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Mike recently posted an article about installing an inverter in his rig. Over the years I installed dozens of inverters and also replaced ones that burned up or melted wires. Thus I want to raise what I think is an important point which his article may not have made clear.
While the common assumption is often a belief that DC power from the battery is not dangerous, nothing could be farther from the truth. So can #4 from the batteries to the inverter be used safely? Bearing in mind that it is always essential (no exceptions to installing a fuse between the batteries and the inverter connection) the fuse has to be sized to the #4 wire and the demand based on a code (Mike has a link to the code in his article) feeding the inverter because fuses are designed to protect wiring. In the absence of a properly sized fuse the inverter will not shut down, the wires will more likely melt and possible start on fire.
As always, my two cents. 🙂
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCNice and neat. Easy to follow and anyone else can follow in your foot steps which I think is the mark of a good installation.
The one thing I would toss about cable sizing is I never deviated from the manufacturers’ instructions or sizing, although I lived in a much different world where I was liable for anything my hands touched and a lot they didn’t.
The issue I saw that most often destroyed inverters was folks assuming as long as a fuse or breaker did not blow they were fine. That meant lots of hair dryers, coffee pots, and microwaves fighting for power right up until something went up in smoke in the inverter. Long heavy amp draws can produce a lot of heat and melt components. Probably not much of a risk in truck campers.
Probably the actual demands are pretty modest. Even our little 16 inch TV and DVD players operate easily off an inverter that plugs into a 12 VDC receptacle and we have a genny for AC and microwave. 🙂
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCI just installed a Cobra 1550 inverter into my 185s. It was supplied with #4 cables, about 3′ each. I set the inverter under the sink, and the battery box is about 6 inches away…two holes in the top corner of the box for cabling and I was using it last night to power my dremel tool for some pilot holes for bungee eyelet mounts.
All good, CheersNo problem going larger with cable. In the olden days when Winnebago still had their surplus warehouse I came upon 50 feet of 2/0 lying on a shelf. The attendee had no clue what it was worth and figured $25.00 would be about right. I agreed the price was fair :). I have used it in a couple of inverter installs, but still have a heck of a lot taking up space waiting for the “next last” install. Don’t forget the fuse. 🙂
Steve
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCSince the subject is inverters, I’ve got a few questions. I thought I read somewhere that the fuse should be really close to the batteries. True or does it really matter? Our inverter has a remote on/off switch. Any reason to put a switch/disconnect between the batteries and inverter? My plan is to take the two circuits we want to use the inverter for(microwave, kitchen GFI) and run them through the automatic transfer switch betweern the inverter and PD charger/controller.
Tom,
The RV manufacturer’s code calls for a fuse within 18″ of the batteries. As to the disconnect, the manufacturers normally have one. I don’t recall if the code requires it. I do not have one on the inverter I installed in our fifth wheel and glancing at Xantrex wiring diagrams I do not see one.
Steve
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCHi Tom, Theres no requirement to have a on off switch at the inverter positive cable but a fuse is required to protect the cables from amperage overload (usually a 300a ‘t’ type)…
As to wiring the two mentioned circuits at the ATS output, it’s not clear to me how you’d do this (per your plan) without also energizing the main panel…This scenario would cause a ‘round robin’ effect with the converter charger attempting to charge the battery while the inverter is simultaneously being supplied by the battery… Another way to do this is with a sub panel…
Phil
Phil, Our friend, who’s an electrician and sailboat owner is coming by tonight to help me with the ATS layout. He’s pretty sharp.
My question about how does one run the whole panel thru the inverter(which we don’t need) without a disconnect of some sort to prevent the round robin scenario you mentioned. I’m unclear as to the internal workings of a Progressive Dynamics 4560 Li charger/converter. I don’t know of a way to disconnect the DC charging if the inverter is supplying power. That’s why I thought I could just run those two circuits thru the ATS. I haven’t sat down and figured it out yet.
One additional question. I read somewhere where the neg. and positive cable from the batteries to the inverter should be of equal length. True?
Tom,
I think the short answer is you can’t do it easily which is why Phil mentioned a sub panel. Your power converter is powered at your distribution panel so if you power the panel by your inverter, you are going to power the converter.
Since the both cables run from the batteries to the Inverter, why would they not be the same length?
Steve
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCThe reason in my mind to use a ATS is to be able power the two circuits mentioned thru the CC or the inverter. The Thor ATS is in a 6″ x 6″ plastic electrical box. So, essentially, that’s the sub panel. I know I wasn’t very clear above. I understand you can’t run the inverter thru the CC w/o disconnecting the charger part of it. Which appears to be impossible. The schematic I downloaded from Thor’s site shows just that though. I also got a wiring schematic from the inverter vendor that cause me some confusion. Hence the question about the switch.
