Chinook RV

I've been wanting to upgrade the electrical so that I've got an AC outlet near the kitchen's DC outlet that runs off the battery. I'm also wanting to add a couple usb outlets as well. I'm looking at the Samlex inverters, they seem to be recommended to be quiet and reliable. Its got a great input voltage range, too.
The 300w one is about the size of my power needs, but maybe i could go up to 600w:

https://www.amazon.com/Samlex-Solar-PST ... 00H8N97E2/

There are a couple issues I'm trying to get my head around. The first is the right wire gauge. I'm looking at this calculator:
https://www.wirebarn.com/Wire-Calculator-_ep_41.html
And I input 12v, 25Amp, and a 2% drop. Does that sound about right? That calculator tells me I can run about 15 feet at 8 gauge. I'll probably go a size up from what is recommended.

The second is how best to hook it up to the dc system and run it. I think what I'd like is for it to turn on along with the house dc power. I'm pretty sure there's a solenoid under the hood that when i flip the battery switch in the cab it flips this solenoid, so i'd connect my inverter wire to that solenoid. I'll then run it under the body along the chassis in a loom over to the 'kitchen' and find a place to pop the wires up. I'll drill a hole in the floor and run it into the cabinet and install the inverter there. I'll just leave it 'on' all the time, so that when the solenoid kicks in, i don't have to turn on the inverter by hand.

I would also assume that an inline fuse is a good idea? I am not seeing a fuse on the inverter.

I'd like this to be a flush outlet on the side of my cabinetry, but the inverter has gfci outlets on it, and no plugs so that I can use my own outlet. In this power range it seems pretty common, and I don't need a 1200w inverter. I could do this in a couple different ways: maybe i could take the face plate off the inverter and take the switch off it, run some wire, and install the switch in a plate. Alternatively I could get an extension cord and cut an end off it, plugging one end into the inverter, and put the other end in the back of my outlet. Both of these ideas don't seem very good but they'd probably get the job done?

Just writing this out here is helping me formulate a plan. I know there's a lot of smart people here who've probably done similar stuff. Any advice is appreciated!

Since you have an '89, and given what you described, I'm guessing you have the house battery under the hood, right? And given that it's probably pretty small (maybe 100ah at best?). That means things are a little tight in you "available power" category so you will want to be cognizant of that. Do you have battery monitor so you can keep track? Or are you on the "well it's a small cheap battery so I just use it till it dies an get another one" plan? (That can be a perfectly valid plan.)

You have noticed about the outlets on the side of the inverter. This is common on small inverters. Even my 1500 watt inverter only has the outlets on the side. Technically you could make a little jumper cord, or a male plug to an electrical outlet box -- although yeah, none of the companies are going to endorse it and it's a slight hack (but will probably work fine).

Couple of notes: When an inverter is on it has a "tare" load. This means that the inverter is using some power just being on. It may be a small amount. BUT, with your small house bank, I don't know that you want any tare load on all the time. There are inverters with remote "on/off" switches, although maybe not the small ones without making your own.

And I see why you want one: The inverter should be as close as possible to the battery(s), and if yours are under the hood, do you want to go out there to switch it on and off? But then..... I don't know that an inverter would want to live under your hood anyway so I'd say put it somewhere where you can reach the switch, or get one with a remote for the switch.

The reason the wire has to be bigger the longer it is, is because of voltage drop. The lower the voltage the larger the drop factor. So usually, the inverter is right next to the batteries. That way the 12 volt wire is short, and the 120 volt wire is long (and can be skinny). But again, you probably don't want an inverter under your hood, nor does it sound like you want the outlet right under the couch or passenger seat.

On the fusing: Yes, you definitely need to fuse the DC wire. You want that wire protected. So the way it works is first you figure out the inverter size and placement. Then you figure out the DC wire size (dependent on length and amperage of load). Then you figure out the fuse size because the fuse is protecting the wire. Then the fuse goes on the DC wire as close as you can get it to the battery (the inverter is the load; the battery is the source).

So, let me ask you something: What do you plan to plug into the inverter? Would a 100 watt inverter do what you need? What made you decide on 300 watts? One of around 100 watts gives you some other options. I'm lying around on the couch bored out of my mind with broken bones, so bring it on

Broken bones?! I'm a little late but I shall 'bring it on' for you to help soothe your bones

So on my '89 the house battery is on the driver's side, and under the hood. There's not a lot of room near the battery unfortunately, but I know what you're talking about with voltage drop, I'm trying to figure out the best way to run the dc as short as possible. I'll look under the driver's seat, i think that might be the best place for it. It will be super easy to route the ac power around internally from that location. Another possibility might be in the space where the old DC-powered tv was. Maybe that even still has decent enough wiring?

I recently replaced the battery (see here https://www.chinookrvforum.com/viewtopic.php?f=8&t=1153) with a Duracell 27m 92ah gel battery. I also replaced the original power converter with a more modern unit that can better top off the charge (i think the original might have boiled the last one a bit). Even with the bad battery we've never had an issue with insufficient power for lighting, the pump, etc.

Which brings me to what i want to run: our laptops. I initially had a macbook which was a 60w brick. My new pc has a 200w(!) dc power adapter. The only other items we really use are things like our phones and an ipad, and those sip power so no problems there.

So the two dc outlets are ok, the one in the cab is way more reliable, being closer to the battery. And the other one, well, I think back in 1989 people weren't running inverters out of these plugs, trying to get 200w or more! Maybe they ran a fan or a radio.

So good point on the tare load. I think you're right, I'll want some kind of remote switch, or put a switch inline somewhere. I'd originally thought it would be ok to have it sipping a little energy, but maybe i should just add a switch or hopefully install it in an accessible location. Giving me a bit to think about before I pull the trigger soon...

