With that said, I’m pretty sure the house batteries have deceived me.
Our three house batteries provide the electrical power for Odyssey whenever we are anchored out. Together they can store a large amount of energy.
Before we go off the dock I make sure the batteries are fully charged. Then, away from the dock, I keep an eye on the voltage. If it gets too low it’s time to figure out how to recharge. During the summer it rarely gets too low because we have solar panels that help charge the batteries when we are out.
This has worked well for us until recently when I noticed the battery voltage was dropping faster then expected, and it was getting worse. In an effort to understand what was happening I installed a device that, when installed correctly, shows the net energy the battery has delivered. Compare that to the rated capacity of the battery and you should have a pretty good idea how much energy is left.
But what if the battery capacity isn’t what it should be? What if, due to age and abuse, the amount of charge the battery should hold has dropped? It would still charge up, but out on anchor it would act like a much smaller battery and you would run out of power quickly.
That’s the situation we found ourselves in last week on our first cruise of the year.
On our second morning the heater low voltage alarm went off moments after we switched it on. The battery voltage had dropped below 10.5 volts! Looking at the shunt information, we had only used a small fraction of the battery capacity and yet we were out of power. Not good.
Time for new batteries.
Over the next few weeks I’ll be replacing the old AGM batteries with LiFePO4 (lithium iron phosphate) batteries, building a system from the ground up. This will include new equipment, a wiring change, and assembling the battery bank from individual cells.
I hope to document our progress with the design, reviews of the new equipment. I hope you enjoy the process.