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FRIDGE TRIPPING OFF 32A FUSE FOR 3KVA HYBRID INVERTER!

mrobinson

mrobinson

New Member
Joined
Mar 16, 2021
Messages
7
G'day, I've attached a pic of my new recent setup which is carrying my lights and ceiling fans OK but when I switch on my LG fridge (which I had upgraded for max efficiency and thus have NO idea what Wattage it's consuming), the 32A fuse attached b/w the 12V 200AH Batteries and 24V 3KVA Inverter, trips off at the initial surge load!

Pls can anyone help me resolve this before I buy my Solar Panels as am currently charging my two 12V 200AH Batteries via Inverter AC Input to my Gasoline generator.

Pls help a newbie Nigerian (African Continent; Lagos-Nigeria) out. PLS, PLS....
 

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Well, I guess, your fuse is slightly too small to put it mildly. If you have a 24V system (based on your 24V inverter), then 32A only allows for 24V x 32A = 768W - far below what your inverter actually can do and probably way too less then the startup requirement for your frigde. You should use a "bigger" fuse - up to 125A should be feasible. For a start try 80A or 100A.
 
Welcome to the forums!

The non-surge maximum amps a 3000W inverter pulls at 24V should be 3000 / 24 = 125 amps on the DC side.

So, the 32 amp fuse should probably be increased. But, make sure the wires have the proper gauge to handle the current so they don't start a fire
(look up the ampacity to see the minumum gauge size then use a calculator to ensure for the length the gauge is correct for the voltage drop). If you decide to use a breaker, be sure it is a DC breaker, AC breakers won't work for DC applications. Also, watch out for cheap breakers, a lot of members have been caught off guard by breakers that failed (some have started putting fuses inline with the breaker just to be safe).
 
KaFun said:
Well, I guess, your fuse is slightly too small to put it mildly. If you have a 24V system (based on your 24V inverter), then 32A only allows for 24V x 32A = 768W - far below what your inverter actually can do and probably way too less then the startup requirement for your frigde. You should use a "bigger" fuse - up to 125A should be feasible. For a start try 80A or 100A.
Click to expand...
Thank you so much
KaFun said:
Well, I guess, your fuse is slightly too small to put it mildly. If you have a 24V system (based on your 24V inverter), then 32A only allows for 24V x 32A = 768W - far below what your inverter actually can do and probably way too less then the startup requirement for your frigde. You should use a "bigger" fuse - up to 125A should be feasible. For a start try 80A or 100A.
Click to expand...
svetz said:
Welcome to the forums!

The non-surge maximum amps a 3000W inverter pulls at 24V should be 3000 / 24 = 125 amps on the DC side.

So, the 32 amp fuse should probably be increased. But, make sure the wires have the proper gauge to handle the current so they don't start a fire
(look up the ampacity to see the minumum gauge size then use a calculator to ensure for the length the gauge is correct for the voltage drop). If you decide to use a breaker, be sure it is a DC breaker, AC breakers won't work for DC applications. Also, watch out for cheap breakers, a lot of members have been caught off guard by breakers that failed (some have started putting fuses inline with the breaker just to be safe).
Click to expand...
Thank you so much
 
The way to find out how much amperage your pulling is to put a dc clamp meter that holds top reading on the negative wire between battery & that all in one unit you have. Then you will know what size fuse you need. Or start with 100 amp in line fuse and if it blows you need bigger. 125 or 150?
 
RStone13 said:
The way to find out how much amperage your pulling is to put a dc clamp meter that holds top reading on the negative wire between battery & that all in one unit you have. Then you will know what size fuse you need. Or start with 100 amp in line fuse and if it blows you need bigger. 125 or 150?
Click to expand...
Thanks, this was helpful
 
svetz said:
Welcome to the forums!

The non-surge maximum amps a 3000W inverter pulls at 24V should be 3000 / 24 = 125 amps on the DC side.

