Adding Inverter

[Not A Clue]

I know this has been discussed many times, but I am looking for information specific to my situation.

Currently I have no inverter in my motorhome.
I have two six volt batteries that are 7+ years old

I am not going to add more batteries, space issue......
I will be probably be changing them out for two AGM's

The easiest path to take is a whole house setup. Replace charger with inverter/charger.
Since this is being done at a shop the labor vs more expensive hardware kind of balances out.

I was quoted two ways to go.

Inverter....MSW 1200w 70A charger.
Inverter....PSW 1000w 50A charger $292 more.

I know that on this setup I will have to watch what I run and not run to many appliances together.

I will be going full time later this year. I am not looking for a setup for lots of boon docking, just looking
to be able to overnight in a non hook up environment if needed, or maybe a couple of days with out hook ups.
I have a good working generator. I have a Traveler automatic dish on the roof.

Based on lots of reading I am leaning towards the PSW, of course.
This will be an exact replacement to size also matters.

Thanks in advance!

[jc2]

Unless cost prohibitive, I would spend the extra bucks and go with a 2000w inverter/charger. PSW is always better than MSW but again, what would be the cost difference, how long to you plan on keeping your current rv, etc. AGM's are very good batts but my choice would be good quality 6v wet cells as It would almost require one to regularly check on them for fluid level, corrosion, etc. AGM's are basically no checkums after install but I'm a hands on person for keeping track of systems on our coach. Your money, your choice.

[Yarome]

I am not looking for a setup for lots of boon docking, just looking

to be able to overnight in a non hook up environment if needed, or maybe a couple of days with out hook ups.

I have a good working generator. I have a Traveler automatic dish on the roof.

 

Based on lots of reading I am leaning towards the PSW, of course.

 

Sounds like you're pretty well set up. I would go with the PSW as well. You didn't mention what you planned on running with your 1200w inverter, so I can't comment there. If all you plan on running is your TV and receiver you could probably go with an even smaller (less expensive) inverter.. but then again.. in a combo unit that would, more than likely, also mean a less capable charger. 1200w kind of stands on medium ground. Not quite large enough to handle say.. a microwave or electric heater, but more than enough for several small appliances. A 50amp charger is adequate for the size of your battery bank.

 

Which inverter/charger are you looking at?

 

Did you have any questions in specific?

 

With a shop doing the install, be sure you fully understand the wiring gauge requirements for your specific distances. That's an area were many shops will skimp on.

[skp51443]

I too would go with the PSW, particularly if going for a whole house setup as you'd have to insure everything connected to power was MSW safe or risk killing it when the inverter comes on.

 

I'm not a fan of a whole house setup, it really is a bad idea if you are less than perfect. Having your fridge, water heater and air conditioner(s) on the inverter is just begging for one to be forgotten when switching from shore power to inverted battery power. Adding a small, 3 or 4 breaker, sub-panel is not much more expensive and really pays off the first time you forget to power down something.

 

Moving all the high power draw devices off the inverter puts a lot less stress on the transfer relay and internal inverter wiring.

 

If doing a sub-panel and if you use an electric heater is to add an additional outlet for the heater that is on the sub-panel.

 

You might consider keeping the converter if it is a modern one, it can come in handy if the inverter has issues and goes out for repair. It can also be used to keep the batteries charged while you are using the inverter to make your AC power. That sounds a bit odd but we often found ourselves in spots where the AC power was bad (high or low) or only a couple amps were available. Letting the inverter make clean power let us not worry about the bad power and gave us plenty of power to run the microwave and our other stuff without tripping the breaker we were plugged into. The converter won't keep up with big draws short term but on average over the day it will keep the batteries up if you aren't going way overboard on power use.

[dontrump]

STAN

I very seriously doubt anyone in this case would be wiring the AC units and water heater through any inverter system

[Yarome]

STAN

I very seriously doubt anyone in this case would be wiring the AC units and water heater through any inverter system

 

In a "whole house" inverter setup.. unless you use a subpanel, as Stan outlined, it's unavoidable.

 

"Whole house" means wiring the inverter output INTO the power distribution panel.. not "wiring the A/C units and water heater" directly to the inverter.

[pjstough]

Unless cost prohibitive, I would spend the extra bucks and go with a 2000w inverter/charger. PSW is always better than MSW but again, what would be the cost difference, how long to you plan on keeping your current rv, etc. AGM's are very good batts but my choice would be good quality 6v wet cells as It would almost require one to regularly check on them for fluid level, corrosion, etc. AGM's are basically no checkums after install but I'm a hands on person for keeping track of systems on our coach. Your money, your choice.

 

To me, a 2000 watt inverter is overkill with only two batteries. It would take longer to recharge then with the generator, than it would to just use the generator for any appliance that required that much electricity.

[skp51443]

2000 watts with two batteries isn't a bad choice, yes it is a lot of draw from the batteries if you use near the full 2000 watts but often a smaller inverter won't run your microwave, satellite box and TV at the same time, same issue if you have a high power (900+ watts) coffee pot.

