Dead house batteries

Tanks,
It has been sitting only a few weeks. We spent 5 months in it last winter.
I do have a charger but no 110V power where it is parked. Any ideas about using jumpers from my car to charge house batteries?

retiredtravelers2013 wrote:
I went to start up my diesel generator Sunday afternoon. Completely dead, not a sign of life.

How long was it sitting ?
In use or not ?
Battery disconnect switch was obviously not operated (assuming there is one).

For about $100 I got a portable jumper battery unit.
It also has a tiny air compressor, a little inverter and a work light.
Of course, you have to remember to top off it's charge every couple of months too.

Thank you for the replies and advise. One slight little issue is that I have a dead fuel pump so I cannot start the engine. My mechanic is coming later today to replace that.

Parasitic drains like the O2 sensor, many other sensors for the varies things like fridge, heater, AM/FM radio, etc can easily drop your trailer battery voltage when just setting for a few days and not on some kind of trickle charge...

A single automotive incandescent light bulb which draws around 1A DC left ON can do it almost over night... The furnace heater fan draws 5-6AMPs DC and can really drain your batteries if it kicks ON overnite...

When your trailer is setting you need to have a DISCONNECT SWITCH for your batteries or just simply remove the NEG BATTERY TERMINAL that goes to the trailer frame ground.

Having a DC POWER MONITOR that sounds off a settable BEEPING alarm will be very useful for me. I would set it for 12.0VDC which is very close to being at the 50% battery charge state. Of course the problem with this you have be there to hear it I guess...

Another problem could be you have run down your trailer side batteries below their 50% charge state several times and not recharged back up to the 90% charge state in a quick manner which starts building up crud on the battery cells and may have shorted out one cell in the battery over time. The one or two times I have seen this happen to one of my batteries usually dropped the DC OUTPUT to around 5VDC. This would also make the battery case get very hot and boil out its fluids etc... You can smell the boiling out of the fluids - mine smells like rotten eggs... In my case this is GAME OVER for the battery...

Another problem you hear about a lot is the constant charging of the batteries over time when just a single 13.6VDC type converter/charger will boil out the battery fluids over time which will also start building up crud on the cells and eventually short out the cells. The standby charge should never be over 13.2VDC... We make it a routine to check the battery fluids on a regular basis especially if we are leaving the trailer sitting being on charge.

RV installed Batteries are your life line - we keep a close eye on ours...

just some of my thoughts.
Roy Ken

retiredtravelers2013 wrote:
I went to start up my diesel generator Sunday afternoon. Completely dead, not a sign of life. I checked the house batteries and they read 9 something volts. Clearly something is draining them since they are only 9 months old. My mechanic suggested I use the Alt. starter switch to get the generator going. I thought that was for if the chassis batteries were down one could use the house batteries to start the engine. He said it works both ways. Anyone have any knowledge about this. And any advise as far as troubleshooting the drained batteries?
Thanks

Works both ways, as said. You should also be able to use the main engine's alternator to charge them up in a hurry.
For troubleshooting, turn everything off, then remove the ground terminal on the house batteries and lightly touch the cable on the post. Seeing sparks tells you that something is still draining your batteries.
No sparks....then disconnect them after charging to see how long they will hold the charge. If they won't do so, then you most likely have one or more defective batteries.

Use the switch, power does not care which way it flows. Lights left on in the cargo bay, slide power may come from house batteries, steps, check to see if something was left on.