2020 Navion House Batteries

[dnixmisc]

I want to send a big, thank you to the folks who helped me with my Mercedes primary and auxiliary batteries! That got my rig up and running
The batteries in the back are not holding a charge. when I connect to shore power things run fine in the back, then, after a while, after being disconnected, no more power back there, solar panels seem to be sending some power along the way, but not quite enough to get anything going.
Is there any simple thing I can check such as water level? No problem if I have to replace them but just need some help getting started on right path.

[bigb]

Originally Posted by dnixmisc

I want to send a big, thank you to the folks who helped me with my Mercedes primary and auxiliary batteries! That got my rig up and running
The batteries in the back are not holding a charge. when I connect to shore power things run fine in the back, then, after a while, after being disconnected, no more power back there, solar panels seem to be sending some power along the way, but not quite enough to get anything going.
Is there any simple thing I can check such as water level? No problem if I have to replace them but just need some help getting started on right path.

Yes definitely check the water level if they are flooded lead acid and after verifying water is up over plates (use distilled water only!) then plug in or attach a charger and give it a good couple of days. If you have a multi meter check voltage while plugged in to verify charging is taking place, you should see over 13 volts. The coach battery switch may need to be in the "ON" position for charging to take place while plugged in. Good possibility you have 2-6 volt batteries in there, if so be careful hooking up a charger, one charger lead goes to each battery, not both on the same battery.

[Morich]

While looking at the coach batteries, I also like to verify that several other things are working since I am there and it is easy if we have the meter out.

Your coach batteries should be connected to the chassis battery under two conditions and those are easy to check.
When looking at the coach battery voltage, it is likely low currently but when we plug in and have the disconnect switch turned on, that voltage should jump way high immediately as we should see the voltage from the converter trying to charge them.
That verifies the converter/charging is okay.

When NOT plugged in the coach is likely to be low voltage but if we hit the switch near the driver labeled boost, aux or something like that which varies, Then the coach and chassis batteries are connected together to give the starter a "boost".
If you have a helper or can set the meter to see while you push the switch, that is easy to test for it working!

That same system also connects both sets together when we have the ignition on. There is an "ignition hot" point that makes a solenoid or electronic gizmo connect them together. So if coach voltage is low, start the RV engine and expect the coach battery voltage to jump high as the alternator and chassis battery connects! Rev up the engine and watch the coach voltage run up and down with the RPM! That system is what lets us recharge a coach battery after we have camped for a while and it does it while we drive to the next site! It may not get a really low battery fully charged if we don't drive 6-8 hours but if does help some so a good thing to do an easy check while we have it all right there in front of us.

This DOES NOT mean the batteries are good but it does tell us that they are getting the voltage, even if they are not good enough to HOLD that charge.

[eyecando]

I would connect a clamp on ammeter at the positive or negative terminal taking care to make sure the jaws go around all the wires connected. You should see current going into the battery (unless it is beng discharged). Depends on the state of charge, your battery size and the capability of your converter, but I would think you would see at least 20 amps. Also verify the voltage at the battery is at least 13.4 volts or the battery is not likely to charge (assuming a good battery). You can check this with the 120VAC (shore power) or with the engine running to verify the charging system is working correctly. This amp reading tells you exactly what is going into the battery. You may have an ammeter in your RV, but that will display total charging current which is the sum of what is going into the battery and what is being consumed by your appliances. If the consumption is greater than what is going into the battery, the battery will be discharging. This is why I suggest you take your amp readings at the battery terminals.

If the AC power is off and the engine is not running, you will see the load current from your appliances. This current should be in the opposite direction (sigh), if your battery is actually being charged, otherwise it is being discharged.