Condition: Terminal

Lumisol · May 2017

I was wondering if there is any advantage current wise to connecting the batteries, controller outputs and inverter inputs to a separate connection point vs just running the controller outs and inverter ins to terminals and stacking them on the battery lugs themselves.

Photowhit · May 2017

It's simpler wiring. Many/most systems will be somewhat modular and have a 'power center' with the inverter and breakers and charge controller with a single heavy wire run to the battery box. You can use an E-panel that already setup to have all your breakers; main for inverter, incoming breaker between panels and charge controller and out going breaker from charge controller to battery and even out going from Inverter to sub panel or load. This would also often/normally have your ground to neutral bond.

https://www.solar-electric.com/midnite-solar-mne175sm-samlex-e-panel.html

You can do all of this in a DC Disconnect box, Has everything, but the AC, with no installed shunt.

https://www.solar-electric.com/midcdipocepl1.html

I've used the smallest of the E-Panels, more as a DC disconnect box with no AC breakers, tight but will have 3 incoming and out going charge controllers, and breakers for the inverter. Al that goes to the battery is a temperature sensor and 2-4/0 cables.

This is what it looked like with 2 array's coming in from the back, makes for a pretty clean install;

Image: https://us.v-cdn.net/6024911/uploads/editor/id/nmwmr8yylc5e.jpg

There are 2 temperature sensors running to the battery box (on right) since I had not linked the charge controllers at this point. I also added a 2nd inverter above the first one and used the open Din rail breaker, where the AC breakers were originally mounted with an exclusion breakers for transferring to generator. Midnite doesn't recommend the use of Din Rail Breakers for inverters, I'm not sure exactly why, but it was a smallish 1100 watt inverter, that I use for yard work and they have din rail breakers large enough...

Lumisol · May 2017

Nice set up.
But as far as the flow of current, is there any advantage to a center terminal? My batteries are agm and are much closer to the inverter and controller than yours are.

Photowhit · May 2017

Yes, since your wires will be larger for the inverter, there will be less voltage drop, but it will be minimal, also a simpler connection rather than stacking connectors (though putting one on either side of the flag will largely solve this.)

BTW - My batteries are in the box on the right, 4 feet...

Lumisol · May 2017

Good points. I was looking at something like this: http://www.autozone.com/batteries-starting-and-charging/battery-terminal-end-and-adapter/battery-doctor-stud-bolt/25419_0/?_requestid=1653946
for the two lugs, one at each connector. My breakers are small and in line.

My batteries will be about where your epanel is now.

This will help explain what I have:

Image: https://us.v-cdn.net/6024911/uploads/editor/5t/9un4ibg8omwu.jpg

What is the white backer board you are using? I like the look of it. Do you use any insulation to help prevent condensation? Is Insulation a good idea or is it better to ventilate the cabinet so air can move through but with louvers to prevent water from entering?

Photowhit · May 2017

I'm not aware of a 125 amp in line breaker, I do worry that you might be cutting too many corners.

It's just wood, the inverter is raised above the wood, The E-Panel should be, I used some spacers and it is too close, but the wood is not the back wall of the enclosure. I may go ahead and install the spacers when I add the 3rd Charge controller. and rewire the E-Panel. I need to take it down and move the shunt so I can install Midnite's amp monitor, the Whiz Bang Jr.

Lumisol · May 2017

125 amp inline breaker for where? I have 70 amps max to the inverter and 30 amps max from the CC to the batteries. I have 2 10 amp breakers (one on each string) in the combiner box.

Image: https://us.v-cdn.net/6024911/uploads/editor/hw/1v7zjqxlhlis.jpg

Photowhit · May 2017

Sorry no specs on system. Please check your inverter's manufacturer's recommendation for breaker. I wouldn't want to run a 2800 watt load on a 3000 watt inverter... Likely want a 4000 watt or better.

Likely your panels will want a 15 amp breaker, but perhaps not...

I do have specs for the charge controller, 2x 8.6 amps at 89 volts or 17.2 amps at 89 volts = @1531 watts, incredibly small for your planned load! 1531 watts/48 volts= >30 amps

Lumisol · May 2017

2800 watt load? For what? My largest load is 700 watts, and that is only for a couple minutes at a time to heat something in the microwave.
The inverter specifies a 70 amp 48 volt breaker or fuse.

Lumisol · May 2017

I just looked and you are right. There is no 125 amp breaker. There is 120 and 150 amp but not a 125 amp.

Photowhit · May 2017

Sorry, I mixed up 2 threads.

mcgivor · May 2017

Photowhit said:

Sorry, I mixed up 2 threads.

Was wondering about that, an air conditioning load perhaps, seems like @Lumisol has a pretty good grasp on things so far, really hope everything works out,, you made some good choices in equipment, going 48v is a plus, you'll never regret that, please follow up when the system is installed and working, there will always be some bugs to sort out but from my perspective things look good.

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