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Old 10-18-2017, 10:41 AM   #1
Mini-Skoolie
 
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How similar are electrical systems from skoolie to factory built motorhomes.

I know the topic is somewhat vague. To be more specific, I know that motorhomes, rvs, coaches all have in excess different relays and solenoids, switches, etc etc etc.

When Doing a skoolie conversion and adding your own components etc, do you find yourself adding in all these relays and solenoids as well?

I know enough to be dangerous with 12v and 120v, when it comes to repairs, basic installs(aftermarket lights, radios, etc) But as far as building a complete system, I am a little hesitant. Does this make sense? LOL.
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Old 10-18-2017, 02:25 PM   #2
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Originally Posted by Tegra1027 View Post
I know the topic is somewhat vague. To be more specific, I know that motorhomes, rvs, coaches all have in excess different relays and solenoids, switches, etc etc etc.

When Doing a skoolie conversion and adding your own components etc, do you find yourself adding in all these relays and solenoids as well?

I know enough to be dangerous with 12v and 120v, when it comes to repairs, basic installs(aftermarket lights, radios, etc) But as far as building a complete system, I am a little hesitant. Does this make sense? LOL.
Howdy and Welcome Tegra1027!

Yes, it makes sense. Electricity is electricity - nothing is different there. Some people have more experience with AC vs DC or vice-versa but by the time you are done with a conversion, you will likely have a reasonable understanding of both.

All (nearly all??) of the "complexity" (relays, automatic switches, power panels, electric motors, limit switches, etc.) is up to the builder. Some of us like "automation" and that requires more electrical goodies. Some don't, and that makes for a simple/less expensive system. It's all up to you. Even better, you can start simple and add complexity as you learn/desire. There really are no "rules" in regards to how you go about your conversion.
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Old 10-18-2017, 02:40 PM   #3
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Not any kind of expert yet, but from what I've seen it depends on what the intended use is for the Skoolie.

Some folks use their Skoolies much like an RV, so their electrical will likely be pretty similar. In other words, primary electrical source is shore power at an RV park or generator. Batteries are there mostly to give you some time in between plug ins so you don't have to fire up the generator for every little thing. Solar is optional, and usually modestly sized and/or an after thought to extend the battery a bit.

Others plan to park their Skoolie out in the wild much of the time, so their electrical may look a lot more like an off-grid homesteading setup. In this case the battery is the primary power source and usually needs to be big, often with substantial solar to recharge it every day. Generator is more likely for backup when the sun doesn't cooperate, or usage is unusually high, and shore power may be more an after thought primarily to top up the battery.

Many will probably end up somewhere in between the two, depending on what their plans and budgets are. And as mentioned above complexity in either case can vary depending on how automatic you want everything to be, and how much you want to spend.

Rob
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Old 10-18-2017, 07:34 PM   #4
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No solar or wind power or water harvesting YET but I am and will go out of my way to keep my bus power/starting completely seperate from anything I do for the house.in my head if I have a problem with the house? Separated from the starting and going? I can always start and go home or wherevr to fix it and if I have a problem starting then I know I can live in my house until I can get the damn thing started?
For me I want to keep the two seperate. I don't want a bad switch or whatever killing/drawing from my starting bus and going home stuff? But that's just me trying to KISS ( keep it simple stupid) I know a lot of things but combine them all together and you get engineers fighting over WHO was the one that MUCKED UP and money?
Sorry it's so long?
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Old 10-19-2017, 12:46 AM   #5
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i knew zero about electrical before i started this. now Ive got a functioning system and have learned a lot. 12 volt really isn't very hard actually. i quite liked working with it. just make sure you comply with all the manufacturers recommendations on fuse sizes and locations for the products you buy. as far as rvs go most of them i know of have power plants of some sort and run nearly entirely A/C power. trailers tend to use the lower voltage appliances though.

and budget high for electrical appliances. i didn't realize it cost quite so much and ended nearly doubling my original budget.
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Old 10-19-2017, 03:22 AM   #6
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Yeah, 12v appliances can be very expensive as it’s kind of a niche market. Can be quite a bit more efficient, but not always. If you get a high quality inverter with 95% + efficiency you might even be able to do better with an AC appliance if there are higher efficiency models available.

