Inverters - are they realy off?

[sigp2101]

Generally speaking are they really turned off when done by front panel ON/OFF switch or do they still drain some power?
I know this will depend on manufacturer and a quality of unit itself. Did anyone test for this?


SIGP2101

[russ_drinkwater]

When my latronics inverter is turned off at its switch there is no current draw, same as switching off the power at a battery isolator switch.
Draw and output is zero.

[sigp2101]

When my latronics inverter is turned off at its switch there is no current draw, same as switching off the power at a battery isolator switch.
Draw and output is zero.

Thanks russ that is encouraging to know. What would be best way to verify it? Would anyone know?

[tecnodave]

Russ....I gotta disagree with that....the switch in the inverter turns off the control electronics in the inverter.......not the huge capacitors in the input section of the inverter...so there will be a bit of leakage there.....need proof? ...turn off inverter to battery breaker and put fluke in DC amps mode across breaker.....low amps range...True not a lot but there is some drain....my antique Brutuses leak maybe 25 ma or so when turned off....not idleing.....the Exceltech is the best, hardly see it.

For most inverters on systems in daily use it's not going to be a problem.

David

[zoneblue]

It so totally depends on the model. Inverters range from fair at best to pretty awful in there idle/standby/aux off draw. I measured the outback vfx here:
http://forum.solar-electric.com/discussion/comment/353799/#Comment_353799

[BioPower]

When my latronics inverter is turned off at its switch there is no current draw, same as switching off the power at a battery isolator switch.
Draw and output is zero.

If that switch cuts all DC to the inverter it will draw nothing but a lot of inverters are switched on by electronics so there will be minimal current flowing to keep the electronic switching circuit on.

[mike90045]

I would not consider capacitor leakage, if you can measure it, they are going bad.  Modern caps in modern inverters are not leaky.
So, some inverters have a standby switch, some have a main power switch.  Gotta read the manual to decide what's what.

[tecnodave]

Mike,

Only the smallest inverters have true power off switches , none of the big inverters do. None of mine do...Magna-Sine....Exeltech XP-1100....Dynamote Brutus....Xantrex ProSine...Cotek SK1500.

All the above inverters have small control electronics switches....the FET's and caps still have power
All except the Exeltech have idle mode. Most with a switch, the Magna-sine idle is done with a setting.

True cap leakage is small but it is there if you can measure it. What happens when you first hook up inverter.....try it with no breaker.......big inrush to charge caps....disconnect and monitor voltage at caps with a truly good meter, you will see the voltage sink away.
I had one that cooked when it was off for several hours after a hard workout. I'm truly hard on inverters in my service truck mobile service in remote areas. I've done in quite a few but many more power amps....David Hafler DH-500...Crown...etc.

Dave

[sigp2101]

So investing in this solution would be worthwhile?

http://www.littelfuse.com/products/dc-solenoids-and-relays/bi-stable-latching-relays/hd-series.aspx

[TomW]

Not exactly sure of the inrush current on those inverters. The input capacitors like to charge very fast so it can be enormous for some devices depending on those caps.

Anyway, it probably might work maybe?

I am not a fan of shutting down power electronics without good reason. Mainly because it seems that the shock of energizing some devices shortens their longevity. Ever notice a lot of electronic failures seem to occur on power up? Maybe just me.

Not a proven thing just from casual observation over the decades in electronics troubleshooting.

"I turned it on and it made a loud POP and smoke came out" was a common description.

Just why I would not power cycle power electronics unless it really needs it.

Just from here.

Tom

[sigp2101]

Just trying to hunt down to eliminate all phantom draws on my solar system. I would rather disconnect my inverters than leave them on for days and weeks at the time.

[russ_drinkwater]

Ur, I have tested my latronics with it switched off (at circuit breaker and unit) and it does not run anything and can not draw any current to charge capacitors or the like. Excuse my ignorance as I am not an electronics tech.

[CDN-VT]

Just trying to hunt down to eliminate all phantom draws on my solar system. I would rather disconnect my inverters than leave them on for days and weeks at the time.

I have a breaker on all power feeds to loads .
Take a DVM of quality / fluke / Pico is what I use .
from line breaker terminal to inverter of the internal switched type ONLY & it's OFF , have the switch off & then the other lead from the DVM to the load terminal of the breaker , have in amps of 10 to begin , and if you want to swap into MA or change wires on the DVM , turm breaker back on , swap to Amp Ma & then turn off breaker .
READ the draw !

VT

HTMS

[clockmanFrance]

From the OzInverter Book.

Regards start up surge.......

Oztules comments….   Caps........  “We have 60000uf@50v to charge, I think .5*(e^2 x C) or about 75 joules

If we look at that as a joule is a watt second, thats 75w for 1 second... imagine that as a one hundredth of a second.... suddenly we are generating 7500 watts... at one thousandth it is getting out of hand at 75000 watts or 75 kilowatts.... in the hundredths scenario we are in the 7500/50 or 150 amps.....
I know from tests it is very very much higher than this.. around the 400 amps and more. ( talking the 15kw boards)

We can see that this takes the end of your screw fittings easily.. so start up current is massive if you don't introduce some resistance into the start-up procedure.... I use a 50R resistor to charge the caps then just connect the battery wire without any fireworks....without it,  it throws the 180 amp o/load I have  and it takes 2 goes to charge the caps.”

Trust this helps explain.

[TomW]

From the OzInverter Book.

Regards start up surge.......

Oztules comments….   Caps........  “We have 60000uf@50v to charge, I think .5*(e^2 x C) or about 75 joules

If we look at that as a joule is a watt second, thats 75w for 1 second... imagine that as a one hundredth of a second.... suddenly we are generating 7500 watts... at one thousandth it is getting out of hand at 75000 watts or 75 kilowatts.... in the hundredths scenario we are in the 7500/50 or 150 amps.....
I know from tests it is very very much higher than this.. around the 400 amps and more. ( talking the 15kw boards)

We can see that this takes the end of your screw fittings easily.. so start up current is massive if you don't introduce some resistance into the start-up procedure.... I use a 50R resistor to charge the caps then just connect the battery wire without any fireworks....without it,  it throws the 180 amp o/load I have  and it takes 2 goes to charge the caps.”

Trust this helps explain.

Clockman;

Great way to illustrate the massive currents that can be drawn.  At the first microsecond those caps look like a dead short and that is easy to miss / forget.

Nicely done.

Tom