House battery voltage under draw?
I have a new (to me motor home) and an upgrade from my old one. In my old RV, I had to check the house battery voltage manually. With the new rv, I have a switch on the wall. However, when I check t...
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Hi tommymsw,
The batteries have never been fully charged. They need to get to 14.8 volts. Driving for 9 or 10 hours for a few days might get the job done.
You don't specify the wattage on the solar, nor the type of charge controller. If the controller does not have a temperature sensor on the battery bank, it is unlikely to fully charge them either.
To be able to use voltage under load you would need to put on the loads, then use a hydrometer to check the specific gravity. That may allow you to have a "much better guess" at state of charge under load. I.E. make your very own chart of what voltages are when particular loads are applied.
For loads you mention "just a few lights". If they are incandescent, the load may be 2.2 amps per light. The jars you have are tested for a 25 amp load. So six lights may be over 50% of the planed for recommended demand. It is a known fact that voltage drop is greater with twin six volt batteries in series.
The batteries have never been fully charged. They need to get to 14.8 volts. Driving for 9 or 10 hours for a few days might get the job done.
You don't specify the wattage on the solar, nor the type of charge controller. If the controller does not have a temperature sensor on the battery bank, it is unlikely to fully charge them either.
To be able to use voltage under load you would need to put on the loads, then use a hydrometer to check the specific gravity. That may allow you to have a "much better guess" at state of charge under load. I.E. make your very own chart of what voltages are when particular loads are applied.
For loads you mention "just a few lights". If they are incandescent, the load may be 2.2 amps per light. The jars you have are tested for a 25 amp load. So six lights may be over 50% of the planed for recommended demand. It is a known fact that voltage drop is greater with twin six volt batteries in series.
tommymsw wrote:
To answer some questions...
3. I am NOT connected to shore. I do have a solar panel and it does in fact charge the batteries (reading over 14v when charging). I have also driven and charged the batteries. They do charge and seem to hold their charge when not in use.
However, if the volts do appear lower when under load, how then do you know when to stop using them? I assumed you could check them in use and know when you need to stop.
