've had the same problem as hil2 with my 750. After alot of trouble shooting with Garmin they agreeded to take it back for repair. If draining the battery completly and then charging it from a solid power source doesn't fix the problem - it's probably a bad battery.

What you say is true of laptops with NiCad batteries.....or even NiMh to some extent.
That does NOT apply to GPS units or cell phones or PDAs, etc. that have LI batteries. Not only are the batteries better but the charging circuitry is better too.

So, for those types of devices, leaving them plugged in all the time should NOT shorted the battery life significantly.

HOWEVER......

Leaving them connected IN A CAR is probably not a good idea for sevral reasons. The simple fact that you get the "remain on battery power" warning indicates that the power is going on and off with the ignition switch. When that happens, there may be unusual spikes and other noise on the power lines that the GPS is not necessarily designed to deal with.......thus your phantom battery warning.

Other reasons for not leaving it connected to the car all the time include stress from extreme heat and cold and the increased likelyhood of theft.

To find out if the battery is bad or not, try running it on the battery a couple of times !!

hi thanks for the info, i have contacted costco and they are sending me a replacement unit,as there are also some mapping errors with this nuvi, sometimes gives wrong names for streets ,Olando airport was totaly confusing for it last week as it did not give the right names for directions around the airport, i drove around the airport terminal roads trying to follow the directions it was giving me for names that were not on the airport signs!!! ,

And are you still going to leave it plugged into the car ALL the time ??

I hope your "mapping errors" are not present with the replacement unit......but they might STILL be there. What you described is NOT uncommon and, alas, is often not fixable.

If the battery icon shows a full charge, then your battery might or might not be fully charged. The icon shows what the internal charger thinks is the state of the battery. It might need to be recalibrated. You can do that by running the Nuvi on it's internal battery until it turns off and then charging it over night without interrupting the charge.

A few of points. It sounds like your cigarette lighter socket is switched off by the ignition key. You wouldn't get the message to power off if it was live all the time. So your Nuvi isn't being charged when the engine is off.

If you switch off the Nuvi using the power switch on the unit, the device is still powered on although the screen is dark. If you then turn off your car, the Nuvi will continue to run with a blanked screen on the internal battery until the battery is discharged.

The internal charger circuit monitors the battery temp and won't charge the battery if it is too hot or too cold. It's possible that the battery really isn't being charged if it sits in a cold or hot car for several hours. It might take an hour or so for the battery to warm up enough to allow the charger to charge it. It could also get overheated by the sun shining on the unit and, if it sits on the dash, it might not cool enough through the day to charge.

Jack

So, you think that when the switch is turned off and the unit goes into charge mode, that the unit is still on and only the screen is blank. You also believe that it stays on when the external 12v power source is turned off. What is your basis for this belief?

hi all, i use the wall charger to charge up the nuvi, so i only plug it into the car socket when traveling, i never leave it in the car, apart from these problems i like this nuvi,so, i hope the new one when it comes in a few days will be ok, if not then i will try a magellan gps, by the way when i flew with air tran to florida 2 weeks ago they gave out complimentry earbud style headphones for use with the seat radio ,when i got home i tried them with the nuvi and they are terrific, great sterio sound ,even my husband was impressed with the quality, so thanks air tran

If your Nuvi is sitting in the house, why does it need to be connected to the charger? The only time mine is connected to power is when it is either in the car or I'm doing work with it connected to the computer. Other than that, it sits in its holder on the "Garmin Friction Mount" (AKA Bean Bag).

My nüvi sat idle for almost 2 months when I had heart surgery. If the nüvi would "continue to run with a blanked screen", the battery would have been dead as h--l ... this was not the case. In addition, if the nüvi was powered on except for the screen power, there would be no map loading or boot time ... it would be up and ready to go. For me, this statement questions the validity of the rest of that post.

RT

Does anyone know if the unit will function w/ a dead battery while still connected to power? I don't know much about the way the power is setup but with everyone talking about different ideas of charging I was wondering if I needed to take better care of my battery (I only use it w/ power however).