Our battery compartment is on the other side of the wet bath from the electrical compartment. There’s space underneath to route wires, but it require the flexibility of Houdini. The only place to put fuse block, terminal block etc is behind a couple of the kitchen drawers next to the bath and in front of one corner of the battery compartment. There’s no place that the 300A fuse block can be mounted easily with-in 18″ of the battery. Hence the question about cable length. Why does Bluesea make them so big? I’m tempted to R&R the battery compartment from the outside to access things a little easier, but still be able to access the fuse if it should ever blow. Getting a screw gun in there is a challenge. 🙂
I’ve never installed an ATS before and the Thor didn’t label the terminals so it has made it a little difficult to follow their schematic.
Thanks for your help gentlemen.
Hi Tom, a practical plan without a downside would be to ensure that the onboard converter-charger, the refer (if absorption type), and the hot water heater, etc do not become inadvertently energized when running from the inverter…This is to avoid the unintentional running down your batteries…Often, the refer when on LPG will sense the presence of 120v and then auto-switch to AC, often without your knowledge…
A better way to do this would depend somewhat on the type of inverter you have (i.e. conventional or a shore power ‘pass-thru’ design w/ATS)…
If conventional, then you would wire the incoming shore power cord in tandem to both the main panel and the ATS switch input…With this scheme:
1) when not on shore or generator power, the ATS will auto-switch to the inverter…
2) the ATS output goes to a sub-panel (with either power source – but does not feed the main!!).
3) the circuits you mentioned (microwave, house plugs, etc) are relocated from the main panel to the sub-panel.
4) it’s in this way that inverter power is directed only to the Sub and cannot go backwards to the Main, yet when on shore or genny power ALL circuits are active as was before…
5) this also ensures no sinusoidal conflict between shore and inverter.
6) if you are planning on a pass-thru inverter, then you’d want to make sure that it has a floating-neutral circuit (NEC code for RV’s), else you’ll experience nagging GFI issues…
7) yes, when dealing with low voltage d.c. (to reduce voltage losses and increase efficiency) it’s best to try and keep + & – cable lengths as fairly close and short as possible – this is called ‘balancing’…
8) don’t skimp on cable AWG gage, I generally upsize by one gauge over Mfg recommendations, just to ensure NO bottlenecks to the inverter (under high amp loads) which can cause nagging inverter alarms and shutdowns…
9) To avoid GFI issues (as per item 6), when installing the sub make sure that the neutral and the grounds are isolated at the buss-bar (easily done by installing a jumper wire).
Hope this helps,
Phil
BTW, the ATS is not a sub-psnel, perhaps you meant junction box…
Tom,
You want to know how to disconnect the power board that does the charging in the bottom of the distribution panel box i.e. turn off the breaker that powers the board?
Maybe I’m not following.
Steve
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCThanks for the help Steve and Phil. You guys are asking the question I didn’t know I needed to ask. The vendor I bought the inverter and ATS from has sort of fallen by the way side after promising schematics.
Here a link for the ATS. https://thorpowerproducts.com/product/thts-30/
Phil, Good info. I’m not planning on running anything from the inverter thru the CC panel. The inverter is a pretty basic one. http://www.cnbou.com/2000w-pure-sine-wave-inverter/
We been so swamped trying to get out house remodel finished to a point to show a very patient prospective buyer, I haven’t have a chance to think that much about this. I still haven’t finished the CC and new Victron solar controller swap. It probably would have dawned on me that I need a sub panel. The question was way in the back of my mind on how I was going to run two circuits thru the ATS. As a general contractor, we use sub-panels all of the time. With the limited space we have, does anybody make a tiny 2-3 circuit panel. I haven’t googled it. The boat industry probably has them.
This is wiring schematic I received from the vendor. It stops at the inverter and they’ve too busy with installations to answer any other questions I have. Hmmm, not sure why it didn’t load. it shows in the reply window.
Thanks again for your input.
Tom,
I think your sticking point is going to be finding a small enough sub-panel. It looks like your inverter is a simple DC in/Inverted AC out so I would be inclined to just go with that directly to a sub-panel and forgo an ATS. You can use your remote to turn it off and on when you need it.
It would be helpful to have a wiring diagram for the inverter. Did one come with it? Are the two inverter legs out independent, 1,000 watts each?
Easy to disconnect the converter, just take the lead off the breaker suppling the bottom power board along with the neutral and ground.
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCSteve,
Well, just a quick google and Bluesea makes small circuit panels. Not cheap thought. $350-190 for a 3 circuit panel. Glad we don’t own a boat.This was not a very expensive inverter. $300 and change IIRC. The vendor is the US importer for this brand from what I found out on the chinese mfr website. I’d still like to be able to run everything AC if plugged in to shore power. That was the point of the ATS. We’re invited on a Grand Canyon rafting trip next April. Our 6th. We be parked at a friends house that are also going. So we’ll be buying supplies, preparing and freezing meals for the trip. Probably there for a week and half before we travel down to the launch ramp. Fortunately, out storage unit with our cataraft and gear is a mile from their house.
I don’t know if the inverter is two independent 1000w legs. It has (2) 110 outlets, so probably. I guess I was expecting something that had to be hard wired. They don’t mention that on the spec page of the website. Not sure how that’s going to work with the M/W. It’s a 1350/900w unit. I’m going to try to call the vendor and see what he says.
