24V Inverter

[luvrbus]

Here throw this word into mix I found in my old Trace manual  "sinusoid curve" my old Trace's were micro chip from the 90's  

[bobofthenorth]

At some point we're arguing how many angels can dance on the head of a pin Clifford.  A rotating field has to make a sine output - that's the ultimate "pure" sine wave or "sinusoidal curve".  The way inverter technology was explained to me is its the electrical equivalent of slamming shut a gate valve which causes the water pressure to momentarily spike up.  If you slam enough silicon switches closed you can turn 12 volts into 120 volts and presumably do it in reverse to get a wave that reverses with respect to ground.  Like I said - my understanding is paper thin but in concept I can understand it.  The concept of gates closing also helps me understand how the resulting wave form inevitably is a series of little square jumps.  In the same way a computer image is pixelated if you enlarge it sufficiently, if you look at an inverter output at sufficient resolution you will inevitably see those little square forms.  Its just if you pay more for the inverter then you have to look a lot harder to see the squares, as I understand it anyway.  Brian's post made me think there may be some radically different technology that overcomes this limitation but like I said, my understanding is paper thin.

[luvrbus]

Dick Wright tried to explain it to me for a hour one time when I was wanting to buy new true sine at the end of the conversation he told me not to replace the old Traces I couldn't better myself with new ones only the load sharing would be a improvement   

[bobofthenorth]

That's how I see it.  For $2500 I could have load sharing but that's the only change it would make as far as I can tell from my 25+ year old Heart Freedoms.  So for $2500 I can manage the power myownself. 

We're sitting at 50.5 degrees of Latitude with fridge, freezer and 3 computers running.  Even with that load we're getting enough sun to more or less hold even at mid day.  Gotta love that when it happens because it doesn't happen very often on the we(s)t coast.  And a view to die for.

[Dave5Cs]

As usual I have made my point clear as mud, corrrect me again, IF your batteries are at 14.2 or 13.8 the PS Wave or MS Wave will make it's cleanest wave (HZ), PS making 60 hz.
NOW when the batteries are no longer at 13.8 and become say..11.8 or 12.2...what quality of wave is your output ? It is not 60 hz ... or is it ?
Trace says it is not ... if i read it correctly.
your battery state of charge SOC, depletes on a daily basis in a coach with say a 4 8d bank..... now a 12 8d bank may not, but who has that.

I am all in favor of the point of use PS wave inverters.  just may not be practical for 1500 watt loads...

PS I read the Lithium test as a fail. as in lithium $$'s for watts are not the best way to spend your money.

Eagle if your batteries are at 11.8 or even 12.2 they are dead and you let them get to low. 12 volt is only said because it was easier by the designer to call it that. And at that SOC and fully being Depleted there would be no HZ 60 or 57. So whats the point to keep bringing it up?

[Iceni John]

I think, at least for short term solution, the idea of a couple small inverters might be a nice idea.  Charging can be done with a nice 24V smart charger when on pole or generator power.  The Modified Wave unit can continue to provide power to the fridge and a few misc items.  Then I could have a small Pure Wave unit for my computer, and another small pure wave unit for my AC (remember my AC pulls much less than most of you). 
My gray matter is churning a bit.....

That will be essentially my approach.   There'll be a 2,000W sinewave inverter for occasional loads such as tools/microwave/hair dryer/etc, only turned on when needed, and a smaller sinewave only for the fridger which will remain on 24/7.   With a MTBF of more than 21 years, I'll probably get a small Exeltech for the fridger.   The emergencies-only charger will probably be a Cotek CX1280  -  there's very few 80A or larger chargers with good (>0.9) Power Factors.   Iotas and other similar ones with only 0.66 PF and huge inrush surges are out of the question for me.   Having two inverters also gives me redundancy  -  I like having backups wherever possible (I have two banks of PV panels, two charge controllers, two banks of house batteries, two Schottky isolators  -  always have a plan B!).

John

[bobofthenorth]

Eagle if your batteries are at 11.8 or even 12.2 they are dead and you let them get to low. 12 volt is only said because it was easier by the designer to call it that. And at that SOC and fully being Depleted there would be no HZ 60 or 57. So whats the point to keep bringing it up?

Its not that simple.  If you put a 2000 watt load on a "normal" battery bank, even one that's right full, it will absolutely pull down to well below 12 volts - maybe 11.8 or even 11.5.  That doesn't mean the batteries are "dead" - it just means you're putting them to work the way they were intended to.  You're talking about resting voltages but that's not what the inverter sees when its working.

