Victron genny & water pump issue

[Justme]

Bit of an odd one that I have not seen anyone post about but here goes.

 

I have a Victron 3000va 120amp 12v 16amp. When its in inverter mode it handles all our loads fine.

 

We have a mains powered water pump that keeps our water system pressured. It comes on & off as you would expect during usage.

 

The problem comes when we have the genny on & the inverter is in pass through/charging mode. When the pump kicks in the inverter drops the genny & takes over. Not every time but about 3 in 4 times. I have tried altering the assist settings & also turning it off completely. Nothing seems to affect it. If I power the pump direct from the genny whilst the inverter is in pass through / charging mode it all works fine so its not a total load on the genny issue. Also its not due to hitting the 16amp pass through as the other loads are very low.

 

 

The pump is rated at 600 watts but runs at 300-350 watts (alters with system water pressure) & shows 450-550 watts when starting. (measured using a plug in meter so take with pinch of salt) The start capacitor did go earlier in the year (but the issue was happening before then anyway) & was changed like for like.

 

I was wondering if there is any Victron setting that might work (I do think I have tried them all via the VE software) or would altering the cap for a larger or smaller one alter the surge which I assume the problem is. I also assume that as it has a capacitor that it does not have any brushes or is it worth checking anyway?

 

I have power tools that are rated to over 1000 watts that dont cause the same effect on start up. The fridge & freezer also dont cause the same issue but have about the same start up loads. Even the 2hp air compressor does not do so. The 1000 watt borehole pump also does not cause the same issue.

 

Suggestions?

Edited November 22, 2012 by Justme

[jelunga]

Bit of an odd one that I have not seen anyone post about but here goes.

 

I have a Victron 3000va 120amp 12v 16amp. When its in inverter mode it handles all our loads fine.

 

We have a mains powered water pump that keeps our water system pressured. It comes on & off as you would expect during usage.

 

The problem comes when we have the genny on & the inverter is in pass through/charging mode. When the pump kicks in the inverter drops the genny & takes over. Not every time but about 3 in 4 times. I have tried altering the assist settings & also turning it off completely. Nothing seems to affect it. If I power the pump direct from the genny whilst the inverter is in pass through / charging mode it all works fine so its not a total load on the genny issue. Also its not due to hitting the 16amp pass through as the other loads are very low.

 

 

The pump is rated at 600 watts but runs at 300-350 watts (alters with system water pressure) & shows 450-550 watts when starting. (measured using a plug in meter so take with pinch of salt) The start capacitor did go earlier in the year (but the issue was happening before then anyway) & was changed like for like.

 

I was wondering if there is any Victron setting that might work (I do think I have tried them all via the VE software) or would altering the cap for a larger or smaller one alter the surge which I assume the problem is. I also assume that as it has a capacitor that it does not have any brushes or is it worth checking anyway?

 

I have power tools that are rated to over 1000 watts that dont cause the same effect on start up. The fridge & freezer also dont cause the same issue but have about the same start up loads. Even the 2hp air compressor does not do so. The 1000 watt borehole pump also does not cause the same issue.

 

Suggestions?

Have you tried changing the dynamic current limiter and UPS settings? Dip switch 4 and 3 in down setting button mode if yours is the same as mine? Explanation on page 13 of my manual

[Justme]

I dont use it in UPS mode. From the documentation it just speeds up the change over from & to other power sources & requires a better quality wave form than most small / medium gennies can provide (ok for land lines). I have no equipment that needs that level of switch over. Even the pc's dont need it.

 

The dynamic limiter is set on max load (IE 16 amps) so should not be an issue as the load is much much lower. I think I have also tried it with it turned off. Will check that next time we have the genny on.

 

As I have the software & link I have access to those settings & more flexible options.

 

 

I have tried power assist on & off with various boost factors.

[Robbo]

Try the water pump without any water, if the Victron doesn't kick in then my guess is that its briefly going over 16amp (although if your bulk charging batteries this would be lower)

[Gibbo]

My guess would be that the start up surge of the pump is really quick and it's catching the genny out so the genny voltage falls for a few tens of milliseconds. That might be enough for the Victron to object. Have you tried the weak AC setting?

 

I had this years ago and the only solution we found was to put a transformer soft start on the pump. That worked in that case but I've heard that some pumps don't like them and don't start up.

[Justme]

Gibbo, wouldnt that also happen then with the pump direct to the genny? IE cause the same voltage drop of the incoming mains.

 

 

I have the AC settings to allow the max drop allowable & the wide hertz setting.

 

 

I have tried dynamic current limit on & off, Assist on & off & all combinations of them both.

 

 

Just tried it with the charger turned off & it works as it should. I think Gibbo is right. With the charger on the full load is just enough to trigger an under voltage fault.

