Converter and inverter Question

I want to install solar on our Big Horn. The first thing I would like to do is install an inverter. Can I just swap out the converter with the inverter or do I have to remove the converter, splice the wires in that location, and wire in the inverter in a different location. I want everything to be able to run off the batteries except the air conditioner. I am going to get a 2000 to 3000 watt modified sign wave inverter that will also be able to charge the batteries when on shore power.

Hi dcwettstein,

A couple of things to note:

• Power Converters take 120V AC as the input and produce 12V DC as the output. Converters charge the battery.
• Inverters do the opposite. They take 12V DC as the input and produce 110V AC as the output. Inverters consume your battery charge and do not recharge it.
• So you can't use and inverter to replace your converter. They do different things.

You should take a look at your various 120V AC appliances and add up the amps they consume. Microwave probably takes nearly 15 amps. TV takes a few amps. Coffee pots and toasters take between 10 and 15 amps. Fan takes a few amps. Computer takes a few amps. You may not need to run them all at once. But figure out what you do want to run at the same time, add up the amps and multiply by 120 to get the watts you need from the inverter output. So if you need 20 amps to run a coffee pot or toaster along with the TV and computer in the morning, that would be 2400 continuous watts needed from the inverter. By the way, that would be quite a drain on your batteries. You'll need a generator or solar panels to recharge them when boon docking.

You'll also have to figure out how to tie the inverter output into your circuit breaker panel and will probably need a transfer switch or some type of power management device to isolate the inverter output from shore power and to only provide power to the loads you specify.

There's a lot to learn to put together a safe and reliable system like you're describing. You may want to discuss it with some local dealers who have done it for other owners.

DC Wettstein:
I have purchased and done most of the install you are talking about. I have just not installed the solar panel.

As per Dan's reply just leave your converter alone. Hopefully you have the Progressive 9260 which is a VERY good device for maintaining batteries at their tip top.

The big question is: Do you have the "generator prep" option? If you have a large shroud of metal in your front storage compartment, you have this. Included in the generator prep is a power source transfer relay in the crawl area usually near the converter. I had such a prep package, removed the shroud to make more battery storage area, mounted my 1500 watt pure sine wave inverter on the vertical wall next to the batteries ( have 3 extra), with remote turn-on wiring going to the kitchen control panel. The output of the inverter feeds into the transfer switch and activates the transfer relay. An important thing to remember when using inverter power (energy supplied by the batteries) is to turn off the AC breaker for the converter. Otherwise you are using battery power to try to charge the batteries through the converter. Since nothing is 100% efficient, you are just wasting battery energy. Be sure to turn the converter breaker back on when on shore power.

I am in a rush this morning, so PM me for more info.

Another more expensive option is an inverter / charger like the Magnum MS series. It serves as both inverter and battery charger and passes shore power through with it's own internal transfer switch while it charges the battery(s) when hooked up to shore power.

Yes. The ME is a Modified Sin Wave vs Pure Sin Wave. PSW is the best but also more expensive. It is still a high quality inverter / charger with a very high efficiency rating. You just need to make sure that everything you want to run is capable of running on MSW.

My inverter is from E-Bay something like this (at a similar price): http://www.ebay.com/itm/1500W-Pure-...233?pt=LH_DefaultDomain_0&hash=item337757c289

Couple of thoughts:

- Standard solar panels output up to 19 volts in full sun and you need a solar charge controller to sense when batteries are charged to shut off the current from the solar panels, to prevent over-charging causing batteries to lose water and require constant maintenance. Each 80 watt solar panel can produce about 45 amp-hours of charge a day best case with full sun all day, typical case you can expect somewhat less given sun angle vs. panel, clouds, etc. Solar panels will still output well over 12 volts even without full sun so even with some clouds you still can get some charge out of the panels.

- If you want to run microwave get at least a 1250 watt modified sine wave converter. If you have a microwave / convection oven combo don't try to run in convection mode off the inverter! Convection mode uses way to much power!

- If you have 200 Amp-Hours of 12 volt storage batteries, then the usable capacity for running the inverter will be about half of that due to the inverter's automatic low voltage shutdown feature. This goes fast if using the AC for heavy loads like coffee maker or microwave oven. For example making a pot of coffee will use about 12 Amp-hours. Microwave for 10 minutes will also use about 12 Amp-hours.

- Put your large inverter near your batteries the shorter the large gauge cables between the batteries and the inverter 12 volt lugs the better.

- Make sure you don't obstruct the cooling fins, air inlets and fan exhausts, When producing 1200 watts the unit will be generating about 200 watts of heat assuming the unit is 85% efficient at converting DC to AC.

- Use the right size very large gauge cables between batteries and inverters, and put a fuse or fusible link in series with the B+ line. When inverter is driving a 1200 watt AC load it will be drawing 100 Amps DC from the batteries. At least #2 for VERY short runs of less than 10 feet. 1/0 is better.

- Inverter will have standard 120 volt 3 prong outlets unless you buy a huge one. Suggest you plug your shore cable into the inverter when dry camping using a standard adapter.

-- If you power from inverter via the shore cable route, then switch off the AC breaker to your AC to DC converter while in this mode. This will prevent you from drawing the AC being output from the Inverter into the Converter.

- Many inverters have a on/off switch and you will have a slight DC drain of 0.1 to 0.2 Amps even without AC load with the inverter switch in the ON position. If you move it to the OFF position this is stopped.

- To make it neat to plug your shore cable into the inverter with the access door to basement closed, you can mount a Electrical Cable Hatch like this:
http://www.campingworld.com/shopping/item/electrical-cable-hatch-white/66682