[bevans6]

I put a volt meter on my truck, so I could monitor the voltage of the charging system.  I about shat myself the first time I started it after - when the glow plugs are on they draw enough current (around 180 amps for around 2 minutes, normally) to pull the voltage of the batteries down to 11.2 volts.  Now, these were brand new, 900 CCA Johnson Controls batteries, two of them in parallel.  11.2 volts, and when it starts and the alternator kicks in it goes all the way up to maybe 12 volts, and jumps to 14 when the glow plugs turn off.  Bloody straight a big load pulls the voltage down, and that is indeed exactly what batteries are designed for.

Brian

[bobofthenorth]

Anybody who is even half serious about living on batteries needs a good battery monitor and I don't mean the POS flashing LEDs that come on the control panels.  We had a Trimetric 2025 in the bus and I put one in the boat as soon as we bought it.  Until you've actually spent some time watching what happens nobody should comment or give advice.  Not that I'm some big expert either but we do spend at least 6 months of the year living on a combination of solar, generator and big alternator power.  You pretty quickly learn how it works if you don't want to listen to the generator rumble all your waking hours.

[Dave5Cs]

Bob, Brian I know that, I just didn't want to get into a discussion with Donald about what Wave is best or whatnot. He is just looking to prove someone wrong. He has done it from the start of this thread and doesn't have a dog in this hunt.
I was only originally telling Dave about what inverter I had and why I like it. The final decision is Dave's to what he wants to put out and needs. This is what works for me. I am not an electrical expert or Guru of any kind. If it wasn't for Brian and Jon I probably wouldn't have ever got this thing hooked up. So have fun talking about the wonders of Pure Sine waves or Modified. I don't really care.
Hope some of this helped Dave to give you an idea what you need.

Dave5Cs

[eagle19952]

Bob, Brian I know that, I just didn't want to get into a discussion with Donald about what Wave is best or whatnot. He is just looking to prove someone wrong. He has done it from the start of this thread and doesn't have a dog in this hunt.
I was only originally telling Dave about what inverter I had and why I like it. The final decision is Dave's to what he wants to put out and needs. This is what works for me. I am not an electrical expert or Guru of any kind. If it wasn't for Brian and Jon I probably wouldn't have ever got this thing hooked up. So have fun talking about the wonders of Pure Sine waves or Modified. I don't really care.
Hope some of this helped Dave to give you an idea what you need.

Dave5Cs

No he's not trying to win anything   , and I think you read something into it that only justifies your decision... If you didn't care why are you responding.
The point is also that many inverters have a set point at which it shuts it self off because it no longer sees a sufficient battery voltage to produce AC current, that safety set point is based on the remaining battery voltage, (the numbers I used are as arbitrary as your notation of "12v because it was easier by the designer to call it that" .... At some point in the discharge of the battery to the shut off point you are losing something...it must be either an AC voltage drop or cycles/sine wave form.

If my batteries are at 11.8...they aren't dead ....they need charged.
They're dead when they won't hold a charge...
As has been said by others in this thread, not every pure sine wave inverter is as good as all others and some modified sine waves are better than some pure sine waves no matter what the salesman tells you...the proof is in the pudding.

Dave...think what you want, your wrong about me my goal is to inform and learn.

PS none of this means a Magnum Hybrid is not a good choice, it simply means that the most expensive fancy optioned choice is not always the best choice when $'s in for watts out is the desire.

[Dave5Cs]

Don you just proved my point thank you!...

[eagle19952]

Don you just proved my point thank you!...

Whatever.

Two of these will make coffee and meet a host of needs. Xantrex PROwatt SW 600, Pure Sine Wave Inverter @ $129.00

http://www.donrowe.com/Xantrex-806-1206-PROwatt-SW-600-p/806-1206.htm

[belfert]

The advantages of a large inverter like a Magnum MS4024 that powers most or all of the outlets in a bus is that things just work.  You don't have to remember which outlets go to which inverter, or which outlets even have inverter power.  The batteries will automatically charge when you have power.

You can go totally manual with everything and save money.  If you and everyone else who uses your bus can make it work then no problem.  It will be a little bit of a pain to get everyone to remember which outlets are live on inverter and what loads the inverter can handle at first.

Personally, I have a big sine wave inverter to make things easy, but I don't have any issue with anyone who wants to save money on this part of their bus as long as it is safe.

[niles500]

Truth is there is NO SUCH THING as a true Sine Wave inverter, only Simulated Sine Wave, due to a "shorter" frequency and duration of square waves, True Sine Wave only comes from the Source {read=generator} - FWIW