Ran into this looking at mini-split ACs. There’s at least one company that makes DC models for about $2k a pop. However there are higher SEER 240V AC models out there that might still end up being more efficient overall with a good inverter.

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Old 10-19-2017, 12:07 PM   #7
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Thanks guys. I'm just getting started with design and planning. Hardest part is getting started... Especially when I don't know where to start.
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Old 10-19-2017, 04:17 PM   #8
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How similar are electrical systems from skoolie to factory built motorhomes?

Although the basic idea is the same, I'm thinking that the systems a DIY guy can build into a skoolie can be MUCH better than those found in factory built motor homes because the diy builder can tailor the system to meet his needs and he can control the quality of the components he installs.
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Old 10-19-2017, 04:42 PM   #9
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How similar are electrical systems from skoolie to factory built motorhomes?

Although the basic idea is the same, I'm thinking that the systems a DIY guy can build into a skoolie can be MUCH better than those found in factory built motor homes because the diy builder can tailor the system to meet his needs and he can control the quality of the components he installs.
... and can learn how to set the parts up so that they work!!
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Old 10-19-2017, 06:19 PM   #10
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Yeah, 12v appliances can be very expensive as itís kind of a niche market. Can be quite a bit more efficient, but not always. If you get a high quality inverter with 95% + efficiency you might even be able to do better with an AC appliance if there are higher efficiency models available.

Ran into this looking at mini-split ACs. Thereís at least one company that makes DC models for about $2k a pop. However there are higher SEER 240V AC models out there that might still end up being more efficient overall with a good inverter.

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I have recently found a mini split/heat pump brand that is 120v inverted down to 12v with good seer ratings. And a 12,000btu is only around 700$. Comes with the lineset and power wire from indoor to outdoor.
That's a lot cheaper than the name brand models
I have also talked to several owners of the units and they have had no problems or complaints after 3-4 years.
Look at pioneer brand. Money wise that is the way I am going to go
Good luck
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Old 10-19-2017, 06:38 PM   #11
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How similar are electrical systems from skoolie to factory built motorhomes.

I already had Pioneer on my list. Seems like very good SEER for the money! Good to hear they are reliable. Unfortunately looking at the service manual the 12v supply looks like itís only for the controller. The rectified voltage for the inverter looks like 200V+ for both the 115v and 230v versions.


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Old 10-19-2017, 06:44 PM   #12
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Thanks guys. I'm just getting started with design and planning. Hardest part is getting started... Especially when I don't know where to start.
Start where we all start. Figuring out what appliances we want to run.

Fridges are about 12-15amps on a 12 volt dc circuit. Your water pump will draw 7-8 amps.
Lights are fairly low amps. 2-3 amps per area it seems. Fans depends on the fan. I used computer fans. Ten inch fan draws .3 amps. Its enough to move the heat around though. They arent super powerful but they have cool leds in them.

Safety devices draw minimal ammounts of power. How much more does a guy need? I calculated my personal dc power consumption at around 30 amps per day without a fridge.

Ac side i wanna run speakers almost always. Fairly large draw there.
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Old 10-20-2017, 01:46 PM   #13
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I would suggest that you look at the fixtures and appliances that you will likely use and get specific power consumption details.

Example: my fridge pulls over 50 amps from my 12volt house battery on startup and settles down to around 20 amps. My lights draw .25 amps - 3 amps depending on the specific fixture.

There are a number of websites around with power consumption worksheets aimed at solar system sizing. These make a great starting point for electrical system design. List all of your specific loads and the duration of their use (duty cycle) and you will have a much better grasp of your power needs.

Edit: give this one a look - https://www.solar-electric.com/solar/calc
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Old 10-20-2017, 02:46 PM   #14
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Just a note to say that even the RV manufacturers are moving away from dual, or triple source fridges. That is those absorption fridges that will run on 12V, 120V and propane.