Our friend, the electrician didn’t feel well, so he blew us off till next week.
Different way of looking at it, but if you are on shore power, your converter would be charging the batteries which would be powering the inverter. 🙂
I’m not crazy about your inverter as it might have been simply if it had a single hard wire connection.
And Bluesea is good, but good Lord, you really have to pay to play.
Steve
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SCIf it’s a conventional type receptacle, more than likely your inverter is 2000w out of either leg as there is just one leg for 2000w total…You can fashion-up a plug-in HD cord and wire that into the ATS…
Phil
The inverter is rated at 1800W from either 110 receptical I found out. I’ve got it hooked up to the batteries and it works.
Holy Moly!!! TCs are a PITA to work on! There was blood involved. Lot’s of sharp corners in there. It took me several days to get the batteries installed and the cables made up and installed. I did manage to place the 300a fuse at exactly 18″ from the first Battery. Wasn’t easy. I had to get creative with the hole drilled through the battery compartment. I thought I was being all smart to be able to get three batteries in there. I didn’t take into account all of the 2/0 cables in there. It’s packed in there for sure.
I also installed a Victron 100/50 solar controller and bluetooth dongle for the Victron BMS. I have to say the app on the phone is pretty cool. Still lot’s to do, but at least that’s out of the way. ATS is next…and a new propane detector, etc
I think those hydraulic cable crimpers are the bomb.
I finally got the ATS figure out. Our friend Brian, a master electrician and live aboard sail boat owner came over last night to help out. After familiarizing himself with the rest of the system, we began to layout the wiring needed for the ATS, charger/converter,inverter interface. The drawing I got off of Thor’s site wasn’t really that helpful since it was drawn around a system with a separate charger and convert. Not like the PD one in our TC. We found a simplified drawing on GO Power’s site(and who sells the same ATS under their name) and after bench testing the ATS to make sure we had all of the terminals figured out(since they weren’t maked), we knew what needed to be done. Brian had it figured out, but was probably humoring me. 🙂 When we first ran 110 to it on the bench….crickets. When Brian looked at the GP drawing, there was a tiny note about time delay, so then we actually screwed the test wires under the terminal screws and…..more damn crickets for a about a minute. Then, click. It was working. Why such a long time delay is a mystery.
Then we broke for beers and my wife’s souped up salsa and chips and talked about sailboats.
I haven’t installed it yet, but it’s good to know what needs to be done.Tom, ATS switches that I’m familiar with typically have a programmed short delay which is intended to allow for a brief amount of generator warm-up time before coming under a full load…Maybe this is what you were experiencing…
Tom, the delay feature may be defeated by soldering a jumper wire across the board, but it shouldn’t really matter much because when your running the inverter and then plug in shore power (or genny power), the ATS delay (at switching back to shore power) would then occur – by design, the transition should be seamless.
Phil
Yeah. I’m not messing around with soldering anything on that. It’s going to take me that long just to put water and filter in the coffee maker & beans in the grinder. One thing I think I’ll do is install an indicator light to let me know when the ATS is engaged, but that’s way down the list of stuff needs doing. So many things to do and so little time.
Tom if wired correctly there should be no delay when you turn ON the inverter…The delay should only occur say if you’re using the coffee pot (or other appliance) and the ATS senses the presence of shore (or genny) power – in this case (were shore or genny power to suddenly return) the ATS would then switch over seamlessly after a brief unnoticeable delay…
Phil, you are correct. No delay when turning on the inverter. It’s all wired up, but haven’t tested it yet. We been living in the TC in the front yard(on shore power) while the hardwood flooring guys proceeded to screw up the first refinish and then had to resand down to bare wood and start the whole process again. Three weeks!
I did get a 3 circuit AC sub panel from PanelTronics. About $125. Apparently, Blue Sea had a fire at it’s facility and is just starting to ship stuff.
I have been working on a ton of things to get this house ready. It payed off. We got two offers w/ one being over asking. No agents on either side. 🙂 We settle on 9/25. Then we’re homeless for the forseeable future.
Well it’s uber nice to see a plan come together, eh!!…Sounds like it’s all falling into place quite nicely!!
Correct, there should be no delay when you fire up the inverter, but after inverter start-up it’s best (for the electronics) to wait say about 10-15 seconds after start before hitting it with a serious load…Reason is, some inverters (particularly shore power pass-thru inverters) do a very momentary self-power assessment just after initial power-up…
Congrats!!
PhilIn retrospect I should have clarified to mean no significant delay (my bad here..) but our previous dialogue about this delay tended more in the context of a 20 to 30 second programmed ATS delay to accommodate a brief warm-up period for a generator…
OK, finally had to test it. We lost the only outlet that we were plugged into when I demoed a wall for a new garage door. It use to be a garage door before someone walled it in to put a entry door. Great two+ car garage now.
Anyway, I turned on the inverter and ground our coffee beans and then fired up the coffee maker. It brews into a carafe, so no warming element. Everything worked great. It was fun the watch consumption on the Victron BMS on the phone. I still need to check the MW. Still just busy as crap. We settle in 8 days.
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