Help with fuse size for inverter?

Hi all, I have recently installed a 12v Solar System in my Allotment shed & I am looking at buying an inverter to charge my cordless drill batteries & use other low wattage items at the allotment. I am looking at the inverter below. I am just unsure what Amp fuse I would need to install between the battery & the inverter? Would i be right in thinking if its a 4000W inverter would I need a 400A Fuse ? Or am I being stupid? It looks like you can plug this into a 12v car cigarette lighter socket so I am assuming it wont need a high amp fuse?

Any help / advice greatly received

https://www.ebay.co.uk/itm/22521944...Q9AF1SES-K&var=&widget_ver=artemis&media=COPY



Cheers DGC808

If you can plug it into a cigarette lighter, it can't be 4000W. Looking at the specs, it is 300W which would pull 25A, it says overload protected so any fuse you supply is to protect your wires. Its modified sine wave, some electronics need PSW.

Hi TacomaJoe, thanks for the reply regarding the ? I too saw the 300W but was confused as it also states 4000W on the inverter. I was looking at maybe a 30A or 40A fuse. What is the PSW you mentioned in your reply

Thanks

DGC808

PSW is "pure sine wave". The AC power in your house is PSW, the voltage follows a nice smooth curve. A modified sine wave doesn't follow the smooth voltage curve but rather jumps in a series of steps up and down so it sort of looks like a sine wave if you squint your eyes.

Thanks for the reply, now the PSW makes sense. I am only going to be using the AC from the inverter for low wattage items like chargers & some power tools & maybe a radio & small TV at the most. So I am hoping the 30/40A fuses will be sufficient to protect the wires

Thanks

DGC808

dgc808 said:

Hi all, I have recently installed a 12v Solar System in my Allotment shed & I am looking at buying an inverter to charge my cordless drill batteries & use other low wattage items at the allotment. I am looking at the inverter below. I am just unsure what Amp fuse I would need to install between the battery & the inverter? Would i be right in thinking if its a 4000W inverter would I need a 400A Fuse ? Or am I being stupid? It looks like you can plug this into a 12v car cigarette lighter socket so I am assuming it wont need a high amp fuse?

Any help / advice greatly received

https://www.ebay.co.uk/itm/22521944...Q9AF1SES-K&var=&widget_ver=artemis&media=COPY

View attachment 121984

Cheers DGC808

Click to expand...

Don’t even think about buying it! Everything about the advert is wrong so buyer beware. Firstly as pointed out it says 4000W when it isn’t. The inverter is nowhere near the size a 4000W inverter needs to be. the cables shown to the inverter are nowhere near the size required for 4000W. The price of the inverter is about 1/10th the cost of what a 4000W inverter should be and the Ebay seller has what I consider poor feedback. Also as previously stated a 4000W inverter does nor run off a cigarette plug nor does it run through aligator clips.

Firstly, work out the total wattage that you will be using at any one time and buy an inverter about 20% higher than that.

dgc808 said:

Hi all, I have recently installed a 12v Solar System in my Allotment shed & I am looking at buying an inverter to charge my cordless drill batteries & use other low wattage items at the allotment. I am looking at the inverter below. I am just unsure what Amp fuse I would need to install between the battery & the inverter? Would i be right in thinking if its a 4000W inverter would I need a 400A Fuse ? Or am I being stupid? It looks like you can plug this into a 12v car cigarette lighter socket so I am assuming it wont need a high amp fuse?

Any help / advice greatly received

https://www.ebay.co.uk/itm/22521944...Q9AF1SES-K&var=&widget_ver=artemis&media=COPY

View attachment 121984

Cheers DGC808

Click to expand...

What a scam! I hope you did not buy it.
It is 300W and also modified sine wave,
Spec from seller: I do not think the seller even knows what he/she is selling.

Item specifics​

Condition:
New: A brand-new, unused, unopened and undamaged item in original retail packaging (where packaging ... Read moreabout the condition
Type:
Power Inverter
Brand:
Unbranded
Manufacturer Part Number:
Does Not Apply
MPN:
Does Not Apply
Colour:
Yellow
Material:
PVC
Model:
4000W Car Power Inverter
Working voltage:
12V-220V
Peak Power:
4000W
Rated Power:
300W
USB Interface:
2.1A x 2
Output Frequency:
220V 50Hz/110V 60Hz
Input Voltage:
DC 10.5V-15V
Output Voltage:
AC 110V/220V
Output waveform:
Modified sine wave
Plug:
UK Plug
Features:
durable
size:
16.3cm, 10cm, 7.7cm (L/W/H)

Add up the wattage from all the chargers (should be on a label on the bottom of the chargers) and add 25% to that for sizing the inverter. As you step up in size on the inverters there is more and more overhead power the inverter needs to feed itself that you won't get going to your batteries.

As an example, my Ryobi 18v fast chargers call for 50w each. If I wanted to have 6 chargers going at a time that's only 300w. There's no reason to spend the money or power overhead on a 3000w inverter when I'm only going to be able to use 10% of the capacity. In my case, assuming I wanted to feed all 6 chargers at once I'd go for a pure sine wave 400w inverter and call it a day.

Realistically on a 12v system you don't want to be pulling more than 1500w worth of inverter. After that you're getting into $tupid cables and fuses and losing quite a bit to inverter overhead.