Problems...300 watt, (3) 12 volt system

[hoosier1]

Having problems...I have (2) panels (300 watts), (3) 12 volt batteries, 30a controller, 3500 (6000 watt peak) watt inverter. All fused with breakers. When I connect a window AC, the breakers trip. My watt meters shows a constant 800 watts, but after 5 min, trips?

[SunEagle]

The simple answer is that AC needs a lot more power to start then what your inverter & solar/battery system can provide.

What is the Ah rating of those batteries and how are those 2 x 300watt panels wired to your 30A CC and is it a PWM or MPPT type?

[Wy_White_Wolf]

3500W is 291 amps @ 12VDC. Can your breakers and wiring sized to handle that?

800W is 67Amps @12VDC. Can they even handle that?

Add to that that your array and battery bank are undersized for that big of a load.

WWW

[hoosier1]

Connected: (2) solar panels total of 300 watts, 30a breaker on positive side, 30a pwm controller, digital readout, (3) 12 volt, 105ah batteries connected in parallel, 150 breaker on positive side, 3500 watt (6000 watt) inverter. The window AC operates on 800 watts, but have read need 2500 watt start up. So, the problem...current greater than 150amp on the AC startup? Inverter output: 2500/120=20.83 amps? What suggestions?

[SunEagle]

First off those 3 x 105Ah battery system can only generate about 3780 watt hours ( 3 x 105Ah x 12v = 3780wh) over a 20 hour period. So a 800watt load will try to drain it way too fast and can cause and under voltage condition on the DC side of the inverter.

Second, a 3500/6000watt 12volt inverter can draw over 300amps (3500w / 12v = 291 amps) so that 150amp breaker on the DC side can trip way before you can power up the Air conditioner unit.

[hoosier1]

So increase batteries 4+? I will only use AC for 4-5 hours in a day. 300 amp breaker between batteries and inverter...or?

[SunEagle]

So increase batteries 4+? I will only use AC for 4-5 hours in a day. 300 amp breaker between batteries and inverter...or?

I am not sure exactly what you need to do. I just tried to proposed a couple of reasons a circuit breaker may trip. Remember that an air conditioner does not just start up and run but can cycle the compressor if the temperature is not met. Sometimes a couple of quick on/off cycles is enough to over heat a circuit breaker causing it to trip.

Maybe you should first measure the amperage being used and record what happens just before the breaker trips. It could be due to a surge or if the amps are higher then you calculated the breaker may trip to over heating.

Adding a 4th battery may help run your air conditioner but it will also increase the chances of not charging or discharging the 4 batteries equally which tends to kill one of them quickly.

[Logan005]

12 volt inverters are mostly junk, A 6000 BTU AC could be run from a 24 volt inverter minimum and you will have much better performance from a 48 volt battery bank and inverter. Let me guess, mix matched, used batteries. reclaimed jumpers and terminals. Got any fuses on this home made bomb?

[SunEagle]

12 volt inverters are mostly junk, A 6000 BTU AC could be run from a 24 volt inverter minimum and you will have much better performance from a 48 volt battery bank and inverter. Let me guess, mix matched, used batteries. reclaimed jumpers and terminals. Got any fuses on this home made bomb?

I believe the OP does have overcurrent protection in a few places. The problem is they trip at some point soon after starting up the air conditioner which could mean they are not sized big enough or the ac unit is drawing higher amp surges.

Oh I just thought about something. So of those window units actually have a heat strip in them that increases the load tremendously. Hopefully the OP does not have one of those ac units or has disabled the heating section.

[hoosier1]

All equipment is new...no mix match. May not be the most expensive, but is mid-line. 12 volt inverters are not mostly junk...not sure where you come up with that idea. I agree 24 volt and even 36 volt is better, but it's all in what you run off your system. My inverter does have overload current, short circuit protection, etc. I believe SunEagle has identified the possible problem...the breaker and number of batteries. Still learning...Thanks!

[Logan005]

good to hear. ditch the 12 volts. get yourself a nice 48 volt inverter and another battery and you can run your AC for an hour or so. yes 12 volt inverters are mostly junk if you expect more than a few hundred watts. 12 volts is for cars and toys, not for running refrigeration.

[Wy_White_Wolf]

What wire are you running on the 12V side that can handle 150 amps? Couple that voltage drop with the voltage sag from the undersized battery bank and your inverters LVD should be tripping off. Is that the breaker that you have tripping?

WWW

[hoosier1]

2/0 between batteries and inverter. 150 amp breaker tripping. May exclude running AC for now.

[Sunking]

Having problems...I have (2) panels (300 watts), (3) 12 volt batteries, 30a controller, 3500 (6000 watt peak) watt inverter. All fused with breakers. When I connect a window AC, the breakers trip. My watt meters shows a constant 800 watts, but after 5 min, trips?

So what is the problem? It should trip.

[SunEagle]

So what is the problem? It should trip.

That is what I told him would happen whenever that AC unit started it would draw a lot more amps which could easily exceed 300amp which is far more than that 150A breaker.

[NiHaoMike]

Having problems...I have (2) 300w solar panel), (3) 12 volt batteries, 30a controller, 3500 (6000 watt peak) watt inverter. All fused with breakers. When I connect a window AC, the breakers trip. My watt meters shows a constant 800 watts, but after 5 min, trips?

I am also facing the same issue.