So, the 32 amp fuse should probably be increased. But, make sure the wires have the proper gauge to handle the current so they don't start a fire
(look up the ampacity to see the minumum gauge size then use a calculator to ensure for the length the gauge is correct for the voltage drop). If you decide to use a breaker, be sure it is a DC breaker, AC breakers won't work for DC applications. Also, watch out for cheap breakers, a lot of members have been caught off guard by breakers that failed (some have started putting fuses inline with the breaker just to be safe).
Click to expand...
Hello again, thanks so much for the helpful info last post. So far, I can only find 2-pole 125A Circuit Breakers here in Nigeria. Though the costs are manageable, it brought up the situation I might meet with the Solar Panels when I buy them; so for my situation where I plan to have a total of 4 12V 200AH Batteries and 4 Solar Panels Max (that's all the space I have in my flat):-

1) Do I buy Mono or Poly Solar Panels?
2) What Wattage of Solar Panels is best for my 24V Inverter and Batteries?
3) Is it even a good idea I increase my batteries by two to a total four batteries for my 24V Inverter?
4) What Amps Circuit breaker do I buy for my Solar Panels ( I want to buy 2 first then increase to 4 depending on Question 2 above)?

Thanks again for your invaluable help on this.
 
KaFun said:
Well, I guess, your fuse is slightly too small to put it mildly. If you have a 24V system (based on your 24V inverter), then 32A only allows for 24V x 32A = 768W - far below what your inverter actually can do and probably way too less then the startup requirement for your frigde. You should use a "bigger" fuse - up to 125A should be feasible. For a start try 80A or 100A.
Click to expand...
Hello again, thanks so much for the helpful info last post. So far, I can only find 2-pole 125A Circuit Breakers here in Nigeria. Though the costs are manageable, it brought up the situation I might meet with the Solar Panels when I buy them; so for my situation where I plan to have a total of 4 12V 200AH Batteries and 4 Solar Panels Max (that's all the space I have in my flat):-

1) Do I buy Mono or Poly Solar Panels?
2) What Wattage of Solar Panels is best for my 24V Inverter and Batteries?
3) Is it even a good idea I increase my batteries by two to a total four batteries for my 24V Inverter?
4) What Amps Circuit breaker do I buy for my Solar Panels ( I want to buy 2 first then increase to 4 depending on Question 2 above)?

Thanks again for your invaluable help on this.
 
RStone13 said:
The way to find out how much amperage your pulling is to put a dc clamp meter that holds top reading on the negative wire between battery & that all in one unit you have. Then you will know what size fuse you need. Or start with 100 amp in line fuse and if it blows you need bigger. 125 or 150?
Click to expand...
Hello again, thanks so much for the helpful info last post. So far, I can only find 2-pole 125A Circuit Breakers here in Nigeria. Though the costs are manageable, it brought up the situation I might meet with the Solar Panels when I buy them; so for my situation where I plan to have a total of 4 12V 200AH Batteries and 4 Solar Panels Max (that's all the space I have in my flat):-

1) Do I buy Mono or Poly Solar Panels?
2) What Wattage of Solar Panels is best for my 24V Inverter and Batteries?
3) Is it even a good idea I increase my batteries by two to a total four batteries for my 24V Inverter?
4) What Amps Circuit breaker do I buy for my Solar Panels ( I want to buy 2 first then increase to 4 depending on Question 2 above)?

Thanks again for your invaluable help on this.
 
mrobinson said:
...Though the costs are manageable...
Click to expand...
Check on the price of fuses over breakers. Breakers are mighty convenient, but often times not worth the cost.

mrobinson said:
I plan to have a total of 4 12V 200AH Batteries and 4 Solar Panels Max (that's all the space I have in my flat):-

1) Do I buy Mono or Poly Solar Panels?
Click to expand...
See Comparing Solar Panels
mrobinson said:
2) What Wattage of Solar Panels is best for my 24V Inverter and Batteries?
Click to expand...
Doesn't make a difference, the SCC just needs to be selected for the panel input range and the battery output range.

mrobinson said:
3) Is it even a good idea I increase my batteries by two to a total four batteries for my 24V Inverter?
Click to expand...
Theoretically a 24V inverter is more efficient and overall less expensive (higher voltages run lower amps so you don't need as-thick wires, but the wire length is generally short). In practice, it may depend more on the inverter's capabilities. The most important things about inverters are:
  1. sine wave or modified sine wave
  2. Continuous and Surge ratings
  3. Efficiency
  4. Standby power consumption
  5. Reliability/warranty/support
#3 and #4 are often overlooked, and quite frequently drag an otherwise good system down. I'd say get one with an efficiency over 92% and standby consumption under 10W (even 10W on 24 hours a day is 240 watts per day).

mrobinson said:
4) What Amps Circuit breaker do I buy for my Solar Panels ( I want to buy 2 first then increase to 4 depending on Question 2 above)?
Click to expand...
The breakers protect the wires. So, definitely less then the ampacity of the wire. Otherwise, less than the watts of the inverter. E.g., if you get a 3kW inverter and decide on 12V, that's 3000 / 12 = 250 amps.
 
