Modified Sine Inverters??

[cody]

John, I got it from trina at RV Surplus in elkhart.

[Sean]

I have purchased one of these with the intention to buy more, I have not used it yet so I can't give any feedback but what is your opinion of these kind of inverters.  I hope I will not be sorry to have asked this question but here is the ebay location of one of these inverters.  They also sell those that have 240A output that can be ganged I believe.

http://cgi.ebay.com/STACKABLE-POWER-INVERTER-2500-5000-W-12V-DC-TO-120V-AC_W0QQitemZ390127064133QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item5ad5629445

Careful.  These units can not be safely (or legally) "stacked" as shown/advertised in this listing.

In order to "stack" inverter outputs, they MUST be hard-wire connections through a listed J-box.  You can't use simple 5-15P plugs such as this unit is designed for.

Also, I don't see any listings or regulatory approvals on these.

It's not worth risking your life or the life of your loved ones for the few bucks you will save using something like this.

FWIW.

-Sean
http://OurOdyssey.BlogSpot.com

p.s. Happy Boxing Day.

[Gary LaBombard]

Now you guys got my butt real nervous.  I only have one now and maybe perhaps should wait to order any more.  I think I will try this one on a few appliances outside of the bus when the weather clears up just to give a test.  I do not have the unit in front of me to see if it was UA approved either.  Will check tomorrow.

I know it is real heavy if that means anything.  I have to respect Sean's input as well as the rest of you guys, it is a cheap price to find out if it works or not to invest $200 before installing in our bus but I will not invest any more if it should fail during testing.

As far as battery charger, I did not plan to use 120v lights etc. all the time.  I planned to be at campsites mostly with hookups and depend upon the battery for power source only occasionally and use the Generator to recharge the batteries on a daily use as the 120 appliances were used with battery power when we had to.  Hope this made sense when you read.  At this time I am not really sure just how much batter power I will really need for our use.  

Thanks for the input and advise, I will let you know if I should find out on my end what also happens.  

Gary

[JohnEd]

Gary,

The words were "I don't see any", not it isn't and none of the European stuff is UL approved unless they intend to sell stateside.

"Careful" isn't the same as DANGER.  Be careful no matter what you are doing.

The drawing is only that: a representation of the electrical hook up.  Instead of using a "J" box I would suggest running the output of each inverter to a breaker box and use the breakers to switch the inverters into the ganged position. Like in my 73 Winniebago.  Better still, I would create different circuits for each inverter and not stack them.

Safety:  Never install a inverter in the battery bay.  Never snuggle anything that might possibly catch fire right up next to the wood floor....duh.  Not that you wood(?).  Inverters get connected to circuits carrying hundreds of amps.  All of them do.  No matter who makes it or what approval it might have, don't mount the thing under your bed and I don't have even the slightest hunch you needed my warning to not do that.  By all means test it but don't get driven to paranoia.

I steal luv ya and otters do also.

John

[luvrbus]

I read ever so often here never mount a inverter in the same location as batteries could someone explain to me why not. 



good luck

[Sean]

... none of the European stuff is UL approved unless they intend to sell stateside.

To use it in your bus, it must be "listed."  UL is only one of many recognized listing agencies; some recognized agencies are, in fact, European (for example, TUV).

I see no listings at all on these.

"Careful" isn't the same as DANGER.

Well, OK.  I meant "danger" -- just to be clear.

The drawing is only that: a representation of the electrical hook up.  Instead of using a "J" box I would suggest running the output of each inverter to a breaker box and use the breakers to switch the inverters into the ganged position.

That's still unsafe (and illegal).  You simply can't stack units that have only receptacles for outputs -- they MUST have a hard-wire provision.  Period and end of story.

Better still, I would create different circuits for each inverter and not stack them.

Well, OK, that would be fine.  But then what's the point of paying extra for the "stacking" capability, complete with stacking cables?  You'd be limited to 15 amps max on either of two "circuits," and 2,500 watts total.  Moreover, with this type of unit, you would have to install it at the point of use -- you can't hard-wire to a plug-and-cord connection -- and so to use more than two different appliances on the inverter, you'd constantly be switching plugs.

These type of temporary-use, integral-outlet inverters are not made for the type of permanent installation most of us contemplate in a conversion.

Personally, I distrust any eBay (or other) seller who would even suggest the connection method outlined on that listing -- it's incredibly dangerous.

-Sean
http://OurOdyssey.BlogSpot.com

[Sean]

I read ever so often here never mount a inverter in the same location as batteries could someone explain to me why not. 

Clifford, that proscription applies to conventional flooded and vented batteries.  The main reason is that inverters can produce sparks, and batteries produce hydrogen gas, and the combination of the two can produce an explosion.

Battery gases are also corrosive and will ultimately damage the inverter.

FWIW, my inverter is right next to my batteries, which is just one reason why I have no option but to use valve-relieved batteries; in my case, I went with AGMs.

-Sean
http://OurOdyssey.BlogSpot.com

[JohnEd]

Sean,

I am in fundamental agreement with everything you have said.....everything. 

they MUST have a hardwire provision.  Period and end of story  I can't see anything that indicates that they cannot be hard wired and even if they don't have that feature, you could easily do it.  I don't like it one thin damn that I am often left with little alternative to buying foreign made "junk".  But there it is and I didn't do this.... I have argued with people till I am blue in the face about "what is going to happen and where all this will lead".  I was way out front.....twenty years out front to be approximate.

