100 watt Solar decision

[Brettmm92]

I'm planning on Boondocking for a few months, plan to run my phone, some lights and hopefully my refrigerator on a 100 watt solar panel charging the Travel Trailer Battery for a short time job.

After looking around I really like the harbor freight setup how it comes with lights and the charge controller has usb ports directly on it which makes me think that for my use, I wouldn't even need a power inverter. But I am pressed for time and don't have access to a harbor freight. I am going to rely on amazon shipping.

https://www.harborfreight.com/100-watt-solar-panel-kit-63585.html

But I see this on amazon and think it would be better cause of timely shipping but also I feel it would be more expandable in the future if I get serious about upgrading.


Amazon link renogy 100 watt Solar panel startup kit


I wish it was more like the Harbor freight where it came with lights and had usb ports on the charge controller as that's really all I need.

I was wondering if anyone had any insight on advice or maybe knows of a power inverter that would work for my situation.

I was also wondering if anyone knows if the harbor freight charge controller usb ports run directly from the panels or do they draw power from the battery or a mix of both. Specifically wondering when I could use lights from that. I could make a drive to a Harbor Freight but it really wouldn't be a cost effective or fun trip and it would suck if they didn't even have what I was looking for.

But I always appreciate y'alls input

[Gdetrailer]

pianotuna wrote:
If you want fine stranded wire, go to a welding supply shop. It is available at Lowes.

Interesting, never seen that offering at my local Lowes or Home Depot.

Have to go to a Tractor Supply store in my area for welding cable, do have a Rural King in my area, but don't recall seeing welding cable in that store (although they do have arc welding supplies there).

But you do make a good point, welding cable is very flexible and most places that sell arc welding supplies and welding cable will also have the lugs (although one would need the proper crimper to make a good solid crimp, crushing via pliers won't cut it).

Another very flexible wire with fine strands is called "stage lighting" cable, might be able to find that in a electrical supply shop (places where electricians go to buy their electrical supplies, most electricians do not depend on Lowes or Home Depot).

Shame the OP can't get mail order items, that would simplify getting the oddball items which are not typically carried in retail consumer outlets.

[pianotuna]

If you want fine stranded wire, go to a welding supply shop. It is available at Lowes.

[Gdetrailer]

pianotuna wrote:
Brettmm92,

Try Lowes or Home Depot

They will have "building wire" in that size, consists of thick strands and will not be flexible enough for this use.

You NEED flexible wire which consists of many much smaller strands.

Better to go to an autoparts store.

You can find short battery cables with a molded battery terminal on one end like this..



Then you can use a REPAIR battery terminal on the other end like this..



and use one of the bolts on the terminal to connect your cable end to for a couple of Dollars.

or for more expensive terminals..



Or you can buy a short 12" cable with lugs like this..



and use the repair terminals to make the connection to the batteries.

You should be able to find these at most any autoparts stores like Autozone, Pepboys, NAPA and more..

Take these photos with you and show them what you need, some places like NAPA may even custom cut to length and put lug ends for you..

Ideally you want this interconnect to be as short as possible, so depending on how you need to place the batteries you can often get away with as short as 6"..

In a pinch building wire at Lowes of Home Depot could be used, but it is extremely stiff and that can make it difficult to work with and it can also place a lot of stress on the battery terminals which may lead to the case to terminal seal breakage which leads to acid creep up the terminals. That causes a lot of acid corrosion of the battery connections when that happens.

[pianotuna]

Brettmm92,

Try Lowes or Home Depot

[Brettmm92]

Boondocker, thanks for the link. Unfortunately I currently can't receive mail so I got to go to a store. I've had bad luck finding a cable larger than 6 gauge so far but haven't checked auto stores

[Boon_Docker]

Here is a 2 AWG cable that will work just fine.

[Brettmm92]

In an odd turn of events, I ended up getting 2 of the 90$ sams club duracell 90$ 6 volts. Only because of a spontaneous job interview that was 400+ miles round trip. THANKS FOR POINTING THEM OUT TO ME. They were super affordable but also the core charge was ONLY 5$ when the core charge for interstate was quoted at 25$ so I will take the small amp hours loss. And the funny thing is even though I only get about 11mpg with my truck, I'd bet the money I spent on going to that job interview driving over 400 miles and getting the sams club batteries with the club membership (45$) was about the same as the interstate batteries cost. But seriously, interstate does have a good reputation and convenience factor.

BTW, does anyone know where I could find a place that has a "pre-crimped" wire that would put the two batteries in a series with thick gauge? The few places that were on my trip only had 6 gauge and im thinking 2 or 0 gauge is what is ideal. But only from articles I read online, maybe I'm wrong?

[pianotuna]

Brettmm92,

The purpose of fuses, in this case, is to protect the wire.

The fuse box you linked to would not be useful for the 400 watt inverter, because it is rated for only 30 amps.

The inverter is rated for 400 watts, Probably it can surge to double that for extremely brief time periods such as 1/10 of a second. So it is never going to approach 60 amps continuous. The inverter will be quite happy with dual #10 wire.

