Inverter upgrade question

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KevinVT
Posts: 74
Joined: Thu Apr 28, 2016 7:04 am

Inverter upgrade question

Post by KevinVT »

Hey folks,

We have a 2003 24RB. Factory installed is a simple Cobra inverter 300W. What I can tell there is a single power line coming off it.... that goes to the outlet by the TV (next to the fridge)... I also know this feeds a second outlet in the over cab bed area under the bed.

I am going to upgrade my inverter to a 2000W Pure Sine. Why? Just to have a little more flexibility - I wish to add 2 more outlets off this inverter - TV, New outlet and another new outlet. For 90% of the time we won't need this kind of capacity... but I wanted to be able to run a toaster or coffee machine, maybe a hair dryer.

As an FYI - this is part of a larger set of upgrades I am working on:
  • A) I am replacing my single stage Parallax 7344 Converter/Controller to a Progressive Dynamics 4655VL
  • B) I am also upgrading my house batteries to 2 x Trojan T-105 6 Volt Batteries
Here is a picture of the two inverters side by side:

https://content.screencast.com/users/Ke ... 001834.png

I have done a lot of reading and research but electrical is not an area I have a lot of experience. For folks out there with more experience, please let me know if I am missing a key step or concept. Here is what I know and plan to do:
  • 1) I have removed the current inverter. This is fed by 10 Gauge Wire. I assume this wire goes back to the battery? And I know there is a fuse for this as well. My inverter fuse is located on a small block outside the main electrical unit - right by our water tank.
  • 2) I plan to install the inverter in the same general place... under sink area - on the opposite side of the wall that houses the water pump. There appears to be room here and the current TV outlet is wired to right here.
  • 3) The new inverter needs BIG wire. My plan is to run 2 gauge wire with a 225 amp fuse directly back to the batteries (recommended by inverter manufacture). I was going to drill a new hole in the floor near where the current power feed comes in the floor and run the 2 gauge wire (red positive and black negative) back to the batteries.
Is this correct? Am I missing something about how the current inverter is tied into the electrical system or how the new one should be?

As for the current inverter wires... they are 10 gauge with 30 AMP fuse - I plan to re-use this wiring. Last year we upgraded our refrigerator to a newer Norcold 3 way - but I had a 2 way before, so my current 5 AMP fuse and current DC wiring to the refrigerator is not thick enough. I have a length of 10 gauge wire to run up and over to the refrigerator. I figure I would save myself some time and splice this wire run to my existing 10 gauge on the old inverter... fuse is all set I just need to get the run to the back of the refrigerator. Since I installed the refrigerator last year, I think I will just pull it out again.. and drill a hole in the wall into the cabinet (above TV) near where the existing wire comes in and then travels over the roll bar to the power center by the sink.

Ok, poke holes... what am I missing or what do I clearly not understand about how things are wired. Thanks! I love all the knowledge here in the forum... and I am still sad BF closed, at least I had a chance to visit the factory in 2016, meet Kim and tour the place.
--Kevin
2003 Born Free 24' RB - No. 6685 -- 11/2003

(Former 2001 Born Free 24' RB - No. 6176 -- 9/2000)
(Former 2001 Born Free 24' RB - No. 6185 -- 3/2001)
tomzleapin
Posts: 485
Joined: Sun Jun 20, 2010 9:15 am

Re: Inverter upgrade question

Post by tomzleapin »

On my coach all the AC outlets except the one near the TV are fed from one breaker. I installed a 30 amp relay in that line so that when there is no shore or generator power the inverter feeds the outlets. In the schematic the K1 relay is the ATS (Automatic Transfer Switch) which already exists. It switches between shore and generator power. The K2 relay that I installed switches to inverter if there is no shore or generator power. Something to note, my drawing doesn't show the circuit breaker for the outlets.

