On to Inverters...

[BradKW]

So I needed a break from learning how to read wiring diagrams...what I really need is colorful pictures with thought bubbles, like "Hi, I'm a Shunt and this is what I do and why I'm sitting here!" 

Moving on to inverters, I once again find that what I thought I knew is insufficient. Perhaps my biggest surprise is just how expensive some of them are...I had no idea you could drop $2 grand+ on one.

I know that I want a pure sine, because charging cordless tools is important and I've read enough times how sensitive they can be to believe it must be fairly valid. Also will power a PC.

So here's some basic questions I have that don't seem to be addressed in product specs, probably because they are too basic:

1) How do you tell if an inverter is made to get wired directly to batteries? I've had little ones before that plug into vehicle AC outlets.

2) Can inverters be powered both by battery and by vehicle? Is this a manual "switchover"?

3) If powered by vehicle AC, will I need to run wires to the a) battery, b) alternator or c) AC outlet?

4) I want to run a microwave...what do I need to look for? peak wats? volts? I read a review of a 1000v inverter that said "it won't even run a microwave"...how do I process this?

5) If an inverter is powered by vehicle, what limits output...just the inverter, or alternator? for example, could I run a Ecosmart50 instant water heater from vehicle powered inverter, or do large draw appliances introduce limitation beyond just a "big enough" inverter?

oh, and how do I tell if an inverter can be wired to a panel, and not just use the # plugs it comes with?

Replies and links to education reading appreciated!  

 

[Reverse Engineer]

So I needed a break from learning how to read wiring diagrams...what I really need is colorful pictures with thought bubbles, like "Hi, I'm a Shunt and this is what I do and why I'm sitting here!" 

Moving on to inverters, I once again find that what I thought I knew is insufficient. Perhaps my biggest surprise is just how expensive some of them are...I had no idea you could drop $2 grand+ on one.

I know that I want a pure sine, because charging cordless tools is important and I've read enough times how sensitive they can be to believe it must be fairly valid. Also will power a PC.

So here's some basic questions I have that don't seem to be addressed in product specs, probably because they are too basic:

1) How do you tell if an inverter is made to get wired directly to batteries? I've had little ones before that plug into vehicle AC outlets.

2) Can inverters be powered both by battery and by vehicle? Is this a manual "switchover"?

3) If powered by vehicle AC, will I need to run wires to the a) battery, b) alternator or c) AC outlet?

4) I want to run a microwave...what do I need to look for? peak wats? volts? I read a review of a 1000v inverter that said "it won't even run a microwave"...how do I process this?

5) If an inverter is powered by vehicle, what limits output...just the inverter, or alternator? for example, could I run a Ecosmart50 instant water heater from vehicle powered inverter, or do large draw appliances introduce limitation beyond just a "big enough" inverter?

Replies and links to education reading appreciated!  

The argument between Pure Sine Wave and Modified Sine Wave (actually Square Wave) inverters is constant.

Based on my experience, for most purposes the Modified Sine Wave inverters work just fine.  You mostly convert to DC anyhow through AC/DC Transformers, and they work fine with SW Inverters.  I can charge up anything, power tools, my laptop, my E-wheelz, whatevah using such inverters.  They are half the price or less of a true sine wave inverter, especially at the higher wattages.

You do want to match the inverter size to your load though.  I have inverters in several Wattages, going from 75W (cig lighter size) just enough for my Laptop, up to 1000W which can run a low power Microwave but I suggest not doing that.  Big power hog, and you can usually use microwaves in convenience stores and truckstops.

You want to match the Inverter to the load, because the bigger the inverter, the more power gets wasted as heat.  Really big inverters need a cooling fan, that wastes still more power, and it is something else that will fail eventually.

I collected my inverters over many years, so not entirely sure what the prices are for each now.  I have one 75W, one 200W, one 500W and one 1000W.  Last 2 need to be clipped to the batt directly, you can't use them with a cig lighter DC outlet.  Total spent when I bought them, about $300.  All SW Inverters, no pure sine wave.  Run my laptop, charge my portables, charge power tools, no problem.

 

[Optimistic Paranoid]

You keep talking about vehicle AC, and I'm not sure what the heck you are talking about.  An RV with ac outlets for shore power?

Anything larger than a small inverter will not have a cigarette plug on it.  it will have a couple of terminals to hook positive and negative wires to it.  The owners manual will suggest tell you what size wires to use, and will also suggest the size of the fuse that needs to go on the positive side.

It doesn't matter, electrically, if you hook up to the alternator or the battery.  They are tied together, and if the inverter needs more power than the alternator can provide, the extra power will automatically be pulled from the battery.  PHYSICALLY, it's usually far easier to hook the inverter to the battery.  Plus, there's nowhere on the alternator to put the negative wire, so that has to go to the battery, anyway.

