I know some may think this an unusual question, coming from me, but I'd like to get the facts straight:
We have the usual battery set-up on our current Teredo Target, it's rather chilly outside and the engine (a Volvo with glow plugs) is being a right pain in the butt to start.
My usual procedure is to switch to Battery #1 (the start battery - topped up irregularly by shore-power float charger) use the glow for the recommended 10-15 seconds and push the start button. At this point, lately, all I get is a click, the cabin lights (LED's) black out and the VHF resets itself to Ch16. I then wander below, change to Battery #2 (the house battery - topped up by solar panel), repeat the procedure and can usually at least get the engine cranking....
I'll get the battery details later today, but they're very ordinary sealed lead-acid marine batteries, NOT identical and about 3 years old (dunno exactly - they came with the boat). All connections have been checked, are tight and smeared with Vaseline. Gut feeling tells me this engine requires plenty of grunt to crank over!!
Battery #1's float voltage is currently 12.68V. I read somewhere that if the cabin lights dim significantly on cranking from a fully-charged battery, then said battery is likely stuffed. Is this correct?
Is there an easy way to verify the condition of a sealed battery?? (I guess I'm asking how to do a definitive load test without access to specialised gear). Ideas anyone??