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Old 01-03-2015, 08:51 PM   #15
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The 2015 Owners Manual is worth downloading since it has wiring diagrams (whoopee) and I can see the heating pads are each 68W - so combined that's just over 1 amp. However, a much bigger problem is if the water heater is on electric: that uses 1400W - 11-12 amps. So with that on, and an electric furnace running, you may be getting near the 30 amp limit, especially if other minor appliances are also running.
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Old 01-03-2015, 08:55 PM   #16
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The 2015 Owners Manual is worth downloading since it has wiring diagrams (whoopee) and I can see the heating pads are each 68W - so combined that's just over 1 amp.
By my calculations, that's 5.6 amps for 68 watts at 12v. But still a lot less than I was led to believe!
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Old 01-03-2015, 09:02 PM   #17
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By my calculations, that's 5.6 amps for 68 watts at 12v. But still a lot less than I was led to believe!
68 watts for each tank pad. There are 2.
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Old 01-03-2015, 09:06 PM   #18
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I should add that when plugged into shore power we're monitoring the systems as seen on the Power Control Systems display, since that will start to shed the major appliances when you go over the limits; and that is at 120V. So I believe you should calculate the amperage based on 120V, not 12V.
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Old 01-03-2015, 09:28 PM   #19
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I should add that when plugged into shore power we're monitoring the systems as seen on the Power Control Systems display, since that will start to shed the major appliances when you go over the limits; and that is at 120V. So I believe you should calculate the amperage based on 120V, not 12V.
That is correct. There will be some conversion loss, but not enough to matter. These pads really are nearly insignificant if you are plugged in.

This does not really contradict the advice that your dealer gave. 11 amps for 8 hours is 88 amp/hours. That will indeed put a serious dent in an average house battery.
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Old 01-03-2015, 09:41 PM   #20
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Watts are watts. You can do the calculation in 12V amps rather than 120V amps if you like, but you will reach the same conclusion (modulus any conversion losses that may be involved, which will not be material).

BTW: There are three kinds of tank heater pads: 12VDC, 120VAC, and those that take both. They do not use significantly different amounts of power, though. These things rely on low, continuous heat, not at all like a space heater.
Watts were not mentioned, we were talking current. So the current at 120VAC would be about 1/10 of the 12VDC current ignoring convertor losses. Since he was plugged in to shore power, I don't think it's a serious AC draw compared to other AC loads.
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Old 01-04-2015, 07:44 AM   #21
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Lily, and before her, Gus, had no problems wth our space heaters.
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Maggie
We ordered a heater that was either the same as one that Protag had referenced in a previous thread, or quite similar to that one. It's called a "desktop" heater and I was assuming that I would put it on top of the galley counter such that dog and heater would not make contact.

I know heat rises and it would be perhaps better for air circulation if I put it on the floor, but given that the space is very small, I didn't think it would make that much difference.

This model does have a tip-over safety switch. Ours is due to be delivered this coming week and we regret not ordering it sooner because we're freezing our butts off doing DIY in the dead of winter when we have to turn off the electrical inside the vehicle to do the work (we could run the heater to the Interstate using an extension cord directly to shore power). (Somebody out there is probably laughing over the image of anyone actually freezing their butts off in Houston Texas, but it can get surprisingly miserable here when the jet stream sags into the Gulf of Mexico).

Amazon.com - Duraflame DFHDH14T Ceramic Desktop Heater - Duraflame Space Heater
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