Batteries not holding charges

This brings up the, only way to truly know the SOC (state of charge) of your batteries is with a battery monitor that measures the current going into and coming out of your battery. The two choices are basically Trimetric and Vectron.

As you realize by now it takes much longer to charge your batteries than an hour or two.

If you can measure the voltage the batteries are getting when being charged, or post the model name and number of your converter we could be of more help.

How difficult is it to add more batteries? That depends on your RV and the available space. It is more a physical than a wiring challenge.

Motorhome house battery charging is essential to operating any motor home. Getting to know the location and understanding basic functions of the converter/charger, the house battery disconnect switch and relay, fuse and breaker boxes, how to check battery voltages with a simple multi-meter, and how to maintain battery electrolyte levels, is basic to having house battery power when you need it on the road, away from home. 12 volt DC supply connections at the converter/charger, batteries and at appliances, and other 12vdc devices must be clean, tight and make good contact. Most appliances need a combination of 12 volts DC for controls and 110 volts AC or Propane for main power. There are some helpful You Tube videos and generic "how-to" RV books. Nothing beats exploring and getting to know your own rig's 12 volt systems.

The answer to your issue is in the above post on how long it takes to recharge a battery. One hour of charge is only going to show a surface charge voltage which is not the true state of charge. A high output converter and time is what your recharge system needs to get the batteries back to a 90% state of charge quickly. Getting to 90% SOC should be your goal. The last 10% takes a loong time.

Jim

If both batteries have been tested and are in good chargeable condition, and converter/charger is supplying 13.6 volts charging voltage measured at battery terminals, and you are allowing enough time for converter to charge both batteries, there may be a short in the 12 volt wiring system or some item that is drawing excessive amps and needs to be disconnected/replaced. Check for lights left on in the storage compartment, etc. If there is a short, it should blow a fuse or circuit breaker if one is in the circuit, if not, a short could cause a fire. You might try feeling for heat in 12 volt wiring. If you had an amp meter, you could check on how much current is being drawn from batteries with everything shut off.

Batteries take much more time than one hour to charge. It depends on the DC Charge voltage you are using and how much DC the batteries are allowed to draw.

The rule of thumb is you will want to have around 18-20AMPs of DC CURRENT available for each battery you are charging in your battery bank. i.e. if you hit a discharged deep cycle battery with 14.4VDC the battery will demand around 18-20AMPS of DC CURRENT from the source charger to start its re-charge mode.

Consider this report from PROGRESSIVE Dynamics on how long it takes to charge a deep cycle battery when discharged down to 10.5VDC

"Progressive Dynamics ran this test on the amount of time it took a PD9155 (55-amp) converter/charger set to three different output voltages to recharge a 125 AH (Amp Hour) battery after it was fully discharged to 10.5-volts.

14.4-VOLTS (Boost Mode) – Returned the battery to 90% of full charge in approximately 3-hours. The battery reached full charge in approximately 11 hours.

13.6-VOLTS (Normal Mode) – Required 40-hours to return the battery to 90% of full charge and 78-hours to reach full charge.

13.2-VOLTS (Storage Mode) – Required 60-hours to return the battery to 90% of full charge and 100-hours to reach full charge."

This is battery charging science at play here - not many ways to get around it...

Just some of my thoughts here...

Roy Ken