question

teloth avatar image
teloth asked

Multiplus II GX under reporting AC loads ?

Hi

Recently bought Multiplus II GX.

1 x American style Fridge Freezer , confirmed power usage around 200W

1 x Freezer , power usage around 80W

I can confirm power usage with Smart Socket adapters , also with a plug in wattMeter type device.

There are some weird discrepancies the way MultiPlus II GX is reporting AC loads.

It appears to be significantly under reporting usage Watts , unless I am missing something here ?

For example

Apparently my total AC usage, when both fridge freezer and Freezer is connected , but neither of them running shows me around 30 Watts usage. FridgeFreezer has around 6W and Freezer is around 2W standby usage. 3 socket power adapters 1W each , should be around 11 wats total standby usage . So , I am guessing it is also adding its specified 11w no load and using some power for inverting to make the 8w , extra 10w to make 8 watts ?? Anyway , this is not the issue.


If I have 30W AC loads with these connected but they are not running ( just on standby , compressor not running ) , how on earth when my Freezer runs , it only shows me 86 Watts ? This should be 116 Watts , but it shows 86 Watts

Likewise , when my Fridge Freezer kicks in , I know it uses around 200W , so this figure should be around 230 Watts , but usage shows 147 watts.

I have included all eventuality screenshots when devices are in passthru mode , showing true power usages , along with my socket power screenshots and inverter mode screenshots.


I thought pictures speak louder than words..


Does anyone have any ideas why this is ?


Any help is appreciated.


Thanks











Multiplus-II
passthrufridgefreezeronly.png (101.3 KiB)
passthrufreezeronly.png (100.3 KiB)
passthrufridgefreezerandfreezertogether.png (104.2 KiB)
passthrufridgefreezerandfreezertogether.png (104.2 KiB)
fridge-freezer-watts.png (55.9 KiB)
freezer-watts.png (64.9 KiB)
invertingfreezeronly.png (98.8 KiB)
invertingfridgefreezeronly.png (97.6 KiB)
invertingfreezerandfridgefreezer.png (100.9 KiB)
invertinnoloads.png (111.8 KiB)
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2 Answers
Rob Duthie avatar image
Rob Duthie answered ·

Hi

Yes these mulitplus AC readings are not accurate as stated by the manufacture as it is not revenue type metering etc, from its internal CTs, but if you use a external current meter ET112 for single phase it is very accurate.

This has being documented.

Regards

Rob D

NZ

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teloth avatar image
teloth answered ·

Hi Rob

Can you please point me to the right direction where it explicitly states on official documentation for these products to say Battery monitor function is not accurate or reliable?

One would expect if a battery monitor is present within capability of a device, I don't think it is unreasonable to expect within reason correct level of AC loads being reported and taken into account which has big impact on SOC displayed by the system.

Even my dealer told me prior to my purchase no need to add an external Battery monitor as there are no DC loads , this unit will do the battery monitoring just fine.

Of course whilst I don't expect a " Basic " monitoring system to be within 1% of true Input / AC loads / SOC , variance of 30 -40% difference is basically a guesswork , I can do better job just looking at my battery voltages.

Even in CCGX manual ( i know we are not talking about CCGX specifically , but Multiplus II GX is basically what it is , an upgraded version of a Multiplus + GX built in ) , explicitly states ...

" No battery monitor is required: the Multi or Quattro is the only product connected to the battery and has full control over all charge and discharge currents. Therefore it can calculate the correct SOC itself. "

Yes, I know this and that can be added , ie. energy meter to get system running as it is supposed to be and promoted as , but disappointing to say the least.

Would any Victron staff / members like to comment if this could be addressed and hopefully if it is a matter of software change / configuration , which can be implemented in future releases?

Thanks

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