Stretch your amps and watts


By Bob Difley
Electricity. We take it for granted. Plug in an appliance and turn it on. What could be simpler. But when you take up boondocking, electricity is more like opening the spigot of a water jug. When it all flows out there is no more, unless you refill the jug.

Your rig’s 12-volt system is sufficient for satisfying your power needs as long as you avoid excessive use of 120-volt current. An inverter — which converts 12 volt into 120 volt — consumes huge amounts of power if you run your air conditioner, toaster oven and microwave oven. Leave your electric blanket and Mr. Coffee at home for the same reason. An extra blanket and a drip coffee maker will replace these necessities of modern living.

stretch bulbIf you observe a few basic electricity conservation rules, you’ll be able to get the most out of your available battery power.

• Use lights only when needed and turn off when not used — even for a short time.
• Don’t leave the porch light on. Carry a flashlight in the dark.
• Use battery-operated reading lights and flashlights.
• Shut off the radio or TV when no one is listening or watching.
• Avoid lengthy use of appliances requiring high wattage to operate, even if they are 12 volt, like your water pump.

The amount of 12-volt electricity in your battery(ies) available to operate your systems is a limiting factor for your length of stay, or the time between recharges. A single deep-cycle 12-volt house battery will produce about 105 ampere-hours of electricity. By calculating the number of amps each of your electrical appliances draws multiplied by the hours used makes for an educated guess at when you need to recharge by subtracting the ampere-hours used each day from the total available.

Only about half of these amps (about 50) are actually available to run your electrical equipment. Take voltage readings at the battery terminals with a multi-meter and when the voltage drops to 12.2 volts, start your engine or run your charger/converter off your generator to recharge the battery. Installing a second house battery or switching to a pair of 6-volt golf cart batteries will increase the total number of available amps.

Practice. Take notes. Keep a log. Soon you’ll be able to accurately judge how long you can go before your system needs rejuvenating.

You can find Bob Difley’s RVing e-books on Amazon Kindle.


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2 years ago

Can I shut off my batteries when l am plugged in for a month or so. Kermitt

Bill T.
2 years ago

Thanks Bob for another well written, to the point and useful article.

Marcus Falco
2 years ago

Yes….all basic common sense ‘tips’….but here are a few things that will REALLY help with power last longer. Get rid of any lead-acid battery (s) and invest in a military style AGM glass mat battery…will last much longer, or better yet if $$ are available a new LITHIUM battery…super long lasting. Next, get a good (Renogy) 100 watt solar panel to recharge your house battery of whatever type. Wish we had done this YEARS before we did! Even in half decent weather, we can now boondock nearly without limit! We once went over 3 months without electrical hookup….and are in the process of doing so again. Common sense use, an improved battery AND SOLAR will/can mostly free you from needing electric hookups…and allow you to finally stay longer in the best places where there is never power available….except that you make it…..!!!

2 years ago

Good article on saving electricity but the 12.2 V reading recommendation is for STATIC, RESTED batts ,,not active batteries and can be quite misleading in an active situation. A REAL battery monitor like the Victrons or Trimetrics should be required equipment for anyone who boondocks and cycles batteries. Not only does it save battery life cycles it provides a host of functions like telling you when you need to start charging, how much you are putting back into the battery and when you are done…saving generator fuel and wear and tear…as well as preventing damaging undercharging.

2 years ago
Reply to  Cam

which Victrons model do you use? Looking on Amazon there is a wide price range.

2 years ago

My electric blanket goes every where my RV goes. I usually have shore power or my generator. I don’t run solar or an inverter. My electric blanket is very power wise. I know this as I run it through a Kill-A-Watt meter. On a very cold night it might use 10KW tops and I don’t need to run my furnace and suck up my propane.

T. Helms
2 years ago

Great advice; Number 1 don’t leave your “Porch Light” on!!! This drives me nuts. Stay in the city if you are afraid of the Dark. I want to see the stars and not your light. Carry a flashlight.

2 years ago
Reply to  T. Helms

Yes, THANK YOU! It is not on for SAFETY, like most think. It is on to {bleeped} of your neighbors….. If you need to turn on to walk your pet at night, that’s fine. Just please turn it off when returning, so we can continue watching the stars! If you are worried about safety, install a motion detector light system that lights up your porch only.