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AC/DC Dynamics and Hubble battery issue


Michaelx3

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Hi all,

I've recently had an inverter/battery (no solar) installed and running into an issue.

While running off the battery, the battery will go into error mode randomly whenever the load seems to be more than about 1kw. The ALM light turns a solid red on the battery and switching it off and on fixes the issue until the next random trip. While connected to Eskom I don't have this issue, I can even run my kitchen appliances with no issue.

Hardware:

Battery: Hubble AM-4 2.75kw

Inverter: AC/DC Dynamics PV18-3K (3kw)

Inverter settings:

Maximum charging current: 40, Maximum Utility charging current: 20, Battery Type: User defined, Bulk Charging Voltage (CV Voltage): 29, Floating charge voltage: 28, Battery stop discharging when grid is available: 23.5, Battery equalization: Ed5, Battery equalization voltage: 28.8

My electrician has been in contact with Hubble and we have tried their recommendations and nothing seems to help.

I'm wondering if this is not possibly an inverter-related issue and what the best way to figure this out would be?

Cheers,

Michael

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  • 2 weeks later...

Lithium batteries should not be equalised by the inverter - the BMS inside the battery will take care of this - disable inverter equalisation.

Your battery seems to be rated at 1C - that means it should deliver +- 2.6kw constant output when required - you have a 3kw inverter - so if you are exceeding the battery output of 2.6kw it may throw an alarm.

It should not do this if your load is less than that though... you will need to monitor things a little closer the next time your power goes out - or simulate an outage by tripping your mains and then see what is happening - your inverter should show you load values.

Then also, I think (others can chip in here) you should set your CV to 28v and Float to 27,5v if it allows for such values, otherwise just make both 28v.

Cheers

 

 

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Thank you for the response Douw.

I've done some more testing and if I unplug my fridge (about 5 years old) the issue stops happening, I've tested this over multiple load-shedding cycles. 

During loadshedding the only appliances connected are my desktop computer  (+-500 watt under max load) or TV (100w), Router and maybe one light. Randomly when the fridge switches on it will "trip" the battery. I tested the fridge with a watt meter and it hits about 1000w when the compressor starts.

Testing with a very high powered device like a toaster (1.5kw) or air fryer (2kw) will also trip it but not every time.

I've adjusted the CV settings accordingly and will test over the next few days. I've also double-checked and the BMS and it is disabled (Ed5=Disabled according to the manual)

Thanks,

Michael

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2 hours ago, Michaelx3 said:

Thank you for the response Douw.

I've done some more testing and if I unplug my fridge (about 5 years old) the issue stops happening, I've tested this over multiple load-shedding cycles. 

During loadshedding the only appliances connected are my desktop computer  (+-500 watt under max load) or TV (100w), Router and maybe one light. Randomly when the fridge switches on it will "trip" the battery. I tested the fridge with a watt meter and it hits about 1000w when the compressor starts.

Testing with a very high powered device like a toaster (1.5kw) or air fryer (2kw) will also trip it but not every time.

I've adjusted the CV settings accordingly and will test over the next few days. I've also double-checked and the BMS and it is disabled (Ed5=Disabled according to the manual)

Thanks,

Michael

You have correctly identified the problem. The fridge can perhaps draw up to 2kw when it starts. Add the desktop and you are at the maximum the battery can provide. I have also alerted to this on another Fred. 

Your power meter does not sample fast enough to actually show the peak. The same one will find with a clamp meter. The best way I have found to get closer to the peak starting power or amps is to take a video and then scroll through frame by frame. I measured a bar fridge at 98Ax12.5V=1.225kW. This might not even be the peak as mentioned. Another example was 140A at 13.5V while car engine was running. 

Thus nothing wrong with the battery or inverter. 

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10 hours ago, Scorp007 said:

You have correctly identified the problem. The fridge can perhaps draw up to 2kw when it starts. Add the desktop and you are at the maximum the battery can provide. I have also alerted to this on another Fred. 

Your power meter does not sample fast enough to actually show the peak. The same one will find with a clamp meter. The best way I have found to get closer to the peak starting power or amps is to take a video and then scroll through frame by frame. I measured a bar fridge at 98Ax12.5V=1.225kW. This might not even be the peak as mentioned. Another example was 140A at 13.5V while car engine was running. 

Thus nothing wrong with the battery or inverter. 

Thanks Scorp,

Last night it tripped while watching TV (TV (+-100w), Media Center PC (<100w), Router (<50w)) so the fridge must be pulling a lot of power during the start but it makes sense.

