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Forum Index : Electronics : Automotive Circuit Breakers

Posted: 07:22am
14 Apr 2024
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Godoh
Guru

I put an automotive circuit breaker in my last inverter build. The inverter runs great, manages to put out 3600 watts to charge the car and runs quietly.
But the automotive type circuit breakers that I tried trip out way under their rating.
I have tried a 200 amp and a 150 amp breaker, they both trip out at around 100 amps.
I am thinking of just fitting a fuse to protect the inverter in case of a blowup, as industrial breakers are very expensive, especially as I would need a 175 to 200 amp breaker.
When the inverter is supplying 15 amps to the car it is pulling around 163 amps from the solar panels.
Does anyone know of a reasonably priced breaker that will do the job?
Any suggestions welcome
Pete
 
Posted: 10:58am
14 Apr 2024
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Solar Mike
Guru

I have used these in several locations: Link

However a suitably rated T class type fuse bolted directly at the battery bank in series with the breaker is a good idea. Breakers are great when isolation is required for working on equipment, but a fuse is more reliable.

Cheers
Mike
 
Posted: 09:56pm
14 Apr 2024
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Godoh
Guru

Thanks Mike, I do have 160 amp fuses on the batteries.
When I am charging the car very little if any current is coming from the batteries, so I wanted to make sure that if there is an inverter fault that there is a breaker to isolate it.
I have circuit breakers on the inlet and outlet of my solar regulators, but did not just want to trust them to trip in the event of a blowup on the inverters.

Thanks heaps for the link
Pete
 
Posted: 11:28pm
14 Apr 2024
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Solar Mike
Guru

Pete are your solar regulators running an inverter to charge your EV directly, if the battery has little loading.

Reason I ask is I want to setup approx 3.6Kw PV array to charge our EV using the supplied granny 2Kw 230vac charger. I was going to make a small 120vDC to 230vac inverter powered from the PV, however if the output drops due to cloud cover etc the main contactor relay in the car clunks off and on excessively, so a small bank of batteries would be required to even out the demand, which greatly adds to the cost.

Cheers
Mike
 
Posted: 02:05am
15 Apr 2024
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Godoh
Guru

HI Mike, my system is setup that the solar panels are connected to the regulators adn to a 660 amp hour 24 volt battery bank.
I have a victron Battery monitor that has a settable relay in it.
So I set it that when the batteries are at 100% charge the relay closes turning on the dedicated inverter that runs the car charger.
I bought a fairly cheap charger that allows me to charge the car at 6, 8, 10, 13, or 15 amps. So I adjust the charge rate to the amount of solar power coming in.
On a totally clear day I can run it at 15 amps easily, on very cloudy days I drop it down.
So once the batteries are full the regulators basically feed the inverter directly, but the batteries act as a buffer when clouds go over the panels.
I found that the MG charger which is only 8 amps output would not reset itself when the inverter turned off at the bottom setpoint ( 95% battery charge)
The newer ebay adjustable one has no problems , if the inverter is switched off by the BMV then the car just waits, when the inverter switches back on the charging starts again.
Pete
 


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