Floating the Engine Battery Class C? UPDATE 3

Could be something else going on, no idea. 1991 rig.

The cig lighter in the dash socket works ok and pops out red hot. (Engine off, no key in ignition) The TV panel 12v socket (on house batts) works ok. Joining them up, nope. Worth a try.

I thought the subject of quiescent power needed to maintain a group 31 battery at 13.6 volts was somewhere in the neighborhood of 600 to 700 milliamps. This was discussed at length on this forum including instrument verification a couple of years ago.

The idea that a less than one volt Delta T would fail a ten ampere fuse for a single battery has my eyebrows raised. Ten amperes is what an old Harbor Fright charger was rated for. Could it be the chassis electrical demand was inadvertently raised by a significant factor?

Long ago I tried recharging a 12Ah AGM battery through a double ended ciggy plug on 16awg. It would work if the battery was not too depleted. but blown glass fuses would get expensive, and I just started wrapping them in aluminum foil.

But the battery never seemed to get much charge. I did not have ammeters or voltemters then, just a digital multimeter.

Now I only trust ciggy connectors to pass ~20 watts or less.

My OEM dash ciggy receptacle got its ground through nearby metal dash and had a 18 or 20 gauge wire from fuse panel.

I've tried running 10AWg to receptacles and connectors. glad I left enough slack to cut them off and install anderson powerpoles.

I still employ ciggy plugs and receptacleson low wattage devices, as they can be connected or disconnected with one hand in the dark.

One 22 watt LED light has a PWM LED dimmer on it. The ciggy receptacle and plug are the Blue Seas version, pretty much as good as a ciggy plug connector can get. The LED light when dimmed, will have the ciggy plug/receptacle emit a whining sound, and pushing the plug deeper into the receptacle can change the volume of the whining, and pushing it very firmly together will stop it together.

So even the best 12v ciggy connection is revealed to be a horrible electrical connection worthy only of contempt.

............and............

that's why I recommended inserting Schottky rectifiers in the cord. Amazing what a .2 - .3 volt decrease in Delta T will do...

I used a couple of 12v plugs that have 10 amp fuses and 16AWG wire, end to end. House 13.6, engine 12.6 Connected to both 12v sockets. No change to engine batt voltage. Both 10a fuses blown.

Didn't even have to start the engine to blow the fuses. So I will go back to using a small charger I have that does that work--stays at 13.4.

I use a battery tender plugged into a 120 outlet and with its output plugged into the cig lighter. I'm still using the original starting battery that Ford installed in 2002. Last year I thought about replacing the battery just because it's long past time, but I didn't and it started every time and without difficulty for our winter travels.

I found that I could not use my lap top computer with my 12 volt plug because the wires were too thin, so I installed a new one with thicker wires direct to battery with a fuse. I use this 12v outlet to charge my chassis battery by using a male plug and a HF trickle charger that I plug into a 120 v outlet. I works great for less than $10.

If you forget to unplug and blow the cigarette light fuse, the hassle of replacing it puts you on a vertical learning curve experience.

Yup

Thanks Mr Wiz.

So the lesson is to always unplug the jumper before starting the engine.

Its so easy its pathetic,.....posted this a hunerd times.
I put a switch on the dash that connect the positives of the starting and the house together. Its marked,....store or use.
Sometimes when camped for a month or 2, I flip the switch to the "store" side so the solar will charge the starting battery.
Spending money on expensive tricklecharge switches is a joke.