855 car battery drain

18 days with a draw, and your complaining about your battery being drained t almost dead? Hummmm sounds like operator error to me.. Your calculations are on a freshly charged battery, however everyday that goes by with a drain the calculation would change... I would in the future just unplug the 855 and not worry about it.

Well, when you go away next time & leave your Garmin plugged in, I suggest you use a battery charger (not a trickle charger) that switches off & on automatically to maintain the proper state of charge of the car battery.

An easier solution - unplug the Garmin.

Fred

I think this is plausible since the draw shows 500 mA when charging. 8x5 users have complained about the nuvi battery being completely drained by leaving it in standby for several days, so I suppose it would be pulling a charge current more frequently than you might expect. I would have easily made this same mistake. I often leave my cell phone connected to charge it up, but I guess I have never tried doing it for 18 days.

While I can't speak to to your particular set of circumstances, there are a great many items that draw current from a battery when parked. The radio draws power to keep its memory alive, the clock continues to draw power, many of the monitoring systems built into the car also draw power.

The question you should be asking is have you ever let the car sit that long before? If the answer is no, then you can't single out any one item. Unless you are certain there are no defects within the electrical system and that the battery can still be fully charged, the charging system is fully functional and putting out the rated capacity you can't assume "the Nuvi did it."

Even "maintenance free" batteries need service. The water level needs to be checked and topped off at least once a year, the terminals need to be free of corrosion, the engine compartment clean and free of grease and dirt buildup. Just too many variables to blame the Nuvi especially when you left it.

If your car had a 100 amp-hour battery and the 855 drew a half amp all the time it was hooked to the battery, the battery would last about 200 hours. But that's all theory, it's hard to say what kind of a load the 855 was actually putting on the battery.

A car battery's discharge curve of current vs time is not linear. The ampere-hour rating of a battery is usually for an 8 hour discharge rate. So a 100 ampere-hour battery would supply 12.5 amps for 8 hours (12.5 x 8 = 100). Your 100 ampere-hour battery should be able to supply 1/2 amp for much longer than 200 hours, maybe as much as 400 hours. Batteries will also self-discharge at a rate that increases as the battery gets older.

If I remember right, the 8x5 series nuvi's can't really be turned off, they go into a standby mode with a blanked screen. But they still draw current. I don't think I'd leave it plugged into my car for 18 days without driving the car.

I have had my battery die also, when leaving my 2xx plugged into my car (for 4 days). I don't do that any more.

Here's what I was taught about batteries when in school:

Most batteries are rated in electrical capacity for a discharge rate of 20 hours. A 20 amp/hour battery should provide one amp of current for 20 hours before being fully discharged. It will still show a voltage, it will no longer be functioning correctly and if rechargeable, it will be in serious need of a recharge.

Some smaller batteries like those used on HandiTalkies are rated in milliamp/hours. It is the same concept, they just use milliamps instead of amps for these lighter duty batteries. A typical rating might be 1200 ma/Hr which is the same as 1.2 amp/hour.

A standard small car battery is about 45 amp/hours. That means that it will supply over two amps for 20 hours. A battery should not be discharged at a higher current draw, or asked to deliver more amps than its amp/hour rating divided by 10 in order to get maximum capacity out of it. In the case of a 45 amp/hour battery that would mean it should not be asked to deliver more than about 4 amps for best service.

I am a retired telecommunication tech. We used flooded electrolytic lead-calcium battery plants for a standby UPS. The cells were wired for either 24 volt or 48 volt plants depending on the office needs. The cells were rated at either 1200 ah / 8hr or 1680 ah / 8hr. These ratings were on the cells from the factory. That is were I get my figures from if they are wrong I apologize.

I don't think you are wrong, that was most likely the manufactures specs for their batteries. Other manufactures probably have other specs. I was taught about batteries and electronics in general using ohms law.

I had a car battery that would stay charges all the time unless I let it sit for a week or to without starting. Thought it was the alarm,glove box underhood light and everything else. Had the battery checked when fully charged and it showed good. Had it checked again when it had set for a week and found a bad cell. something else to check.

