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24- Why are my trailer batteries always dead?

RV batteries go dead for a few reasons. The first reason is age; RV batteries are designed for deep cycles of use which means they get charged and then discharged often times, severely. This type of use is what they are designed for. A couple of issues come up with this pattern of use; the first issue is that many RV batteries never get fully charged.

Most every device in an RV, less maybe the microwave and air conditioner, require 12 volts to operate. After a couple of days use doing what is called “dry camping” (no power hook ups), the average RV battery will be pretty depleted and have less than 12 volts. Once the voltage drops, things don’t work well and if the voltage drops too much, nothing will work but perhaps dim lighting.

RV’s are built with electric devices called inverter/chargers. These units are designed to convert 110 volts (shore power) to 12 volts. When plugged in, the same unit charges the battery. All works well when plugged in, but when unplugged, is when things get dicey. The charger that is in these units only put out a low level charge. So, even if you plug in for a day or run your generator for hours, it won’t be enough to properly charge your battery. It would take 2-3 days to get a seriously depleted deep cycle battery up to a full charge when using the inverter/charger and that’s without use. The average built-in chargers just don’t have enough amperage to charge any faster. So, although you may be able to produce enough voltage to get by, the battery is still not 100% charged in most cases.

So, what are your options? There are only a few. First, make sure that your batteries are full of water, have good clean connections, and are fully charged before your trip. Try to get some type of charge on your batteries every day during use. If you have a 7 pin plug and it is properly wired, your tow vehicle may be able to charge your battery if you let it run for a while (1-2 hours). Another way to keep things fresh is to run your RV generator as often as you can. This will take some heat off of the tow vehicle and allow you to run larger a/c units.

Aside from always plugging in to shore power your next best bet is to run a solar panel charger. This will allow your battery to continuously get a charge while in use or in uncovered storage. I believe this is a great option as it is always on and it’s free after purchase.

The last viable option is to have an 110v battery charger that is separate from your inverter/charger. When you are hooked up to shore power, an auxiliary battery charger (the type used for cars) can charge your batteries at two to four times the rate of your inverter/charger. So this is a faster option if needed; but remember, a slower charge is better for your batteries than a fast charge.

So, to recap, here are the bullet points:

  • Keep battery connections clean and tight.
  • Charge batteries with an auxiliary charger a few days before your trip
  • Charge batteries daily while on your trip
  • Mount a solar panel on your RV’s roof for continuous trickle charging.
  • Always fully charge your battery after your trip
  • Make sure that your RV’s battery disconnect is engaged (off) before storage or simply disconnect your (+) battery cable
  • Never leave your RV plugged into shore power continuously unless you have a built-in computerized battery charger. That way you won’t overcharge (cook) your batteries by charging 24/7/365.

For a free battery inspection, bring your RV to Sturken RV. Make an appointment now by calling us.