 

 

Setting it to weak AV input seems to make the matters worse as the input amps go up for the amount of charge amps to the battery.

 

At the min I have 107amps to the battery & 8.1 amps from the genny with 0.5 amp going to the mains.

 

With weak AC I have 85amps to the bats 12.5 amps from the genny & 0.5 amp to the mains.

 

 

On Weak AC it allows the input AC v to drop quite low. The wattage on weak AC is 2.3kW yet with it off its just 1.8kW.

Edited November 22, 2012 by Justme

[Biggles]

I have exactly this problem when I try to run my combi oven while charging.

 

I can get rid of the problem if I use the software to either turn off the charger or turn on weak A/C.

 

I have the same inverter but with the 50amp pass through.

 

I contacted Victron about this an asked if there was a manual switch that could be briged in instead of using the software but there is no option to just have the inverter and no charger, but strangly there is the other way.

 

This was on a simular thread I started a week or so ago. Not sure how to post the link. I will try.

 

Found it Linky

Edited November 22, 2012 by Biggles

[Gibbo]

Setting it to weak AV input seems to make the matters worse as the input amps go up for the amount of charge amps to the battery.

 

At the min I have 107amps to the battery & 8.1 amps from the genny with 0.5 amp going to the mains.

 

With weak AC I have 85amps to the bats 12.5 amps from the genny & 0.5 amp to the mains.

 

On Weak AC it allows the input AC v to drop quite low. The wattage on weak AC is 2.3kW yet with it off its just 1.8kW.

 

I would suspect dodgy measurements there. Where is that 500 watts going?

[Biggles]

Actually I'm now wondering if I need to up the amperage setting on my remote panel. Currently I have it at 23amps which is the gennt output.

[Justme]

I would suspect dodgy measurements there. Where is that 500 watts going?

 

 

I can only guess as heat. It was not left on long enough for the heat to show.

 

Would the PF of the inverter charger also change?

 

Roughly in normal mode the charger is about 80% efficient but in weak genny mode its much nearer 50%.

[Gibbo]

I can only guess as heat. It was not left on long enough for the heat to show.

 

Would the PF of the inverter charger also change?

 

Roughly in normal mode the charger is about 80% efficient but in weak genny mode its much nearer 50%.

 

I'm not buying it. A unit that size, producing 500 watts of heat would melt itself within a pretty short period of time.

 

I think it can't measure current properly except when the waveform is a clean sinewave. I think all those measurements are complete red herrings.

[Justme]

How efficient should a charger be (not inc the battery) just purely energy in / energy out?

 

Or should that be power in & power out?

 

I agree 500 watts is a lot of heat to loose.

[Gibbo]

How efficient should a charger be (not inc the battery) just purely energy in / energy out?

 

Or should that be power in & power out?

 

85% to 90% would be about right.

 

I agree 500 watts is a lot of heat to loose.

 

It's not just a lot. It's just plain wrong.

[Justme]

Wont the genny wave form be the same no matter what you set the Victron too?

 

During bulk at 85% efficiency it would be loosing 260 watts.

[Biggles]

 

 

Roughly in normal mode the charger is about 80% efficient but in weak genny mode its much nearer 50%.

 

Really, how would it know where the mains was coming from? (serious question)

 

Wont the genny wave form be the same no matter what you set the Victron too?

 

During bulk at 85% efficiency it would be loosing 260 watts.

 

 

Judging by the amount of heat generated under the stairs requiring me to put some exhaust fans to cool it. I would say 250w of heat output would seem about right. The metal top of the inverter would be about 40-45c with the steps on and no extraction. I can measure the difference if anyone is really interested.

 

Wont the genny wave form be the same no matter what you set the Victron too?

 

During bulk at 85% efficiency it would be loosing 260 watts.

 

 

Now I have mine set up right I get from the genny 230v - 235v at 50-51Htz

[Justme]

Really, how would it know where the mains was coming from? (serious question)

 

Judging by the amount of heat generated under the stairs requiring me to put some exhaust fans to cool it. I would say 250w of heat output would seem about right. The metal top of the inverter would be about 40-45c with the steps on and no extraction. I can measure the difference if anyone is really interested.

 

Now I have mine set up right I get from the genny 230v - 235v at 50-51Htz

 

You change a setting on the Victron that alters how it uses / loads the supply. Bit like altering the mapping of an ECU for a car I guess. Even with the same supply when the setting is changed it drastically alters the load it applies to the supply.

 

I have used the weak setting & lowered the max charge amps when using a small genny whilst fixing the big one.

 

Mine gets hot too. I have fitted an additional fan that comes on when the genny starts to aid cooling air flow.

