PIP-4048MS and PIP-5048MS inverters

[offgridQLD]

I think I will get one and share the results. I hate measuring equipment that dosn't do the one thing you purchase it for.....measuring things . I guess I can then show how misleading the inexpensive ones is for anyone that is on the fence about justifying the cost.

Without me reading through all the user manuals.If someone knows off hand. What is the main difference between the lite and the standard version. As in what am I giving up if I get the lite?

Kurt

[Johny]

The major problem with the Lite is the 10A maximum (as I see it).
I would get one if a 15A version was available for a similar price to the Lite.

[offgridQLD]

Personally I don't see myself wanting to accurately measure any single AC plug in loads over 2400w. It was more if I Was sacrificing accuracy or key features with a lite.

Kurt

[Johny]

Personally I don't see myself wanting to accurately measure any single AC plug in loads over 2400w. It was more if I Was sacrificing accuracy or key features with a lite.Kurt

The Lite doesn't have the serial port so logging to a PC isn't possible. The accuracy appears to be the same. They also mention that the "others" (not the Lite) can handle inrush loads up to 15A briefly.

The Lite chucks a wobbly:

When the current exceeds 10A, the display flashes the message “WARNING, OVER/LOAD”

[PlanB]

Have you had an opportunity to compare your 15A powermate to the $29 wonders Reecho?

[offgridQLD]

From a few online reviews comparing similar cheap meters to the power mate over a variety of loads. Showed that when measuring small loads Sub 10w then the accuracy and resolution of the Powermate stood out. Non resistive loads with varying power factor is where the biggest discrepancy's were shown.

A It all depends on what kind of loads you want to measure and how accurate you need to be.

Some examples below from a review I read.

"A 100W incandescent globe.
Arlec 96W
Power-Mate 94.1W

A 40W incandescent globe.
Arlec 40W
Power-Mate 40.95W

soldering iron rated at 21W full power.

Arlec 21W
Power-Mate 22.67W PF 0.999"


The power mate is only rated at +/- 2% the arlec was +/- 4% To me both of them are not that impressive. But the cheap one would be way out if it wasn't 100% PF load.

Like this example in the test review of a compact fluro. shows how its out by a lot due to PF error or just isn't considered in the calculations.

"18W compact fluro. Rated between 220V and 240V, current 130mA
Arlec 16W 0.07A PF 100%
Power-Mate 20.65W 0.142A at 241V, PF 0.603"

Kurt

[reecho]

Have you had an opportunity to compare your 15A powermate to the $29 wonders Reecho?

I have played with some cheapies through work. The accuracy with them is a spin of the chocolate wheel i'm afraid....

[coulomb]

It was more if I Was sacrificing accuracy or key features with a lite.

... The accuracy appears to be the same.

Actually, the Lite has a maximum error of 2%, but the non-Lites are 1% (both typically better, they claim). For home use, I would think that 2% would be fine.

I imagine that the errors for certain types of non power factor corrected load would be really bad, like an order of magnitude out. This is because the really bad devices draw power for only 1% or so of the cycle, and the cheapies don't sample the current waveform often enough to even see the current peak. They may also run out of range, with the peak current being in the hundred amp range. Measuring such power consumption accurately is non trivial. I wonder if the cheaper utility meters like EM1000s actually get it right.

[coulomb]

Antiscab did some research some time ago:

Testing kWh meters. It looks like he didn't pony up the money for a PowerMate.

[antiscab]

That's true, I never did spring for a PowerMate

I did however buy an energy meter (no longer for sale) that did appear to measure both leading and lagging displacement power factor, as well as harmonic distrotion

That, and it's kwh measurement matched my utility meter

[offgridQLD]

I started a new thread as this energy meter discussion is starting to get off topic.

viewtopic.php?p=57654&t=4592#p57654

Kurt

[PlanB]

I can see that 4.7A~ mains current into the 2 boxes must be an out-of-phase power factor anomaly but still intrigued as to what the box has connected across the mains to give such a bad power factor?
The change from 4.7A (batteries charging with bypass) to 3.4A (batteries not charging with bypass) suggests the mains battery charger in the unit has a reasonable power factor (4.7-3.4=1.3A~ for a one to two hundred watts of batt charging).
So if bypass just switches the mains direct to the resistive load of the 60w lamp what else is in there to draw the 3.4A of out-of-phase current? When bypass is off the mains current drops to 0.1A~ which also seems reasonable for 2 boxes in stdby.

