House Battery Charger

House Battery Charger

by Chris (Petersburg, VA)

Question: I have a 2001 Thor Hurricane 32ft. The coach has 3 house batteries which I just replaced. After about 1 day of use running heater and lights the batteries have been drained.

I have looked through the coach trying to find a charger. The coach has not been used in a while but I do not ever recall having these batteries drain on me like this. Is there a onboard charger? Any trouble shooing advice?

You did not mention if you were plugged into external power while you were running the heat and lights. If you were plugged into power, then you have a charging system problem.

If you were not, then it does not surprise me that your batteries are dead. If I used the heating system and lights on a cold day my batteries would be drained too – if I were unplugged from power.

I am assuming that you do not have an owners manual which tells you if you have an on board charger. I visited the Thor website and looked for an owners manual for your year coach – unfortunately I was only able to locate a manual from 1996 and one from 2007. However, both refer to a charger, so I can only surmise that you also have a charger. (You might try contacting Thor to ask for an owners manual).

From your question, I can’t tell if you have a generator; or if you replaced the original batteries with the same amp hour ratings; if the new batteries are deep cycle AGM or flooded lead acid batteries (there is a difference in charge rates); or if the batteries were recharged successfully after they went dead. So I will make some assumptions and try to provide some general assistance.

Caution: If you are not familiar or comfortable working on live circuits do not attempt to go any further. Please take the RV to a repair facility. You do not want to take any chances and create a bigger problem than you already have. If you feel comfortable please read on just be careful, the life you save maybe your own.


  1. Your flooded lead acid batteries are still dead.
  2. The RV has not been plugged into power.
  3. The RV engine has not been started.
  4. If you have a generator, it has not been started to recharge your batteries.
  5. You have a volt meter that can read DC voltages in the range of 0 – 24 volts

Trouble shooting the charger:

  1. Make sure all of your battery connections are clean and tight and the water level is adequate. Do not add water at this time unless the plates are showing. Add water (distilled only) only after the batteries have been fully charged. It may take hours or days depending on the charge rate and the batteries to reach a full charge.
  2. Locate you charger and associated wiring and fuses. Contact Thor Industries, as they may help you identify where you can find the charger.
  3. Make sure all wiring, fuses and or circuit breakers associated with the charger are good.
  4. While unplugged from power and with the RV’s engine stopped, take a reading of the state of each of your batteries. They should read at least 10.5 volts. If they are lower than 10.5 volts you may have damaged the batteries and they may never recover.
  5. If the batteries are at 10.5 volts, start your engine and take another reading. Each battery should now read at least 13.6 volts or there is a problem with the engine charging system. Do the same test with engine off and plugged into outside power (Ditto on the readings).
    If you have a generator start it and perform the same test. The idea is to try to isolate the problem. If one or more of the charging systems are good then that should point you to the faulty charging system. If all the charging systems are good then it is time to take your RV to a service center to have them help isolate the problem.

Please let us know the outcome, as it may help other RVers.

We also welcome additional comments and suggestions.

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