Battery life

[Bill]

Q: How long can we expect the TM battery to last when we are camping without an electrical hookup?

A: The answer depends on many factors, of course. Dry-camping (no hookups) requires a mindset based on conservation. You learn to conserve water, you learn to conserve holding tank capacity, and you learn to conserve battery charge. For the OEM battery and conservative use, somewhere around 3 days might be typical after you learn some of the battery-conservation skills. There are several things to remember - you will develop your own additional rules as you go along.

The first important point is to leave home with fully charged batteries. The tow vehicle will top up your battery as you drive, but 4 or 5 hours of driving will not bring a discharged battery back to full charge. Beyond that, if you run the refrigerator from battery power as you drive, the refrig will consume most or all of the power provided by the tow vehicle. In fact, with some TM/tow vehicle combinations, the refrig actually draws slightly more power than the tow vehicle can provide, and you may arrive at your destination with a badly depleted trailer battery. If this is your case, you might do well to pre-chill the refrig very cold at home, load it only with very cold food, add some blue ice packs, and turn it off while you travel.

As soon as you arrive at your destination, it is important to switch your refrigerator to propane (gas) operation. On the DC setting, the refrig consumes a LOT of electrical power.

Another surprisingly large electrical load is the furnace. Although the heat is generated by burning propane, the blower runs from 12 volt power - lots of it! If you are camping in cold weather, and run the furnace a lot, you will NOT get three days out of your battery. Many TMers buy a separate catalytic heater (no electrical connection at all) for this situation. Be sure you select one that is rated for use indoors - and one that is rated for high altitude if that's where you plan to camp. And be prepared for all the moisture that a cat heater produces, and the annoying condensation that can result.

Use lights sparingly. The factory-installed lights are not particularly conservative when it comes to power use. If you run several lights for several hours in the evening, you will be disappointed with battery life. Many TMers have substituted 12-volt fluorescent lights for the original fixtures - they provide more light while using substantially less power. More recently, several owners are experimenting with LED lights for the same purpose (search the site for LED), though the jury seems still to be out on this.

Use of a TV and/or VCR will reduce battery life, of course, particularly since these appliances tend to be used for several hours at a time. If you decide to bring a TV for rainy days, get a relatively small one (some have a built-in video player) that runs directly on 12 volts DC. Compare models, and choose one with a low amp drain.

Intermittent loads like the water pump and the toilet flush pump don't run for long enough to draw any significant charge from the battery, so you need not consider these in thinking about battery life. And of course the battery won't run heavy loads like the air conditioner or the microwave - these aren't available to you when you are dry camping.

UPGRADES TO EXTEND BATTERY LIFE:
If you plan to dry camp for extended periods, there are several ways to extend your battery life. The first, of course, is to get a bigger battery. The OEM battery is rated at a relatively small 75 amp-hours. A physically-larger battery can double or triple this capacity. When increasing capacity, many owners use two 6-volt batteries in series rather than a single 12-volt battery, and so-called golf-cart batteries are popular. Remember that a large battery is very heavy, and weight is the enemy of lightweight RVs, so there is a tradeoff here.

Another common method is to use a generator to recharge your battery, and perhaps to run some of your appliances. All generators require you to carry fuel - almost always gasoline, which is a disadvantage. And without exception, a cheap generator is both heavy and noisy. Generator noise won't make you popular with your neighbors, and for this reason, they are forbidden in many dry camping areas. Lightweight quiet generators are available from Honda and a few other manufacturers, but as with all things, there is steep tradeoff with cost.

Another solution rapidly gaining adherents is solar charging. Solar panels are quiet, of course, visually unobtrusive, relatively lightweight, require no fuel, and they work all day without any effort or attention on your part. Solar has a reputation for being expensive, but prices are coming down rapidly and are now quite affordable.

This discussion board contains a lot of experience-based information on how to get the most out of your system. Spending an hour with the search engine will help you find the solutions that work best for you.