They work by employing a heating element rather than a compressor, and it makes them very power hungry.

There are some high-dollar 12V compressor fridges meant for marine use, that use a very efficient 12V compressor, but the trend is towards using domestic fridges, and the apartment sized are pretty frugal with your batteries.
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Old 10-20-2017, 02:51 PM   #15
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I've heard that the 3 way fridge is the most dangerous component of an RV. They cause a lot of fires.
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Old 10-20-2017, 04:31 PM   #16
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I already had Pioneer on my list. Seems like very good SEER for the money! Good to hear they are reliable. Unfortunately looking at the service manual the 12v supply looks like itís only for the controller. The rectified voltage for the inverter looks like 200V+ for both the 115v and 230v versions.


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Your ahead of me on that one?
Thanks for the info. I was already trying to break it down and figure out how to run on 12v. in my head?
Haven't seen the book on one yet.
But still a 120v unit for that price is real good
Thanks
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Old 10-20-2017, 05:58 PM   #17
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I've heard that the 3 way fridge is the most dangerous component of an RV. They cause a lot of fires.
I have heard that too.

To back it up, in the 20+ years I have been RV'ing, I have actually seen one case of it actually happening.

Perhaps it is more urban legend than a real concern?
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Old 10-21-2017, 10:11 AM   #18
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I would suggest that you look at the fixtures and appliances that you will likely use and get specific power consumption details.

Example: my fridge pulls over 50 amps from my 12volt house battery on startup and settles down to around 20 amps. My lights draw .25 amps - 3 amps depending on the specific fixture.

There are a number of websites around with power consumption worksheets aimed at solar system sizing. These make a great starting point for electrical system design. List all of your specific loads and the duration of their use (duty cycle) and you will have a much better grasp of your power needs.

Edit: give this one a look - https://www.solar-electric.com/solar/calc

Thank you everyone. As soon as I read these latest posts,a lightbulb turned on. As i said, getting started is the hardest part and that was exactly what I needed to get my head going in the correct direction.

Regarding amperage... If I set up my bus to run a 50amp shore cable, and the fridge pulls 50 amps when it starts... Wouldn't that pop breakers?

I've been reading a great book on rv electrical...I have a fair amount of 12v knowledge already and this book has helped a bunch. I haven't had any opportunities to put my learned info into motion though. I still have a whole lot to wrap my head around. I fear I will get too excited and not be able to wait long enough to start my project.
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Old 10-21-2017, 10:26 AM   #19
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Thank you everyone. As soon as I read these latest posts,a lightbulb turned on. As i said, getting started is the hardest part and that was exactly what I needed to get my head going in the correct direction.

Regarding amperage... If I set up my bus to run a 50amp shore cable, and the fridge pulls 50 amps when it starts... Wouldn't that pop breakers?

I've been reading a great book on rv electrical...I have a fair amount of 12v knowledge already and this book has helped a bunch. I haven't had any opportunities to put my learned info into motion though. I still have a whole lot to wrap my head around. I fear I will get too excited and not be able to wait long enough to start my project.
The 50 Amps shore power is at 120V. The 50 Amps starting current of the fridge is, I presume, either 12V or one ginormous fridge.

Nope, it won't pop a breaker
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Old 10-21-2017, 11:43 AM   #20
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Regarding amperage... If I set up my bus to run a 50amp shore cable, and the fridge pulls 50 amps when it starts... Wouldn't that pop breakers?
No.

Look at little closer. I said that my fridge draws 50amps from my 12volt battery bank on startup. Running on shore power (120volt) it draws closer to 5 amps.

It's as easy as P=I*E

Example: A 120watt load on your 12volt battery will draw 10 amps. So 120watts=10amps*12 volts.

A 120 watt load running on 120 volt shore power will draw 1 amp. 120watts= 1 amp*120 volts.

That said... My point in the post was not the particulars of my fridge but was intended to point out that power requirements for various appliances etc can vary significantly.

Your best path is to do your best to pick out the specific devices you will be using and get the specific power consumption of those devices to use in designing your system.
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