Is Your RV Charge Controller Damaging Your Batteries?

You might need to upgrade your charge controller if your RV house batteries running low faster than they used to? Maybe they are still fairly new but just don’t seem to last very long. Here’s what I’ve learned.

charge controller

Since I started boondocking last fall, I’ve battled with my batteries. They just don’t hold a charge as well as they should. My batteries are two-year-old, high-quality, AGM (Absorbent Glass Mat) batteries. They are rated at 92 Amp Hours.

What are amp hours?

Ampere-hours: Symbol Ah is a unit of charge. Example: Drawing a current of one ampere (1A) from a battery for one hour (1h) equates to one ampere-hour (1Ah). via

I should be able to go through the night with the heat set at 50 degrees and not have my batteries drop below 50% charge. You should never discharge your batteries below 50%. The only other draw is my refrigerator and whatever parasitic draw (see below) there may be around the Airstream.

I’m almost certain I need to replace my two house batteries. The bigger question is, why aren’t they holding a charge as they should be?

I’m a member of the Airstream Addicts group on Facebook. There are nearly 56,000 members in that group and there is a vast amount of information in the archives not to mention the knowledge of the people in the group. In searching the archives, I discovered a common problem, a single-stage charge controller.

What is a charge controller?

The charge controller recharges the battery and supplies power to your rig when 120–volt AC power is hooked up. In other words, when you are hooked to shore power or generator power, the charge converter recharges your batteries along with running all the electric things in your RV.

My Airstream came with a single-stage charge converter. Single-stage converters charge at the same rate, about 13.6 volts, all the time. They just keep pumping the same level of charge into the batteries. This can overcharge your batteries and make their life much shorter. Well cared for AGM batteries like mine should last 5 to 7 years.

There are multi-stage, smart charge controllers on the market that are much more battery-friendly. Multi-stage converters have the technology to allow them to change the level of charge according to your battery’s needs.

I spoke to Randy at Best Converter and he suggested the Progressive Dynamics PD4655VL 55 amp Converter Upgrade as a replacement. At the time I wrote this the cost, including shipping, was approximately $250.

Here’s how my new multi-stage charge controller functions.

Inteli-Power 4600 Series models can recharge the battery to 90% in 3-6 hours using our patented Charge Wizard technology:

  • BOOST Mode 14.4 Volts – Rapidly brings RV battery up to 90% of full charge.
  • NORMAL Mode 13.6 Volts – Safely completes the charge.
  • STORAGE Mode 13.2 Volts – Maintains charge with minimal gassing or water loss.
  • EQUALIZATION Mode 14.4 Volts – Every 21 hours for a period of 15 minutes prevents battery stratification and sulfation – the leading cause of battery failure.

I installed my new charge controller yesterday. I won’t say it was easy because the instructions were beyond useless and I have very limited electrical experience, but I got it done.

I’ve been instructed to wait to replace my batteries as there is a chance their condition will improve with proper charging. I’ll follow up to let you know how well this works and if I need to buy new batteries.

Additional Information

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2 thoughts on “Is Your RV Charge Controller Damaging Your Batteries?”

  1. I like your easier to understand information on the charge controller. I feel like I am absorbing knowledge over time of my trailer’s systems rather than studying any one thing. Not long ago I knew nothing but never felt overwhelmed.
    I am enjoying your blog

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