(may be a premature question as I've only had the 760 a few weeks, but having had many a dead laptop battery after using primarily AC power I was wondering)

HB,

Just guessing and throwing things out here... Are you certain you have power to the accessory outlet when the ignition is off? Many cars have an 'always hot' outlet and another that's unpowered with the key off. Others don't power the outlet at all unless the key is on.

Based on your description (getting a power off message when you shut the engine down) it sounds like power is being removed from the unit. If you're pressing "leave unit on" (or whatever it says) then you're running the battery down between trips in the car/truck.

Another thought, If you take lots of short trips the battery may not be getting fully charged.

Cheers

One thing to watch for is making sure the auto shut-off is actually working. I had a c550 that would not always shut off automatically. I think the reason is that there was some type of warning window up when I shut my car off... ie "Are you indoors?" When I didn't notice this by looking at the unit itself, I would notice a while later when my cell-phone was still connected via bluetooth.

1. Watch the screen when you turn the unit off but still have the power cord plugged into a live cigarette lighter. The backlight will go out but the screen will say it's charging the battery.

2. Leave the unit off but plugged in for a minute or two. Then turn it on, it will power-up with the satellite bars fully green.

3. Unplug the unit and then turn it off. Wait for a minute or so and then plug it back in. It will power-up with the satellite bars empty.

My 750 behaves this way. That tells me that if the unit has external power when it's turned off, it blanks the screen put the internal circuitry is still active and keep track of the satellites.

Jack j

I would agree this would point to the unit being smart enough to recognize that external power is available and therefore keeps the acquisition circuitry powered; in fact, I know my 660 does the same thing when plugged into a wall wart. However, as you mentioned, the screen says the battery is being charged as well. Why would you conclude that this would run the battery down?

And thanks for taking the time to explain your thinking.

I thought the 700 series have an automatic shutoff so the battery will not drain down. Once power is removed the unit asks if you want to stay on or automaticaly shutoff to protect your battery from draining.

Only if the unit is turned on when power is removed. If you turn it off and then remove power it definitely behaves differently. Jackj180 has discovered something. I'm in the midst of testing and will have some info momentarily.

I don't know what I saw that made me think your car had a lighter that stayed powered even with the ignition off. Obviously, I misread something. Thanks for staying with me to explain.

Your point is a very interesting one and I think I may have just found corroborating evidence. I turned off my unit while charging via a wall wart; then I unplugged my unit from the wall wart. As you indicate, the screen is dark and from all visible evidence, everything is off. However, if I touch the screen, it pops up an announcement that the unit is completely charged. After either another touch or timeout period (not sure which triggered it) the screen went dark and at that point the unit appeared to be totally off. At least no screen touches were rewarded. Really weird -- I can't believe you figured it out.

Note that this behavior only occurs if the unit reaches the "Battery Fully Charged" before you unplug it. If you unplug while it is still charging the unit, the unit does not respond to a screen touch and is presumably off.

I have both kinds of cigarette lighter sockets, a Mercury that is hot all the time and a Toyota that is switched by the ignition switch.

This is a software glitch and I found it by accident. I had turned off the unit while in the Mercury and took it inside thinking that the unit was off. I wanted to play with it a couple of days later but the battery was dead. After recharging the battery using my computer, I got my 120v to 12vdc RadioShack power supply and played around with the 750 on the car mount and discovered that quirk.

Just be sure that you unplug the unit and wait for it to sense the loss of power before thinking that it is really off.

Jack j

Try going into the advanced diagnostic mode (not the normal press the screen and turn it on mode) and set your $LL_BA_LION to "START UP STABLE ON RESET" mode. After you do this, simply reset the unit. Your problem will go away and batter will recalibrate each time you unplug the unit or remove it from the mount.
Jen

I was unable to find any setting called $LL_BA_LION. My 750's diagnostic mode is accessed by pressing the battery charge icon for about 5 sec. That's the only diagnostic mode I'm aware of.

Jack j

How does one get into the advanced diagnostic mode on the nuvi 750??

5 to 10 seconds...

My 760 is used from 2 - 3 hours per day listening to audible.com books during my commute. At those times it's on the car mount that is plugged into the cigarette lighter. The unit automagically turns on when inserted into the mount regardless of whether the key is on or off.

