Help with troubleshooting house battery

[Donovan75]

Hi All,

I bought a brand new house battery (SRM-24 Interstate Marine Battery) as the old one was dead. The new one still does not power the appliances and am trying to troubleshoot the possible cause.

The appliances (fridge+microwave, house lights, etc) work when the generator is running and when I'm plugged into shore power. I took the previous owner's word that the House batt simply needed replacement.

Appreciate any troubleshooting tips as I familiarize myself with my new toy and am unsure as to where to begin (inverter/ wiring/ etc)

Donovan
'92 Four Winds / E350

[Bordercollie]

One of the first things to learn for an innocent new RV'er is the 12 volt DC and 120 volt AC electrical system.These include the 120 volt AC generator, the 120 volt AC "shore" cable, the method of getting 120 volt AC generator or shore power into the RV, the house batteries, house battery disconnect switch/relay and the converter charger. The converter/charger operates on 120 volt AC generator or shore power, to slowly charge the house batteries and power the interior lights. The engine's alternator also charges the house batteries while driving. Getting to know where these devices are located in your rig and, how they work, and how to maintain and troubleshoot electrical connections and batteries is essential to having electrical power and operating your appliances and roof air conditioning when you need it. Most important when boondocking with no camp/shore power available.I wish it was all simple and quick to learn.I'm still learning. Typical RV 12 vdc and 120 vac systems are adequate when working properly for camping with shore power. For boondocking with no AC power you'll need to conserve 12 vdc power carefully to have power for 2-3 days and get by without air conditioning or microwave unless you run the generator.

[tenbear]

Your Magnetek converter is a single stage converter. That is, it has a constant voltage output of about 13.8v. I will take many hours for it to recharge your battery. If you are off the grid for a week at a time you will have to run your genny several hours every day.

There are things you can do to help.
1. Replace your incandescent light bulbs with LEDs. They draw much less current.
2. Replace your converter with a modern 3 stage converter. It starts charging with a high voltage and as the battery charges the voltage is reduced to prevent boiling the battery. I switched to a Progressive Dynamics 9260.
3. Replace your marine battery with several deep cycle batteries.

[tenbear]

The RV has two power systems, 12 volt dc and 120 volt ac. Most things operate on the 12v system. Other things, the AC, microwave and ac outlets require 120vac either from shore power or the generator. Some require propane or 120vac, refrig and possibly water heater.

Your AC outlets will not work on 12v unless you have a big inverter which requires a big battery bank.

No one has suggested that you read The 12v side of life. This may help to clear up some of the mystery in the RV power systems.

[Mich_F]

Those 3 empty slots could be for 3 extra circuits. Just look on the cover for the fuse panel under operation guide - DC distribution panel - it will tell you what each fuse/circuit controls.
Normally most coaches have a switch mounted by the door which controls the overhead light closest to the door. The light can usually be turned on or off on the light itself. So it has to be set right to work properly. Many MHs have overhead lights that have switches only on the lights. Check the bulbs - they could be part of your problems.

[robsouth]

Check the bulbs as well. Even if good bulbs, they sometimes corrode a little and need cleaning. I think you are beginning to get the gist of 12V vs 120 volt services.

[Donovan75]

Roger that- No Microwave/AC on the house batt. Thanks!

I was tooling around. The converter is a magnatek 6300 series model 6345, for which I've found the manual. (link here)

I found that the 3 slots for the 20 amp fuse was empty so I installed 3 fuses but it didn't seem to change anything. (pic 1)


New discovery just now: The interior lights on the drivers side, along with the oven light and fan now work (I hadn't checked those earlier). However, all the lights on the passengers side remain non-functional. I found a couple of switches (one by the door), and another next to the interior generator switch, set both to "on" but nothing happens. The odd thing is that even with the generator running all the passenger side lights are off.



Really appreciate the tips and advice. I will keep plugging away at this. (Next step is to...1- check all the 15a fuses and 2- plug into shore power and see what happens.... Was gonna do that tonight but ran out of steam and daylight).


Edit..... The culprit was one of the 15a fuses. all good now....




Onto my next round of silly questions:
I was reading up on 12v batteries at this link http://rvroadtrip.us/library/12v_system.php

1) how do I set up the 110v electrical outlets to run off 12v? I just tested all of them using my phone charger and they were not functional (didn't run the genny this time as it's late) Is this possible or will I always need the generator for this (I'll be dry camping and will need to recharge phones/cameras/laptops etc)

2) how long can I typically run the interior lights as pictured before the Marine battery needs a recharge? I will be dry camping for about a week at a time.

[Mich_F]

Donovan75 wrote:
Thanks- it is the roof a/c, microwave and fridge that do not work off the house batt (only when it is on shore power or generator is on). I had assumed, based on the prior owner's advice to replace the house batt, that these would run once it was replaced.

I found an unlabeled kill switch next to the interior generator switch.... I'll go play with it to see if that changes anything.

The roof a/c, and microwave do not and will not work off the house battery. They need 120V which is supplied by the generator or shore power, not by the battery which is 12V.

[stew47]

things on a rv that are 12 v powered:
lights, fridge(powers circuit but propane is what cools),furnace(powers circuit) house fans,

120v: ac, microwave

check to make sure battery is being charged when shoreline is plugged in. check grounds

[Donovan75]

Thanks- it is the roof a/c, microwave and fridge that do not work off the house batt (only when it is on shore power or generator is on). I had assumed, based on the prior owner's advice to replace the house batt, that these would run once it was replaced.

I found an unlabeled kill switch next to the interior generator switch.... I'll go play with it to see if that changes anything.

[robsouth]

Only those items which operate off 12 volts will run with the battery. Microwave, Air Conditioner, wall plugs, etc will not without shore power or generator. Please be a little more specific as to what will not work.

[ntjpmm]

Check if there is a disconnect switch, on our 99 Fourwinds it is right by the door, next to the switch to keep the step from retracting. I had the same problem last week and had forgotten that I had hit that switch.