[weber]

To skip backwards over the preceding digression on power meters, click the following link:
viewtopic.php?title=pip4048ms-inverter& ... 332#p57600

I can see that 4.7A~ mains current into the 2 boxes must be an out-of-phase power factor anomaly but still intrigued as to what the box has connected across the mains to give such a bad power factor?
The change from 4.7A (batteries charging with bypass) to 3.4A (batteries not charging with bypass) suggests the mains battery charger in the unit has a reasonable power factor (4.7-3.4=1.3A~ for a one to two hundred watts of batt charging).
So if bypass just switches the mains direct to the resistive load of the 60w lamp what else is in there to draw the 3.4A of out-of-phase current? When bypass is off the mains current drops to 0.1A~ which also seems reasonable for 2 boxes in stdby.

It has to be the battery charger (mode of the inverter). Even if it is not charging the battery (but presumably floating the battery) it is still connected across the mains.

This charger has no reason not to be operating in Power Factor Correcting (PFC) mode. However I note that there are two completely unrelated things that are commonly included under the heading "power factor". One is the phase shift between current and voltage sine waves. The other is when the current waveform is far from sinusoidal, typically spikey -- called more specifically "harmonics". So-called PFC is really "harmonic reduction". It may well be reducing harmonics, but there may still be some inductance or capacitance that is causing a phase shift.

It may be the inductance of the LC filter needed to filter the PWM from the output of the inverter (when operating in inverter mode).

[coulomb]

It may be the inductance of the LC filter needed to filter the PWM from the output of the inverter (when operating in inverter mode).

[ Edit: turns out this is not relevant, as Weber points out next post. ]

Actually, the inverter should be compensating for this phase shift. It basically sets its power by adjusting the phase shift between the inverter output and the mains; the inductor's voltage is the difference between these two, and is almost at ninety degrees to both. Its current will be ninety degrees out of phase with that voltage, so it will be in synch with the mains.

If the output of the inverter has the wrong *amplitude*, however, then the angle of the voltage across the inductor is no longer 90 degrees, and you end up with reactive power. It's easy to get this wrong, and end up with a poor power factor.

The other thing is that the mains is rarely perfectly sinusoidal, and typically has a good component of fifth and seventh harmonic in it. (I assume also third harmonic for single phase systems; I'm used to 3-phase systems at work; with three phase systems, the third harmonics often go away.) This can cause non-sinusoidal current, since it's hard for the inverter to match the distortion of the mains while maintaining a phase shift, and this can lead to poor power factor.

One of the three phase inverters at work has very considerable ripple in the instantaneous power; at low output power, some of the peaks of the ninth (!) harmonic instantaneous power cross zero (so power is going back into the mains for part of the cycle, even though on average, it is coming out of the mains to supply the load and losses). I don't know what that would look like for a single phase inverter; it certainly would not have a pronounced ninth harmonic component to the instantaneous power. I suspect it has to be mostly second harmonic (100 Hz).

[weber]

That's all very interesting, Coulomb, but I think completely irrelevant because the PIP is not acting as an inverter in what is being discussed -- only as a charger. And when it does operate as an inverter its output is never connected to the mains. I believe you are talking about a grid-feed inverter.

[PlanB]

I'm guessing the battery charger is maybe not connected when I first power up (mains current 0.1A) & the LCD shows just an isolated battery pack for a few seconds.
Then the display switches to show bypass only, battery still isolated (mains current 3.4A) Then, after a few more secs, battery charging with bypass (mains current 4.7A)
So we're thinking the 3.4A of reactive current is all down to an unloaded charger then?

[coulomb]

That's all very interesting, Coulomb,

Aren't I, though?   

but I think completely irrelevant because the PIP is not acting as an inverter in what is being discussed -- only as a charger.

Excellent point, and my bad. I was confused when you correctly mentioned the inductor on the output of the inverter, and I switched to the inductor I'm familar with.

It's also confusing because I've been assuming that charger is essentially the inverter, operating in an unusual mode where only the lower pair of IGBTs is switched. But now I realise that this discussion (between Weber and I over email) was with respect to the Power Jack inverter, which may be completely different in how it performs battery charging.

But I would think that a filter inductor would be pretty small (less than 1 mH, say), so its reactance at 50 Hz would be quite small (well under an ohm). I would not expect this to cause such a low power factor.

[offgridQLD]

Just using the PIP4048 now to charge the imiev in the Landsborough train station. It's consuming 44 amps from the battery at 50.5v (2222w) and showing 2100w AC output (over 90% efficancy) My imiev is showing 1600w to the battery. All this conversion wastage. Just under 30%. Total loss (Only using the data from the PIPs display and my inboard OBD port logger.

Kurt

[weber]

That's all very interesting, Coulomb,

Aren't I, though?   

Always.

