Full-time battery read out display in Scamp - is this okay?

[Byron Kinnaman]

1) This type of meter typically draws less that 1 amp, closer to .5 amp. If in fact it draws 1/2 an amp was left on for 48 hours (2 days) that would 24 amp hours drawn from the battery. Not a good idea if you're boondocking even with solar.

2) There's a couple of safety considerations when it come to trailer wire. One is the gauge, the other is the insulation. Automotive wire has insulation that resists abrasion and won't sustain fire (It's basically teflon).

One more 3) properly fused would be a fuse just slightly larger than the current drawn.
FYI A fuse is NOT considered adequate protection by URL if the fuse can be replaced by the user. The take away from this is to always be sure to have the correct size fuse.

[k0wtz]

well the same fuse has been in our rig for 22 years no problems yet!

bob

[lisantica]

It is now off.
I put nuts on the two load wires.
I had the two wires going directly to the battery and attached directly on the posts that have wing nuts on them.

[Jann Todd]

Originally Posted by lisantica

Is it okay to have a 24 hour meter attached to my 12 volt battery?
Should I install an on/off switch?
I want to keep track of my battery level and I came up with this arrangement. I don't know if I will keep it where it currently is.

Thoughts?
Attachment 113816
Attachment 113817
Attachment 113818

I fed the black and red wire here.
Attachment 113819

Here is a link to the meter, purchased from Amazon:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

We just use a 12V meter that plugs into a 12V receptacle like a cigarette lighter that we can use for a 12V TV also. Safe, simple and no wiring since the receptacle was already there from the factory. It doesn't measure the exact voltage like 12.2 but it is good enough to know if the battery is going down. The meter is about 2X2 inches with the part that goes into the receptacle sticking out. Doesn't seem to run down the battery at all.
Available at all RV stores and probably Walmart in some places.

[lisantica]

That would be a good solution, but I don't have a 12 volt receptacle in my Scamp.

[Jann Todd]

Originally Posted by lisantica

That would be a good solution, but I don't have a 12 volt receptacle in my Scamp.

A 12V receptacle is real easy to put in. I did one for a stereo hook up and I don't know much about electric. I used one that surface mounts so that I didn't have to cut any holes. The 12V meter is about $12.

[John Linck]

Originally Posted by lisantica

Agreed, just went out there and although it may not look bright in the photo, it makes a bright night light.
May I ask what kind of switch you used?
Thank you.
Attachment 113822

I like these little round rocker switches. on eBay at 5 for $5.00 and free shipping. Just drill a hole, attach the wires and the install is done. You can also choose switches with a indicator light, which is kinda useless in this case unless you want to find the switch in the dark. Amazon has them too.

BTW for folks buying a panel meter, I recommend a 4 digit meter (12.75 volts). Three digit meters are less informative.

John

BRAND NEW 12V ROUND ROCKER SWITCH

* 5 Pieces

* 3 Prong

* Diameter: 7/8"

* Depth: 1"

* 6A 250V

10A 125V

[EricAllyn]

Lisa,
I installed one of these in the side of the sink cabinet. Gives you a couple of USB chargers, a lighter plug and a voltage readout. Simple crimp wire connectors, and it goes in pretty easy, with nuts on the back of the three power outlets. Yes you would burn up the meter if it runs all the power through, but I think you will note on the paperwork, that it is simply monitoring, not taking the power through it. Putting a switch on it will not shut off all the power in the camper, just make sure the switch is on the feed to the meter, and it will be no different than turning off a light. You wouldn't run all the voltage through a single light, and you wouldn't turn all power off if you shut off the meter. You have only hooked up the meter part.

https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

[Buggeee]

Here's a link to a page full of charts and useful information about wire sizes and the amount of amps they can carry for different distances and good stuff like that. It's 12v marine info, which is useful as 12v camper info too. Bathe in that for a while and see what soaks in (I am a bit thick when it comes to math so I'm a soaker). I love that page.

https://www.westmarine.com/WestAdvis...e-And-Ampacity

The device you have there is beefy, handling up to 60v and 130amps. So the limiting factor for your fuse selection is your wire size. Your wires look 10 awg from the pics (I know Gordon, I can't tell from that, just saying), which would be up to a 30 amp fuse. If it's 12 awg it would be up to a 20 amp fuse, 14 awg would be 15 amps... Anyway, don't take my word for it I'm just some fool typing on the internet... Study until you're comfortable you are your own expert. Always fuse for the smallest wire or weakest device in the run.

Originally Posted by lisantica

When I bought it I thought it would be better to have something that could do more even if I wasn't intending on using all of its features at first.

Amen to that!!!! Solar hobby parts are like shoes for kids... I like to get ones to grow into.

[Buggeee]

....oh and directly to the posts (with a fuse) gives the most accurate reading as distance travelled increases voltage drop.

[Byron Kinnaman]

Originally Posted by Buggeee

Here's a link to a page full of charts and useful information about wire sizes and the amount of amps they can carry for different distances and good stuff like that. It's 12v marine info, which is useful as 12v camper info too. Bathe in that for a while and see what soaks in (I am a bit thick when it comes to math so I'm a soaker). I love that page.

https://www.westmarine.com/WestAdvis...e-And-Ampacity

The device you have there is beefy, handling up to 60v and 130amps. So the limiting factor for your fuse selection is your wire size. Your wires look 10 awg from the pics (I know Gordon, I can't tell from that, just saying), which would be up to a 30 amp fuse. If it's 12 awg it would be up to a 20 amp fuse, 14 awg would be 15 amps... Anyway, don't take my word for it I'm just some fool typing on the internet... Study until you're comfortable you are your own expert. Always fuse for the smallest wire or weakest device in the run.



