Comparing Power from Different Solar Panels on a 12 volt Array

[BajaBob]

Hi,

We are looking to expand our 12 volt solar power system.
We currently have two Kyocera KC130 panels.
(Full system info at the bottom)

We've been told this:

I recommend adding at least two more big solar panels, minimal. Something like the BP3230T (230 watts each = 460 watts, @ 8 amps each = 16 amps), plus the two Kyocera KC130TM 130s, would deliver approximately 32 amps of energy

The two KC130s are delivering a total of 15 amps to the batteries.
__


So, I'm confused.
It would appear that the 230 watt panels would provide no more power than the current 130 watt panels.

Am I misunderstanding this situation ?
What is the best way to compare the power of different solar panels ?


Also-

I've been told by others that,
if put in the same array on our 12 volt system-

the 130 panels at 12 volts
would limit the 230 panels at 20 volts
to no greater power output than the smallest panel,
the 130 panels.

Is that true ?

Thanks for your time !

Sincerely,
Baja Bob
__

The system is 12 volt:
Outback MX60 PV MPPT (Maximum Power Point Tracking) Charge Controller,
Trace Inverter model DR2412 (2400 watt) Modified Sine Wave,
Samlex Inverter Full Sine Wave PST-60S-12A 600 Watt Pure Sine Wave Inverter, 12VDC-120VAC,
2 Kyocera 130 W Solar Panels 12 volt
6 Crown L16 batteries

[Sunking]

So, I'm confused.
It would appear that the 230 watt panels would provide no more power than the current 130 watt panels.

Am I misunderstanding this situation ?
What is the best way to compare the power of different solar panels ?


Also-

I've been told by others that,
if put in the same array on our 12 volt system-

the 130 panels at 12 volts
would limit the 230 panels at 20 volts
to no greater power output than the smallest panel,
the 130 panels.

Is that true ?

Both statements are true. When you parallel solar panels the output voltage is limited to the lowest voltage in the pairings. This is why you do not mix solar panels.

[Mike90250]

You would need to put the new 230W panels on a MPPT type charge controller, in order to harvest their full power into a 12V system.

read this article about MPPT

http://www.windsun.com/ChargeControls/MPPT.htm

[Sunking]

I would say also it is time to move up from 12 volts to 24 volts. 12 volt systems are really for RV's and experiment projects. You are moving up to a power level that dictates you to move up to 24 volts or higher. A 60 amp MPPT charge controller is limited to around 700 watt power input, where as 24 volts you can go up to 1400 to 1500 watts.

[BajaBob]

Comparing Power from Different Solar Panels on a 12 volt Array

Hi,

Thanks very much for your responses.

This has been recommended to deal with our situation:

The remedy is to wire the two of them in series to produce double the voltage or 34 volts, that will do the job. Fortunately you have the mighty fine Outback MX60 MPPT charge controller that is capable of bringing in up to 150 vdc from the solar array; higher is better, more efficient.


I recommend this for the KC130s (series connecton) and parallel wire two BP3230Ts, keep the voltage at 36.7. Doing so would create a voltage that is almost equal for the two two different makes.


This arrangement would produce 720 watts/hr of solar energy for the battery bank. That would make them happy!


What do you think of this proposal ?

Thanks for your help !

Sincerely,
Baja Bob
__

The system is 12 volt:
Outback MX60 PV MPPT (Maximum Power Point Tracking) Charge Controller,
Trace Inverter model DR2412 (2400 watt) Modified Sine Wave,
Samlex Inverter Full Sine Wave PST-60S-12A 600 Watt Pure Sine Wave Inverter, 12VDC-120VAC,
2 Kyocera 130 W Solar Panels 12 volt
6 Crown L16 batteries

[BajaBob]

Hi,

I received this email message from the forum last night, but the new reply does not appear in the forum. I'm confused. Very interested in seeing all responses !

BajaBob
_______

In a message dated 5/5/11 1:54:26 AM, feedback@solarpaneltalk.com writes:


Dear BajaBob,

ledlightmax has just replied to a thread you have subscribed to entitled - Comparing Power from Different Solar Panels on a 12 volt* Array - in the Technical Solar Talk forum of Solar Energy Forum | Solar Panel Questions | Solar Help Desk.

This thread is located at:

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Here is the message that has just been posted:
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There may also be other replies, but you will not receive any more notifications until you visit the forum again.

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[Sunking]

I received this email message from the forum last night, but the new reply does not appear in the forum. I'm confused. Very interested in seeing all responses !

Not the Moderator on this forum, but my guess is it was SPAM and a Moderator deleted the post. Don't worry about it as the info was worthless.

[BajaBob]

Thanks for the info !

Any thoughts about this latest proposal ?

BajaBob
___

The remedy is to wire the two of them in series to produce double the voltage or 34 volts, that will do the job. Fortunately you have the mighty fine Outback MX60 MPPT charge controller that is capable of bringing in up to 150 vdc from the solar array; higher is better, more efficient.


I recommend this for the KC130s (series connecton) and parallel wire two BP3230Ts, keep the voltage at 36.7. Doing so would create a voltage that is almost equal for the two two different makes.


This arrangement would produce 720 watts/hr of solar energy for the battery bank. That would make them happy!

