Monday, December 22, 2014

Fw: [Electric Boats] Inaccurate volt meters

 

I've got a number of ways to read battery pack voltage:
1) The original XBM battery monitor reads current, amp hours, % battery and voltage.
2) The Morningstar Solar controller also has a digital meter that I can look at in the main cabin.
3) Anyone of the several Digital Voltmeters I carry on board
4) My helm mounted instrumentation  panel that I can monitor when underway while at the helm: http://biankablog.blogspot.com/2013/03/instrumentation-project-part-seven.html
It's got cheap five buck digital meters to monitor each individual battery in the 48 volt bank as well as the whole pack voltage. I can tell at a glance if something is not quite right. I checked them in parallel on the bench before install and found the accuracy good enough for my needs.

Capt. Mike
http://biankablog.blogspot.com



On Monday, December 22, 2014 9:40 AM, king_of_neworleans <no_reply@yahoogroups.com> wrote:


 
LED panel voltmeters and also the cheap DVMs I have used are all over the place in accuracy. Or I should say, inaccuracy. I mounted one unit right on my control box, along with a tachometer. I ended up assuming a fully charged bank is 50.9v open circuit after resting for 6 hours, and comparing that to the meter reading, for an approximate correction to the meter. This doesn't sit well with me. I would much rather have a digital panel voltmeter that is accurate and reads to the hundredth of a volt, or at least one that reads to the tenth and is adjustable, so I don't have to do so much arithmetic figuring my state of charge. Sure, I could pay several hundred bucks for a Fluke, but my budget is just too tight. I don't want to use an analog meter on my control box because moving the box disturbs the meter movement. Even the motion of the boat disturbs an analog meter.

So what does everyone else use for a voltmeter?


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Posted by: Mike <biankablog@verizon.net>
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