So my options are:

Upgrade the batteries to allow for higher peak draw, take the kitchen off the inverter or replace the fridge. 😞

Thanks guys for all the help

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8 hours ago, Michaelx3 said:

Thanks Scorp,

Last night it tripped while watching TV (TV (+-100w), Media Center PC (<100w), Router (<50w)) so the fridge must be pulling a lot of power during the start but it makes sense.

So my options are:

Upgrade the batteries to allow for higher peak draw, take the kitchen off the inverter or replace the fridge. 😞

Thanks guys for all the help

A fridge using high power might also draw more power while running. Thus buying another is a gain for years to come. Buying another battery just for this will also cost more than the fridge :)

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4 hours ago, Scorp007 said:

A fridge using high power might also draw more power while running. Thus buying another is a gain for years to come. Buying another battery just for this will also cost more than the fridge :)

I fully agree with Scorp - new fridge first if you can.  Otherwise take kitchen off inverter for now until you can get a new fridge - your fridge will stay cold for at least 4-5 hours while off.

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1 hour ago, Douw G. Gerber said:

I fully agree with Scorp - new fridge first if you can.  Otherwise take kitchen off inverter for now until you can get a new fridge - your fridge will stay cold for at least 4-5 hours while off.

A have mentioned the high draw of up to 10 times the running power when a fridge starts. I was waiting to see members reporting this when using smaller lithiums with a 0.5C peak current. Now we have a smaller 1C battery with some other loads on cracking when a fridge starts. 

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11 hours ago, Scorp007 said:

A have mentioned the high draw of up to 10 times the running power when a fridge starts. I was waiting to see members reporting this when using smaller lithiums with a 0.5C peak current. Now we have a smaller 1C battery with some other loads on cracking when a fridge starts. 

I have to say though - my Dyness is a 0.5c battery and I have not had any such issues with my fridge.  I do think the more modern fridges are more efficient. I think aircon's are also something to consider.

Cheers

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13 hours ago, Douw G. Gerber said:

I fully agree with Scorp - new fridge first if you can.  Otherwise take kitchen off inverter for now until you can get a new fridge - your fridge will stay cold for at least 4-5 hours while off.

😞 unfortunately, I'm in a very old flat and there is only 1 breaker for all the plugs so I don't think the kitchen can be removed off the inverter but I will get an electrician to check it out.

It's a Whirlpool fridge and only about 8 years old and I see it says 280w on the sticker (attached) so using Scorp's calculation it could max out at about 2.8kw then.

Oh well, thanks for the input, looks like I'm doing some shopping.

IMG_20230111_104759.jpg

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4 minutes ago, Michaelx3 said:

😞 unfortunately, I'm in a very old flat and there is only 1 breaker for all the plugs so I don't think the kitchen can be removed off the inverter but I will get an electrician to check it out.

It's a Whirlpool fridge and only about 8 years old and I see it says 280w on the sticker (attached) so using Scorp's calculation it could max out at about 2.8kw then.

Oh well, thanks for the input, looks like I'm doing some shopping.

IMG_20230111_104759.jpg

Wait before you go buy a fridge - get an electrician to check out your DB - one breaker for all plugs?  Could work if you have very few plug I guess.  I agree fridges have a high start-up surge, however my Samsung friddge is 10 years old and doesn't trip my battery...

Can you maybe post a pic of your DB

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54 minutes ago, Douw G. Gerber said:

Wait before you go buy a fridge - get an electrician to check out your DB - one breaker for all plugs?  Could work if you have very few plug I guess.  I agree fridges have a high start-up surge, however my Samsung friddge is 10 years old and doesn't trip my battery...

Can you maybe post a pic of your DB

Yup, I'm going to ask him when he gets back from holiday, he mentioned to me why he couldn't remove the kitchen but I can't remember exactly what the reason was.

Here is the board (he replaced the breakers for me as the originals were super old). The flat was built in the 60's, with less than 10 plugs in the whole place.

image.thumb.jpeg.9aad10749865bcbe8b3a187270297e73.jpeg

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8 hours ago, Douw G. Gerber said:

Wait before you go buy a fridge - get an electrician to check out your DB - one breaker for all plugs?  Could work if you have very few plug I guess.  I agree fridges have a high start-up surge, however my Samsung friddge is 10 years old and doesn't trip my battery...

Can you maybe post a pic of your DB

Just looking at the details. Does your Samsung draw 280W when running? 

Are you having a 24V battery that can only provide 50A before hitting the 0.5C level? This is about 1200W available to start the fridge. 

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