Redoing the Electrical Audit

Another thing I did yesterday was redo all my reading about RV electrical systems to figure out why I’m having such a hard time when boondocking more than one night and properly determine what I need to upgrade. Things made sooooo much more sense this time around. For example, I finally figured out why watching a movie through the inverter runs down my batteries. Old timers are going to roll their eyes at me as this is really one of those DOH! moments.

I watch movies on my iMac. The iMac runs at about 100-120 watts. According to my initial energy audit, that meant that it uses at most 1 amp (120w/120v=1a), no more than a light. Therefore, I could definitely run my iMac on the battery for a couple of hours.

(Old timers are going waitaminute…)


What I failed to understand is that the inverter doesn’t really give me 120v power, so I should have been dividing that 120w by 12v, not 120. Meaning that my iMac uses 10 amps!!!

Okay, it’s clear. I can’t run the iMac when boondocking. It’s also the only power hungry thing I’d want to run for any length of time when boondocking. Therefore, my solution for long term boondocking isn’t to upgrade my electrical system but to get a slightly newer laptop that is faster and has a DVD player, a solution costing a few hundred dollars rather than a few thousand. Talk about my getting smarter!

That said, I most definitely need to replace my battery and I won’t even bother getting this one load tested. It has surpassed its lifespan and I doubt the POs did any sort of maintenance on it. So, two new 6V golf cart batteries are on my priority list for this winter, and then I’ll shop for a new-to-me laptop in the spring when I start boondocking again.

At any rate, I quit running the iMac while Walmarting quite a while back as well as running a million lights to either read or embroider as I’ve picked up a new hobby that requires no electricity and very little light. No, I’m not going to tell you what it is so don’t even bother asking. 🙂

Further evidence that I’m getting smarter about all things RV came about when I arrived in Edmonton on Monday night. It was really cold and damp in the rig, but I didn’t turn on the furnace since I was only on 15A service. Then, I actually questioned if the furnace would use as many amps as an air conditioner. I pulled out the manual and learned that the furnace only uses 8A. Add the 1 for the iMac and 1 for a light and I was still at only 10A. Ah, no more shivering. 🙂

Electrical heaters are next on my to-buy list and I’m still debating catalytic heaters. I have really mixed opinions on those.

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  • From the sound of it, you are right about the battery. It should be performing way better than it is. Two 6 volt is the way to go. We have run the furnace all night on battery and still not drained them. The furnace fan is 12 volt, not 120, so the 8A is at 12 volts. I think the new batteries will handle the iMac as well. Just make sure you charge them properly before you use them.

  • We want to know what the new “hobby” is that requires no light or electricity!!! 😉

  • Yeah, my battery sucks!!! I can’t believe it took me so long to clue in to this fact! LOL

    The furnace runs on 12V?! You’re not the first person to have told me this, but I’m certain I can’t get the furnace going unless I’m plugged in to shore power or am running the generator… Unless it has something to do with my sucky battery?

    As for charging, you should see my charger. So nifty! It has brains of its own. I don’t even have to think about charging, it knows what to do and when to stop.

    And it can start the engine batteries on the car or coach so if both wind up dead one day or one vehicle isn’t in position to boost another, I can still get going. What a fanastic tool!

  • I’m not telling! People who know me are going to mock me and spoil my fun!

  • “Unless it has something to do with my sucky battery?”

    You have hit it! The furnace is very sensitive to low voltage for safety reasons. If the voltage is low, the furnace will not run. It is telling you something.

  • I especially love the irony that I’m having generator issues because of the low battery.

  • Just for the information of others who may read this, if your coach battery gets too low to start the generator, try starting it before you shut the vehicle engine off. Unless the battery is completely shot this trick will work as the battery is being charged by the engine at the time and will contain the best charge.

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