When I remove the unit is asks if I want to leave it on or turn it off. I select "turn off" and the unit powers down.

When I attempt to use the unit OUTSIDE of the car I get maybe 20 minutes of battery life at the most. This is totally unacceptable. I set the back light to only 30% to save power. I tried geocaching with it and got a little over half an hour. I tried listening to my audible.com book and got maybe 20 minutes.

I've read all of the BS regarding the type of battery etc. It seems that there are plenty of people who will talk from their rear orifice regarding battery life when they don't know anything about the type of battery in the nüvi.

What I want to know is: Is there anything that can be done to make the stupid thing work for a reasonable amount of time when running on the battery?

I've run the unit down and then charged it on the wall charger for many hours. It doesn't help at all.

If you have already tried conditioning it and it hasn't made a difference, your battery is shot. Either search the forums for the discussions on how to replace it yourself or send it to Garmin and pay them to do it.

My 760 is about 8 months old, and I get close to 3 hours of battery life out of it.

At risk of sounding like I'm talking from my "rear orifice" (sounds just as rude when I say it..) Check eBay. You can pick up a brand new battery for the 760 for about $10. Then visit YouTube where you'll find a video showing how simple it is to replace the battery. A few minutes with a small screwdriver and you'll be back to hours of running time.

Cheers

I'm having strange charging issues with my 760 which is about 4 months. I rarely use it on the battery, it's normally plugged in or on the A/C cord. Yesterday I was getting the low battery warning signal every few seconds. I charged it overnight on the A/C adapter and it doesn't appear to have charged the battery at all.

I don't think I've ever fully discharged the battery.

I read thru this thread and it sounds to me like you guys are saying to disconnect any external power source before turning off. Is that right?

I've got the unit on the charger again, power turned off so it's kind of in its "standby" mode. I touch the screen and get a dim message: Charging Battery ... Slide the Power Key to turn on.

I'll leave it for a few hours to see what happens.

One of the updates fixed the issue with the Nuvi's not turning off when unplugged from the 12v power, I'm not sure which one. If you've done the update to 4.6, then that problem should be fixed.

After the unit has been charged for about 4 to 6 hours, disconnect all external power (including the USB) and turn it on. Leave it turned on until it shuts down because of a low battery. Then charge it for around 6 hours either on the car cradle or the USB port. Turn it on and if you still get low battery warnings after only an hour or so, you have a bad battery or a bad charging device. Substitute another charger and try again.

Good luck
Jack j

Jack, you prefer the USB or car charger over the A/C power cord?

(I updated this morning from 4.5 to 4.8)

Unless purchased elsewhere, the nuvi 7xx series is shipped with a USB cable and a 12V car charger. No AC charger is what most of us have to deal with.

I have a Nuvi 360 and that came with an A/C cord and that's what I have been using.

I don't think it really matters which you use. My 750 didn't come with a wall charger so all I have is the cradle or the USB cable. Both work fine for charging.

Jack j

OK, thanks...just trying to look at all options.

I called Garmin and they didn't have much to offer apart from sending it back. I'm not going that route as I have an expensive screen protector in place which I'd lose. I guess I'll order a new battery and throw it in.

Are these Li-Ion battery ever subject to reverse charge? I wonder if my unit has been on low charge for a long time and I was not aware of it. I rarely use it on battery power. I typically turn it off before removing power, not vice versa

...and anything else I could think of, I did get the battery fully charged this afternoon on my work computer via USB. No other method of charging worked, not even in the car. All of this after ordering a battery, T5 Torx tool and the pry bar.

Well, at least you'll have them for next time.

Jack j

One thing I have noticed with my c330 is that it only charges when I turn the unit off, but it is still connected to 12v or USB. If the unit is turned on and using either power source, it will not charge regardless of how much battery juice is left. I tested this by letting the battery get halfway down (about 2 hours) then put it on a power source and left on for 2 hours. When I removed the power source (leaving unit on), it still showed 1/2 battery.