Amen to that!!!! Solar hobby parts are like shoes for kids... I like to get ones to grow into.

Fuse sizes are related to the current usage of the device. It would not be wise to use a 20 amp fuse on the device that draws less than 1 amp. Yes the larger wire doesn't heat up as easily as smaller wire. Just for your information fuse amp ratings are current over time. At one time we ran a test on a 1 amp fuse by putting 2 amps through it. After several hours the fuse still hadn't blown. I have to admit that was many years ago so I suspect that some 1 amp fuses would blown much sooner.

[gordon2]

Originally Posted by Buggeee

..

The device you have there is beefy, handling up to 60v and 130amps. ..

While they claim 130 amp rating, the manual says:

To reduce meter heating, measure currents over 65 Amps for reduced time and consider using connectors which can handle large current

Now of course 65 amp rating is still plenty for a 30 amp camper, but also as I mentioned, at least one Amazon customer released the magic smoke in his, even when within specs.

[gordon2]

Originally Posted by EricAllyn

Lisa,
I installed one of these in the side of the sink cabinet. Gives you a couple of USB chargers, a lighter plug and a voltage readout. Simple crimp wire connectors, and it goes in pretty easy, with nuts on the back of the three power outlets. Yes you would burn up the meter if it runs all the power through, but I think you will note on the paperwork, that it is simply monitoring, not taking the power through it. Putting a switch on it will not shut off all the power in the camper, just make sure the switch is on the feed to the meter, and it will be no different than turning off a light. You wouldn't run all the voltage through a single light, and you wouldn't turn all power off if you shut off the meter. You have only hooked up the meter part.

https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

While what you say is correct, it defeats the purpose that the meter that Lisa bought is designed for. Hers is meant to be installed in series with the load to be measured, which would usually be all the 12 volt stuff in the camper. That generally gives you a much better idea of the state of charge of the battery than using a voltmeter.

If all you want to do is monitor voltage (with all the limitations that implies), then thats fine. In fact I have a volt meter just like the one that you referenced (removed from the panel), and another one that plugs into a cigarette style 12 volt outlet, both of which I don't need and will give away to anyone who wants to come get them (your can get them on eBay cheaper than I could ship them).

[lisantica]

Thank you all for the input.
I went ahead and bought the item from Amazon that Eric linked me to.

You're right Gordon, shipping something small like that which you offered usually costs more than the item is worth or can be purchased for. But thank you for the offer.

[lisantica]

Originally Posted by Buggeee

Solar hobby parts are like shoes for kids... I like to get ones to grow into.

Here's something I bought that is in route to help me begin my solar explorations.
https://www.ebay.com/itm/Blue-Sky-So...72.m2749.l2649

[Buggeee]

Originally Posted by lisantica

Here's something I bought that is in route to help me begin my solar explorations.
https://www.ebay.com/itm/Blue-Sky-So...72.m2749.l2649

Dang Lisa... MPPT? I'm jealous!!! Wait til you see the voltage levels you can feed that thing with. I'm not even running my 30 amp PWM yet and already gazing at that tech. Focus Buggeee, Focus.

[lisantica]

Originally Posted by Buggeee

Dang Lisa... MPPT? I'm jealous!!!

Well, the price was right and it is more than I need (which is how I like to buy) so that I can grow into the system.

[gordon2]

Originally Posted by lisantica

Here's something I bought that is in route to help me begin my solar explorations.
https://www.ebay.com/itm/Blue-Sky-So...72.m2749.l2649

Good choice. Blue Sky is a respected brand (IMHO) and a 30 amp controller is a good size for a Scamp. Not too big but big enough to use as many solar panels as you might reasonably want to carry and/or mount. MPPT offers little advantage over PWM for this application (See FAQ C1). On the other hand, MPPT (and the BlueSky SB3000i) would be better than PWM type controllers for a residential or commercial installation where you might want higher voltage panels for less loss over longer transmission lines. But you will almost certainly stick with 12 volt panels with 36 cells (which actually will be around 19 volts, but that is another topic).

Its also good that it can be used with flooded, GEL and AGM lead-acid batteries so you can chose the type that works best for you. See if you can pick up the battery temperature sensor also. That will allow the controller to adjust its charging based on the temperature for maximum effectiveness and battery longevity.

[lisantica]

Originally Posted by gordon2

See if you can pick up the battery temperature sensor also. That will allow the controller to adjust its charging based on the temperature for maximum effectiveness and battery longevity.

I will look for that, thank you for the tip.

[lisantica]

Originally Posted by gordon2

MPPT offers little advantage over PWM for this application (See FAQ C1). On the other hand, MPPT (and the BlueSky SB3000i) would be better than PWM type controllers for a residential or commercial installation where you might want higher voltage panels for less loss over longer transmission lines.

Thank you for both of those links. I see now that MPPT has some advertising hype attached to it, but still a good system.
I appreciate being able to read the BlueSky manual before my item arrives.
Thank you Gordon.