Posted: Wed May 23, 2012 9:13am

A little while ago, I noticed that the battery charger was louder than normal. Since then it has varied, sometimes loud, sometimes normal and sometimes very whirry. About a week ago, I was on the boat and noticed that there was no running water. I thought that maybe the fuse had come loose and when I checked, found that it was actually quite hot. I quickly pulled it out, slightly burning myself in the process. Also at this time the battery charger was whirring and didn't want to stop even though nothing seemed to be switched on. Eventually, it stopped but came on more often than normal. I tried putting a spare fuse in place for the water pump but this didn't work and it also started to warm up. Because I was a liitle concerned about the battery charger coming on too often I decoded to turn the battery isolation switches to off and remove the knobs (there are two isolation switches, one for the starter battery and one for the leisure battery). However, much to my surprise the 12volt lighting still worked even with these switched off and the battery charger still came on. After a while I checked the water pump and found that the area underneath it was slightly wet. The pipes seemed to be dry. In the week since the area has dried fully although I noticed that there is condensation on the outside of the water tank but only from a point about six inches from the top downwards. I put this down to the fact that it was a particularly hot day and the water (which I hope is still in the tank) would be cool. The battery charger seems to be charging only when something is on now but is still noisier than usual. I have still not replaced the water pump fuse. I suspect that there may be more than one problem but what I would like an answer to is: 1) What would make the battery charger noisier than normal? 2) How can 12volt items still work when the isolator switch is turned off? 3) Why would it be damp under the water pump without there being any obvious sign of a leak? My battery charger is a ProBudget digital automatic battery charger from Sterling Power. The water pump is a Diaphragm Pump for Shurflo. Both of these were fitted before I bought the boat about two years ago. The isolation switch is a single circuit 6005 from Blue Sea Systems with a max 40V. These were fitted last Summer together with a new engine. I hope you can help. Many thanks. Claire Collinson

Posted: Wed May 23, 2012 6:19pm

1. A simple battery charger will make no noise so one can assume that your charger has a fan in it to keep it cool, it is probably a high output charger. If something makes the charger work harder or run hotter the fan circuit might be designed to speed the fan up. This could relate to discharged batteries drawing more current than normal, perhaps caused by a faulty water pump. It may also be caused by the ambient air temperature being higher than it has been for a long time. 2. Because it is incorrectly wired. You are allowed to bypass the master switch for a very few items of equipment like the bilge pump, radio code memory feed and possibly a burglar alarm providing the supply is fused close to the batteries. This certainly does NOT include lights and the water pump. 3. I think the pump might have frozen during the winter and damaged something or a seal has failed between the pump and motor. I also think the pump motor has seized up - hence the hot motor and fuse. Motors draw very high currents when stalled. I expect the pump leaks when there is pressure in the system built with weather like we have had over the last two days any slight weep would dry up very quickly. I fear it may be new pump time and then I suspect the charger will settle down. You are correct about the condensation on the tank. The battery charger is supplied by the mains and it may well be weird to the battery side of the master switch so you can isolate the 12 volt boat circuits but leave the batteries charging. However it should have a fuse close to the batteries. I trust this helps but come back if it does not. Tony Brooks