So one option is to just turn it off and leave it on the cradle to charge for a short time, or bring it in and charge inside. Sometimes just to make sure it is used, I will leave it on battery power for an hour or two as I drive around, then charge it when I get home. This helps cycle the battery and make sure the battery and charging circuit are in good working condition.

Following this incident, I have concerns about whether the unit has switched off or to "standby". On a bright, sunny day, it's nearly impossible to see the faint display when it says "charging battery". I've never had this issue with my 360. I'm going to be keeping a much closer watch on this so the battery doesn't become depleted again. I suspect I've been putting the unit away in "standby" mode.

It's odd, I see a 6 battery charge cycle count on my 360. I don't see any such reporting on the 760.

The battery isn't helped or harmed by 'cycling'. The 'fuel gauge' is re-calibrated which should make it more accurate but cycling does nothing for a Li-ion battery.

The power management software for the c330 must be different from that used on the 750. My Nuvi 750 does charge the battery while it is being used and it doesn't appear to make any difference to the amount of time it takes. One thing I might add, the unit limits the amount of current it draws from the USB cable to 500 ma (1/2 amp) because that is the maximum a USB port can deliver.

Jack j

The auto shutoff on my nuvi 660 stopped working. It would continue on battery. This was making me bring the unit in the house to recharge every day. I contacted Garmin, who recommended I send it back in to them. The unit is aobut 13 months old.

Are you saying that when the ignition is turned off, the 660 doesn't present the screen asking whether you want it to stay turned on, or alternatively to turn off?

Or, are you saying that you run the unit on battery and it doesn't turn off just prior to the voltage level at which it will turn on and charge via the adapter in the car?

This probably doesn't address the OP's problem. However, it sounds like many have problems related to power bar indications and low battery capacity (not fully charged or bad batteries).

I have a Garmin Nuvi 760 which is about 10 months old. Great little device. I keep it in the car a lot of the time. The battery capacity became very low and run times short. My cigarette lighter is only powered when the ignition is on, or on ACC.

I was always showing a full charge indication after removing from the cigarette lighter or turning the car off, but the unit would only operate for 10 minutes of so before shutting off due to low battery. It would drop from 4 chips to 3 in about 10 seconds. I was about to get a new battery. However, I tried charging overnight with the unit turned off and now have close to normal capacity (maybe slightly less then when new).

If you keep your GPS plugged into the car all the time and never let it charge except with the unit on it may not get or stay charged to full capacity. I think the cigarette lighter does a fairly good job of maintaining the charge level with the unit on, but will not recover from a discharge while the unit is in operation, or it takes a lot longer then I ever give it around town with 15 to 1 hour on intervals to raise the charge level.

So, before you send it back or try replacing the battery yourself (which isn't very difficult), try charging it overnight first.

Hum....I have had the low battery warning once or twice on my 780 and it did not make any sense as I pretty much only use it on the car mount plugged in.

I will hook it up to my computer for a good charge and see if that improves things.

Monoprice has an AC charger for less than $3.00. It uses a standard USB-to-mini-USB cable which they also have for a buck or so. I got 2 of them, one white & one black (one for home, one for office).

I had trouble with my nuvi not holding a charge even 30 minutes. I bought a replacement battery after about 18 months. The battery install is straight forward (be slow and gentle) and the results have been great. Price was about $20. I use the nuvi to Geocache, so it's charging in my car all of the time, and unplugged when I use it hiking. Since the replacement has been installed I haven't needed to do an overnight, wall-plug, recharge yet.

I see a number of battery vendors on Ebay. Any recommendations on vendors to use, or ones to avoid?

I can't recommend any specific eBay vendor but make these suggestions:

1) Buy from a vendor that includes the tools needed: the small driver and the plastic pry bar.

2) don't overpay. I see that BatteryShip.com offers a battery with tools for my nuvi 750 for $20.95 with free S&H.

http://www.batteryship.com/

I've not bought from this vendor or the one below and would like to hear if anyone's had good or bad luck with them.

Or if you already have the tools, here's one for $15.20 with free S&H:

http://www.batteriesonthego.com/battery-shop/pc/Garmin-GPS-B...