inverter fuse size

[roadroamer]

I am fitting a 3500w 7000w pure sine wave inverter and I am baffled as to what size fuse/circuit breaker to put in the positive lead from the battery your help please the reason for fitting a large inverter is I had a 2500w 5000w inverter which went bang using a 1500w coffee maker and the supplier said it is not man enough for it so rejected my warranty claim

 

[wildebus]

Maths would tell you that I = P/V . So Power (3500W) / Voltage (nominal 12V) would give you a current of ~300A. If you want to cope with the 7000W peak, then you need a 600A fuse.

I find in the real world I draw a touch under 200A when using either my 2kW Water Heater or 2kW Induction Hob at Full Power. For the use you have, I would probably go with a 200A and 50mm2 cable between Battery and Inverter to cope with that current level (recognising you cannot run the inverter near to close power with this fuse + cable combo).
The other thing to decide is what TYPE of fuse - at this current level, fuses get pretty warm. The main choice at that level of current rating is between ANL and MEGA Fuses - You need a fuse AND Fuse Holder that can withstand the heat.

If a supplier says his 2500W inverter cannot run a 1500W coffee maker, then he is saying his inverter is not a 2500W inverter (or even a 2000w one) and not fit for purpose. I draw 2200W from my 2400W inverter with no problems.

 

[DTDOG]

I had a 2500w 5000w inverter which went bang using a 1500w coffee maker and the supplier said it is not man enough for it so rejected my warranty claim

Seems a bit dodgy to me?
a 2,500w isn't 'man enough' for a 1,500w power draw? Yes, it is!!
Even if you used a 1,000w inverter and tried to run a 1,500w source I'd just expect the inverter to shut down and restart once the drain source has been removed.

 

[wildebus]

Seems a bit dodgy to me?
a 2,500w isn't 'man enough' for a 1,500w power draw? Yes, it is!!
Even if you used a 1,000w inverter and tried to run a 1,500w source I'd just expect the inverter to shut down and restart once the drain source has been removed.

Many Inverters (poor ones) will blow their internal fuses if used above their capabilities rather than go into overload shutdown.

 

[jagmanx]

Inverters Aaaargh !
Why ? anything over 500 Watt = enormous draw on battery bank
OK Wildebus is an exception as he has

• the knowledge
• an enormous batter bank
• loads of Solar

But he says that in winter he needs EHU sometimes !

Same with "Geeky Phil" and some others

 

[roadroamer]

just a quick update on the inverter problem the company has now agreed to replace the old inverter like for like so I wont be fitting a 3500w 7000w inverter it will be the same as the old one 2500w 5000w and I have ordered a 200a fuse/trip switch to put in the large + wire hope this is the right size thanks for all your help

 

[wildebus]

just a quick update on the inverter problem the company has now agreed to replace the old inverter like for like so I wont be fitting a 3500w 7000w inverter it will be the same as the old one 2500w 5000w and I have ordered a 200a fuse/trip switch to put in the large + wire hope this is the right size thanks for all your help

Be interested what Inverter you bought.
Ref the breaker/trip ... I may have been unlucky but I have not had a great deal of success with the Breakers - they have tended to trip way before the quoted current rating so while they are a neat idea, I've stuck to fuses

 

[roadroamer]

this is the fuse/breaker I got from amazon
Almencla 200AMP DC 12V-24V Car Protection Audio Inline Circuit Breaker Fuse Holder
and the inverter is from ebay same as this one 0764880646863 but I ordered mine from Germany

 

[wildebus]

this is the fuse/breaker I got from amazon
Almencla 200AMP DC 12V-24V Car Protection Audio Inline Circuit Breaker Fuse Holder
and the inverter is from ebay same as this one 0764880646863 but I ordered mine from Germany

The breaker looks identical to the ones I have used and that tripped early. Please do test and report back if works as required or not.

The Inverter is very similar to one I had. I also had an Edecoa 2500W (5000W Peak) PSW unit but looked slightly different (FWIW, I had this one - https://amzn.to/2MB874j). I used this inverter with a 2000W+ load and it worked fine and I regard EDECOA as a decent brand so I think you were probably just unlucky with the first one.

 

[roadroamer]

I will report back once I get the fuse/trip I should receive it on the 10th Nov that's when it's should be delivered (that's the trouble when you order from China) LOL

 

[St3v3]

My edecoa was really noisy, and died very quickly at very low load. Went back to Amazon for a refund, which went very easily Went Victron after that.

 

[St3v3]

It was good to prove the fridge principle though

 

[wildebus]

My edecoa was really noisy, and died very quickly at very low load. Went back to Amazon for a refund, which went very easily Went Victron after that.

Interesting. I also got a refund on my Edecoa but that was after 10 months of use (and when used, high power use). I also found it very quiet.
I guess maybe their QC needs to be tightened up?

I still maintain that if you want a fully reliable inverter you sadly need to spend proper money on it and get a Victron or something of that class (which is one of the reasons the 2500W Edecoa is now a 2400W Victron)

 

[St3v3]

TBF, it was a sensible price, and could have been quite good.

 

[Avocadopicker]

I blew the 8 x 40A fuses on my 2500W PSW inverter, driving an 800W microwave. Now using a Photonics 3000/6000W PSW inverter with thermal resettable fuses. At those high amperages not sure that 50mm cables are enough (I use 70mm). Also found that the '300A' resettable circuit breaker crapped out at less than 100A, the (Chinese) supplier instantly refunded, suggesting that the real rating is far less than the sticker, but that most users don't approach it. I'm now using 250A Mega fuse and run hairdryer, microwave, coffee maker, toaster, with no bother at all. Hairdryer runs around 65A, microwave maybe 130A. Having 400AH of Lithium battery helps too, as lithium is quite happy with high discharge rates

 

[wildebus]

At 3000W draw you would be wanting 100mm2 cable if any distance from the battery bank.

There are so many inverters out there that are very poor. I think the suppliers know that few people who buy them do - or are actually able to run them with their battery bank - at close to the rating and so never get found out.