 

Not sure what your last comment is all about. Wave form can only be checked with an oscilloscope (I think).

Edited November 23, 2012 by Justme

[Biggles]

I got the Htz reading from the Victron software.

 

So if the settings are left as is and not changed between generators or shore power the inverter has no way of self sencing the incomming mains, it just does the best it can with what it is dealt?

 

With that in mind that would be a really neat update to the Victron O/S.

 

BTW Victron said new or updated S/W can be flashed to the Victron. Have you done this or looked at it>

Edited November 23, 2012 by Biggles

[Gibbo]

Wont the genny wave form be the same no matter what you set the Victron too?

 

During bulk at 85% efficiency it would be loosing 260 watts.

 

You're missing the point of what I'm saying.

 

You said...

 

At the min I have 107amps to the battery & 8.1 amps from the genny with 0.5 amp going to the mains.

 

With weak AC I have 85amps to the bats 12.5 amps from the genny & 0.5 amp to the mains.

 

By setting weak AC, somehow, the efficiency has absolutely plummeted to some horrible figure. It's hard to say without the actual voltage reading so let's assume they're the same in both cases.

 

Your first figures give an efficiency of 85%

 

The second figures give an efficiency of 44%

 

I'm not having it! It would melt itself.

 

I think it can't measure the current properly unless it's a true sinewave input. And I further think that setting it to weak AC input is causing it to try to draw more current which is distorting the generator waveform. In which case all the figures it gives are bollocks. But it makes more sense than the charger suddenly becoming a 750 watt heater when you change a setting.

[Justme]

The voltage instantly plummets when you set it to weak genny.

 

From memory it was at 230 vac & 14.? dc but sunk to 185 vac & stayed at 14.? dc on the weak setting. I should have checked the hertz but forgot.

 

Normally even with a full load the genny V stays nearer the 230v mark.

 

I'm wondering if there is some interaction between the inverter & the genny voltage control or governor.

 

As I dont intend to use the weak genny setting unless I have to use a small back up genny its not an issue anyway. Just seemed very odd.

 

Will have to keep a look out for a larger shunt so I can get the management panel working on the main feed again & see what's what. The last one was getting very hot if you remember so was removed.

 

 

Biggles the hertz is only a small part of the wave form, IE just the number of oscillations, wave form is more about the shape of the wave. Even a square wave inverter can hit 50 hertz exactly, yet the wave form would be pants.

[Biggles]

Of course. I have no access to a scope so will probably never know what the wave form looks like. I would like to think that as it is a well known make of alternator that it would be making PSW. My wifes GHD hair straighteners run or it and they are renowned for their intolerance of dirty wave form.

[Gibbo]

The voltage instantly plummets when you set it to weak genny.

 

From memory it was at 230 vac & 14.? dc but sunk to 185 vac & stayed at 14.? dc on the weak setting. I should have checked the hertz but forgot.

 

Normally even with a full load the genny V stays nearer the 230v mark.

 

This is what makes me think it's a measurement issue in the Victron. You change the setting to weak AC, it pulls more current, the generator voltage collapses, the actual charge current drops. None of it makes any sense except for a distorted waveform which fools the Victron measurements.

[Justme]

Yep its very odd.

 

It actually looks like the weak setting is making things worse. Yet I know it help when you do have a small weak genny as I have used one on it.

 

Might be easier to look for a different pump that does not trigger the Victron as the starters seem costly & might not work anyway.

[Biggles]

Yep its very odd.

 

It actually looks like the weak setting is making things worse. Yet I know it help when you do have a small weak genny as I have used one on it.

 

Might be easier to look for a different pump that does not trigger the Victron as the starters seem costly & might not work anyway.

 

 

Could you just not use a bigger start capacitor?

 

Also why are 12/24v pumps always pulse type (sure there is a better description) whereas the ones on 230v are spinny (again sure there is a better description). At home I have a 3bar pump on the hot water system so I get HW at all taps (large old house with long pipe runs) in seconds instead of minutes.

 

We also have a 3bar shower pump for hot and cold on the master shower which is the spinny type.

 

Both spinny types are much quieter than the pulse one on the boat.

[Gibbo]

Also why are 12/24v pumps always pulse type (sure there is a better description) whereas the ones on 230v are spinny (again sure there is a better description).

 

"Spinny" uses much more power than "pulse" (we know what you mean) for the same pressure. It doesn't really matter in a house but it's big issue on boats.

 

Could you just not use a bigger start capacitor?

 

I think that's likely to make it worse. A smaller one might not start it up properly.

[smileypete]

Suggestions?

Depends, what's the minimum time between starts?

 

cheers, Pete.

~smpt~