magicsurfbus
Free Member
After another foreign trip plagued by control panel battery monitoring problems and a fridge that refuses to work on 12v I bought myself a brand new multimeter this morning (despite B&Q's best efforts trying to flog a duff batch of said items) and have been round my van testing everything. My leisure battery is a four year old Carbon Fibre 110Ah, hardwired via a charge controller to an 85W solar panel. It has discharged a couple of times in the extremely cold winters of 2010, which I realise is not a good thing.
Here's what I found, bearing in mind we've driven 1800 miles in the last couple of weeks and returned less than two days ago, and the van hasn't been driven any distance for about 24 hours. The control panel shows both batteries to be topped up.
With solar panel working in April sunshine, leisure battery terminals read 13.5v
With solar panel covered (and all devices off), leisure battery terminals read 12.7v
With solar panel covered, engine running, (and a reading of 14.5v at the engine battery terminals) leisure battery terminals read 12.68v
With solar panel covered, engine running and the 130W fridge switched to 12v, the fridge relay clicks on and off every few seconds and the leisure battery voltage jumps between 12.27v and 12.46v with each click of the relay. 12v Socket voltage in the living compartment drops just below 12v while the fridge is on.
With a full load on the engine battery (lights on full beam, heater and fan on full, wipers on constant) the voltage at the engine battery terminals reads 13.9v, which suggests the alternator is doing its stuff.
This would suggest to me that the solar panel (when on) is masking the fact that the leisure battery is no longer holding sufficient charge for the fridge to run properly on 12v - or am I missing something here?
As always, your thoughts, observations, advice and insults are most welcome.
Here's what I found, bearing in mind we've driven 1800 miles in the last couple of weeks and returned less than two days ago, and the van hasn't been driven any distance for about 24 hours. The control panel shows both batteries to be topped up.
With solar panel working in April sunshine, leisure battery terminals read 13.5v
With solar panel covered (and all devices off), leisure battery terminals read 12.7v
With solar panel covered, engine running, (and a reading of 14.5v at the engine battery terminals) leisure battery terminals read 12.68v
With solar panel covered, engine running and the 130W fridge switched to 12v, the fridge relay clicks on and off every few seconds and the leisure battery voltage jumps between 12.27v and 12.46v with each click of the relay. 12v Socket voltage in the living compartment drops just below 12v while the fridge is on.
With a full load on the engine battery (lights on full beam, heater and fan on full, wipers on constant) the voltage at the engine battery terminals reads 13.9v, which suggests the alternator is doing its stuff.
This would suggest to me that the solar panel (when on) is masking the fact that the leisure battery is no longer holding sufficient charge for the fridge to run properly on 12v - or am I missing something here?
As always, your thoughts, observations, advice and insults are most welcome.