Update December 2020
If you don’t already have an amp counting monitor, see my update at the end of the last chapter before reading on since there is now a better way to get this done without going through the next two chapters of aggravation. That said, I have left said chapters up for those who already have amp counters and want to know how to make them work properly.
In the last chapter I looked at the two types of battery monitors—volt measuring and amp counting—and concluded that which type we choose is all about how anal retentive and technically nerdy each of us is.
Now here’s a test for you: Since I chose an amp hour counter, which type of monitor is right for anal retentive nerds? (If you fail this test you have not been reading my stuff for long!)
Yup, this post is for card-carrying nerds with a side interest in being a control freak. The rest of you can stop reading now, go buy a volt measuring monitor, and live happily ever after…OK, I can’t guarantee that last part.
Still with me? OK, put on your propeller hat and let’s dig into which amp counting monitor to buy and why.
Hi John,
Nice job and appreciate the parsing out of “necessary” information to do the job. You wrote, “So if you have, as we do (and recommend), a house bank split into two parts with a 1-2-Both switch,”. Do you have a location where you make the rational for a split house bank (with a starter battery) vs one house bank and a starter battery?
Thanks, Dick Stevenson, s/v Alchemy
Hi Dick,
Thanks for the kind words.
On splitting the house bank:
https://www.morganscloud.com/2017/01/28/three-tips-to-make-your-cruising-boat-more-reliable/
https://www.morganscloud.com/2010/10/05/equalizing-batteries-the-reality/
Hi John – We installed a Philippi PSM system (German) three years ago that we are quite pleased with. While this system is similar to the Victron in that it will only count AH for one battery and measure voltage for a second battery, it does allow one to install additional shunts in source and load circuits and build a simple diagram of your power system and that will display voltage, current flows, etc. We monitor all charging sources to our house battery including alternator, solar, and AC charger, so we get a nice visual graphic of flows to and from the battery. We do not monitor loads as it’s easy to compute by looking at the visual system representation, although it would be easy to do with another shunt. The PSM system does allow for setting the Peukert constant for the specific battery type. The system will also monitor tank levels and control heavy duty switches from the PSM display if you want that type of integrated capability. We purchased our system components from Bruce Schwab in Bath, ME, who specialized in marine power systems. He is also now selling the Victron units.
That said, I totally agree with your recommendation of the new Victron 712 battery monitor system. We use a Victron Blue Solar 100/50 controller with the remote display on our boat and are very impressed with the quality of their products, the regular firmware updates, and responsiveness of their customer service representatives located in their US offices in Thomaston, ME. We also purchased the bluetooth dongle and plug that in occassionally. The Victron bluetooth is flawless and provides all the information that even a techy like yourself would want. The new Victron units with the built-in bluetooth eliminate the need for the dongle and are a teriffic value. We would upgrade our solar controller to the new integrated unit, but its only three years old and working fine. Another feature we like with the Victron products is the full setting capability that is very easily accessed via bluetooth, and the firmware updates that are easily done with your iphone via the bluetooth connection.
Love your web site and recommend it to all my boating friends, whether sail or power, as the information is invaluable to any type of boater. Keep up the excellent work.
Gary
Hi Gary,
Good to hear the Philippi is working well for you. Whether of not to add more shunts to get more ways to measure is an interesting one. For me, I have decided that keeping things as simple as possible wins, but there are certainly other good ways to get the job done.
Also good to hear that you too are having a good experience with Victron kit.
Hi John,
Nice post, I also have the Victron 702 and am very happy with it. But I have to confess that I bought it simply because the prior model which had died was a Victron, and there was already a nice round hole in my wood panel to accept it. So perhaps another factor when looking at comparable monitors.
Now, on the bluetooth side, I have to wax eloquent about my Victron solar MPPT controller. Watching the action on that from a phone or iPad in the cockpit can get very exciting indeed. .
All the best
Fred
Hi Fred,
Exciting…you need a life. Just kidding, I know what you mean about gear that works properly, it is exciting.
I think you should add power consumption to your list.
All the Victron units are pretty good.
702 <4mA
712 <1mA
Hi Roland,
Good point. That said pretty much all modern monitors have very low consumption and we are talking thousandths of an amp here, so I’m not sure it’s a core requirement.
Hi John,
If it is important depends on the use and technology of your battery bank. The Victron unit for example is sometimes used also as low voltage protection for LiFePo4. In those applications you want to reduce the consumption after disconnect to a minium in order to protect the batteries. For the same reason the 712 have the advantage to controll a bistable relay (instead of a standard relay 702).
I have seen other brands that have as much as 90 mA when all the features are activated. Then it can make a difference even for lead/acid. (67 Ah in a month compared to 0.75 Ah for a 712)
Hi Roland,
Both good points, although not being a fan of lithium batteries the former is a bit academic for me. And I had not seen a monitor taking at much as 90mA. Must be really complicated with a lot of functions, or alternatively poorly designed, I would think.
Anyway, I agree, I would not buy a monitor that was going to take that much.