Adding Solar to my RW

[kjm1970]

great thanks. I did turn off all but the refer. I guess that 8 amps is what is doing it. How long could I run the AC if I had to you think? i have a total of 1500ah with the batteries.

 

[Brazos]

I might jump in and ad my two cents to this. If you did get your air to kick on you would have limited use of it before you depleted your batteries. You said you have a residential frig. During our Colorado campout last week at Camp Hale my frig used about 120 to 130 Amps from the time my charging stopped at low sun to about 7:00 the next morning. Now if you consider you have about 375 useable Amps (50%) from your 6 batteries with a full charge. You would have about 245 Amps left if your frig was similar to mine. Using other things in the rig if you do, those amps start depleting pretty quickly. You may be expecting to much if you want to run your air. Do you use a Bogart Trimetric to monitor your system or some other gauge to tell you what it is doing.
Let me ask, are you using an inverter that came with the rig for the frig along with the 3000 watt inverter you have. They both get their power from the same place, the battery bank or banks. You might want to consider using an adequate generator for the air when you want to use it and conserve your batteries. You can always switch between the two.

Remember with solar the best policy is to conserve. This will extend your battery storage. The air can be a killer.

Joe

 

[sjandbj]

great thanks. I did turn off all but the refer. I guess that 8 amps is what is doing it. How long could I run the AC if I had to you think? i have a total of 1500ah with the batteries.

Kyle,
If you had nothing else pulling power from the batteries and assuming 50% battery use you would have a little less then 30 minutes. I based that on the A/C drawing 20amps at 120 volts with a real simple calculation. To have a real accurate time more things need to be taken into account. Such as the panels providing power during the time the A/C is running the efficiency of the converter ect. Others might have a better handle since I am just starting to install my system and just basing this on a few numbers.
Regards,
Steve

 

[kjm1970]

Hi Joe,

I have two inverters. The fridge can run on the factory one if I want it. I only turn on the big inverter when we are watching TV at night, microwave, coffee in the morning. We camp on the beach a lot and we have quiet time after 9pm so we can't run the gen (I have a 5kw Onan). I just thought all of the $ I spent on the solar and accessories, I should be able to run the AC for even a little bit if I wanted to cool the rig down.
I do not have a battery monitor, I should get one. Just looking at the installation is absolutely frightening to me (I am not at all proficient with any type of electrical work).

 

[scottyb]

The only rigs I know of that try to run AC's off off batteries have 16 6V batteries and two inverters. Even then they are very limited to how much run time. I have 6 batteries and can run the RF easily overnight, with a little TV, satellite, and LED lights.

 

[Jim.Allison]

how would I fix that? my inverter is 3000w. I thought that would be plenty.

IMHO, You are not going to get any satisfaction from trying to run your A/C on inverted power.

BUT, what is happening to you is that when the load from the AC is on it demands more voltage from the batts than they can provide. Even Though they are fully charged to 12.7 plus, they may only be able to supply 11.7 (example only). Your inverter may have a setting (that might be adjustable) that tells the inverter to shut down at 11.8 (example only). This is called the "Low Voltage Cutoff".

I experienced this problem with a 1500 watt microwave. I could not understand it. I had a 3000 watt inverter, with no reason to shut down. When I started to look into it, I found that my Low voltage cutoff was set at 12.4v. It does not take much to pull more than your batt system can deliver. I adjusted the inverter LVC through the interface to 11.7 and cured my problem. Even a temporary dip below the setting will disable the inverter.

The "Low Voltage Cutoff" is designed to disable the inverter in the event that the charge of the batts drops below X charge. But temporary loads can cause the inverter to sense the low voltage even though the batts remain completely charged.

Let me state the obvious, in case you are not applying the fact that 1 AC amp is 10 DC amps. 10 AC amps is 100 DC amps. What this means is that your inverter must consume at least 50 amps DC to create 5 amps DC. So it should be easy to see why your batteries may pull down when the a/c is activated.

Good luck

 

[Jim.Allison]

I have an auto gen start for my onan. Onan has a accessory for auto genstart but Xantrex also has a auto gen start for the inverter.

I have it set to start the generator anytime my inverter cannot handle the load demand. It also starts when the batts become discharged, or if shore power is lost.

The auto gen start also has a lead to the thermostat, and will start the generator when A/C is called for.

The upshot of this is that I can boondock in Texas and cut down on LP usage because the generator only runs when needed. One of the neat features of the auto gen start is that you can set on and off times, and you can set "quiet time" if needed. You can also manual on and manual off.

This might serve your purposes if you have the components for a system like this.

 

[rxbristol]

The only rigs I know of that try to run AC's off off batteries have 16 6V batteries and two inverters. Even then they are very limited to how much run time. I have 6 batteries and can run the RF easily overnight, with a little TV, satellite, and LED lights.

VERY nice, clean, professional setup!