Here's a suitable relay that can be purchased at Grainger:
120VAC, 8-Pin Surface Open Power Relay

If you prefer a prewired box, here's one from Amazon:
Progressive Dynamics PD5110010V 5100 Series Automatic Transfer Switch
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Tom
2005 24' RB
Towing 2016 Mini Cooper convertible on tow dolly
New Hope, MN
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whemme
Posts: 2110
Joined: Mon Aug 15, 2005 8:05 pm

Re: Inverter upgrade question

Post by whemme »

Kevin,

You did not say exactly how you were going to use the extra capacity of your upgrade to a 2000 watt inverter. Your correct 300 watt inverter is connected only to an outlet to power your AC TV. I assume when you install the 2000 watt inverter, you will be connecting its output to additional AC outlets in your coach. I believe all other outlets in your coach other than the TV outlet will be connected in parallel and protected by a single 30-amp circuit breaker. You may want to select a certain AC outlet or install a new AC outlet which you intend to power heavy AC loads from (such as a 1500 watt toaster or heater) and that outlet will need to be rewired directly to your 2000 watt inverter and wired with 10 gauge wire and connected by a separate 20-amp circuit breaker.

Also the wire size to feed your 2000 watt inverter connected directly to your coach batteries should be size 0 gauge, not size 2 gauge.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
KevinVT
Posts: 74
Joined: Thu Apr 28, 2016 7:04 am

Re: Inverter upgrade question

Post by KevinVT »

Bill,

Thank for the information. A few additional questions.

I got the 2 gauge wire figure for the inverter from Power Tech On support- they told me for the 2000W - "Total cable run up to 10' would require 2 gauge wire with a 225 amp fuse or breaker. if the cable run is longer then you would need to size up to 0 gauge." I was thinking I could drop through the floor to the batteries and that run should be less than 10 feet - thats why I was thinking 2 gauge would be ok.

I plan to plug the TV outlet wire into one of the Inverter outlets... just like the outlet is currently plugged in. It looks like the wire is interior house hold Romex 12/2 wire - yellow casing - at least that is what it and all the other outlets look like. Are they 10 gauge? As far as I can tell the wire runs to the TV outlets without any breaker or fuse on it - it bypasses the electrical panel.

You are correct - I am going to add two more outlets. I understand these will also by pass the main electrical box - so these outlets will always be on the inverter. I don't want to touch any of the current outlets. My plan was to run the two new outlets just like the TV - using Romex 12/2 and each with a plug.

My inverter is a Power TechOn PS1003 Pure SINE Wave Inverter 2000w Cont/4000w Peak

https://www.amazon.com/Power-TechOn-Inv ... 601&sr=8-5

The inverter has 3 outlets - I was going to plug each outlet into one of these. So in the end... the 3 outlets plugged into the 3 outlets on the inverter.

Based on your recommendation, would you suggest I add a separate 20-amp circuit breaker to each of the 3 outlets? Any suggestion on what that might look like, some kind of inline breaker for each line?

I have seen inline 20 AMP breakers for 12-24DC systems like this = https://www.amazon.com/Car-Audio-Inline ... way&sr=8-2

But it seems I would need a 120V breaker - since this is past the inverter so we are dealing with 120V going to the outlets.

Or, since I am plugging in each outlet to a different outlet on the inverter - would the inverter provide adequate overload protection? The description reads "5 Protection systems: Thermal protection, Overload protection, Over Voltage protection, Under Voltage protection, Low Voltage protection alarm".

-------
Or should I consider just making all the outlets run off the new Inverter by trying to figure out something like Tom recommended? I don't fully understand the concept but it seems like I could have some switching that auto know if I have generator power, shore power, or if neither - use the inverter. Seems like a 2000w is big enough having all the outlets on it wouldn't be a bad idea. Just seems a bit more complicated.

Thanks for your insights!

--Kevin
--Kevin
2003 Born Free 24' RB - No. 6685 -- 11/2003

(Former 2001 Born Free 24' RB - No. 6176 -- 9/2000)
(Former 2001 Born Free 24' RB - No. 6185 -- 3/2001)
User avatar
whemme
Posts: 2110
Joined: Mon Aug 15, 2005 8:05 pm

Re: Inverter upgrade question

Post by whemme »

Attached below is a standard wire gauge vs current carrying capacity table. Since your run from the chassis batteries to the 2000 watt inverter is going to be about 10 feet. If you plan on ever using the full 2000 watt output of inverter and assuming an inverter efficiency of 85%, the input current to the inverter under those assumptions would be 196 amps at 12 vdc. So, you should fuse or circuit breaker protect the input to the inverter at 200 amps and the wire size between inverter an house batteries should be 1 gauge.

Since your are planning on wiring 3 AC outlets to the 3 separate outlets on this inverter, I would suggest a 20-amp 120 vac rated circuit breaker in each feed line to each outlet.
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Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
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