... I've been assuming that charger is essentially the inverter, operating in an unusual mode where only the lower pair of IGBTs is switched.

I assumed the same, and still do.

But I would think that a filter inductor would be pretty small (less than 1 mH, say), so its reactance at 50 Hz would be quite small (well under an ohm). I would not expect this to cause such a low power factor.

An excellent point. In which case, PlanB, I must fall back on the hypothesis that we cannot believe the current measurements, and they are really much lower. Does the clamp meter claim to give a True-RMS reading? Maybe the current waveform really is spikey.

[coulomb]

... showing 2100w AC output ... . My imiev is showing 1600w to the battery. All this conversion wastage. Just under 30% total loss

Well, don't forget that the iMiev is also using power, to drive coolant pumps, all the 12 V loads via the DC/DC, and so on. So the losses aren't quite that bad.

But yes, you are converting DC to AC, then AC to DC; two main conversion steps. (Though I think that there are actually three conversion stages inside the PIP, a DC/DC, a buck stage, and the final DC/AC inverter. But who cares, that combination seems efficient enough.)

If you did want to improve this efficiency (and I think you don't you could build your own Chademo setup to DC/DC directly from the eJerry Can to the pack. I think I read somewhere that the protocol details are all available on the 'net. But I think that just the Chademo connector plus cable on its own would be a big proportion of the cost of the PIP inverter, then there would be the moderately sized DC/DC, and the protocol would be a nightmare. Tritium claim that they finalised approval in Japan the quickest of any company, in about a week! You don't need that level of compliance, of course, but it has to be pretty daunting.

[offgridQLD]

Yes the PIP4048 was only contributing to about 8-10% of the losses. The Imiev (base loads) and charger inefficacy was the other 18-20% and you get that if your charging from mains or inverter and it becomes less in percentage terms the faster you charge (3200w)charge rate would be better.

I need to come up with some kind of precharge arrangement (To avoid the zap when the PIP's caps charge initially) for the PIP4048 as I need to disconnect it regularly at the 120A Anderson and remove the PIP4048 and battery separately.

Kurt

[coulomb]

I need to come up with some kind of precharge arrangement (To avoid the zap when the PIP's caps charge initially) for the PIP4048 as I need to disconnect it regularly at the 120A Anderson and remove the PIP4048 and battery separately.

I've experienced one of the zaps, and it's not pleasant. But Weber claims that there is a pre-charge circuit in the PIP, just that it doesn't operate if the battery has only recently been disconnected. He says he's had many connects where there was no splat at all.

According to the Main Board Repairing Service Guide, there is a "bus soft start circuit", and "reverse protection MOSFETs on DC side". The "bus" might refer to the DC bus (battery capacitors), but more likely it refers to one of the two (!) higher voltage buses. It seems likely that they would include DC bus pre-charging along with the reverse protection on the DC side of the bus.

Have you perhaps not allowed the DC bus capacitors to discharge before re-applying the battery? If you have, perhaps there is some other trick to getting the pre-charge circuit, assuming there really is one, to take effect.

[offgridQLD]

"Weber claims that there is a pre-charge circuit in the PIP, just that it doesn't operate if the battery has only recently been disconnected"

It could well be that I haven't given it time. Typically I Would disconnect the battery and remove the Inverter and battery from the car. Place them both on the bench and then plug the battery back in to PIP to charge the battery back up again via the PIP's Ac mains charger.

It hasn't happened all the time perhaps 2 times over 20 or so disconnect/reconnects. Enough to show some small arcing damage on the leading face of the Anderson pins than needed to be polished out.

I will keep that info in mind and give it some time befor reconnecting the battery and see how I go. Hopefully it wont happen again.

Kurt

[PlanB]

Well no sign of a precharge here! Everytime I connect my battery there is an almighty spark even if the ESS has been sitting overnight!
The $29 power meter says 4.9A~ mains stdby current for 2 boxes in parallel with the pack on light charge (1.1ADC=65w from each box) with a 0.24 power factor. So, if it's right, that's still about 4.9x250x0.24-130=60wtotal or 30w/per box.
Also battery current into 2 boxes in parallel (no external load) is about 2.5ADC, so that's another 70w/box!
Each box is chewing through ~100w just sitting there. In case you're wondering, I wandered into this energy black hole because I stumbled across perpetual motion, ie the boxes reporting a power output greater than the sum of their inputs from battery, solar & mains charging.

[offgridQLD]

PlanB,
      I think you my as well be giving us the football score or lotto numbers if your metering is not accurate.

I measured the DC idle consumption of one PIP4048 with a more accurate inline shunt based power meter and it was 48W. So I would expect 96w for the two.

Kurt