question

Hi !

Hair dryer is probably 1500W...

Man, something is seriously wrong with your keyboard. The caps are all over the place..

On a more serious note: people are willing to help if you rant less.

And then to the solution:

150W should be possible. As a hairdryer is a resistive load I assume the in rush current can't be the problem. So:

- Check the voltage drop. Your cable is very thin. Can be problematic. Although I agree that it should be able to handle 150W

- check another load. Does it work with another 150W? And a 500w load and so on.

I'm sure something is wrong. Maybe you can share some details. Is it the overload warning you see? Not the low battery?

It's odd that an admission of using the wrong type and gauge of cable to install the unit to an undersized battery bank, followed by "...but it WORKS XD" is both preceded and followed by a full report of it not, in fact, working at all.

Datasheet specs only apply when a product is properly installed to begin with, so start by correcting the installation.

It still may not work very well, since a hairdryer is a non-linear load which presents its own special set of challenges, but the first problem -that of the installation- is well within your control to be able to correct.

@UltimateSolar used 6mm2 PV cable for connection to 100Ah LiFePo4 battery, i know this is not IDEAL but it WORKS X-D

This is something that needs to be remedied. At full load your inverter will draw over 100a out of the battery. You need 25mm cable (or thicker) depending on cable length.

You dont mention if your LiFePo4 battery has a BMS capable of 100a output needed to power the inverter.

As mentioned, some hair dryers wont run on Victron inverters.

thanks for all CONSTRUCTIVE replies: The Battery is NOT the problem, it does not really care about the startup current, the voltage barely flinches... it is the Victron Inverter that says "oh u have been pulling like too much startup current... this is too much for me... shutting down for 5sec.. cya later plz with less startup current"

the problem: have only 2 weeks to return this thing... so will borrow some hairdryers and report back? X-D

just tested THE SAME HAIR DRYER starts up works fine (even for only a short time because of the tiny tiny USV AGM batteries 10Ah~ each?) on https://www.ebay.de/itm/126423659027 APC Smart UPS rated only 1000VA !!!

Sorry should have been more SPECIFIC: the HAIRDRYER actually starts (level 1 = 150W = cold) but shuts down after 2sec with "overload"

how does this make ANY sense? X-D

what is going on in "the brain" of the Phoenix? (it clearly has one, updated the firmware and all)

Phoenix: "uh... detected overcurrent 2sec ago... will shutdown"

Some Updates: double the cable size: did not matter. In the App it can be seen how it draws 400VA for like 2 seconds... then it shuts down.

The way a 1500W resistive element appears to draws 150W is by cutting into the sine wave to only draw 1500W for 1/10th of the cycle.

It's still drawing 125A at 12V in huge spike for a fraction of a second (over and over) - that appears to the inverter like a large surge load.

There aren't different resistance coils inside the hair drier for each power setting. Just a single 1500W element, and then a switching circuit that cuts the power in and out. 1/10th of the cycle for 150 W, 1/2 cycle for 750W, etc

The way to measure this is with a high frequency oscilloscope. Multimeters and the built in measurement of the inverter are not fast enough to see high currents for a fraction of a second (they will show the average over a cycle, or even multiple cycles, which are happening 50 times per second).

The overload circuit is fast enough though, which is what you're seeing.

For this kind of the load the best thing to do is to get a 12V DC hair dryer (intended for RV use) and bypass the inverter and just run it off the DC bus from the battery.

https://www.awardrv.com.au/portable-hairdryer-12v-simply-glam

in the Phoenix's defense: it can really handle 1200VA = Watts constant load, it powered a 1200V STEBA induction cooking plate just fine over a time of 10min (while massively draining battery + yes the cables got a bit warm X-D)

PS: the highest level of the 1200W STEBA induction cooker is = 1200W and if put to lower settings, it probably operates like the HAIRDRYER (1200W on... 1200W off... 1200W on... 1200W off...)

looks like the HAIRDRYER AND the STEBA is "cheating"

offer to send the specific HAIRDRYER to Victron for further testing :D

PS: But WHY is it that the APC USV rated to 1000VA can handle the hairdrier? (probably with MASSIVE distortion to the SINUS can not meassure don't have oszi)

thanks for all the PRODUCTIVE answers, yes it might really be the hairdryer that instead of actually reducing Wattage is in a fast on-off mode which of course is no good and puts massive strains on the grid? X-D (that's why Melmak exploded!)

update: bought a second hand travel hairdryer "Braun", same problem

Hi @UltimateSolar

Sometimes, in order to reduce power on first stage, the hair dryers are using a simple diode to power the resistive element only by one side of the sinus wave.

This could be very tricky for many inverters, UPSes, etc, because it is a very unbalanced load.

That APC ups we are talking in this topic, is a LOW frequency inverter, with a slim low frequency transformer inside. Some of them (3kW rackable ones) are even using two transformers, in parallel. And it works with the above hair dryers, but are not happy and make some strange noises, but they work. Way to go APC for their very interesting schematic / conversion power stage.

Don't know if you have noticed, but the APC are not using at all those small chokes that Victron are using for smoothing out the high frequency chopped low voltage before the big transformer. This is because of the way they are driving the FETs and the way they are monitoring the inductions on the big transformer.

Alex