Heading out on a sunny Sunday we expected to have an easy morning of removing hatch lids (details in our next post). Instead, when we got to WeatherWitch the battery monitor wouldn’t turn on…a problem we’ve had before so at this point, maybe just a serious irritation? However, this was promptly followed by the discovery that our service battery bank was completely flat…
According to the manufacturers, the batteries are 100% discharged when they reach 10.8V…ours were at 3.5V!
Luckily we have a jump start pack (never used by us until today), with which we able to start our generator. Now it’s a waiting game to see how much charge we can get in to the batteries today and then see how they hold the charge as to whether they have been damaged by this low voltage experience.
The culprit!
After starting to get some charge back in the batteries, our next main concern was what on earth had so completely drained them in the week since we’ve last been on board.
The first suspect was the bilge bump as this is pretty much the only bit of electrics that is not connected to the isolator switch (and the fact that, for a change, we hadn’t been playing with any of the main electrics last time we were onboard).
Our suspicions about the bilge pump proved to be spot on – sometime in the last week, most likely during one of the several storms that have come through recently, the pipe for sucking the water out of the bilge had managed to get wedged under the float switch for the bilge pump. This meant that it was stuck permanently in the ON position even when no water was left in the bilge…and instead just drained our batteries.
A temporary fix of rearranging the pipework to move it away from near the float switch is in place for now while we figure out a more permanent solution to ensure that this never happens again!
A bit more about our battery management system
Some more technical info for those who are interested:
Over the winter we fitted a new MasterVolt battery management and monitoring system to go along with the new charger. This consists of a shunt, that tracks the flow through the batteries, the viewing and (limited) control screen (shown in the image above) and the charger itself. To fully control and adjust most to the parameters to do with the charging we plug in the laptop to use the MasterAdjust software:
Today this program allowed us to increase the charger ampage input to speed up charging the batteries, so hopefully leaving them in a better state than not doing so. Once we’ve finished upgrading our battery cabling, we’ll be able to permanently increase the charger ampage, but today we were able to do it as just a temporary change while we were there to keep a check that no overheating of cables was happening.