If the inverter has nothing but an ac outlet on it, it is not possible to hook it up to the RV's ac electrical system.  The inverters capable of doing that have terminals for 3 wire ac electrical cords to be attached.  Usually, it's wired to a crossover switch, which is also wired to the shore power inlet and a generator.  The switch allows only ONE energy source to provide power to your system.

http://www.sterling-power-usa.com/m...rsourcesareusedsuchasinvertersshorepower.aspx

Regards
John

PS:  download an operator's manual or two for some of the inverters and read through them.  The one for the Morningstar SureSine is good, as are the ones for the Samlex PureSine inverters.  The Morningstar one even tells you WHICH brands and model numbers of GFCI outlets are compatible with their inverter.

 

[LeeRevell]

The wattage rating of a microwave is it's heat output for cooking.  A 1,000W microwave will take approx. 1,200 to 1,500 watts input.  You can find smaller microwaves around 700W cooking power which will need about 1,000W input.  So this gives an idea of needed inverter power.
There are youtube videos of folks powering microwaves with both MSW and PSW inverters, showing why PSW is really needed.

 

[Optimistic Paranoid]

Run my laptop, charge my portables, charge power tools, no problem.

I've seen lots of posts from people who say that they recharge power tool with MSW inverters with no problem, and I've seen lots of posts from people who say that MSW inverters FRIED their charger and battery. Apparently, some are ok with it and some aren't.  I've seen the same thing with microwaves.

Regards
John

 

[BradKW]

The inverters capable of doing that have terminals for 3 wire ac electrical cords to be attached.  Usually, it's wired to a crossover switch, which is also wired to the shore power inlet and a generator.  The switch allows only ONE energy source to provide power to your system.

Thanks...I don't why I call it AC, just mean power source is vehicle.


So I see many inverter/charger combos. Would I be correct in assuming that any with this combo could be switched from solar batteries to vehicle alt/battery as power source? And if receiving power from the vehicle, it will somehow know to charge solar batteries?


Or maybe the better question would be: under what circumstances is the inverter/charger combo desirable, and when is it better to just skip the charger option? 
tyty

 

[GotSmart]

I've seen lots of posts from people who say that they recharge power tool with MSW inverters with no problem, and I've seen lots of posts from people who say that MSW inverters FRIED their charger and battery. Apparently, some are ok with it and some aren't.  I've seen the same thing with microwaves.

Regards
John

I have an OLD 200W power Star I found at a yard sale. This is so old there in not a internet reference to it!  

I have charged batteries, run the laptop, and even a powersaw.

 

[Optimistic Paranoid]

Some of the larger units have a the inverter combined with a converter, and the crossover switch is built in, and automatic.  When you are plugged in to shore power, the converter charges your house batteries and provides 12 volt power to the lights, water pump, etc.  When you are NOT plugged in to shore power, the inverter part provides AC power to certain outlets, like the microwave.  The fancier rigs include the built in generator in the crossover set up.  When you start the generator, shore power is disabled, even if you are plugged in. 

The pros are that it's all designed to be idiot proof, and to keep all the functions in as small a package as possible.

The cons are that it's expensive, and if one part or the other fails, the whole unit is usually non-functional, whereas with separate inverters and converters, if one fails, the other goes on working.

Regards
John

 

[Sabatical]

BradKW are you putting this setup in a van/car or in a camper?
In our last travel trailer we had a 1000w psw inverter. I plugged the shore power plug into the receptacle on the inverter and powered the tt's receptacles that way. I didn't necessarily think a psw inverter was needed but that's what we had. It is a go-power unit with a retail of $330. In our "new" travel trailer i am installing a 1000w bestek msw inverter in the same fashion. It was $90.
I have read where some folks got a fault light on thier inverter when doing what we do, but i believe the difference is that i disconnected the tt's converter. I'm not knowledgable enough to say for sure that this is why it works for me. Just a guess.
If you are installing your inverter in a vehicle and want to power a microwave, you may find you don't have the juice to start the vehicle later. If you are also installing "house" batteries then it would be a good idea to seperate the two systems with a relay and install a fuse in your positive wire to the house batteries.

 

[Sabatical]

...another thought Brad is that you may want to look for an inverter with external fuses once you figure out what size you need. The less expensive ones have internal fuses which you may not be able to replace should something go wrong. For a few bucks more you would have the option to replace fuses instead of replacing the inverter.

 

[Optimistic Paranoid]

BTW, you HAVE read Handy Bob's rant on inverters, right?

https://handybobsolar.wordpress.com/inverter-issues-spring-2013/

Regards
John

 

[Sabatical]

BTW, you HAVE read Handy Bob's rant on inverters, right?

https://handybobsolar.wordpress.com/inverter-issues-spring-2013/

Regards
John

If you were asking me if i've read it, the answer is yes. I read and reread handybob's blog and still didn't know what i needed. I didn't get any closer to figuring it out until after we started living with solar and batteries. Heck, i'm still figuring it out and learning more daily, but we are doing it and it isn't painful at all. Our inverter did shut down at the top of the absorb phase of charging (when it was installed in that manner) but that doesn't last very long and isn't an inconvenience for us. We don't use much a/c power and typically it's in the morning or evening when absorb voltage isn't a factor. It worked for me is all i was saying. What anybody else does is fine by me. I guess what i would suggest is find something that works, even if it isn't perfect, so you can get on with living more simply. So often we get tied up with trying to find the perfect setup and we delay moving ahead with the simple living plan. There's more than one way to get the job done.
When searching for an inverter to install in the new tt i looked for one that was labeled for a/c distribution. I couldn't afford the options I found and they were way more watts than i need. I am more concerned with power consumption when the inverter is turned on. Larger inverters and psw inverters want more power to do the job. It doesn't take that many watts to satisfy our needs.
This is all just my experience and oppinion so take it for what it's worth.

