Community Forums

superflygary · 04-07-2016, 09:21 PM

Hi all,

I have a really basic question, I must admit to being a bit picky on details so indulge me.

I understand you are not suppose to let a battery drain down to half strength as it will shorten the cycles. Can we tell that from the battery display on the command centre? Like when there are only two lights out of four illuminated does that mean that's is only half charged and that I should start charing it, or is it when it's down to zero lights it means it's at half?

Our maiden trip is this weekend and I was going to see how long batteries could last till reaching half charge, then i was going to plug it back in... then I realized I didn't know how to tell it was half charged lol.

Sorry for the noob question, but that's what i am

twinboat · 04-07-2016, 10:20 PM

OThe only way to know in a working situation is to install a battery monitor.

The lights are a crude volt meter and not real accurate.

Even testing with a digital volt meter requires a sitting time of no draw before the voltage settles.

A couple of lights running will lower the voltage, giving an inaccurate reading.

Most battery monitor measures amperage used against amperage replaced, along with voltage calculations thruout the cycle to come up with a % of charge calculation. They require a shunt to measure the amps in and out of the battery.

There is also some like the one in the link that can do it just with voltage readings.

This guy has a few articles about batteries.

http://www.pbase.com/mainecruising/b...tate_of_charge

http://www.pbase.com/mainecruising/smart_gauge

l1v3fr33ord1 · 04-08-2016, 07:21 AM

superflygary-

There are a number of threads on battery monitors; here are links to two of them.

http://www.irv2.com/forums/f54/new-b...ld-282782.html
http://www.irv2.com/forums/f56/magnu...-248034-2.html

1bigmess · 04-08-2016, 10:43 AM

A Low Voltage Disconnect will give you immediate feedback on when you've reached a set low voltage, and cut the power to protect your battery(ies).

http://amzn.com/B00GZOP53M

A cheap voltmeter like the kind they often give away with any purchase at Harbor Freight will be much better than the "command center" and it's four light meter system. Get the reading at the battery(ies) for more accuracy.

superflygary · 04-08-2016, 01:28 PM

Ok thanks all, another thing to add to the shopping list.

Thanks for the links too!

txdad · 04-09-2016, 08:41 AM

As you have learned, there is no simple battery question. There are however many good answers.

Skip426 · 04-09-2016, 08:50 AM

Here's another link for your questions, and others about 12 volt systems

www.marxrv.com/12volt/12volt.htm

1bigmess · 04-09-2016, 08:58 AM

The 12volt Side of Life (Part 1)

rideandslide · 04-09-2016, 11:43 AM

Well- I must say,in this world of maintenance free batteries, i never even thought of ever checking the acid level in our 2015 battery, now almost 2 years, level was really low in a few cells ( not quite exposing the plates ) added distilled water, and hope no damage was done.

So i guess Deep Cycle batteries are not maintenance free !!! Learn from my ignorance !

superflygary · 04-10-2016, 08:20 PM

Thanks folks, I'll check out all the info you shared.

Just got back from our first weekend trip in our new trailer, all went well and we had lots of fun.

And yes no such thing as a simple battery question lol!