How much power should 265 watt grape solar panels put out?

[ice2484]

265-Watt Mono-Crystalline Solar Panel (4-Pack) Grape solar
http://www.homedepot.com/p/Grape-Sol...b1x4/205481289


Are these panel good and how much power should they put out?

[sensij]

265-Watt Mono-Crystalline Solar Panel (4-Pack) Grape solar
http://www.homedepot.com/p/Grape-Sol...b1x4/205481289


Are these panel good and how much power should they put out?

To answer half of your question, by definition, they will put out 265W under standard test conditions.

To answer the other half requires a lot more information... what do you plan to do with them?

[SunEagle]

Did you check out the one review for those panels. The person indicated that the 265watts was calculated using the open circuit voltage Voc time the short circuit amperage Isc. That is wrong

A panel wattage is determine by the max power voltage Vmp times the max power amps Imp. I did not see any mention of the Vmp or Imp for those panels so beware they might not be what they claim to be.

[sensij]

Did you check out the one review for those panels. The person indicated that the 265watts was calculated using the open circuit voltage Voc time the short circuit amperage Isc. That is wrong

A panel wattage is determine by the max power voltage Vmp times the max power amps Imp. I did not see any mention of the Vmp or Imp for those panels so beware they might not be what they claim to be.

The data sheet is on the right hand side of the product page, where it normally is for Home Depot stuff. It looks fine, the person commenting was wrong, and I flagged that review.

[Sunking]

Did you check out the one review for those panels. The person indicated that the 265watts was calculated using the open circuit voltage Voc time the short circuit amperage Isc.

I read that, but the reviewer is blowing SMOKE. One conclusion he did make was bogus about the panel would have to be 41% efficient. The panel square area is 1.62541/m2 Based on the Watts / M2 = 265 / 1.6254 = 163 watts per square meter is 16.3% efficient which is within reality for a mono panel with 17% being average. Based on that observation the reviewer has no credibility.

After a little research I found the manufacture specs. Vmp = 31.2 Imp = 8.5, Pmax = 265 watts. The numbers jive. However you will never see that wattage, and if you look at the specs they will tell you that because they also specified the PTC rating which is real world application of PTC = 236 watt and efficiency listed as 19%

[SunEagle]

The data sheet is on the right hand side of the product page, where it normally is for Home Depot stuff. It looks fine, the person commenting was wrong, and I flagged that review.

You are correct. I didn't see that spec sheet just the short specification description which was not very clear.

[ice2484]

So should you take off about 20 to 30 percent and you have your real world
watt output?

I am curious to how many watts you really should get out of a solar panel?

[Sunking]

So should you take off about 20 to 30 percent and you have your real world
watt output?

I am curious to how many watts you really should get out of a solar panel?

Look for the PTC or CEC rating. If your panel does not have either PTC or CEC rating pass it up. The Grape solar panel has a PTC rating.

[russ]

For a location near you - a 1 kW DC system which is about like 4*265 watt panels

Requested Location
Weather Data Source	(TMY2) MOBILE, AL 43 mi
Latitude	30.68° N
Longitude	88.25° W
DC System Size	1 kW
Module Type	Standard
Array Type	Fixed (open rack)
Array Tilt	20°
Array Azimuth	180°
System Losses	14%
Inverter Efficiency	96%
DC to AC Size Ratio	1.1
Average Cost of Electricity Purchased from Utility	0.11 $/kWh
Initial Cost	3.70 $/Wdc
Cost of Electricity Generated by System	0.22 $/kWh

1,358 kWh per Year *
RESULTS

3.51	89	10
4.33	99	11
5.00	120	13
5.58	131	14
5.67	133	15
5.63	126	14
5.39	124	14
5.30	122	14
4.95	111	12
5.06	122	13
3.75	90	10
3.68	92	10
4.82	1,359	$ 150

[sensij]

deleted. previous posters covered it.

[jimindenver]

My 230w poly peaks around 216w. My 245w mono's peak around 220w. So 236w from the 265 panel sounds pretty normal.

[ice2484]

Do you have to have all the same kind of solar panels on one charger conroller?

Say if you got some mismatch panels that are 30v and some 36v.
Seem like they would fight each other.

If the charge controller goes up to 55v.

[inetdog]

Do you have to have all the same kind of solar panels on one charger conroller?

Say if you got some mismatch panels that are 30v and some 36v.
Seem like they would fight each other.

If the charge controller goes up to 55v.

A very good question.
There is a rule of thumb that applies to MPPT CCs, namely that if you are putting panels in series (which you cannot do with your low input limit) you need to match Imp values within 5%, 10% if you are willing to accept larger losses for a good reason.
If you put panels in parallel, then you need to match Vmp within 5% instead.
In your case the mismatch is close to 20%, and you will lose a lot of power by paralleling the panels.
If the MPPT algorithm of the CC is particularly simple, you might not get any contribution from the lower voltage panels at all because their Voc is lower than the Vmp of the higher voltage panels.

Now if you have a PWM controller (or a fake MPPT controller) you will not lose any more power than you would from the bad voltage mismatch of both sets of panels to the 18V Vmp ideal.

[ice2484]

Is it ok to run 2 charge controllers on same battery bank?

[Mike90250]

Is it ok to run 2 charge controllers on same battery bank?

yes, if you have both of them set up right. Each controller should have it's own PV array.