Analog DC Three Battery Voltmeter

mmitchell · Posted: Mon Dec 20, 2010 2:50 am Post subject: Analog DC Three Battery Voltmeter

I just installed a Blue Sea Analog DC Voltmeter for better battery management. My question is it has a amperage draw of one (1) Milliampere. Our boat does not have shore power in the summer. Will this be a concern if the boat sits for over a week?

rogerbum · Posted: Mon Dec 20, 2010 7:23 am Post subject:

Most batteries are rated for somewhere around 60+ amp hours. That's the number of amps x the number of hours that the battery can supply. 1mA = 1/1000 of an amp. To find out how long it will take a 1mA draw to drain the battery to say 1/2 capacity (30 amp hours for a 60 amp hour battery) all one has to do is divide 30 amp hours by 1/1000th which is equal to multiplying 30 amp hours by 1000. That is a 1mA draw will drain a 60 amp hour battery to 1/2 capacity in about 30,000 hours = 1250 days = 3.4 years. E.g. a 1mA draw is inconsequential relative to the loss through the internal resistance of the battery.

journey on · Posted: Mon Dec 20, 2010 11:39 am Post subject:

Roger's right.

Or you can put a switch in the line. I hate to leave anything hot when the batteries aren't being charged.

Boris

jkidd · Posted: Mon Dec 20, 2010 11:59 am Post subject:

Or just add a small solar panel to keep the batteries topped off.

mmitchell · Posted: Mon Dec 20, 2010 2:26 pm Post subject:

Thanks Roger. Looks like it will not be an issue. Only have it in the water for 5 month and we use it almost every week end.