Maintenance & Restoration

ckayaker · 05-29-2015, 07:39 PM

I want to install a battery monitor inside my Trillium 4500, but I am unsure how to do it. The unit I'm looking at seems to require a shunt to be placed close to the batteries negative pole outside on the tongue via a very heavy cable. This is fine except the wiring harness that comes with it won't be long enough to reach the spot where I want to mount the readout display if I do this.

So I'm wondering if the shunt really needs to be close to the battery. Do I really need anything more that the original 10 gauge wire that runs off the battery? What I'd like to do is install the shunt right at the fuse box. Does this sound logical?

Byron Kinnaman · 05-29-2015, 08:49 PM

Ah yes!! the battery monitor. One more thing to spend time and money on.
To properly measure the current into and out of the battery the shunt is necessary. 1 would think 10 gauge wire would be large enough to go from the shunt to the current meter.

If it was me I'd mount the monitor next to the door, on the wall of the storage area under the bottom bunk. Or some place close to the battery. You'll watch it closely for a while then you'll forget about even looking at it.

Carol H · 05-29-2015, 10:52 PM

Quote:

Originally Posted by Byron Kinnaman

If it was me I'd mount the monitor next to the door, on the wall of the storage area under the bottom bunk. Or some place close to the battery. You'll watch it closely for a while then you'll forget about even looking at it.

If it was me I would save myself some time and money and buy a simple one that plugs straight into a 12 volt plug already in the trailer and plug it in only when needed. That way you don't have to worry about it running your battery down over the winter.

Byron Kinnaman · 05-29-2015, 11:21 PM

Quote:

Originally Posted by Carol H

If it was me I would save myself some time and money and buy a simple one that plugs straight into a 12 volt plug already in the trailer and plug it in only when needed. That way you don't have to worry about it running your battery down over the winter.

Actually I wouldn't and haven't put in a battery monitor. I'd rather spend the money on gas getting to another camping experience. After 10 years and hundreds of nights I have a pretty good idea when the battery needs to be charged. I do have a voltmeter to check it with just to verify what I already know.
Winter time (by that I mean down time when I'm not camping) the battery is maintained by a, you guessed it, a Battery Minder.

padlin00 · 05-30-2015, 05:47 AM

Ckayker, what kind of monitor is it? The wiring from my shunt to the Bogart monitor is just a cat 6 cable. You can put the shunt farther from the batteries if you wish, just need suitable cable from the shunt to the negitive battery post. What is the distance between the battery and where you want to put the shunt? Do you have, or do you plan to install, an inverter?

patrick crawford · 05-30-2015, 05:50 AM

And here's the view from the other side of the coin... The plug in voltmeters read the output from the trailers converter if you're on shore power so, at those times their readings don't tell you much about the battery. My meter is a pretty inexpensive "Morningstar" and reads directly from the battery. It's very useful when I camp host and remain on shore power for an extended period. I cut the battery off (with, you guessed it, a battery cut off switch) to avoid overcharging. The Morningstar lets me monitor and recharge the battery when needed. Tending to these details hopefully will extend the battery's life and that's some serious gas money. Oh yeah, I do have a slight OCD (some might say it's a tad beyond slight) and we all posses unique motivations for venturing out in our little boxes. So...if the OP wants a meter then, by all means, he should get one. As to the question about the shunt and wire, I'll have to leave that to the electricians in the crowd.

p@

ckayaker · 05-30-2015, 08:32 AM

The distance I'm thinking about is in the order of 10 feet or perhaps a bit more, much longer than most of the ready made up 6 ga cables I've seen. So my question is can I get away with a 10 ga wire from battery to shunt? I am solar powered exclusively, hence my interest in monitoring the battery state.

Jon Vermilye · 05-30-2015, 08:43 AM

The shunt should be placed as close to the battery as possible. The further away, the less accurate it will be. The connection between the monitor & the shunt is low power & in most cases can be made as long as necessary (at least in a small trailer). In my case i have the monitor over 10' from the shunt, using a 4 wire twisted pairs between the two. (The monitor is a Bogart TriMetric 2520, combined with a 500 amp shunt.)

My battery wiring is a bit heavier than #10 since I have a 1000 watt inverter, but if your maximum current between the battery & the shunt is less than 30 amps, #10 should be OK.

ckayaker · 05-30-2015, 08:58 AM

Quote:

Originally Posted by Jon Vermilye

The shunt should be placed as close to the battery as possible. The further away, the less accurate it will be. The connection between the monitor & the shunt is low power & in most cases can be made as long as necessary (at least in a small trailer). In my case i have the monitor over 10' from the shunt, using a 4 wire twisted pairs between the two. (The monitor is a Bogart TriMetric 2520, combined with a 500 amp shunt.)

My battery wiring is a bit heavier than #10 since I have a 1000 watt inverter, but if your maximum current between the battery & the shunt is less than 30 amps, #10 should be OK.

Thanks for this info Jon! I'm way less than 30 amps draw from the battery, so this ought to work. I'm going to wire it up temporally and see whether the accuracy drops below useful levels. If it seems okay, then I'll route the wiring properly.

padlin00 · 05-30-2015, 09:53 AM

You can buy heavier wire from HD by the foot, just not that pliable.

