Furstrated- Unable to get rated solar Amperage

[Sunking]

Hello again
I had the tech visit again.
They checked the controllers are found them fine. Now they are thinking to replace the Panels.
Perhaps they'll give me 42v ones like you suggested.

However I have insisted that i'd like to try MPPT before swapping anything. Lets see how it goes.

Your so called tech is dumber than a rock. A single good quality MPPT controller is a lot less expensive then new panels.

[bhvm]

Sorry for the delayed update. I had a heated talk with the Dealer and He is finally giving me MPPT. He already tried various PWM and max i got was 550W out of a 1000W worth of 4 Panels.

The MPPT he's giving me is-

http://www.systellar.in/solar-power-backup-system.html

http://www.systellar.in/public_html/systellar.in/userfiles/files/Charge%20controller/MPPT/MPPT%20CC%20-%20Technical%20specs%20Apr%202014.pdf

http://www.systellar.in/public_html/systellar.in/userfiles/files/Charge%20controller/MPPT/User%20Manual%20MPPT%20Charge%20controller.pdf

Problem is, the model is rated only upto 20A. 40A model is not available.
Is it okay to use two MPPT in parallel to generate 40A for batteries? (By putting 2 panels per controller)

However this MPPT is on Non-refundable basis, so if I get less output, damage is mine. What ya say folks? Jump the gun?

[mapmaker]

Problem is, the model is rated only upto 20A. 40A model is not available.
Is it okay to use two MPPT in parallel to generate 40A for batteries? (By putting 2 panels per controller)

Yes, you can use 2 controllers on the same battery. Each controller will need its own array... that means each array will need its own cable to its own controller.

I know nothing about the quality of the controllers you mention, but given that your installer has proven himself to be unqualified, why do you trust him to sell you a controller that he has never used or installed?

--mapmaker

[bhvm]

Yes, you can use 2 controllers on the same battery. Each controller will need its own array... that means each array will need its own cable to its own controller.

I know nothing about the quality of the controllers you mention, but given that your installer has proven himself to be unqualified, why do you trust him to sell you a controller that he has never used or installed?

--mapmaker

I understand your concerns,map maker.
as I have paid advance cash for lump sum project to him, I will be for a loss if I leave him. that's why it's mandatory to get the project done from said person.

that aside ,reading the pdf spec and manual makes me feel that these are absolute high end controllers one can have in India. actually it's me who found these controllers but he will be buying them on my behalf.
I will report back once they land up here. thanks

[Sunking]

Sorry for the delayed update. I had a heated talk with the Dealer and He is finally giving me MPPT. He already tried various PWM and max i got was 550W out of a 1000W worth of 4 Panels.

That would be correct for PWM.

[bhvm]

That would be correct for PWM.

oh my! you mean pwm is only 55 percent efficient? and how efficient I'd Mppt then?

wish I had come to this site before. could have saved a lot of headache!

[mapmaker]

oh my! you mean pwm is only 55 percent efficient? and how efficient I'd Mppt then?

A PWM controller can be much more efficient, or much less efficient than 55%. It depends on the overall system design.

Same holds for MPPT. I could design a system where the PWM would be more efficient than the MPPT.

--mapmaker

[Sunking]

At the very best a PWM is 66% efficient. MPPT up around 95%.

[inetdog]

At the very best a PWM is 66% efficient. MPPT up around 95%.

When used with the standard V_MP to nominal battery voltage ratio anyway.... (e.g. 18V panel for 12V battery system.)

[bhvm]

bad news

I bring in a Bit of bad news folks,
One of the Battery in the system seems to be giving up.

Battery-
Flood Lead Acid Tubular Deep cycle (exide branded)
12v Nominal
165 AH

Of late the battery feels hot to touch. Assuming ambient near 35.C, be battery temperature stays around 42~43.C Irrespective of Charge or Floating voltage or Discharging load. Similar battries in other units do no exhibit such behaviour.

What could be the issue? Why is Battery heating up?

P.s- My Clamp meter says that battery is continuously eating about 6 amps from neighboring batteries or charger.

[mapmaker]

Batteries- 12v Lead acid 150 AH in series for 24 system

I bring in a Bit of bad news folks,
One of the Battery in the system seems to be giving up.

Battery-
Flood Lead Acid Tubular Deep cycle (exide branded)
12v Nominal
165 AH

Of late the battery feels hot to touch. Assuming ambient near 35.C, be battery temperature stays around 42~43.C Irrespective of Charge or Floating voltage or Discharging load. Similar battries in other units do no exhibit such behaviour.

What could be the issue? Why is Battery heating up?

P.s- My Clamp meter says that battery is continuously eating about 6 amps from neighboring batteries or charger.

That hot battery is ruined, probably has a shorted cell. Remove it immediately... it is going to ruin the rest of your batteries. How many batteries are in your battery bank?

--mapmaker

[bhvm]

Thanks for the blazing fast reply. I have removed the battery promptly. It appears to be around 50.C. even after removal.

As an upgrade, I am thinking to Parallel 2x 150AH batteries for total 300AH.

How many batteries can be charged using a 20A MPPT charge controller? One? two?
Some people say single battery should not be charged more than 10A? How true is that?

Reason is, The new MPPT charge controller is only rated at 20A. I am thinking to get 2 Charge controllers, and Hooking each one to its own battery system. The batteries will be finally paralleled before sending to the inverter.
-------------------------------------------------------------------------------------------
I have 2 batteries in my 24v system 150AH
and Single battery in a separate 12v system 165AH

Both the Systems are in the que for MPPT charge controller upgrade. The MPPT in question is auto select 12 or 24v, with 4 stage temperature compensated charging but rated at only 20A.

[mapmaker]

As an upgrade, I am thinking to Parallel 2x 150AH batteries for total 300AH.

So that would be four 12 volt batteries in a 24 volt system. How many did you have before you removed the hot one?

Previously you wrote:

My Clamp meter says that battery is continuously eating about 6 amps from neighboring batteries or charger.

That implies that you already had at least 4 batteries.

How many batteries can be charged using a 20A MPPT charge controller? One? two?
Some people say single battery should not be charged more than 10A? How true is that?

You should be able to charge at 10% (in amps) of the capacity in amphours. For a 300 ah battery bank you can put in 30 amps. I forget... are those AGM batteries? If so, you can double or triple that charge rate without harm.

I am thinking to get 2 Charge controllers, and Hooking each one to its own battery system. The batteries will be finally paralleled before sending to the inverter.

If the batteries are in parallel then so are the charge controllers. That's not a problem... you can parallel as many chargers as you wish. Generally you should NOT parallel batteries. If you parallel new batteries with old batteries, the new batteries will last no longer than the old batteries. It is difficult with parallel batteries to get the charging current to divide evenly among the parallel pathways... especially so with AGM batteries.

--mapmaker

[bhvm]

1) I tried shufling the battery to troubleshoot any issue with chargers or Location, But the battery stays hot even after shuffling. As a result i have marked it as bad battery

2)My batteries are Flooded lead acid, tall Tublar ones. AGMs do not suceed in India due to Heavy heat and poor power conditions.

3) I have placed order for amaron 150AH x 2 Tall tublar units. As a result I won't be mixing new and old battery.

[paulcheung]

Sorry to tell you the MPPT charge controller you listed won't work with your system. The maximum input voltage is 70volts and one of your panel VOC is 36volt which will be 72 volt when you put them in series. So that is no no. hope you didn't buy them yet.