Multiplus II with induction cooktop problem

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markeroonie asked Jan 17, '24

Multiplus II with induction cooktop problem

Hi all, thanks in advance for any help and apologies for such a long post, but wanted to give as much details as possible

I have a caravan with 400ah (delivering 200a continuous) of pylontech lithium batteries. 2000Va multiplus ii inverter/charger, solar charger and bmv, all victron.

induction cooktop is a westinghouse dual cooktop

https://westinghousesmallappliances.com.au/products/westinghouse-dual-induction-cooktop

one hob is 1400w and the other 1000w, when running off the inverter i only use the 1000w hob.

the caravan came with a 1600 multiplus, and the sales person led me to believe it was 1600w (not Va) so i thought i could easily run a 1400w induction cooktop on it. Wrong. It threw a fault and gave me the solid red light alarm on the multiplus. I dind't hear any earlier alarms, if there were any, since it is under a mattress in the caravan. Disconecting the muliplus for 48 hours didn't help, but when it was returned for repair they said it was working just fine, so somehow it reset itself while in transit over a few more days

so, research told me that the 1600 was only good for 1300w continuous, although peaked at over 2000w, so i thought the induction cooktop was peaking for too long for the unit to handle.

I then upgraded to the 2000Va multiplus, this should give me 1600w continuous power.

like the first time, everything worked ok for a few days, then when boilding some water at 800w on the small hob, the multiplus gave out again, and once again gave the solid red alarm light and would not reset.

i am checking on the bmv and it tells me that the watts/amps are in line with what i am expecting the unit to pull. I also use a nespresso machine and it pulls 1500w briefly, so the bms seems to be telling me the right numbers

i am careful not to have several appliances running at once so can be fairly certain that's not the problem

I will be taking it back for repair to the place i bought it from, but i really want to be able to use a induction setup and want some input on what to look for in such a unit.

Since this has happened twice now, i suspect the induction cooker is the cause, but i can't work out why.

is the induction cooktop pulling power in such a way that it is overloading the electronics? square wave instead of sine? I think when running at 800w on the 1000w side, it cycles at 100% for 80% of the time, but that still shouldn't overload the multiplus.

thanks again for reading all this, looking forward to any advice

mark

Multiplus-II

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Answer 1 · 2024-01-17T23:54:23Z

k-k answered · Jan 17 at 11:54 PM

The cooktop pulsing in combination with country-code-regulations are the problem. Inverters are often limited in delta-u to delta-t. (e.g. no more than 400w change per second). If you have an amper-clamper, use it to find a programm-setting for your cooker without pulsing.

My induction-plate has a setting 'water-boiling' with settable wattage from 2000W down to 200W in 200W steps BUT only down to 1000W with duty cycle 100% - going further down (800W to 200W) it uses 2000W but pulsed.

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markeroonie commented · Jan 22 at 03:30 PM

I went and got the amp clamp and this is what I found.

2 hobs. 1 x 1400w 1 x 1000w 240v

The 1400w hob on full pulls about 6A

On 1000w it pulls about 4A

On 800w it cycles between 4A and .5 about 6 seconds on and 2 off

The 1000w hob on full pulls about 4A

On 800w it cycles between 4A and .5. Sit 6 seconds on and 2 off

On 400w or cycles between 4A and .5 about 3 seconds on and 3 off.

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k-k markeroonie commented · Jan 23 at 06:09 AM

For just boiling water i recommend an small 'euro-style' electric-kettle* with power usage from MP ii 1.6kVa * 0.8 = less than 1.28kW**.

If you have a hotpot (as cooking alternative) check how it is pulsing or not.

AND: your are in the upper range of power from the MP so your cabling must be on top. Nothing small (mm²/awg), nothing loose, nothing too long.

By the way: pylontech, so i assume 48V? How many amps can they deliver peak for how long? Have you measured the dc-amp INTO your inverter while shorttime running nespresso or while cooking potatoes fullpower a longtime? Does it fit to your batt

I assume the amp clamp can also be used for volts. Start the hob in 800w mode, you might see great deviations up to 25x volts when power demand goes low. (without grid-code on the MP you might see better results).

* the ones with click-on, when boiling auto-shutoff, pure electric (=resistive).

** rule of thumb

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Answer 2 · 2024-01-23T09:48:45Z

markeroonie answered · Jan 23 at 09:48 AM

The pylontech are 12v , 400A and can deliver 200ah continuous.

I have the 2000va multiplus so should have power to spare.

Can't measure anything in the van side of things since the multiplus is returned for warranty repair.

It's my first amp clamp, not sure if it can check volts.

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Answer 3 · 2024-02-02T00:20:56Z

markeroonie answered · Feb 02 at 12:20 AM

Update:

The tech support guy here in Australia thinks the problem was that the multiplus "thought" that the batteries were under 5% state of charge since it hadn't registered any charge going to them so shut down.

However the batteries were being charged by the solar system but the multiplus can't detect that.

Have changed a few settings and hopefully problem solved

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Answer 4 · 2024-02-02T00:21:50Z

markeroonie answered · Feb 02 at 12:21 AM

Oh, no voltage ripple worth mentioning was detected

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Answer 5 · 2024-02-02T12:04:33Z

prein answered · Feb 02 at 12:04 PM

for inductive loads, double the power is recommended by Victron. so you should be able to run a 1000W inductive load on a MP2000.

I have a MP2-3000 at 12V and can (just) run a 2000W induction cooktop on it at full power.

What I don't understand: If the MP goes into overload. normally it just continues operation once the load is removed or de MP powercycled. So what is the reason for returning the unit? Is it completely broken after one overload?

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