Garmin 855 sucking up power

I don't know the answer to your question, but I do know the 855 is one of the nuvi's that goes into a "sleep mode" instead of full shutdown. In this mode, it draws more current (to keep the battery charged) than nuvis that completely shut down. I have read posts in other forums about the nuvi 8xx causing a car battery to go dead if left plugged in for an extended time (several days or more).

I think if you remove the battery from the nuvi 855 it will not go into sleep mode and will eliminate this problem. You can still operate it through the vehicle power/cradle with the nuvi battery removed.

I just checked my 855 for the first time in about 8 months, after re-installing the INACTIVE STORED battery...and it appeared to be fully charged.

I stopped using my 855 when I bought the 3590 last April, and only wanted to install a new map, and that's my only use in 8 months. Yeah, I love the 3590.

[NOTE: I actually store the battery inside the unit, but with a thin layer of Saran-type wrap between it and the 855 terminals; that keeps it from discharging, and insures that I don't mislay the battery somewhere. I am still able to lock the battery COVER in place.]

I don't have a number for draw from the internal battery, but, as I reported http://www.poi-factory.com/node/38523 on another thread on February 12, 2013, I recently measured the drain on the car's 12V line from my turned off but plugged in 855. It was 90mA. The car was turned off at the time, and I estimate the 12V accessory socket was actually supplying an average of 11.8V. I repeated the test while driving the car, during which time I estimate the 12V accessory socket to have been at 13.8V. With that higher voltage, a lower amperage was required to supply the 855 demand--75 mA, in fact.

As the internal battery is a single-cell Lithium-ion type, the equivalent power from it would require over three times the amperage. Call it 300 mA in the "off" state to a first approximation when powered by the internal battery, if in fact it behaved the same when off with 12V absent as it does when plugged into an active accessory socket

I don't think call the 855 "off" state with 12V present a sleep state conveys how active it is an how much power it consumes if the 12V supply is provided. On the plus side it gives you wonderfully fast satellite "acquisition" when you turn it "on". On the minus side it imposes an appreciable 12V drain on the host.

Now, when 12V is not provided, the 855 does find a way to burn far less power--else the internal battery would always go dead in a very few hours of disconnection--instead of just sometimes.

Thanks for the replies, I think I will use the saran wrap idea also, good tip.