What is going on inside the 855 that causes it to draw that much current? Shouldn't sleep mode have minimal drain?

Battery—Drain Tests (copied from Ford PTS web site 2002 Crown Vic WSM)

NOTE: A periodic pulsing of up to 80 mA (0.080 amp) is caused by the integrated control panel (ICP) and should be considered normal. However, no production vehicle should have more than a 50 mA (0.050 amp) continuous draw.

Check for current drains on the battery in excess of 50 milliamps (0.050 amp) with all the electrical accessories off and the vehicle at rest. Current drains can be tested with the following procedure:

WARNING: Do not attempt this test on a lead-acid battery that has recently been recharged. Explosive gases can cause personal injury.

CAUTION: To prevent damage to the meter, do not crank the engine or operate accessories that draw more than 10A.

NOTE: Many modules draw 10 mA (0.010 amp) or more continuously.

NOTE: Use an in-line ammeter between the battery positive or negative post and its respective cable.

NOTE: Typically, a drain of approximately one amp can be attributed to an engine compartment lamp, glove compartment lamp, or luggage compartment lamp staying on continually. Other component failures or wiring shorts may be located by selectively pulling fuses to pinpoint the location of the current drain. When the current drain is found, the meter reading will fall to an acceptable level. If the drain is still not located after checking all the fuses, it may be due to the generator.

NOTE: To accurately test the drain on a battery, an in-line digital ammeter must be used. Use of a test lamp or voltmeter is not an accurate method due to the number of electronic modules.

Make sure the junction box/fuse panels are accessible without turning on interior and underhood lights.
Drive the vehicle at least five minutes and over 48 km/h (30 mph) to turn on and exercise vehicle systems.
Allow the vehicle to sit with the key off for at least 40 minutes to allow modules to time out/power down.
Connect a fused jumper wire between the negative battery cable and the negative battery post to prevent modules from resetting and to catch capacitive drains.
Disconnect the negative battery cable from the post without breaking the connection of the jumper wire.
NOTE: It is very important that continuity is not broken between the battery and the negative battery cable when connecting the meter. If this happens, the entire procedure must be repeated.

Connect the tester between negative battery cable and the post. The meter must be capable of reading milliamps and should have a 10 amp capability.
NOTE: If the meter settings need to be switched or the test leads need to be moved to another jack, the jumper wire must be reinstalled to avoid breaking continuity.

Remove the jumper wire.
NOTE: Amperage draw will vary from vehicle to vehicle depending on the equipment package. Compare to a comparable vehicle for reference.

NOTE: A periodic pulsing of up to 80 mA (0.080 amp) is caused by the integrated control panel (ICP) and should be considered normal. However, no production vehicle should have more than a 50 mA (0.050 amp) draw.

If the draw is found to be excessive, pull fuses from the battery/central junction box one at a time and note the current drop. Do not reinstall the fuses until you are finished testing.
Check the wiring schematic in the wiring diagram for any circuits that run from the battery without passing through the battery/central junction box. Disconnect these circuits if the draw is still excessive.

Battery — Electronic Drains Which Shut Off When the Battery Cable is Disconnected

Repeat the steps of the battery drain testing.
Make sure all doors are closed and accessories are off. Without starting the engine, turn the ignition switch to RUN for a moment and then OFF. Wait a few minutes for the illuminated entry lamps to turn off if equipped.
Connect the ammeter and read the amperage draw.
The current reading (current drain) should be less than 50 mA (0.05 amp). If the current drain exceeds 50 mA (0.05 amp) after a few minutes, and if this drain did not show in previous tests, the drain is most likely caused by an inoperative electronic component. As in previous tests, remove the fuses from the battery/central junction box one at a time to locate the problem circuit.

Thanks for this post. The procedure is wonderfully detailed, and would let me measure more than one thing of current interest to me, including the active and "off" power consumed by my 855.

My problem is that jumper. Staring at my battery terminal, I see a reasonably flat top of lead, surrounded by the connector which is going to rise up past it as I remove the cable. Not an attractive attachment point for a jumper.