Carol H · 05-30-2015, 10:26 AM

Originally Posted by Carol H
If it was me I would save myself some time and money and buy a simple one that plugs straight into a 12 volt plug already in the trailer and plug it in only when needed. That way you don't have to worry about it running your battery down over the winter.

Quote:

Originally Posted by Byron Kinnaman

Actually I wouldn't and haven't put in a battery monitor. I'd rather spend the money on gas getting to another camping experience. After 10 years and hundreds of nights I have a pretty good idea when the battery needs to be charged. I do have a voltmeter to check it with just to verify what I already know.

LOL whats the difference Byron between plugging in cheap simple 12V plug in battery monitor to a 12V outlet when one feels then need to confirm the state of the battery vs attaching a Voltmeter to the battery to obtain the same info needed?

Both will give you the one number you want and and neither will consume unnecessary power then not in use. Although I have to say the simple 12v plug in battery meter I have was a lot cheaper than my voltmeter and way easier to use & understand.

rick in arvada · 05-30-2015, 12:36 PM

I avoided the whole shunt problem and installed a MidNite Solar MNBCMS Battery Capacity Meter. It gives me enough information to monitor my solar system without all the complications involved with a shunt/big wire installation. I also added on an on/off switch so that it does not have to be running all the time.

MCDenny · 05-31-2015, 04:08 PM

All the current from the battery flows through the shunt so the the wire from the battery needs to be robust. You can google wire current capacity and find a voltage drop calculator. That will tell you how much power is consumed by the battery to shunt wire. The meter won't be able to measure this so that's why the accuracy could be affected by the length of wire and the size (gage).

It's good to have the shunt close to the battery as that means short wire which means lower resistive loss. Do the math, though, and you will likely find a few extra feet of wire will make a trivial difference. 20 amps through a 2' 10 ga wire will have a 0.04V drop. 20 A thru 3.5' of 8 ga wire or 5' of 6 ga wire have the same drop.

You could also call the tech support, tell them how far you want to mount the shunt from the battery and ask what wire ga they recommend.

The wires that connect the display to the shunt can be very light gage and as long as you want.

A simple voltmeter won't count the amp hours in and out, which you need to learn the actual state of charge. To accurately correlate voltage to state of charge the battery should "rest" with no load or charging for between 4 and 24 hours. Who's going to do that?

I get battery cables from genuine deals.com. They custom make them to your specs. Not very expensive either.

Denny Wolfe
Wanderingourway.wordpress.com

ckayaker · 05-31-2015, 04:34 PM

Thanks for this information Denny! I'm beginning to think extending the monitor leads is the way to go as you suggest. It will give peace of mind at least! Now to figure out how to isolate the shunt etc from the weather way out there in the tongue...

Rick, I like your capacity monitor, but I want more than just knowing the state of charge of the battery. I want to monitor what is going into and coming away from the battery in real time. I know, it's a bit anal, but some of us are built that way... LOL

Steve L. · 05-31-2015, 05:13 PM

I'm a gadget freak and an engineer. Some mods are not necessary but do add to my enjoyment. Some people's hobbies involve futzing about; Some just lay in the hammock.

I briefly had the voltmeter that plugs in but I shortly gave it away as useless other than telling you the charger was running. It's a lousy indicator of the battery's state of charge. The more I read about batteries the less impressed I was with the meter.

Back when I was doing more boondocking I put in an Xantrex Linkpro. I opted for it because I had good prior experiences with the brand. I wanted to track amp-hours out and ran a Honda 1000 about every 3 days just long enough to return the amp-hours. I feel I get a better sense of what's happening with the battery. It would do the same with solar. Or wind.

My sense is that the shunt should be close to the battery but the monitor can be farther away since it's not carrying the amps that the shunt is.

I suspect that there are people out there who track down iron meteorites to pound out sporks to eat their granola. Whatever floats their boat. As you suggest, it's just a different way to camp. Better for them, less so for me.

ckayaker · 05-31-2015, 06:24 PM

Thanks Steve, I appreciate your input! I'm going to run wires from the battery to the monitor readout as I mentioned above. Like you seeing what is happening to and from the battery makes me happiest...

MCDenny · 06-01-2015, 06:49 AM

The camping gear section of Walmart, Kmart, etc will have weatherproof plastic boxes you can modify to house the shunt.

Denny Wolfe
www.wanderingourway.wordpress.com

Steve L. · 06-01-2015, 07:05 AM

I put a shunt in a Radio Shack (RIP) kit box for what I call my trailer test box. I wanted a device I could insert between the tow vehicle 7 blade receptacle and the trailer tow plug and measure amps passing between the two. I'd call it "splash protected" but not weatherproof. But the shunt in the trailer for the monitor is unprotected from water.

Night Sailor · 06-18-2015, 06:24 AM

I've owned four battery monitors. Of these the best is the Victron and it is the cheapest. I believe they make these for other vendors. The round plug types are easiest to install. The cable assemblies are expensive and you can make your own.

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