[russ]

He was a spammer - so post deleted

[Mike90250]

Thanks for the info !

Any thoughts about this latest proposal ?

BajaBob
___

The remedy is to wire the two of them in series to produce double the voltage or 34 volts, that will do the job. Fortunately you have the mighty fine Outback MX60 MPPT charge controller that is capable of bringing in up to 150 vdc from the solar array; higher is better, more efficient.


I recommend this for the KC130s (series connecton) and parallel wire two BP3230Ts, keep the voltage at 36.7. Doing so would create a voltage that is almost equal for the two two different makes.


This arrangement would produce 720 watts/hr of solar energy for the battery bank. That would make them happy!

I don't knw the specs on the panels, but as long as the series panels are within 10% of the same amps, and the parallel panels/strings are also within 10% of Vpmax, your MPPT controller will be happy.

[BajaBob]

Thanks much for your response !

With these specs below, will it perform as proposed ?

Thanks again !
BajaBob
__

Specs for Kyocera KC130TM 130:

Electrical Specifications:
Maximum Power: 130 watts
Tolerance: +10%/-5%
Maximum Power Voltage: 17.6 volts
Maximum Power Current: 7.39 amps
Open Circuit Voltage: 21.9 Voc
Short-circuit Current: 8.02 amps

Max. System Voltage (12/24/48V Nominal): 600 volts
Series Over-current Protection: 15 amps


Specs for the BP3230T 230 watts panel are:

[BajaBob]

Whoops!
That image didn't post.
And I don't have a font that can handle their terms . . .

Here's the website where those BP3230T 230 watts solar panel specs can be viewed:

http://www.posharp.com/bp3230t-solar-panel-from-bp-solar_p1054696977d.aspx

Thanks much for your time !

BajaBob

[BajaBob]

So to put these both in the same posting for easier comparison:

Specs for Kyocera KC130TM 130:

Electrical Specifications:

Maximum Power: 130 watts
Tolerance: +10%/-5%
Maximum Power Voltage: 17.6 volts
Maximum Power Current: 7.39 amps
Open Circuit Voltage: 21.9 Voc
Short-circuit Current: 8.02 amps

Max. System Voltage (12/24/48V Nominal): 600 volts
Series Over-current Protection: 15 amps
__

Specs for the BP3230T 230 watts panel are:

(Guessing their terminology equates to. If I've got that wrong, pleasee let me know.)

Electrical Specifications:

Maximum Power: 230 watts
Tolerance: +5%/-3%
Maximum Power Voltage: 29.1 volts
Maximum Power Current: 7.90 amps
Open Circuit Voltage: 36.7 Voc
Short-circuit Current: 8.40 amps

Max. System Voltage (12/24/48V Nominal): 1000 volts
Series Over-current Protection: 20 amps

[zdavesf]

Like Mike and others have already mentioned if you parallel the old panels with the new ones and use one controller you will not be using the full potential of the new panels. The there max voltage on the new panel is 29.1 and the old panels is 17.6. meaning that the new panels will only work at 17.6 volts a loss of 11.5v (40%) which if using a MPPT controller (assuming 100% which its not) your new 230watt panels would really only be around 138 Watts!!

leave the existing setup as it and buy a new MPPT charge controller for the new panels and attach it to the existing battery bank (parallel the outputs of the charge controllers.)


at least that's the way i see it, someone else jump in if I got lost... I too am still new to the whole solar world

Dave

[BajaBob]

Hi Dave,

Thanks for your response. I've been involved with the solar power system in Baja for about 6 years, but I'm no expert. Our trusted technician has recommended this setup, but I've gotten mixed reviews on it from various knowledgeable sources- so I am compelled to understand more of the situation before Green Lighting it.

I'm wondering if these separate Series/Parallel wired panels will make for the voltage being indeed higher?

Or if what you have said is indeed true, and there is no way to get the higher voltages from the 230 watt panels without a second charge controller ?

All info on this greatly appreciated !

BajaBob

This, again, is that recommended setup for these two types of panels on our 12 volt system:

I recommend adding at least two more big solar panels, minimal. Something like the BP3230T (230 watts each = 460 watts, @ 8 amps each = 16 amps), plus the two Kyocera KC130TM 130s, would deliver approximately 32 amps of energy

The two KC130s are delivering a total of 15 amps to the batteries.


The remedy is to wire the two of them in series to produce double the voltage or 34 volts, that will do the job. Fortunately you have the mighty fine Outback MX60 MPPT charge controller that is capable of bringing in up to 150 vdc from the solar array; higher is better, more efficient.


I recommend this for the KC130s (series connecton) and parallel wire two BP3230Ts, keep the voltage at 36.7. Doing so would create a voltage that is almost equal for the two two different makes.


This arrangement would produce 720 watts/hr of solar energy for the battery bank. That would make them happy!

And this is the current system:

The system is 12 volt:
Outback MX60 PV MPPT (Maximum Power Point Tracking) Charge Controller,
Trace Inverter model DR2412 (2400 watt) Modified Sine Wave,
Samlex Inverter Full Sine Wave PST-60S-12A 600 Watt Pure Sine Wave Inverter, 12VDC-120VAC,
2 Kyocera 130 W Solar Panels 12 volt
6 Crown L16 batteries