How to monitor batteries?

[Bill_AirJunky]

OK, you stereo gurus ought to have this easily. Is there a way I can install whatever gauge so that I can keep tabs on my batteries?

It's been raining for like a week here (seems like it anyway). The boats sitting on the lake, in it's slip. And I'm sure it's fine. But I was thinking that IF the bilge pump had been running, or someone left something on, I'd want to know if either of the batteries were getting low. Thinkin some sort of LED gauge mounted to the side of each battery box.... maybe like this?

I've seen the terminals with the gauge on it. But then I'd have to open each box to read it. This way I just have to pop open the spotters seat & I'd know if I need to charge either one.

I have 2 batteries, a deep cycle marine & a starter marine, plus a Perko switch. Is there any issue with the charge from either battery effecting the gauge or readings on the other?

[shawndoggy]

Here's a dumb question back... I think I know how a perko works. If you have it on "1" then your boat only "sees" battery 1, right? Same with setting on "2"? In that case, can't you just set the switch on "1", turn the key and check the voltage on the dash? Then flip over to "2" to see how that battery looks?

If that doesn't work for some reason, then yes, your solution with the gauge totally works. If you have your stereo headunit direct wired into one of your batteries, you could T off of that run and mount the led gauge by the helm too, and then you don't even have to stick your head in the observer's compartment.

[Bill_AirJunky]

You got the idea of the Perko right. Unfortunately I didn't install this one. My boat was previously owned by one of the Pdxwake.com guys, who had Stereo King in Portland do the install (and I assume the batteries). So the stereo & amps will come on no matter what the Perko is set at, ie; 1, 2 or All.

I was under the impression that the voltage on the boat was measuring output, not stored voltage. Not so? If it's not, then I think your idea may very well work. But I'm wondering why it doesn't show 24 volts when the Perko is set to All.

[Bobby Light]

You got the idea of the Perko right. Unfortunately I didn't install this one. My boat was previously owned by one of the Pdxwake.com guys, who had Stereo King in Portland do the install (and I assume the batteries). So the stereo & amps will come on no matter what the Perko is set at, ie; 1, 2 or All.

I was under the impression that the voltage on the boat was measuring output, not stored voltage. Not so? If it's not, then I think your idea may very well work. But I'm wondering why it doesn't show 24 volts when the Perko is set to All.

Becuase it parallels the batteries and doesn't connect them in series. Parallel double the reserve, series double the voltage.

Edit: Your voltage guage is supposed to read available voltage, not input voltage although I guess they could be the same at some point.

Edited June 3, 2010 by 06vlx

[Bill_AirJunky]

Becuase it parallels the batteries and doesn't connect them in series. Parallel double the reserve, series double the voltage.

Edit: Your voltage guage is supposed to read available voltage, not input voltage although I guess they could be the same at some point.

Gotcha, figured it was something like that.

So voltage available is what is on the dash. That means that if the Perko is on 1, and the key is on, the gauge will read what is available in that battery (like SD said)?

And likewise, if I start the boat, the gauge will read what is available.... but in that case, the alternator is in the loop so it would be much higher, right?

Probably like 13v in the first case, and 14v in the second?

[Bobby Light]

Gotcha, figured it was something like that.

So voltage available is what is on the dash. That means that if the Perko is on 1, and the key is on, the gauge will read what is available in that battery (like SD said)?

And likewise, if I start the boat, the gauge will read what is available.... but in that case, the alternator is in the loop so it would be much higher, right?

Probably like 13v in the first case, and 14v in the second?

Pretty much except your battery will read more like 12.4-12.6 volts with the boat off, and should read over 14 most of the time with the boat on depending on what load demand you have running at the time. There is a slight voltage drop between the batteries and the voltage guage as well.

[Bill_AirJunky]

Pretty much except your battery will read more like 12.4-12.6 volts with the boat off, and should read over 14 most of the time with the boat on depending on what load demand you have running at the time. There is a slight voltage drop between the batteries and the voltage guage as well.

Cool. Sounds like I just need to read the gauge thats on the dash at the right time (key on, engine off, accessories off) & I'll have a pretty good idea what each batteries' charge is like.

Thanks guys.

[shawndoggy]

Cool. Sounds like I just need to read the gauge thats on the dash at the right time (key on, engine off, accessories off) & I'll have a pretty good idea what each batteries' charge is like.

Thanks guys.

Exactly.... you want to read the voltage at key-up, but not running. Then turn off, switch to the other battery, do the same.

06VLX is also right about the voltage drop... on a multimeter my battery will show 12.7 at the posts but only 12.4 at the dash. But once you know that you've at least got a point of reference for how charged the batteries are. So you should prolly check that once, so you don't freak that your batteries won't stay charged.

[Octane]

Here's a dumb question back... I think I know how a perko works. If you have it on "1" then your boat only "sees" battery 1, right? Same with setting on "2"? In that case, can't you just set the switch on "1", turn the key and check the voltage on the dash? Then flip over to "2" to see how that battery looks?

If that doesn't work for some reason, then yes, your solution with the gauge totally works. If you have your stereo headunit direct wired into one of your batteries, you could T off of that run and mount the led gauge by the helm too, and then you don't even have to stick your head in the observer's compartment.

My boat dealer told me not to switch the Perko from battery to battery with the engine running. I've never questioned it... anyone know if this is a fact?

~ Octane

[shawndoggy]

I'm not suggesting Bill do this with the engine running. That would sorta defeat the purpose because the dash gauge would show the incoming charge.

[Bobby Light]

My boat dealer told me not to switch the Perko from battery to battery with the engine running. I've never questioned it... anyone know if this is a fact?

~ Octane

The issue is turning the switch to off not between batteries.

[Bill_AirJunky]

The issue is turning the switch to off not between batteries.

Yea, I read somewhere that you should make your Perko switch changes with the engine turned off. Even the switch between the two batteries could go bad if it's not done quickly. Something about the alternator current not having anywhere to go for any length of time?

But like we discussed, monitoring the batteries' current charge, I'll make those one at a time, turning off the key between the two, checking the dash gauge each time.

Thx again.

[dalt1]

Perko claims to be a make before break system in their switches. That means you can switch between 1 and 2 and or both to 1 or 2 with no damage. Just NEVER go to off while running. That being said, I usually switch mine with engine off but not always. Never had a problem.