diy solar

diy solar

Measurement question ...

It almost has to be the MC4 splitters then, don't you think? Maybe try some different ones from a different manufacturer? I've had the metal sleeves in them come loose before.
 
Each of the three ports on both splitters test ok, meaning they show no resistance on the ohm meter and they pass the full 21 volts and 110 watts that each panel was producing. With all three panels connected, the result was 185 watts, why not 330 watts?
 

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Thank you for the photo showing infinite resistance when measuring ...well, cant tell what. But, I'm confident that it eliminates St. Elmo's effect, field suppression effects from alien UFOs, and that the DMM battery has some power. ;-)

Any luck in getting any of these?
svetz said:
,,,What sort of power do you get from them if they are in series or the power from two in parallel (using panels A+B, B+C, and A+C)?
Click to expand...
svetz said:
  • While testing charging, put a big load (heat gun?) on the bluetti DC or AC output (depends on the manufacturer/model, but some will both run the load and charge from solar, so if with no load it's trimmed back the input wattage perhaps that will convince it to stop that)
Click to expand...
 
svetz said:
Thank you for the photo showing infinite resistance when measuring ...well, cant tell what. But, I'm confident that it eliminates St. Elmo's effect, field suppression effects from alien UFOs, and that the DMM battery has some power. ;-)

Any luck in getting any of these?
Click to expand...
\

Infinite resistance, hardy har har! I didn't have the test leads hooked up I was just showing off my old meter which by the way is not an entirely good meter for this application for two reasons: One, it is not designed to read DC amps. Two: It doesn't readout voltage to the 1/10 of a volt; instead rounds up or down to the nearest whole number, boo.

I like the idea of increasing the load and taking a bluetti watt meter reading when the sun is out but before that we are going to be hooking up a fourth panel as follows: Two pairs in series and the two pairs will be connected in parallel. We will see what doubling the voltage will do.

Notes:

a) The Bluetti's watt meter reads 215 watts when hooked up to the shore power charger and I have calculated that the charger output pretty much matches the watt meter reading, (42 volts x 5 amps = 210 watts).

b) The two, 150', new, stranded copper lines running from panels to the Bluetti lose about 20 watts and 1 volt over its length, (the input of 185 watts @ 21 vdc at one end of the wire = an output of 165 watts @ 20vdc at the other end of the wire).

1594391230000.png
 
Ampster said:
This is just a hypothesis. Perhaps the Bluetti is limiting it to 185. You can test that hypothesis by connecting any two panels as suggested by @Craig and I.
Click to expand...
THE bluetti accepts 215 watts from the shore power charger with no problems and the bluetti's built in SCC is spec'd at 500 watts maximum input. Perhaps there is a problem with the SCC, we will try two panels instead of three and see what happens thanks.
 
offgriddle said:
Each of the three panels at test time were producing 110 watts @ 21 VDC.

When all three panels were connected using the factory three way, parallel Y connectors. they cumulatively produced only 185 watts at 21 VDC according to the Bluetti's wattmeter readout. RED FLAG, shouldn't that have been about 330 watts?

The 42 volt, 5 amp DC output shore power charger supplied with the Bluetti charges at 215 watts according to the Bluetti's readout.

Is there a problem with the new Bluettti's built in MPPT charge controller that prevents it from taking in the rated maximum of 500?
Click to expand...
Why parallel?
Hook the 3 panels in Series.
The MPPT is only 10 amps on the EB240.
 
MBR said:
Why parallel?
Hook the 3 panels in Series.
The MPPT is only 10 amps on the EB240.
Click to expand...
The three panels are in series but they are rated at 11 or 12 amps each, none the less, I think that your on to something with the ten amp spec. limitation, but what about the 500 watt maximum input spec.?
 
I wouldn't consider that strange at all. Watch a charge controller closely and it will drive you nuts. I have external (not CC supplied) solar power diversion to heat hot water. I can harvest thousands of WH a day and still I'm not getting all the wasted power. If you would like an estimate of how much power isn't used find yourself a small panel. Load it down with a resistor low enough so on even the brightest day the voltage doesn't get near the power point voltage. That will give you a percentage of what the panels could produce on other days. To have a working system, most times your system will be horribly inefficient.
 
offgriddle said:
The three panels are in series but they are rated at 11 or 12 amps each . . .
Click to expand...
You seem to be in parallel though, because in post #4 you said that the Bluetti cables were parallel, and that "cumulatively they only produced 185w at 21 VDC"; the photo in post #24 looks like parallel; and in post #26 (b) you said "185w 21v at one end and 165w 20v at the other end" [i.e. at the Bluetti's input].

Were you able to test 2 panels in series? Also,
- what gauge wire was used for the 150' run?
- If you were getting 20v at the Bluetti input, I don't see how you're going to get any more than the 185w, since you have a limit
of less than 10a on the input.
- Could you measure the actual input voltage and amps to the controller when producing that max of 185w?
 
offgriddle said:
The three panels are in series but they are rated at 11 or 12 amps each, none the less, I think that your on to something with the ten amp spec. limitation, but what about the 500 watt maximum input spec.?
Click to expand...
RichPower
  • Maximum Power(Pmax): 160W.
  • Maximum Power Voltage(Vmp): 18.2V.
  • Maximum Power Current(Imp): 8.79A.
  • Open Circuit Voltage(Voc): 22.3V.
  • Short Circuit Current(Isc): 9.29A.
Three 160 watt panels in Series is 66.9 volts open circuit and about 9 amps total.
Three 160 watt panels in Series at 18.2 Vmp is 54.6V x 8.79A is 480 watts.

