How to Connect Solar Panels to Charge Batteries

Use this site for some examples and plug your values into the calculators for answers about your capacity questions.

thanks alot pal. The site was most helpful

solar panels→breakers→charge controller→breaker→battery bank

pump #1= 1120 watts

pump #2= 746 watts

total load 1866 watts

Battery bank 400 ah @ 24 vdc

So the inverter (assuming it is 2.2 kVA) can run both pumps simultaneously. Not enough info on how long they could run without know insolation and PV array.

The only problem might be starting the motors since starting current can be 6 times running current.

Agreed. But most inverters allow for a short surge.

Proceed as below.

(1) Connect two solar panels in series i.e. positive output of solar panel 1 to negative output of solar panel 2. This will form the Negative output of series connection. Similarly connect negative output of solar panel 1 to positive output of solar panel 2. This will form the Postive output of series connection.

(2) Repeat (1) with other two panels.

(3) Connect Positive output of set 1 with Positive output of set 2 & Negative output of set 1 with Negative output of set 2.

Now you have the solar panels ready for usage.

(4) Connect Positive output & Negative output to circuit breaker input, if not provided in charger controller. If PV circuit breaker is already provided in charge controller then connect Positive output of solar panel set obtained at (3) to PV positive terminal of charge controller & Negative output of solar panel set obtained at (3) to PV negative terminal of charge controller.

DONOT SWITCH ON THE CIRCUIT BREAKER AT THIS STAGE.

(5) Repeat steps 1-3 with Battery.

(6) Connect positive output of battery set thus obtained to Battery positive terminal of charge controller & Negative output of battery set to Battery negative terminal of charge controller.

PLS. TAKE CARE OF POLARITY, WHILE CONNECTING.

(7) Connect Positive output of charge controller to Positive input of inverter & Negative output of charge controller to Negative input of inverter.

(8) Switch ON Battery circuit breaker in charge controller.

(9) Switch ON PV circuit breaker.

(10) Check PV, Battery & charge controller output voltage.

(11) If all three voltages are correct, then switch ON inverter input circuit breaker.

If all equipments and connections are correct, then you are ready to deliver power to connected load.

Thanks

Ashok Toshniwal, Bangalore, India.

Sorry. Your step 1 will short-circuit and demolish panels 1 and 2, and your step 2 will do the same for panels 3 and 4.

Firstly, solar panels donot get demolished by short circuit. Inherently there is a blocking diode.

Next steps 1 & 2 are to connect the solar modules in series.

But step 1 (likewise 2) is wrong (as phph001 points out)--draw yourself a diagram and pay careful attention to your words. You are creating a "loop" of each two panels, i.e., a short circuit.

Agreed, and apologies for this silly error. Connection should be Negative output of panel one to Positive output of Panel two. Similarly for the second set as well. Positive output of panel 1 in set 1 is to be connected to Positive output of panel 1 in set 2 & Negative output of panel 2 in set 1 is to be connected to Negative output of panel 2 in Set 2. Positive output thus obtained is the positive output of solar bank & Negative output thus obtained is the negative output of solar bank.

Similar procedure for battery also.

Thanks and regards

Ashok Toshniwal

Sorry. Think again. All that a blocking diode does is prevent reverse flow (from the battery to the solar panel when there is not enough light). If you short circuit a solar panel when the light is bright you will get maximum current flow, just like shorting a battery.

A solar panel is not a battery. If short circuited, Isc, the short circuit current will flow, that's all. This should be measured anyways so that it's as close to the same as possible for each panel in a string.

Be careful setting up your string and diligent when grounding. An electrician I know says a bite from DC is a real kick in the ass.

Thanks alot. Your reply is very detailed. ' will get back to you should i encounter any challanges.

Read comments 5, 6, and 8 before following the steps in #4.

Pls read my comment 4 along with reply 15 which is correction to 4.

Thanks and regards

Ashok Toshniwal,

You're assuming what the nominal voltage of the PVs is and what the charge controller is. The panels may be 24VDC and the charge controller may be MPPT allowing 96VDC input.

Yes, I am assuming this as a standard requirement. It is very plain and obvious that ALL equipment, including charge controller, must be of matching voltages.

Thanks and regards

Ashok Toshniwal

Obvious to you, yes. As for the original poster, they can speak for themselves. As an engineer, people will act on your recommendations, complete or not, correct or not. Safety, money and project completion will be affected- don't give them room to screw it up.

You should be able to put your DC side (solar array, battery array, and DC inverter input) in parallel.

When you do this, the input and output voltages need to be compatible. If the inverter DC side voltage is nominally 24V, then you should configure the battery array in 2 parallel strings of 2 batteries in series to produce 24 V.

Same for the solar array. If you have 24V panels, an array of 4 panels in parallel will work, if you have 12V panels arrange same as the batteries, a string of 4 6 volt panels in series will produce 24V for you.

You need to configure things so that things

http://www.google.co.uk/search?q=solar+panel+charge+controllers&sourceid=ie7&rls=com.microsoft:en-US&ie=utf8&oe=utf8&rlz=1I7GPCK_enGB411&redir_esc=&ei=yv8VTaX1Jsm0hAfP7PW2Dg

Happy Christmas