I think Gary is going to be OK.

Clifford.....Regardless of what type bat you buy, it is critically bad design to install the inverter in the battery compartment.  In Sean's case I know he had absolutely no alternative and was pushed into that configuration.  He is that safety conscious that he must have deep and visible scars from the confrontation that led to the compromise.  You can't tell who might put whatever bats in that space somewhere down the line.  I have seen bats with the inverter mounted on top of them  but the bats were installed in a box that vented under and behind the bay and up and out the side.  Up for the hydrogen gas and down for the ox.  That a man with your talent and wealth of experience would not know this proves my point.  Take this the right way now.

John

[luvrbus]

John, I have no problem the only reason I ask was reading my Trace manuals and they say mount as close to the batteries as possible no mention of boxes also I have a place in Idaho with solar and the inverter and batteries are in the same small shed with flooded batteries.
I seen to many Marathons and other high end coaches with the inverters in the same area with flooded batteries doesn't make it right but they were there. I was just asking to be sure 




good luck

[Sean]

they MUST have a hardwire provision.  Period and end of story  I can't see anything that indicates that they cannot be hard wired and even if they don't have that feature, you could easily do it.

Well, I've looked at the photos (on the previously linked listing as well as other sites) and there is no hard-wire provision visible, nor are any icons or text that would so indicate.  Nothing in any of the promotional text would indicate this either.

As far as forcing a hard-wire configuration where none was designed, there are two problems.  First is that this will void any listing the device had to begin with, and the second is that it will also void any warranty.  The first issue makes it illegal to use, and the second issue means, in practice, most folks would not do it.

Regardless of what type bat you buy, it is critically bad design to install the inverter in the battery compartment.

FWIW, I don't agree with this statement.  One of the key and well-known and understood advantages of VRLA batteries is their ability to be installed immediately adjacent to equipment.  I feel it is perfectly acceptable design to choose VRLA batteries explicitly to facilitate these sorts of issues.

As Clifford pointed out, the cable distance from the batteries to the inverter should be as short as possible, and using VRLA batteries can be a real boon here.  It is often the case that the added expense of VRLA batteries over flooded can be justified solely on the savings from not having to separately box and vent the batteries and/or reduce cable expense.

In my case, the batteries are actually inside the living space (in the driver compartment downstairs) as well, so they had to be VRLA no matter where the inverter went.

Obviously, it is important that anyone who owns my coach after me understands not to replace the VRLA batteries with flooded ones; this will be in the documentation they receive.

Remember, AGM batteries were originally developed for and deployed in the telecommunications industry (where I have been using them for well over a decade), and they revolutionized the design of remote outside plant installations, completely eliminating external battery enclosures.  Batteries are now designed directly into the equipment racks along with everything else.

-Sean
http://OurOdyssey.BlogSpot.com

[bevans6]

http://www.varleyredtop.com/history.htm

Interesting (to some, I guess  ) link on Varley batteries, which I know from racing cars.  They were were among the first, if not the first, absorbed acid batteries developed for use in fighter aircraft in the 1950's.  A unique characteristic of absorbed acid batteries is that they can retain their charge for very long periods of time, 80% charge after two years storage comes to mind, and they are very resistant to cold temperatures, which along with their ability to be installed in any orientation made them very useful in aircraft that tended to fly upside-down a lot, and race cars which tended to come to rest upside-down a lot...

They used "fullers earth" as the absorption media up till the 1980's, so I still have a battery or two on the shelf that would have the fuller's earth inside.  No idea why I keep the old batteries, just a pack-rat.  Now Odyssey batteries are very popular in small race cars.

Again with the trivia...   

Brian

[cody]

I'm following these threads with great interest because I've got so much work yet to do on the anti-KOA before i can turn it over to the bus nut community, I also got another new catalog from northern tool that has some great wind generators in it, one that kicks out 2400 watts, super cool stuff, another thing I'm corn fused about are the different kinds of solar panels, they list 3 different kinds with different specs and prices, I want to keep the anti-KOA as far away from the grid as I can, even if it costs a little more at first, so I'm following these with interest.

[Barn Owl]

FWIW, I use a cheap inverter from Sam's Club to run a flat screen and DVD player. At night, sometimes a couple of cheep fans. So far so good. I have read here where some use a larger modified unit to run most things, and a small pure to run the picky things. A good compromise to a large expensive pure sine wave machine I think.

[Gary LaBombard]

Barnowl,
Does your inverter have a (hardwire) connections on the inverter?  do you have a photo if not how you choose to hook it up for use?  I thought of using a smaller full sine wave also for the fussy appliances, oh heck this can drive you nuts.  It is just difficult to set up and be as efficient as Sean is even though you want to be.
Gary

[JohnEd]

Clifford,

Every inverter I have handled, 4 or 5 has had the installation recommendation to "mount as close to the bat as possible".  As possible without being in the same space.....wet cells.  You can engineer around almost anything and God knows I have cut some corners but having been present when a couple bats have exploded, I follow the rules there carefully.


Never ever put a bat inside the car.  The consequences of that explosion boggle my mind.  That being said, my Beetle had the bat, wet cell, mounted under the rear seat.  My rear seat was NOT hermetically sealed....trust me.  Krauts are known for their tech savvy so I gotta ponder.  The violence of that explosion is endelled in my mind and influences my decision process.  Can't really argue with Sean's logic, however.

respectfully,

John