I'm toying with the idea of making up a fixture with enough batteries in series to give about 12 volts, a suitable resistor to limit excess current in either direction, with the though of attaching it across the power connection as available at an accessory socket (this car does not disconnect the accessory sockets in Ignition off state). The idea, as with the jumper, would be to supply continuous voltage to the electronic things that need it when the battery cable is disconnected, then hook up the meter, and disconnect my expedient when the meter is in place. Obviously the same measure needs to be applied again when testing is over and the cable is about to be re-attached.

Any better ideas, or thoughts on how I could make the original jumper idea work in the real world?

My 855 draws ~400ma when charging (screen off) and has dropped to ~100ma now that the battery is near or at full charge.

After another 6+ hours the draw has dropped to ~70ma.

Steve

You can pick up a battery drain adaptor at an auto parts store that clamps onto the battery post then the cable clamps onto it. The jumper has a knob that when turned, after an amp meter is hooked across the circuit will disconnect the path between the post and cable. here is a link to one that Matco sells
http://www.matcotools.com/Catalog/toolcatalog.jsp?cattype=T&...

Interesting my 760's if I leave them on charge will kill my truck battery in about 5 days if I don't drive it. So to prevent this I unplug the GPS now.

I finally worked up my courage and made and acquired a supply of jumpers, meters, and a hand-made alternate battery supply to cover the inevitable breaking of connection to the battery and made measurements today.

While the display jumps around a bit, it appears that with no GPS plugged in at all, the total battery current is about 28mA on my car. After shutting off the GPS, getting the "battery charging complete message" and waiting a little while, the total is about 143 mA, and is still that an hour later.

So on this measurement It seems my 855 in the "off" state which is really a lower power standby (including satellite reception, I believe) burns about 115 mA.

As that multiplies my car's measured parked battery drain by five, and the number is in the ballpark of my original estimate, I do believe that leaving the 855 plugged in during my vacation considerably contributed to my problem. Given that my car had about 18 days of loss, that would give an estimated total of about 62 Amp hours, of which the Garmin would have contributed 50.

I think in general it is probably good to limit battery depletion to about 5 Ampere hours where feasible, so I resolve to unplug the 855 and remove the batter for times when I expect not to use the car for two days or more, and I resolve to use the battery charger for a couple of hours before attempting to start the car if it has been off with the Garmin plugged in for more than a week, or without the Garmin plugged in for more than a month.

For the original question of 855 current alone, the whole rigamorale of interrupting the battery connection, fancy jumpers, and the like was not needed. I plan to procure one of those cigarette lighter socket extension cords, and just break into one of the lines to make a series attachment point for the ammeter. That way I won't have to subtract out the rest of the (varying) car, nor take multiple risks.

Still, I'm glad I did it--I know more about the car off state current than before, and as a huge bonus, the CD player/radio which I considered completely dead came back to life when I plugged in the radio fuse for the first time in a week. It seems the radio wanted a "hard power-down reset", longer than the minute or two I tried back when I pulled the fuse. By the way, when operating the radio pulled about 1.4 A, and the glove compartment light about 0.5 A.

Check your manual / fusebox diagram to see whether your car charger port is powered via battery (BAT) or accessory (ACC) power. If it's on battery power, then obviously it's being powered by your battery when your ignition is off. If it's accessory power, then it's only powered when your ignition is either ON or in ACC mode.

On my Nissan Altima 09, I have two charger ports. One is ACC (the one I plug the GPS into), and one is BAT. If you accidentally leave your GPS on when plugged into a BAT charger, then you may drain the battery.

I leave a car in the garage in Florida (High heat in summer) for months on end and it starts up every time.
Radio and clock don't do drain the battery enough to kill it.

So, looks like I have a choice to make... Let my motorhome battery drain (it sets for months at a time) or drain my GPS. Thanks Garmin, wish I would have known this BEFORE I bought it!!!

There's a third solution: remove the battery from your 855 when not in use. A 4th solution is to recharge the nuvi via USB as needed with a computer or other compatible charger with a USB connector. Removing the battery when not in use is the easiest fix.

