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What if you could double your battery bank capacity without any cost or adding any additional weight to your boat? Wouldn’t that be awesome? Well, that is essentially what we accomplished yesterday.

Have you read my Voltage vs. Amp Hours Consumed post? One of our most popular, as of this morning it had garnered 93 comments. A large part of that discussion related to the fact that, in order for a battery monitor to give accurate readings, it not only needs to be hooked up correctly but it also must have the proper info inputted into it. Specifically, you need to tell the monitor just how big your battery bank is so that it can tell you what percentage is remaining.

After checking the distilled water in our batteries yesterday, and noting that the fluid was down a bit in half of them yet hadn’t moved at all in the other half, I was inspired to ask a question. That being, just how do I know that all of the batteries are actually connected? I mean, although they appeared to all be connected, I didn’t run the wires myself nor had I traced each wire or checked the current flow through them. And so, I went exploring.

My exploration didn’t take long though. In fact, in mere seconds I took note of the two breakers which are hidden way back in the far corners of our center battery compartment, one on each side. Can you guess what I’m going to say? They were both off! Yes, off, and being so, they took half of our battery bank completely out of the circuit. How long have they been this way? A wonderful question for which I have no answer. A week? A month? Since we installed those new batteries 1.5 years ago? I have no idea. All I know is that, as soon as I flipped those breakers on, current started flowing and our battery bank doubled in size.

Before all the “doom and gloomers” start suggesting that the batteries, having been out of the circuit and not charging for a period of time, are either dead or damaged, they are not. The voltage reading on each battery showed it to be at, or above, 50% charge. Once the batteries were connected we fired up our generator and ran it for the better part of the day, bringing the entire 8-battery bank up to full charge.

Did having these four additional batteries affect our morning readings, which was the impetus for the post that I linked above? Definitely. This morning, instead of reading of 12.1-12.2V, the Link monitor showed the bank’s voltage to be 12.4V, a significant improvement!

Moral of this story? If you didn’t do it yourself, or check it, how do you know that it is set up correctly? In this case, there is no tell-tale indicator that those breakers are off. Nothing stops working nor do any warning lights flash. If you have things like that on your boat that you are assuming are working, you might want to give them a look, just in case.