Can I safely charge/maintain this battery from my car's cigarette outlet?

[dwh]

Then you don't need a diode either, which is a plus.

[off-roader]

Thanks for this thread. One of my 4x4 buddies has been doing exactly this for couple of years now in his Montero.

For 4x4 trips he uses a small AGM battery mounted in back to power a freezer-fridge overnight then during the dday he plugs it into the rear acc power plug to recharge it.

If my memory serves me correct, they are off during engine starts. It has been working fine for a while now and I'm sure he's well aware of the possible starting issue since he is a retired aerospace engineer (very knowledgable on electronics) and an avid fisherman (knows boat electronics & engines inside & out).

Now I just have to properly mount this puppy in back.

[Jay H]

There a ton of very smart universal smart chargers out there that are designed for the RC hobby industry. They charge from a DC input voltage of 10.5 to 15V or so, have adjustable low input voltage disconnect and are capable of constant current and or constant voltage. They are cheap and high precision. I use mine to balance charge lithium ion, do AA Nimh cells and on occasion sealed or flooded lead acid. These things have USB connectivity and temperature probes. These things are great. I have one that I use from 12v vehicle power or off of AC grid power with a modified computer power supply to provide 12A 12V DC. Most are capable of putting out at least 6 amps with some able to do much more. They will display input power voltage, output current ect. I would recommend a Turnigy or icharger brand. Hobbyking.com is a good source for chargers, watt meters, high current DC power connectors and they also have high quality silicone insulated fine stranded copper wire.

Here is a really nice not crazy expensive charger that can charge practically any thing and will probably be firm ware upgradeabe for future battery chemistrys. http://www.hobbyking.com/hobbyking/s...e_Charger.html