DIY RV Electricity

[Btruck]

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Hello! We’re currently working on an RV conversion project and are gearing up to install electricity. Since we do a mix of boondocking and campsite camping where we have power access, I’m looking for a system that will compliment both. It also takes into account the equipment we already have, which is everything that doesn’t have a price underneath it on the chart Above. Since we already have an inverter, and want to conserve our batteries when camping we’re thinking about a converter/charger. Most of our rig is built to run of DC, with the exception of a possible air conditioning unit in the future (which we wouldn't run off grid). Because of this, we wanted an idiot proof way to keep our converter from running at the same time as our inverter without the complication of a sub panel. I ran across this post in the process: Cam Switch Inverter Installand felt that a cam switch was the way to go. Please let me know if you see any pitfalls in this design that could hurt us in the future. I tried to include all information of the equipment we have and the equipment we are planning to buy. I also haven’t decided on a distribution panel. I understand they have ones with the converter built in, but I’m more privy to keeping them separate for ease of future modifications. I’m currently leaning towards this one from Progressive Dynamics. Thanks so much for looking!

[bukzin]

This blog thinks you may not need a generator at all.

http://handybobsolar.wordpress.com/about/


He has a lot of good info on powering your rig.

[shooted]

Here are some additional cam options, including 100 amp if so desired. They also have a 60 amp already mounted in a box as well.

[Btruck]

Thanks a ton everyone for your responses,especially to shooted for sharing his build and to 12thgenusa who summed up the benefits of the CAM switch really well. We're going to go ahead and move forward with the CAM switch. Maybe as we grow our rig we'll change that in the future, but for now it feels like the best option. The one thing that we are considering more heavily is upgrading to the 50amp panel - or a panel that can handle a 50amp set up, along with a 50amp surge protector (since from what I've read the 50amp hard-wired progressives will work just fine on 30amp services). A bunch of you mentioned the limitations that 30amps could have on future upgrades, not the mention the fact that you can wire 50amp to 30amp but not the other way around ... it makes sense to set up for 50amps now. Thanks again for looking over everything and providing your feedback. I hope to have pictures up soon as we move along in the process and to share the issues we come across in the future.

[12thgenusa]

I copied shooted's manual transfer switch installation and used the same cam switch. It has performed as advertised for two seasons. There is a lot to like about the installation.

1. No sub-panel required
2. All CB functionality is retained
3. All circuits to be powered by shore power only are automatically switched off when inverter is selected
4. Center "off" position assures "break before make"
5. All 120V AC outlets are powered by inverter
6. Wiring is a bit of work, but not complicated or difficult
7. Shore power cord can be connected to shore power or generator and not require an additional transfer switch

I fail to understand how a manual switch with 32A rated contacts would not perform as well as a 30A rated ATS. Also, I never change switch position under load.

[Gdetrailer]

Gdetrailer wrote:

Btruck wrote:
Thanks for the response Gdetrailer! We looked into the option regarding the inverter with the transfer switch/built in charger. We already have an inverter though that does not have the internal charger/transfer switch, and don't want to put out the money at this point. We may switch to that in the future, but currently want to stick with what we have. The cam switch is a cheap fix in the meantime. I'm curious about what you said regarding the cam switch rating. I went with what the OP in the linked post went with, but I can choose a different rating.

Switch contacts have different "ratings" depending on the TYPE of load (IE resistive or inductive), 32A resistive rating won't cut it when it comes to inductive loads like your A/C unit. Not to mention you need to know the actual voltage the contacts are rated for at that current rating, hopefully your switch is rated for at least 120V.

Something else to take into consideration is if the switches switch in the correct order. Must be careful that the contacts BREAK (the old circuit) before MAKING (the new circuit). Some switches actually can MAKE (the new circuit connection) before breaking (the old connection) which can cause a lot of problems.

A 30A ATS switch at $75 HERE is not going to be all that much more expensive than any high current multi-pole 120V switch and it will greatly simplify the whole process in the end...

On edit.. I should also mention that a ready made ATS also has built in switch over delay protection. This can be extremely important since many devices can get rather confused or even damaged when you flip from one AC source to another unsyncronized AC source.

