Cigarette lighter power source?

[Reddeer]

Hi there,

Does the cigarette lighter outlet in a 1993 draw off just the coach battery when the ignition is off? Has anyone tried running small amp DC devices off this source?
Thanks!

[EricZ]

In my 1993 Airstream 190 there are two cigarette lighter sockets: one in the dash and one above the refrigerator and microwave.

The dash cigarette lighter socket is powered by the starting battery. In my 190 this is live even when the ignition is off.

The rear cigarette lighter socket, which is part of a panel with a TV antenna connection, is powered by the house battery. In my 190, this is through the purple wire in the fusebox (which also supplies the water pump). Thus when the ignition is off, the power to that rear cigarette lighter socket is coming only from the house battery circuit.

I have routinely used that rear socket to power small fans, cell phone chargers, etc. Though it is protected by a 15 Amp fuse, I'd hesitate to pull that much power from it, as the cigarette lighter socket itself might not handle it. A few Amps, though, should be no problem.

[EricZ]

By the way, here's how the 12-volt fusebox in my 1993 Airstream 190 was wired from the factory:

Red wire (far left):
- Overhead lights (bathroom, main hallway, couch)
- Overcab bed lights

Blue wire:
- Sink light
- Stove light
- Stove fan
- Water heater

Brown wire:
- Furnace

Purple wire:
- Roof antenna amplifier
- Above-fridge cigarette lighter socket
- Water pump

[Reddeer]

Thanks Eric. I'll check both outlets when she gets back from RV rehab. Thanks for the breakdown also.

If you have a 93, what type, make, and model of coach battery are you running? Also have you seen a chart that lays out how many amps each appliance pulls?
Thanks.

[Wakeslayer]

I too am curious what the correct battery is for the house. Both my batteries in the 94 are seemingly shot. I charged them up good for a couple days earlier this month. Down to sub 12v after two days. Also, my house battery has a jumper clip over to the starting battery that I want to at least disconnect, and cover, and only use in the event of a dead starting battery. I assume this was a previous owners attempt to never have a no start. Not sure. The Bus is in dry dock until Spring anyway, but want to have batteries at the ready when it warms up. Festi season is just around the corner !!

[EricZ]

Here are my measurements for power consumption in my 1993 Airstream 190:

Ceiling fluorescent: 1.4 Amps
Sink fluorescent: (not yet measured)
1141 bulb (installed over couch): 0.9 Amps
1156 bulb (installed in overcab bed area): 1.3 Amps
20w halogen bulb (installed in bathroom): 1.6 Amps
Furnace: 2.5 Amps [label rating: 2.9 Amps]
Water pump: 3.5 Amps (but intermittent)
Fridge (RM2310): (not yet measured; probably about 11 Amps, but only when on DC)
Water heater: (not yet measured, but probably very little)

[EricZ]

In my 1993 Airstream 190 I initially used cheap group 51 or 51R starting batteries (i.e., not deep cycle).

As would be expected, these didn't work well because they were small (thus not many amp hours) and weren't deep cycle (thus didn't last many cycles).

I then switched to an Optima group 31 yellow-top sealed AGM battery. This was rated at 80 amp-hours and was a true deep cycle. Though I couldn't fit any other group 31 battery in the passenger-side battery bay, this Optima just BARELY fit (with some modification to the metal cross-piece in front of the battery). Note that once I got it in, it was hard (well, awkward) to get it back out.

The Optima was better, but expensive (about $200 back then, closer to $300 now), still didn't have as much capacity as I'd like, and had a fairly short life. It was also easily overcharged with the stock converter/charger, which may have explained its short life (though this had nothing to do with the Optima; any battery would be hurt by the stock charger).

I eventually bought three relabeled Odyssey PC2150 100 amp-hour sealed AGM batteries, placed them under the couch, and installed a Xantrex PROsine 2.0 inverter/converter/charger. (Note that you can get a good converter/charger for $100-200; the Xantrex is overkill for most uses.)

Sealed batteries, such as AGMs (absorbent glass mat) can typically be installed inside a closed space (thus my placement inside, under the couch).

Another idea I've though about: what about reversing the locations of the starting and house batteries? Maybe a small but good quality starting battery would start our big V8 engine (I don't know if this is true!), and that would leave the larger space in front of the driver for an affordable reasonable-sized deep cycle battery. (I'd think a medium-sized (i.e., group 24) deep cycle battery would fit in the starting battery space (though I'm not sure); I don't think a large deep cycle (i.e., group 31) would fit.)

[EricZ]

Wakeslayer,

If your house and starting battery are jumpered together (by which I assume you mean they have a wire connecting their respective positive terminals), they will both always read the same voltage, regardless of their condition.

Ideally you'd want to disconnect them from each other, fully charge each one individually, and then assess the condition of each one.

[Wakeslayer]

If your house and starting battery are jumpered together (by which I assume you mean they have a wire connecting their respective positive terminals), they will both always read the same voltage, regardless of their condition.

Ideally you'd want to disconnect them from each other, fully charge each one individually, and then assess the condition of each one.

Eric

Agreed. I am going to eliminate the wire for sure. I am suspicious that both batteries are getting to be junk. I have a load tester, and as soon as I can get the mercury up this Spring, will charge both, and test. We just got the bus in June. Pretty much expecting to need new batteries on both sides. Even if they test ok, I may remove and keep on hand for other uses. Not worth having crappy batteries on the road.