Battery Bank Question

[Blackhawk]

I'm starting out this new project with a concept of running garage off of Solar. I have been researching this for a long time but have one question, Do all your batteries have to be the same in AMP Hours? If I have 8 batteries all of them need to be 100AH? What if it is not? Do you get over charging? Fire?

I am getting ready to buy a battery to start out and needed to make sure that the battery is still going to be around if you have to stay the same.

Thanks for your help.

APC

[Mike90250]

Sort of like tires on a car. Works best if they are all matched (from the same mfg lot ! )

And filled up (air pressure = charge volts) one low one affects the whole car, and will eventually go bad

(I'm heading out this AM to get some drain rock and sand in the trailer, which uses 90psi in the tires)

[thastinger]

What are your load demands?

[Blackhawk]

Awesome explanation - OK another question!

Thank you for that answer. Makes sense.

Another question bear with me:

Running off the bank of batteries you have an inverter. That inverter is 5000w. I'm fine with that part, but what if I wanted to replace the 5000w inverter with 2 inverters at 2300w.
Can I parallel them together on the output side to make 4600Ws? Or do I have to run both the 2300w separate to its own set of breakers?

****Thought Process***** Better to have 2 inverters just incase one fails you are not all the way down.

Thank you,

APC

[Blackhawk]

Load demands

What are your load demands?

I'm going to be running a few lamps, little TV, radio and a freezer. Freezer is not going to be until I get a bigger bank of batteries. I'm starting with one battery right now.
Plan on running every thing in the garage in the future. Watts total about 3500 for everything.

My panels right now are (3) 100w 12v panels. Not big at all to start out with, I know.

Thanks,

APC

[inetdog]

Thank you for that answer. Makes sense.

Another question bear with me:

Running off the bank of batteries you have an inverter. That inverter is 5000w. I'm fine with that part, but what if I wanted to replace the 5000w inverter with 2 inverters at 2300w.
Can I parallel them together on the output side to make 4600Ws? Or do I have to run both the 2300w separate to its own set of breakers?

****Thought Process***** Better to have 2 inverters just incase one fails you are not all the way down.

Thank you,

APC

You can only parallel two inverter outputs in two situations:

1. They are grid tie inverters ,so the grid synchronizes them automatically.
2. The are off-grid inverters of the same model from the same manufacturer and the manufacturer supports synchronized output with some sort of communication harness between the units. Xantrex and Outback among others have inverters with that capability.

A typical interconnect will keep one inverter shut down to standby mode when the power demand is low and split the load between inverters as the load increases above the maximum efficiency point of a single inverter. (Not necessarily only after it exceeds the maximum load of one inverter.)

[Sunking]

Running off the bank of batteries you have an inverter. That inverter is 5000w.

You neeed to know what you are asking for. To run a 5000 watt Inverter requires a 48 volt battery that weighs 2400 pounds, cost $8000 every few years with replacement. All that to use a few dollars of electricity a year. Why do you want to do that? Just send me the check for $8000 and we will both be tinkled pink.