Voltage drop from fridge start up!

[Westbranch]

I just started using Graham's new Android App for data collection/observation and noticed a very deep drop in voltage every-time the Fridge started,  screen capture below...

Comments anyone?

[Vic]

Hi Wb,

WOW!  Something looks seriously wrong.

If I am reading the color-coding of the graph correctly,  the Vbat drops to about 3 V,  but  the battery current has NOT increased during these events.

Looks like a very poor connection,  or one/some batteries are very high impedance ... Perhaps cannot read the legending well ...

Whatta you think?   Vic

[Westbranch]

Vic, I do not have a clue! I expected a sag but to zero...? There is no other evidence that this is happening as the inverter covers it over in delayed reactin time I guess...

Grahams App, latest version,now  does 2 second sampling.
I am hoping some one else is using the Android App on an FLA or ?  to compare to...

[CDN-VT]

BAD sampling !!
NEXT !!
Check sample leads or a new program , better yet , use a Fluke in min-max and stop record  on the feed right at the inverter .
BASICS  FIRST !!!!!!!!!!!!!!!!!

[Resthome]

WB

The local App uses 2 sec samples so you should see it there if you look at the raw data not the displayed graphs which have long times between refreshes. Just select all the data with check marks to graph and then export the local data to a file. You can read the file with Excel. And look for the voltage to drop as you are seeing with Graham's app.

[russ_drinkwater]

I agree with checking with a good multimeter first when the load starts. Had the same issue with old raylites. But they were toast as I eventually figured out. Not saying there is anything wrong with your cells, but it is unusual occurrence from healthy batteries with no other system problems!
Ur, I do not have any mobile app devices, sigh!

[Resthome]

WB

Is that frig running off an invertor or is it DC?  Do see the Battery Current drop down with the voltage in the 10 o'clock range. Suspect you had little sun on the system in the early part of the graph.

I checked my data from the local app with a 30 amp vacuum cleaner load and the voltage sagged less than 1/2 volt for less than 2 sec off an invertor. And the Xantrex invertor is bad with things that have a high start up surge. I have a shop vacuum that really likes to make the invertor choke. In fact it usually kicks the inventor off for a few seconds which likes to mess with my sat tv mobile antenna. 

[CDN-VT]

I have a shop vacuum that really likes to make the invertor choke. In fact it usually kicks the inventor off for a few seconds which likes to mess with my sat tv mobile antenna.

You have a shop vac that is 120Vac / 15 amp plug in North america power & it stumbles a 2000W Xantrex PROwatt SW2000.
?

Check that the brushes are not gouged into the commutator & that the commutator bars are not melding (moving to the next bar ) do a cleaning & under-cut of the commutator.
There is only air load ..
& wb needs a fluke set on min-max to see real , don't believe programs till proven against a known good DVM.

VT 

[Westbranch]

I posted in the Android App thread too and Graham noted that the bottom green line is broken and should be solid its entire length across the bottom of the screen.  I am headed out again tomorrow AM and have to try another scan and PM the results to him.  He is also checking the code...

More later.

[tecnodave]

I have a real problem in using a Fluke DMM or for that matter any DMM to look for a very fast spike!
DMM's  do not do a continous sample!   Even the high end ones...maybe 4 samples/second....not going to see a fast spike or dip that occurs right after a sample.

I analyze large 3 phase motors that are >200 amps startup at 480 volts. Using three Fluke 87-5's &Fluke 334 Amp clamp ammeters on rapidly changing voltage/currents at startup will give me garbage data because of the sampling time. I use 3 Amprobe analog amp clamp meters model RS-3PRO on motor startup loads and get real time info not sampling rate info.    Ok I'm way old school, digital wasn't around back then, but as I have discovered DMM's have their limitations.

If I want to see real fast stuff I use Amprobe display less pickups with a 100 MHz scope.

Note....Fluke bought Amprobe to get the patent library.....Amprobe is the Technology leader in inductive and Hall effect ammeters.

I have written technical articles on Fluke users website.  Was Fluke beta tester.


David

[tecnodave]

I think VT nailed it and graham confirmed.....the green line?

Possibly the fridge startup is causing display electronics to give false readings here.

Dave

[Resthome]

I have a shop vacuum that really likes to make the invertor choke. In fact it usually kicks the inventor off for a few seconds which likes to mess with my sat tv mobile antenna.

You have a shop vac that is 120Vac / 15 amp plug in North america power & it stumbles a 2000W Xantrex PROwatt SW2000.
?

Check that the brushes are not gouged into the commutator & that the commutator bars are not melding (moving to the next bar ) do a cleaning & under-cut of the commutator.
There is only air load ..
& wb needs a fluke set on min-max to see real , don't believe programs till proven against a known good DVM.

VT

VT ..

Yep and there is nothing wrong with the brushers or anything else on that shop vacuum. It was fine on a previous invertor but not on the Xantrex ProWatt SW. It does run but it is the initial start up draw after that it runs the shop vacuum fine. There have been a few articles on the ProSine that have stated the same issue with starting large motors. And it runs the 1500w u wave just fine because it doesn't have the start up issue that motors have.

And for WB issuea it appears Graham has seen the problem with the app

[grgdgreek]

I had the same problem with xantrex-sold it and went with victron 24/3000.
No more problems since.
I'm really looking foward to midnites new line of inverters!!

[tecnodave]

Resthome,

FYI,

The ProSine and ProWatt are not the same, I've used both and the PROSine is a much better unit. I've smoked 3 of them now, 2 fresh newbies and 1 beat used flea market deal. The ProSine is much cleaner sine wave but does not like start surge, smoked 2  2kw  ProSine 24 volt newbies and 1 1kw ProSine 12 volt unit......power tools, I still have another one just waiting for smoke.  To be fair I use a Bosch Impact hammer driving electric ground rods, Skilsaw Mag77M, and lots of beefy power tools
I've lost track of the Honda generators I've smoked with their tiny windings.

My Onan burns twice as much fuel, but is a true workhorse, never fails to start and has whopping overload capability. Maybe 10 kW plus out of a 4 kW continous duty unit.

I like stuff that works good and lasts, don't like imports but the Cotek SK line does me real good. I have several SK 1500 and SK 2000's  bought cheap at out of business sale, I bought spares...well more than several.

Dave

Edit. Add,    I confirm that the ProWatt will stumble on startup surge from 15 amp shop  vac

[Resthome]

Resthome,

FYI,

The ProSine and ProWatt are not the same, I've used both and the PROSine is a much better unit. I've smoked 3 of them now, 2 fresh newbies and 1 beat used flea market deal. The ProSine is much cleaner sine wave but does not like start surge, smoked 2  2kw  ProSine 24 volt newbies and 1 1kw ProSine 12 volt unit......power tools, I still have another one just waiting for smoke.  To be fair I use a Bosch Impact hammer driving electric ground rods, Skilsaw Mag77M, and lots of beefy power tools
I've lost track of the Honda generators I've smoked with their tiny windings.

My Onan burns twice as much fuel, but is a true workhorse, never fails to start and has whopping overload capability. Maybe 10 kW plus out of a 4 kW continous duty unit.

I like stuff that works good and lasts, don't like imports but the Cotek SK line does me real good. I have several SK 1500 and SK 2000's  bought cheap at out of business sale, I bought spares...well more than several.

Dave

Edit. Add,    I confirm that the ProWatt will stumble on startup surge from 15 amp shop  vac

Thanks Dave, I did get the two of them confused and thanks for the verification. My upright Eureka vacuum doesn't bother it. I just know it is going to do it with the shop vac and avoid it if the spouse is watching or recording TV.