trikle charge

We have the big Battery Tender($50) on our chassis batteries. It is connected directly to the battery and plugged into a shore outlet in the bedroom. We have our original batteries. We have the small Battery Tenders on our motorcycle and our mower. We replaced the cycle battery at 8 1/2 years because we were leaving on a long trip. 6 watt sounds awfully small for a chassis battery. We will take a look at ours tomorrow.

I have the Magnum smart battery combiner, this is the way I would go when hooked to shore power.
http://www.lslproducts.net/ALS_Overview_Page.html
Here is one for less $$$$
http://www.rvupgradestore.com/SearchResults.asp?Search=AMP-L-START&Submit
JR

On some vehicles the ciggy lighter only works if ignition on.

On others it will work just fine.

if going thru the cigarette lighter, you best makes sure it is live when the ignition switch is off. Some turn off, and if it is off, the solar charger isn't going to do anything anyway.

And pianotuna already gave you a very adequate answer in you similiar post of the same question under solar chargers.

My choice would also be the Trik-L-Start!

If Power = Volt x Current wouldn't a 6 watt charger provide a half amp (500 mA) of current? Am I overlooking something? If you measure the discharge current on your battery at rest you will get an idea of how much current you need to provide to overcome it. On mine I had a 45mA current at rest which was the radio memory. So I put a switch on the dash to disconnect the unswitched wire to the radio that I use when I do not intend to use the RV for any length of time. I have a 1.5W solar charger and it keeps my starting battery topped off as long as it was fully charged when I parked. I doubt it would charge a partially discharged battery. A 6W charger could be hooked up either through the cigar lighter or directly to the battery as the current is in the milliamp range. If you wanted to go that route for the cabin batteries there are usually more phantom loads to address where disconnecting may not be an option and the size of your battery bank would need to be considered. In that case a 6W charger may not be an option but you have to look at all the variables I listed.

I recommend Trik-L-Start combiner. 6w is not much power.

At 6w, approx. 0.3a, it won't matter.

That will barely keep up with the phantom loads.