Removing the battery in the 8XX series is a "slaps head in disgust" type of epiphany. The battery will hold its charge for months with no drain and popping it back in will also cause the unit to reboot and reload all the files.

some cars have power sockets which turn off when switched off. i use this with the GPS charger plugged in.

I obtained a Fluke 117, a really nice DVM which includes a min/max/avg function. And with the Fluke name on it my hopes of correct readings are rather higher than with my $2 models from HF Tools.

On an 18 hour averaging run, the "off" 855 settled down to a 100 mA average within a few minutes, and stayed there, though the peak high number walked up a little. At the end I had:

min 97 mA
max 143 mA
avg 100 mA

I just now averaged a real world trip to the post office, including a little route calculation, a little voice recognition, the usual amount of voice prompting, and continuous navigation.

min 133 mA
max 226 mA
avg 157 mA

The shocking thing is how little of the higher "operating" vs. "off" power appears actually to be from more computation or more actual satellite reception power consumption. As the power consumption after I'd hit the off switch but before the exit text message disappears was 151 mA, I think most of the extra "on" power is just the display backlight.

As are others, I'm pretty annoyed. This thing should, I think, have been designed for considerably lower off-state power. I recognize the merit of maintaining a "warm" solution so we get very quick resumption, even after many hours of non-use. But surely it could peek out once every few minutes or less and still meet that goal. Given the power consumption it does have, I'd expect the user manual to contain a loud warning about the risk of depleting a healthy car battery to non-start levels in a few weeks, and more like a few days for a late in useful life battery.

It would be trivial for me to use my meter and modified extension cord to measure other units. If someone in Albuquerque wants to collaborate for a measurement on their unit, just give me a call. I'm Peter A. Stoll, and I'm in the phone book.

I have experance where my 886T battery was unexpectly low. I brought the unit in and charged it with the USB cable and placed it back into my car the next day. After work that day my batter was low again. This happened for two days and I hardly used the unit.

My guess is the MSN receiver battery was drawing power draining the units batter while the car was turned off. Every thing is now normal.

I can appreciate having a warm startup. When I go someplace, it is nice to get back in my car and have my 855 start right up. But, there are lots of other times where I want a full power off - if nothing else than to avoid having a dead battery when I want to use it.

So, for daily use, I have been using it without a battery. I just keep the battery stored nearby for when I want it - and just plug it into the car and let it fully restart. No car battery drain and little drain in the lithum battery - I just have a longer startup process.

I go looong periods without using my 855, perhaps a month or two at a time. I have long since adopted the following practice to avoid battery drain...AND keep the battery handy and with the unit at all times:

I have folded over a small piece of Gladwrap, about 3 folds thick, making it about 1/2 inch wide and 1.5 inches long. I wrap it around the battery so as to cover the three copper terminals...and re-insert the battery...with a portion of the wrap sticking outside the Nuvi/battery cover. [The wrap "sticking out" always reminds me to remove it before making a futile effort to just turn the Nuvi on.]

I have always enjoyed the simplicity of this process.

Thus, I never have to wonder where the battery might have wandered off to...and always find it basically fully charged when I need it: Remove wrap and GO! I have a wallet style Nuvi case, where I keep the Gladwrap (in a tiny web pocket) when the unit is in use.

NOTE: Gladwrap is easier to fold and re-use than Saran. I imagine any thin wrap would do the trick, as long as it is folded thin enough to allow the battery cover to slip into place.

With a German car, anything is possible. Mine has already had a computer, intelligent battery sensor, fuel pump, etc., replaced when the car has less than 20k. I notice that the ignition must be fully on to get any juice from the cigarette lighter sockets. But as far as not driving it, it has sat for 4 weeks in the winter and had no problem starting up.

On my 200k Japanese car, I was using a power inverter for a laptop causing the battery to fully drain--but the battery was on the way out.

I just don't think it's the Nuvi is my point. For my car the battery is $500--is that ridiculous? Oh, you cannot just go to sears or wal mart, no, you have to pay the dealership to reprogram the computer if the battery is replaced. LOL

I little off topic but I believe the dealership is taking you for a ride. Worst cass is you replace the battery without losing power, the car will never know.