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Inverter/UPS/Hybrid standby power use
#1
Have been looking at a few UPS/inverters and one of the interesting elements is the parasitic load (the load the inverter uses even if these is nothing connected to it). With a limited energy supply the choice of inverter can get interesting as to which one to use, at the moment I have a 2200VA UPS switched on 24x7 but I am realising that this is not going to work in winter (or when I don't have a surplus of power) because the UPS unit on it's own uses around 75W, which is nearly 2kWh per day or nearly half of my 24x7 equipment.

With this in mind, I'm trying to find an option that will work and has minimal wasted energy. My smaller 24V Belkin unit is very good, but limited load so wondering what route / inverter, ideally 48V...

This is my list so far... will update it

Make       Volt   Model            Rated VA  Rated W      No Load use
APC        48V    Tower 2nd Gen    2200VA    1980W        75W (approximate)
APC        48V    1U rack 3rd Gen  2200VA    1980W        60W (approximate)
Belkin     24V    ?? 2000's        650VA     350W ?       5W (approximate)

MGE        72V    ?? old           3000VA                 80W (approximate)
Eaton      36V    Evolution 1550   1550VA    1100W        20W (need to measure again)

The limited power location is a 20ft container with solar on top and a small wind turbine closeby, so every watt counts...
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#2
I love the grid charging f a UPS but I also hate the Low Load losses. One thing I have noticed is that once you hit that magic 75W of Load the losses diminish greatly. So if you have a constant load of at least 50W the APC will be just fine but when zero usage it sucks. For my setup if I cannot find a good Low Loss UPS I will be forced to go the route of an inverter and separate charging system
******Hi My name is Jason and I have SOCD (Solar Obsessive Compulsive Disorder)*******
Current Powerwall - 1400 Cells 7s200p (modular 40p packs) ~ 12kWh of storage     4x 315W Canadian Solar Panels

Working on the next 7s40p packs     ~2.5kWh

Waiting on 2000 Cells of unused Sony vt4 (2000mah 30A) ~ 15kWh      hehehehehe  More Power
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#3
The lower power non server grade UPS units seem to have lower losses. The Belkin unit I have is great, but it is limited to 300W or so (will check on my next trip) and have thought about using multiple units. Tempted to buy a used non server 1500VA sized UPS but they seem a little more rare (at a siensible price).
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#4
I gotta check the 500VA APC I have here and the 1500VA triplite 36V to see how they are
******Hi My name is Jason and I have SOCD (Solar Obsessive Compulsive Disorder)*******
Current Powerwall - 1400 Cells 7s200p (modular 40p packs) ~ 12kWh of storage     4x 315W Canadian Solar Panels

Working on the next 7s40p packs     ~2.5kWh

Waiting on 2000 Cells of unused Sony vt4 (2000mah 30A) ~ 15kWh      hehehehehe  More Power
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#5
Schneider SW4048 Inverter/Charger
Self consumption : 27 Watts
Source : http://www.backwoodssolar.com/schneider-...0v-240v-ac

Interesting bit : "Stacking two units together doubles the inverting and battery charging capacity; BUT surge capacity is NOT doubled when stacking this inverter."
Do the other PIP units have stacked/parallel surge capacity greater than a single unit ?

Power Star IR3048C 3000W : 56.7V 1.6A = 90W standby !!!
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#6
Reading through a very long thread on another forum (only part way through 138 pages...) the higher standby load on some inverters is there by design.... The reason is so that the transformer when coupled with a smaller capacitor then also acts as a line filter to smooth out the primary input switching from the MOSFET's. Plus, having a badly selected transformer does not help if the voltage is saturating the transformer and creating additional magnetic losses....

Inverters with toroidal transformers will also have far lower standby losses.
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#7
I’ll try and test what I have sitting around for your list… I have a couple of those older black pure sine APC Smart-UPS 1000VA and 1500VA units and I was a bit curious myself.

I have a <300 watt load project for my office computer and networking gear, but after reading this thread, I might be better off just getting a small Victron inverter for $120-130 bucks.

I’m going to end up paying for it one way or another… either efficiency or have to add more capacity just for a high idle load.
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#8
I'm now looking at toroidal transformers as a modification option.

Just switched off the inverter (IR3048C) after it had been on for about 4 hours (forgot to switch it off after seeing it it would run the 3ph circular saw with a soft starter and it does!) and the unit was warm... reading 55C, on idle, nothing plugged in... I'm now having second thoughts on which inverters to use or to make sure I switch them on/off only when I need them. Unless I'm cold and need the heat Tongue
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#9
(09-04-2018, 09:34 PM)completelycharged Wrote: Reading through a very long thread on another forum (only part way through 138 pages...) the higher standby load on some inverters is there by design.... The reason is so that the transformer when coupled with a smaller capacitor then also acts as a line filter to smooth out the primary input switching from the MOSFET's. Plus, having a badly selected transformer does not help if the voltage is saturating the transformer and creating additional magnetic losses....

Inverters with toroidal transformers will also have far lower standby losses.
Hi i'm new in this forum, reading your posts i'm wondering and i have a question, how to wire a  1 secundary and 1 primay toroidal transformer 230v to a Apc with the same characteristcs, i'm asking if is possible replace the 2 APC's  original transformers have 4 wires, with a normal torroidal transformer. Thank you in advance.
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#10
Your toroidal transformer would need 2x primary windings to work the same as the APC's original one.
This is due to the APC's circuit design which will have two halfs.
Check the APC circuit, it will join the two primary windings in series, with the centre tap connected to battery +ve.

Maybe try to find the right transformer with 2x primary + 1x secondary.

You might be able to add you own new 2x primary windings as not too many turns are needed, maybe only approx 10.
To be sure, try to (carefully!) measure the turns ratio of the APC original transformer, eg from one primary to the secondary.

Note that toroidal transformers saturate much more easily than the E-I core type because there is less air gap.
Running off solar, DIY & electronics fan :-)
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