Great, something to do

200 watt power brick? Geez, how big IS that laptop? I have the Mac that came with the 60 watt brick, but I have bought a straight DC cord for it. Takes around 3 amps in real life (12 volts) when I'm using it and it's charging (figure derived by amp counter).

So, question, can you get aftermarket 12 volt bricks for that laptop? Not that it takes fewer watts, but then you wouldn't be converting up/down/up as much (presumably the laptop runs fairly close to 12 volts - I think mine is actually 19 volts, but the 12 volt plug handles that).

Before I was needing proprietary Mag Safe adapters, I used to use ones by Targus on my older Mac. Anyway, I'd at least check into that. But technically 200 watts is about 16 amps so that could be a bit much for a cigarette socket, if it really draws that much. So back to the inverter...

Hmm, under the driver's seat might be slick. Good idea. Out of the elements and heat, you could provide reasonable ventilation, and the DC cables wouldn't have to be a mile long. Then, as you say, you're home free once you are on 120 volt wires - you can run those in circles around the Chinook without any appreciable voltage drop. You would have to do the "home built" remote outlet cord. I don't see anything technically wrong with that (that I can think of), although like you, I wish they made smaller sized inverters that you could hard wire to, instead of just having their own outlets only and making you "hack" something.

For the phones and iPads I would definitely use DC to charge them vs. using 120 volt plugs. It's just too easy.

One thing to note is that the USB plugs that plug into a cigarette lighter (or are hard wired) do use a small bit of power (vs. cigarette plugs alone which don't). It's not much but start adding even tiny things up 24/7 on small house battery bank and it can begin to hurt. As a result of that I tend to just get the USB sockets that plug into a 12 volt cig socket and then remove them, or put a switch/light on a USB socket and shut it off (plus I don't like the leave the rig with any of these types of things powered - I've seen too many melt or malfunction over the years).

Just to run a calc, if you have a 300 watt inverter, and let's say you are maxing it out, plus a little extra for the reduced voltage if your house bank is low. So let's make that 30 amps. Then let's say the cable from the house battery to the inverter is ... oh, I don't know.... 8' long? (Run forward from stepwell maybe?)

In order to get a nice low voltage drop (say 2% for kicks) --- let's see, you could do that with 6awg cable, I believe. That's perfectly reasonable, in my book. Not even remotely tree trunk sized

Since the inverter is a load, you will want to put the fuse as close to the battery as possible. 6AWG can take many more amps than you will want to pull through with this inverter, so if the inverter, say, calls for a 30 amp fuse you can use that. If you don't already have a main battery fuse (like say you are running it right off the battery? vs. bus bars?), then (well you would want a main battery fuse, but if not) you will want something with at least some decent AIC rating. Say 3,500 amps or so (if you don't have the exact spec). A blade fuse won't do that, but a MRBF will go down to 30 amps (smallest one) so that is an option. An AMI/Midi fuse would also work, as would an ANL type. (But saying this, I don't know what your overall distribution setup looks like - I'm not saying to run it right to the battery post if you don't have to - some sort of bus bar after the main fuse would be better (then you could also use a fuse without a high AIC rating).

Okay, back to the ice packs Thanks for the diversion

200 watts is common in todays world for top of the line performance laptops. I have a RAZOR 15.6 inch 144hertz screen versus the standard 60 hertz on 99% of the laptops on the market today, core i7 8750 H processor 6 cores, Nvidia Geforce graphics, 16 GB ram, up to 4.1 GHZ processor speed.It uses a 260 watt power brick....

Why you using ice packs?

I never noticed that my laptop also comes with a 200W brick. 19.5V at 10.3A. But it can use a smaller brick if I don't use the docking station.

Anyway, may electrics are running on 19V-19.5 V DC. I have been looking for a 1080p or 4k monitor that takes 12v, but they are either very heavy, or cost more than I want to pay. Many nice TV and monitor are running on 19V. I wish there are more choices for the 12V, but I may have to get a 12V to 19V DC-DC converter and be more flexible with what I can run without doing a up/down conversion. There are many blu-ray and DVD players that runs on the 19V and 12V too.

About Apple, there are 12V car and airplane adapter available.

dougm wrote: January 22nd, 2019, 8:53 pm 200 watts is common in todays world for top of the line performance laptops.

Geesh, who knew?

dougm wrote: January 22nd, 2019, 8:53 pmWhy you using ice packs?

I broke my foot - marooned on the couch

So anyone: Feel free to start a few dozen threads to entertain me

chin_k wrote: January 22nd, 2019, 9:48 pm About Apple, there are 12V car and airplane adapter available.

That's what I use. It just became slightly trickier when Apple went to MagSafe proprietary ends, but eventually DC adapters became available. The newer ones use USB-C, IIRC (for which DC adapters are easier to come by).

The MagSafe does (did) have its advantages - when you trip over the cord it pulls out instead of pulling your laptop off the table in a swan dive.

Blu Goo...

How about i just buy you a book to read to help pass time... "15 things to know about walking", "Baby Steps" or "Put one foot in front of the other"

You heel!

Man, these jokes made me WALK away for a bit, but I’m back.

So I know its been a while, but the night I read your reply Blue I spent the night researching potential dc-only solutions. You got me thinking why not get a boost converter and put it under the seat along with the inverter, and see if I can use that for direct power to the laptop?

Something like this:
https://rover.ebay.com/rover/0/0/0?mpre ... 2570085111

And I can just create a dc adapter (i’ve got the adapter and wire already). I figured the 20A size should be decent, but maybe 15A would suffice. We’ll see! Ok, I think I’ve got enought to start buying some stuff.