Battery gauge


Member I
I'm thinking of installing a gauge to monitor my 3 batteries. They are AGM 105 amp ones installed a year ago. It is my understanding that they can be damaged if they go below a 60% charge. Your thoughts/suggestions are welcome!



Frank Langer

1984 Ericson 30+, Nanaimo, BC
There are lots of fancy options some of which are expensive. However I have been very pleased with a simple volt meter, which is connected to our three AGM batteries and placed on a very visible spot in our galley so both my wife and I see and monitor it. It only cost about $10 on Amazon, and has been perfect for over 5 years. It shows battery voltage to one decimal - - ours charge at 14.3, are charged at 13.4 and we allow it to go down to 12.4 and then recharge with engine or shore power.
Our previous batteries lasted 13 years, and are current ones are doing well at 5 years with lots more to go.

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
We still like our "Smartgauge" as added detail to the factory analog volt meter. Note that this company now has an 'improved' version out that does use a standard gauge round hole, which is a good thing.
Here is ours:

I have replaced our 1988 round analog volt meter once, and do like the straightforward simplicity of it. I like having a little technical redundancy for this vital part of managing our batteries.

Newmar still sells the OEM replacement gauge for their late-80's Ericson panels.
(8 - 16 volts DC, full scale.)
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Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I have a Victron battery monitor, and any similar unit no doubt works fine. It is very useful to know battery charge at a glance, and to be able to see the draw of each appliance. The computations are beyond easy calculation, but the gizmo does it well.



Member I
Great to hear Christian, thanks. My son in law installed the exact same one in their off road RV and thought the world of it. I thought that the BlueSea one might be 'marine grade' and provide extra protection. Just curious if you installed also the battery connector Loren mentioned.


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    Battery connectors.png
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Kenneth K

Contributing Partner
Blogs Author
Some info about installing a Balmar SG200 batter monitor near the end of this blog: