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Ever wonder why your battery monitor doesn't seem to be in sync with what you think your battery capacity [music] should be? Check out this video to understand why. Whether you need a remote consultation design or perhaps inviting us aboard your boat, Pacific Yacht Systems is here to help. Check out the link in the description below. Hey everyone, Jeff Cote with Pacific Yacht Systems and we've got another installment of Tech Talk. A question from a fellow boater. Mike asks, "I think my battery monitor is lying to me. What's going on? Can you help me figure out if my batteries or my battery monitor is the problem?" This is a great question. In reality, a battery monitor is not the name in itself is not that accurate. It's quite misleading. Battery monitor, you would think, you hear the word and I'm thinking, I remember when I started, I'm thinking, oh, it monitors the battery. But it doesn't. Battery monitor does not monitor the battery, which is sort of explicit in its name. In actuality, what a battery monitor does is it actually counts all the transactions going in and out of the battery, assigns a weight to it, and then approximates the capacity of the battery depending on the battery bank capacity, the current as it fluctuates in and out of your battery, and the associated weights with that, and then it does all that and it gives you an approximation of what your battery bank capacity is going to be. So, already there you know that it's not a monitor, right? It's just a counter looking at all the transactions going in and out of your battery, and it approximates what your battery capacity is going to be. So, and this happens quite a lot because as battery ages, your battery monitor is always assuming that your battery capacity its original stated capacity. So, for instance, if you had a four golf cart battery bank and it's 12 volts, let's call it around 400 amp hours. It could be higher, but let's just keep round numbers. When you actually are installing a battery monitor or changing a battery bank, you actually have to enter in the battery monitor and say, "What is the my battery bank capacity right now?" Unless you say it's 400 amp amp hours. But that's 400 amp hours on a brand new battery bank. As the battery ages, the capacity of the battery also diminishes. So, you might be in the situation 5, 7, 8 years later where your battery monitor says you're at 80% capacity, right? Because it's assuming that, you know, you've only your batteries are still full and they're still healthy. And yet your voltage is at 11.7. And how could a battery bank be at only 20% discharge, 80% full, and be 11.7? Who's lying? Well, the battery monitor's not lying. It's actually going on outdated information, right? It's thinking your batteries are still 400 amp hour capacity, which probably aren't after 7 or 8 years. Voltage and amp hours don't always align and there's caveats on there, too, because as you draw heavily or charge, your voltage fluctuates. And voltage is only really how should I say this? An indication of capacity if the battery's neither been charged nor discharged for a 24-hour period, which obviously doesn't happen when you're using the boat. So, that's why voltage is not a perfect gauge for battery capacity and why a battery monitor is. But again, a battery monitor is making a lot of assumptions. So, it's very And it happens. Battery monitors sometimes are going to be out of sync with the battery and generally that's a function of either the battery capacity hasn't been updated when the battery bank was changed. Also, some battery monitors also ask for the battery chemistry. Is it a lead acid flooded, lead acid AGM? Because that's going to affect the weight of the current in or out of the battery. And then also as I mentioned as our batteries age the overall capacity of the battery diminishes and over time that is dramatic because batteries that are very old have maybe not even half or maybe are down to a quarter of their initial stated capacity. So the question, which is valid, is why is my battery monitor lying to me? Well, it's because things change and the battery monitor doesn't know. Because it's just it's just like a counter. It's really and that's what I use in a lot of my videos. I call battery monitors battery counters. They just sound count the transactions in and out and they've just give you an estimate. The devil's always in the details. Thanks for making this far and watching the video. If you've liked what you heard and help us support the channel, don't forget to subscribe and like this video. Also, if you've got further questions or maybe wondering more about battery monitors, check out our website. You'll see all the links below. We have [music] dozens and dozens of articles on battery monitors and if you want to geek out join me as I go deeper in the [music] battery monitors and the pros and cons. Thanks for watching. Hey fellow boarders, [music] we're going to be doing a lot more tech talk videos. If you've got any suggestions for future videos, leave them in the comments below. Once again, thank you for watching.