Back up heaters

We were 100 miles into an 800 mile 4 day round trip, and we pulled into a service station. It was very cold so I went to turn on the Truma heater.  It wasn’t having it.  There was no spark for the ignition.  I tried changing the battery in the igniter, but to no avail.  So we faced several nights in the van at temperatures below zero without a heater.  Oh the joys of motor homing. 

But we have two other back up heaters in the van. 

  1. The engine. We found that leaving the engine running and switching on the heater fan helps, but the coolant temperature, and thus the heater effectiveness drops when idling for a while.It’s considerably better than nothing, but noisy, inefficient and expensive.  
  2. The cooker. We have a cooker with three gas hobs, a grill, an oven and an electric ring.We used the rings to heat the van. We found that alternating between one and two rings kept the van nice and warm. Although there was a very strong layering effect.

We would quite happily leave the Truma running on a low setting all night, but we were not happy to do that with the gas rings. So we just made sure we used the seat covers over the duvet at night and we stayed warm.

It’s a handy thing to know.  The Truma is a wonderful piece of kit, but it struggles in windy conditions.  The direction of the wind makes a huge difference so we sometimes turn it around.  But if it’s very windy, it just blows out continually.  But the cooker will be fine under those conditions.

The problem was the igniter.  I opened it up (I’m an engineer, it’s what I do) but the inside is encapsulated.  I ordered a new one on line. It cost me £95 and it was waiting for me when I got home.  It’s fitted now and we have a working Truma again. (That will be handy for doing the investigations below)

To add to the fun,

We got a surprise cold snap in the second week of December.  This does not usually happen in Cornwall. The loo hatch was frozen and it took me about 45 minutes and four kettles of boiling water to free it. I greased the rubber when I finally got it open. Hopefully fixed. 

 I had not had a chance to winterise the van (i.e empty the water out) so we set off with the pipes frozen. We finally got running water after 4 hours driving at an outside temperature of around 3C.  But the tank does not seem to hold much water now.  I hope it’s not cracked.

Investigation 1 24/01/2023

I poured 25 litres of water into the tank, and none ran out.  I think it’s not a problem.  Maybe we had simply used more than I thought.

While we were away, the fridge stopped working on battery – it just gave out a buzzing noise, like a relay  switching in and out.  It worked OK on gas though.
Looking at the circuit diagram, if I have power to F1 then the problem is either in the fridge, the wiring inside the SPDU, or the wiring from the SPDU to the fridge.  But the van is parked 8 miles away on a farm so it will have to wait.

Investigation 2  24/01/2023

Here’s the problem.

This connector takes the 12V to the fridge and it has overheated and burned out.  There is no connection between the yellow/red wires on each side of the connector.

The connector is at the back of the fridge and accessed quite easily from the outside of the van via the top vent.

The heat had also melted the plastic which had fused making it impossible to open the connector.  What is really need is another connector, but I decided to use a jumper across the connector.  The fridge is specified as 120W at 12V – so 10Amps. But the fridge only works on low voltage when the engine is running so the voltage will be 14.4V. so closer to 12A. The line is protected with a 20A fuse in the SPDU.  I decided to us use blue bullet crimps which are rated at 17A.  I’ll replace the entire connector when, and if, I ever have to take the fridge out.

And on the way home the fan in the van heater stopped working on anything but high (and very noisy) speed.  It was the connector to the little resistor block.  I wiggled it a bit and it worked, off and on, then settled down working after a while.

Investigation 3 22/01/2023

I disconnected the plug and found that the side of the socket on the cable could be removed allowing me to get to the connectors with a pair of needle pliers.  Squeezed ’em up a bit and job done.

It also seemed to struggle to start on the cold mornings.  The starter battery is now around five years old and when the van is stored only has our 40W solar cell to keep it charged.  
Many years ago I had a Lada.  The instruction manual recommended switching the lights on for 10-15 minutes before trying to start the engine.  This was to warm the battery slightly. Crazy, I thought.  But all of the lights would have been around 120W and that would only take 2.5AH from a 90AH (Guess – it was quite big) battery.  Maybe I’ll try that and see if it will last another year. 

Hmm, does the solar panel keep charged??  The meter only measures the leisure battery which has zero drain other than self discharge. The vehicle battery voltage could be lower if the solar panel was not compensating for the remote locking.
Maybe change the push button on the meter to SPDT  switch to look at either battery? Even connect both batteries together via a resistor so that they can share a small load. 

Investigation 4 22/1/2023

I measured the batteries after three weeks standing. The starter battery was 13.03V and the leisure battery 13.1V. Both were fully charged off the solar panel.  The started battery was fitted in February 2018 so it is five years old.  Maybe a bit old for really cold days.  I’ll change it next Autumn ready for the winter.  BUT I will measure it’s capacity and it may be my next leisure battery.  Although it’d cranking capability may be down it’s storage capacity may be good enough.

I also measured the current from the solar panel.  At around 3:30pm the sun was too low to shine directly on the solar panel. All the panel could see was clear blue sky.  The output was 52mA.  This is not a lot, but the leisure circuit has NO drain, and the vehicle drain is around 50mA.  So when the sun was reaching the panel, around noon, it would have been supplying more.  Anyway the panel is keeping both batteries charged but starting is still a bit laboured.

So our normally super-reliable van was being a little temperamental this time.