[Brettmm92]

Pianotuna, that would be a good solution especially since I'll have some to spare. But the one thing in the back of my mind is that if I end up doing that and it will allow 60 amps, or 720 Watts through (of course I am not going to intentionally provoke such a thing) does that test the safety that the fuse is there to provide in the first place? Forgive my bad wording of that. What do you think a realistic "danger" energy (any unit of energy) would be running through the wire? And the fuses are to protect the battery, right?

Opnspaces, that's some good advice. I'm glad you posted that because the light most convienent to add on the plug is right on the corner and I might have not thought of that as well. They even have small usb powered fans that make the idea even more appealing.

And I got the fuses that I got but I think something like this would have been the way to go-
Fuse box with screws

[opnspaces]

Brettmm92 wrote:
Opnspaces, I took a peak behind one of the wall lights and was glad to see that the wiring would be relatively easy to fix up a usb plug. And I was going to go without an inverter but I found a 400 watt cobra modified sine wave for 20$ refurbished with wires and had to get it. But I ordered a 12 volt plug because it will be nice to have and didn't break the bank for pure dc and convenience.

Awesome, I think the USB plugs are the way to go. Now that you decided to add one there are a few things I can think of to be aware of.

If you tap into an existing light fixture your install is already fused But I'll bet the manufacturer used 14g wire so you should probably do so as well.

Wherever you drill the hole for the outlet be aware that you need to have access to the back of the hole. If you can't get behind the outlet you can't tighten the big plastic nut that holds it all in the hole.

Don't drill too close to a corner because again that back plastic nut needs to be able to fit and screw down. If you get too close to a structural member or corner you might not be able to turn the nut. Yes I ran into just that problem with the first one I installed.

[pianotuna]

Brettmm92,

Here is what I would do in your shoes.

Since the fuses are "on the way" you can get to the DC amperage that the inverter wants to feed on by "doubling up" on #10 wire.

i.e. two positive cables and two negative cables with dual thirty amp fuses on the twin positive cables (one for each positive wire). The fuses should be as near the battery bank as is possible.

That would allow the inverter to draw 60 amps of DC--far more than it will call for.

[Brettmm92]

Opnspaces, I took a peak behind one of the wall lights and was glad to see that the wiring would be relatively easy to fix up a usb plug. And I was going to go without an inverter but I found a 400 watt cobra modified sine wave for 20$ refurbished with wires and had to get it. But I ordered a 12 volt plug because it will be nice to have and didn't break the bank for pure dc and convenience.

Pianotuna, I think I'll just keep the fuses I ordered already and upgrade eventually. Looks like they're already shipping.. I'm glad you liked your inverter, I have confidence I will enjoy mine.

Profdant, head spinning, maybe slightly. But I feel like I'm starting to get a grasp on this solar thing. Especially a lot more than before I made my post. Hearing about your success makes me feel more confident in the future. I'm really excited to test out my own propane refrigerator.

[profdant139]

Brett, your head must be spinning with all of the conflicting advice you have gotten so far -- hang in there!

I'll try not to add to the confusion and will just describe our setup, which might work for you. We have two group 31 NAPA deep cycle batteries. They are each rated at 110 amp hours. We have a 120 watt suitcase style portable solar panel. (It is a knock-off of a Renogy -- I bet that Renogy is better made than my panel.)

We do a lot of boondocking, for days at a time. Unless the weather is really cloudy for days on end, our solar panel tops up our batteries every day.

Our fridge runs off of propane, not batteries. And we are pretty minimal users of electricity. We run the lights (LED, of course). And we run the furnace for a short time every evening. But no coffee grinder, and no haircuts. 😉

Someone mentioned a concern about theft of the portable solar panels. I suppose that could be a problem. When we are in a crowded campground (as seldom as possible), I use a long cable to lock the solar panel. When we are boondocking, I generally don't bother to lock up.

Hope this helps!

[pianotuna]

Brettmm92 wrote:
Whats the math on the fuse? I can actually change my order. I was going on 30A fuse based from the charge controller being 30 amps.

Brettmm92,

The converter often has 2 or sometimes 3 30 amp fuses on the DC side. Those are 'reverse polarity' fuses. The wire they feed into will have either an "automatic" circuit breaker or another fuse very near the battery bank.

Brettmm92 wrote:
I got a really cheap cobra 400 watt modified sine inverter and want to use it safely.

While a 30 amp fuse with #10 wire would work (360 watts), it would be much better to move to #8 wire with a 40 amp fuse would be better (480 watts). As a bonus there would be much lower voltage drop to the inverter, and the costs of moving from #10 to #8 are not that big.

Brettmm92 wrote:
Maybe I will keep the solar, but I'm thinking about enjoying the solar setup until late in the year. Without it the solar and my current plans I just wouldn't have electricity but me needing to be accessed by phone provoked the whole solar thing. And I actually don't have an RV battery because I junked it (recycled) after realizing it was dead.

By all means--get some solar and if nothing else works, lay it on the ground. 200 watts as a minimum.

ps I loved my cobra msw inverter.