 

[Sabatical]

Neither one of these two inverters care for high end absorb voltage. Look for one with and input range greater than your absorb voltage if it is a concern for you. The little guy (400w) runs the dog's radio fence and the on demand water heater. The big guy (1000w) runs the kitchen aid or food processor. If in absorb and they shut off, we wait a bit.

 

[GotSmart]

Neither one of these two inverters care for high end absorb voltage. Look for one with and input range greater than your absorb voltage if it is a concern for you. The little guy (400w) runs the dog's radio fence and the on demand water heater. The big guy (1000w) runs the kitchen aid or food processor. If in absorb and they shut off, we wait a bit.

Electric fence, food processor.   :huh:

I need more panels!

 

[Sabatical]

Electric fence, food processor.   :huh:

I need more panels!

We ran this stuff in the camper with 450ah of battery and never went below 90% soc. In the tiny house the bank has grown to 675ah but we added the water heater and Grape Solar 5cf 12v fridge. We have 840w of solar. This time of year, with many gray days, i'm thinking another panel would be nice, although we still aren't really taxing the batteries. I would like to see 100% daily but i'm coming to realize that it isn't really necessary as long as we don't go below 50% and see a full charge every few days. Maybe next year we'll be able to add more solar.

 

[Sabatical]

...btw i like your inverter. I grew up right down the road from Cupertino...and made in Scotland? That's almost like made in America these days.

 

[GotSmart]

...btw i like your inverter. I grew up right down the road from Cupertino...and made in Scotland? That's almost like made in America these days.

I bought a tool box for $5 to get the picklefork inside.  That was deeper along with a lot of other goodies.  

I am from Calistoga myself.  I spent a lot of time working in the Bay Area.  

I have about 450 AH of batteries with only one 100W panel.  Not much draw at this time.  I had an exceptional buy on batteries, and went for them.  The first 6 months was entirely recharged by the Alternator.  Soon comes the 12V freezer, then I can justify another panel.

 

[Sabatical]

I bought a tool box for $5 to get the picklefork inside.  That was deeper along with a lot of other goodies.  

I am from Calistoga myself.  I spent a lot of time working in the Bay Area.  

I have about 450 AH of batteries with only one 100W panel.  Not much draw at this time.  I had an exceptional buy on batteries, and went for them.  The first 6 months was entirely recharged by the Alternator.  Soon comes the 12V freezer, then I can justify another panel.

Great find for $5.

I grew up in San Jose. The USAF relocated me and i married a local gal so stayed put in NY. Thankfully she's got the travelling bug too along with a serious dislike for winter weather.

We got bigger panels because we bought from a local residential distributor. Shipping cost on panels made it an easy decision.

 

[BradKW]

Neither one of these two inverters care for high end absorb voltage. Look for one with and input range greater than your absorb voltage if it is a concern for you. The little guy (400w) runs the dog's radio fence and the on demand water heater. The big guy (1000w) runs the kitchen aid or food processor. If in absorb and they shut off, we wait a bit.

I will be using it in a van conversion, and I'd really like to hear more about your on-demand heater powered by a solar setup. I was beginning to think the only realistic options were propane or a slow heating element, that instant hot water with electric was just too big a demand for a battery bank.

I saw a very expensive Sprinter build where the guy added a 2nd heavy duty alternator, and I always wondered why. I guess this might be one way to actually turn your van engine into more of a generator...?

 

[Sabatical]

I will be using it in a van conversion, and I'd really like to hear more about your on-demand heater powered by a solar setup. I was beginning to think the only realistic options were propane or a slow heating element, that instant hot water with electric was just too big a demand for a battery bank.

I saw a very expensive Sprinter build where the guy added a 2nd heavy duty alternator, and I always wondered why. I guess this might be one way to actually turn your van engine into more of a generator...?

I'm afraid my post was a bit misleading Brad. The on demand is controlled by 120v but heats using propane. I saw that many folks liked the Eccotemp units so i found one of thiers that is good for indoor mounting. It works well if the gpms are right. It was $279. If you use propane then maybe one of thier smaller units (outdoor model) would work for you.
When we are on the road we use a garden sprayer covered in black spray paint. It sits in the sun all day and we shower after dinner. If it's a gloomy day, a teapot of boiling water added to it works well. It's a super cheap alternative and works pretty well IMO.