 

It is good to be aware of the limitations of a small number of batteries and just how short a time they will support the loads you intend to put on them but realizing that you can choose what and how long to run things. Heating something in a 1200 watt microwave on 50% power for five minutes or an early morning pot of coffee is easily doable while cooking a roast at 100% for 30 minutes is pushing things if you intend to have power left over for other things.

 

Going with AGM batteries is also a good solution if you are going to recharge from a generator as they will charge faster, needing less generator run time.

 

dontrump, Pretty much what Yarome said. The main feature of a whole-house inverter is that it (and only it) is fed by your shore power cable and the output from it goes to your breaker box. If you have a generator with an auto-transfer relay that can be ahead or behind the inverter but it still powers everything. When you put in a sub panel you bring the power cable to the sub-panel and the inverter inputs so both get power when plugged in, when on the inverter only the items connected to the inverter get power.

 

 

Different folks go different directions on what remains in the main breaker box versus what goes to the sub panel. I have seen folks take a few circuits they want to be inverter powered and move them from the main box to the sub-panel and then power that from the inverter but I have also seen folks go the other direction and just move a few high power things to the sub-panel and having the inverter supply the main box.

 

Something not recommended but that has also been done (by the brave, foolish and cheap) is to use a 240 volt breaker box and wire one phase to the power cord and the other to the inverter. Don't do it.

[Yarome]

Something not recommended but that has also been done (by the brave, foolish and cheap) is to use [redacted]. Don't do it.

 

Don't even bring that up! Ya know there's gonna be at least one feller that's gonna think that's a slick idear.

[skp51443]

If someone does, I hope his wife has a video camera and Youtube account, the income from the video of the first oopsie could help offset the replacement costs of the stuff he burns up!

 

It is a seriously bad idea but it keeps getting suggested by folks looking to scrimp on every cent up front or looking at limited space.

[Retiredin1993]

I will just add that I would go with the PSW inverter. Many digital things don't like MSW and it will toast

them. Like electric blankets/pads, coffee makers with timers, some refrigerators and fans with remote controls.

[Jack Mayer]

I have a couple of comments. Take them for what they are worth.

 

1) Doing a "whole house" install it not possible with virtually all the inverters on the market today. The transfer switches are not rated to transfer two legs of 50 amp. Now, if it is a 30 amp coach then no issue. And a coach that size may be 30 amps, although many these days are 50.

 

2) You can SAFELY do a split box inverter if you do it right. (Split box, meaning take one leg of the 50 amp service and run it through the inverter first. And properly balance the loads in the loadcenter.) I don't recommend it, but electrically it can be done, and done correctly. Again - I DO NOT recommend it. I really don't want to start a discussion on this, because I don't want to encourage anyone to do it.

 

3) I'd also recommend pure sine wave.

[Not A Clue]

Thanks everyone for your input, The coach is 30A. I think I will be going with the PSW 50A charger and 1000W inverter combo.

I really don't plan on heavy usage, maybe watching TV a few hours at night when without power.

I have a perfectly good generator to use for the heavy stuff..

 

I understand I will have to learn to monitor the system. But I think I can handle that.

 

We are retiring this year and should be living in the coach by this fall.

 

Thanks again everyone.

[dontrump]

Thanks everyone for your input, The coach is 30A. I think I will be going with the PSW 50A charger and 1000W inverter combo.

I really don't plan on heavy usage, maybe watching TV a few hours at night when without power.

I have a perfectly good generator to use for the heavy stuff..

 

I understand I will have to learn to monitor the system. But I think I can handle that.

 

We are retiring this year and should be living in the coach by this fall.

 

Thanks again everyone.

your spending $500 or less on a inverter/charger why not go 1500 and be sure your covered. As far as monitoring, just wire it with only the systems you want to run

with the inverter

[Randyretired]

The 1000 watt inverter sounds like it will work for you. We have 2000 watts and it works for us. We like to use a drip coffee pot and the mocrowave occasionally but if you are aware of the limitations and accept that I don't see a problem. As others have noted you will need to turn off the electrical side of the refrigerator and hot water heater before using the inverter. Also a whole house setup can tax the transfer relay in the inverter if it switches with much power being used. It is a trade off for a less expensive unit and the penalties for forgetting are clear.

[Yarome]

I think I will be going with the PSW 50A charger and 1000W inverter combo.

I really don't plan on heavy usage, maybe watching TV a few hours at night when without power.

I have a perfectly good generator to use for the heavy stuff..

 

I understand I will have to learn to monitor the system. But I think I can handle that.

 

Sounds like a decent plan to me. You might consider adding in a decent battery meter (above a simple voltmeter type) capable of monitoring your amps in and out. It really takes out a lot of the guess work on genset times and let's you see exactly what reserves you have available at a glance. Cost to features/reliability I'm still rather partial to the Trimetric, but there are others out on the market that would get the job done.

 

Have fun!!