Really recommend you do an energy audit.

With 24 volts and 400 ah of power, that is around 4800 watt hours of usable battery power. That may be the correct, but you don't know until the energy audit. Some fridges are energy hungry, and will go through that much in a day, others the same size may only go through 1200. If you have a couple of bigger fans running, this all can add up. You've only mentioned fridge and lights, but this needs to be done with whatever high energy appliances you use for the hottest and coldest times of year.

Typically I use 400 watt hours in a night, but when its cold and my Propane heater uses the blower motor, I jump up to 2000 watt hours a night. I can't even consider AC off the system I have.
 
Connecting panels: back of panel will tell you amperage & voltage & watts of panel, either kind is good (about the same) Connecting in parallel voltage remains the same, amperage & watts is sum total of all panels. Connecting in series amperage remains the same, voltage & watts is sum total of all panels.
Charge controller input rating will tell you max amount of input. So no need to buy more panels than controller can handle. You can buy less and add later if you want. Remember your batteries & inverter are 24v so your panels connected must be more than 24v total. or they will not charge the battery. "Note" Mppt controller= parallel or series connection of panels/ PWM controller=parallel connection of panels only
 
Last edited:
RStone13 said:
Remember your batteries & inverter are 24v so your panels must be more than 24v total. or they will not charge the battery.
Click to expand...

Since the 24 volt batteries probably float around 27 volts and charge around 29 volts, and equalization around 32 volts, probably need panels rated for 33 + volts. The minimum panel wattage will be in the SCC owners manual. PWM chargers tend to be less above charging voltage, and MPPT charge tend to be more above charging voltage.
 
Chrisski is correct. I said more than 24volt, it should be more. The higher voltage the better just not more than controller can handle.
 
Last edited:
mrobinson said:
Hello again, thanks so much for the helpful info last post. So far, I can only find 2-pole 125A Circuit Breakers here in Nigeria.
Click to expand...

Be careful - if those circuit breakers are rated for AC not for DC, they will probably fail to function and could catch fire if opened under load.

Fuses rated for your DC voltage and current are more common. Some cheaper fuses are adequate for car batteries that can deliver about 3000A into a short circuit. Higher quality fuses rated 10,000 AIC or 20,000 AIC are available and are needed for larger battery banks.

If your batteries are lead-acid then a fuse rated 6000 AIC (amps interrupting capability) is probably sufficient but if they are lithium then use a class T fuse rated 20,000 AIC.

There are circuit breakers suitably rated for DC. I don't know what you can find. One available in the US is:

www.invertersupply.com

Outback Power PNL-175-DC - Inverter Supply

Shop for Outback Power PNL-175-DC at Inverter Supply for best prices online. Outback Power PNL-175-DC, Outback Power, PNL-175-DC, 175 Amp 125 VDC 3/8 stud terminals, Outback Accessories
www.invertersupply.com


The battery wires in your picture look skinny. If carrying 125A, those should be 2 awg or larger.
And shorter is better, to reduce voltage drop.
 
svetz said:
Check on the price of fuses over breakers. Breakers are mighty convenient, but often times not worth the cost.


See Comparing Solar Panels

Doesn't make a difference, the SCC just needs to be selected for the panel input range and the battery output range.


Theoretically a 24V inverter is more efficient and overall less expensive (higher voltages run lower amps so you don't need as-thick wires, but the wire length is generally short). In practice, it may depend more on the inverter's capabilities. The most important things about inverters are:
  1. sine wave or modified sine wave
  2. Continuous and Surge ratings
  3. Efficiency
  4. Standby power consumption
  5. Reliability/warranty/support
#3 and #4 are often overlooked, and quite frequently drag an otherwise good system down. I'd say get one with an efficiency over 92% and standby consumption under 10W (even 10W on 24 hours a day is 240 watts per day).


The breakers protect the wires. So, definitely less then the ampacity of the wire. Otherwise, less than the watts of the inverter. E.g., if you get a 3kW inverter and decide on 12V, that's 3000 / 12 = 250 amps.
Click to expand...
Thanks so much, the info from the Cali Go DB was very helpful.
 
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