[Gdetrailer]

Btruck wrote:
Thanks for the response Gdetrailer! We looked into the option regarding the inverter with the transfer switch/built in charger. We already have an inverter though that does not have the internal charger/transfer switch, and don't want to put out the money at this point. We may switch to that in the future, but currently want to stick with what we have. The cam switch is a cheap fix in the meantime. I'm curious about what you said regarding the cam switch rating. I went with what the OP in the linked post went with, but I can choose a different rating.

Switch contacts have different "ratings" depending on the TYPE of load (IE resistive or inductive), 32A resistive rating won't cut it when it comes to inductive loads like your A/C unit. Not to mention you need to know the actual voltage the contacts are rated for at that current rating, hopefully your switch is rated for at least 120V.

Something else to take into consideration is if the switches switch in the correct order. Must be careful that the contacts BREAK (the old circuit) before MAKING (the new circuit). Some switches actually can MAKE (the new circuit connection) before breaking (the old connection) which can cause a lot of problems.

A 30A ATS switch at $75 HERE is not going to be all that much more expensive than any high current multi-pole 120V switch and it will greatly simplify the whole process in the end...

[time2roll]

50 amp panel can be wired with one side direct power and the other side inverter only if that helps. Since you have the 30 it is fine also.

I would use an automatic transfer switch to connect the inverter. If no subpanel get a switch with converter outlet to avoid the loop. Not sure how the cam switch will have four feeds into the distribution panel that generally has one main connection.

I would go 80 amp PD converter with all that battery. Mount the converter close to the battery with #4 wire. No second connection to the 12v panel is needed.

Not sure about solar penney charge controller. Can it be programmed to automatically adjust between storage and in-use charging profiles? I think you may want more than 200 watts of solar so this might push into 24v panels and a quality MPPT controller.

I assume you meant 2 in series, 3 parallel for the batteries.

[shooted]

My experience has shown the 32 amp switch to stand the test of time in my application. Your design appears sound. You will garner little support for considering options to ATS and a sub panel.
Is P4 for the air conditioner?

[Queens_Carriage]

O one other thing why do you need a inverter? The only time we have ever had a need for one is to make coffee in the morning. We run the gen for 30 min in the morning to make coffee and at the same time we are charging the batteries. The computer, TV will run on 12v dc.

[Queens_Carriage]

One of the big reasons for using 50amp. If you run your ac you can only run the ac can't run the toaster, microwave, coffee pot etc. You could put the ac on the other leg with 50amp.

[ScottG]

I can see it know - something changed.

[christopherglen]

I would think about small Breaker Panel. Put an automatic transfer switch between the generator, and shore power inlet (to automate things), then the small breaker panel, with a 30 amp breaker feeding a second automatic transfer switch (with the inverter feeding the other side), powering your main breaker panel.
Move your AC, water heater, and converter to the (new) sub-panel.
Theory is on generator, or shore power (automatically switch between if available) you have ac, electric water heater, battery charger (converter), and the entire rest of the trailer. Lacking shore / generator power it load sheds the big stuff, and powers the entire rest of the trailer off the inverter.
You said you already had a automatic transfer switch, if it is in good shape, use it for the inverter input. You can plug the shore power plug into the generator if you want to pinch pennies.

[Teacher_s_Pet]

I can see it also.

[Btruck]

Thanks Brian! Yes! The CAM switch is set up so that the converter is never run off the inverter. Since the circuit is never closed when the inverter is selected, it makes it more idiot proof. I originally had an auto transfer switch set up between the shore power and the inverter and a relay between the inverter and converter (The relay switch I saw done here -option 3, but with a different configuration overall: Relay Switch ) to make the transfer automatic. However because of the transfer switch it made it would make the relay switch no longer work since I don't think it could tell the difference between shore and inverter power. What I was most worried about (why the cam switch install), was like you said - running the inverter and converter at the same time.

The reason that the generator is not on a transfer switch between the shore power is because the Generator is not actually wired in and I don't see a use for both ever at once anyway (not to mention that our Genny has a 30amp plug straight into it). When boondocking we'll plug in our genny, when camping we wont. I didn't think about what you said regarding 30amp plug arcing/over-heating - are the related issues something that the Surge protector would guard against (other than, well, fire - of course)? Thanks a ton for your feedback, a transfer switch between the genny and shore power is something that I'm going to look at more seriously.