800 watts microwave output is a lot less than input. Our 900 watt has an input of 1400 watts.

 

Your battery can't cope with amps required.

What type of battery do you have?  

The answer to your question and the solution has been provided if you have an AGM.  If you have a LiFePO4 voltage is not an accurate way to measure SOC so without a shunt a battery could a display a SOC higher than it actually is.

I note in an earlier post you had a Redarc Manager 30, which would mean you have a shunt.  You also posted that you installed a 120Ah Itechworld LiFePO4.

If this is your setup now then I would suggest that something could be wrong but my first question is whether the system has been working previously when the battery is at this SOC level.

You may actually be drawing more current than the BMS is capable of and it could be that the BMS is shutting down resulting in the low voltage alarm on the inverter.

We also need to ensure that that you set up the battery capacity in the Redarc Manager.

If you do have LiFePO4 then at 65% SOC I would not expect an inverter shutdown except for the reasons above.

Tim 

 

-- Edited by TimTim on Friday 25th of October 2024 07:05:54 PM

Firstly thanks to everyone for their comments Yes Tim I have a 120amp lithium Started using the microwave at a lower setting of 700 watt The voltage of battery dropped down to 11.7 and it remained for the 2 mins I normally use it for To add another battery am I right in saying more solar would be needed to support this ? Currently only have a 150watt panel on roof Plus another portable used when in the shade Im very much aware that microwaves are battery killers and I use sparingly few minutes at a time depending on time of day

Firstly thanks to everyone for their comments Yes Tim I have a 120amp lithium Started using the microwave at a lower setting of 700 watt The voltage of battery dropped down to 11.7 and it remained for the 2 mins I normally use it for To add another battery am I right in saying more solar would be needed to support this ? Currently only have a 150watt panel on roof Plus another portable used when in the shade Im very much aware that microwaves are battery killers and I use sparingly few minutes at a time depending on time of day

goldenyears wrote:

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Firstly thanks to everyone for their comments Yes Tim I have a 120amp lithium Started using the microwave at a lower setting of 700 watt The voltage of battery dropped down to 11.7 and it remained for the 2 mins I normally use it for To add another battery am I right in saying more solar would be needed to support this ? Currently only have a 150watt panel on roof Plus another portable used when in the shade Im very much aware that microwaves are battery killers and I use sparingly few minutes at a time depending on time of day

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 Well we do not know whether your SOC was accurate when you first stated you were at 65% when it occurred. So without extensive testing you will never know.  You could try charging your battrery until it does not accept any more current, as it may display 100% SOC before that occures.  You should then have an accurate SOC to commence with provided the Redarc Mangers setting are correct.  You could then test the microwave on full power down to a level where the alarm is activated again.

As Are We Lost stated another battery will prevent it from happening.  Having another battery does not necessarily mean you need more solar.  Provided you are producing more power than you are using each day then your solar is sufficient.  The advantage of having another battery though would be that your power would last you longer through inclement weather.  Then when the sun is shining it doesnt matter whether it takes a couple of days or a week to get back up to be fully charged.

If I were you I would put out your portable, whether in shade or not, to maximise your solar production.