The EB240 should be good for ~68Voc imput + or - 2%
Are you series connecting 3 panels?
150 feet of cable? What guage?
 
MBR said:
RichPower
  • Maximum Power(Pmax): 160W.
  • Maximum Power Voltage(Vmp): 18.2V.
  • Maximum Power Current(Imp): 8.79A.
  • Open Circuit Voltage(Voc): 22.3V.
  • Short Circuit Current(Isc): 9.29A.
Three 160 watt panels in Series is 66.9 volts open circuit and about 9 amps total.
Three 160 watt panels in Series at 18.2 Vmp is 54.6V x 8.79A is 480 watts.

The EB240 should be good for ~68Voc imput + or - 2%
1) Are you series connecting 3 panels?
2) 150 feet of cable? What guage?
Click to expand...

THANK YOU MBR and everyone for responding:

1) Correction: I meant to say that the three panels are presently hooked up in parallel.
Also, as soon as me and my homesteady neighbor both get the same day off from our for money gigs in Babylon, we will be adding a fourth panel and then we will be connecting two panels each in series with the outputs of the two pairs to be combined in parallel.

2) The cable is 8 gauge stranded copper, new. The Bluetti's wattmeter reads 185 watts @ 21VDC from the combined, parallel output of the three 160 watt panels feeding the 150' cable at the head end. At the far end of the 150' cable, the reading is 165 watts at 20 volts. Note: the Blueettti was at 40% charge at the time of testing.

Specifications of the RS-P-160 Rich Solar Panels as follows:
* 160 watts max power
* Minimum Power Voltage (VMP) 18.2 volts
* Maximum Power Current (IMP) 8.79 amps
* Open Circuit Voltage (VOC) 22.4
* Short Circuit Current (ISC) 9.35
* Maximum System Voltage (VMAX) 1000 VDC
Designed in Cali,. made in Nam.


 
Fred S said:
You seem to be in parallel though, because in post #4 you said that the Bluetti cables were parallel, and that "cumulatively they only produced 185w at 21 VDC"; the photo in post #24 looks like parallel; and in post #26 (b) you said "185w 21v at one end and 165w 20v at the other end" [i.e. at the Bluetti's input].

Good Questions Fred S:

1) Were you able to test 2 panels in series? Also,
2) - what gauge wire was used for the 150' run?
3) - If you were getting 20v at the Bluetti input, I don't see how you're going to get any more than the 185w, since you have a limit
of less than 10a on the input.
4) - Could you measure the actual input voltage and amps to the controller when producing that max of 185w?

1) Time and reliable sun so far has prevented us from performing the two panel test but we will soon.
2) Gauge is #8 stranded copper.
3) That's a great point; I wonder why the Bluetti's maximum PV input specs. = 500 watts?
4) I could measure the input voltage by piercing the wire insulating with my test probes. Sadly, my VOM does not read DC current, therefore, the only current reading I can produce at this time will be from dividing the watts by the voltage under load, which I will do.

Thanks, Og

Correction: At present the three, 160 watt panels are connected in parallel, not series as I had previously, incorrectly noted.
Click to expand...
 
efficientPV said:
I wouldn't consider that strange at all. Watch a charge controller closely and it will drive you nuts. I have external (not CC supplied) solar power diversion to heat hot water. I can harvest thousands of WH a day and still I'm not getting all the wasted power. If you would like an estimate of how much power isn't used find yourself a small panel. Load it down with a resistor low enough so on even the brightest day the voltage doesn't get near the power point voltage. That will give you a percentage of what the panels could produce on other days. To have a working system, most times your system will be horribly inefficient.
Click to expand...

I concur and yes a great great idea would be to use a couple thousand watts of hot water heating elements to divert excess solar power once my batteries have reached their full SOC, however, my puny system only produces about ten amps per hour @ about 38 volts in full sun and I use it all to charge my 40 AH's of Lifepo's!
Yee for sure eliminating variables and using known loads to produce accurate measurements is essential.

~~~​

Oh No, it looks like one of the homesteaders up here spent seventeen hundred of Auntie Samantha's incredible shrinking federal reserve notes on a 2,400 amp hour Bluetti that can only absorb ten amps of charge per hour no matter how many amps you throw at it!

Yikes

OG
 
Wire gauge is good. It looks very likely that if you would simply connect your three panels in series, you'll be all set.
 
offgriddle said:
THANK YOU MBR and everyone for responding:

1) Correction: I meant to say that the three panels are presently hooked up in parallel.
Also, as soon as me and my homesteady neighbor both get the same day off from our for money gigs in Babylon, we will be adding a fourth panel and then we will be connecting two panels each in series with the outputs of the two pairs to be combined in parallel.

2) The cable is 8 gauge stranded copper, new. The Bluetti's wattmeter reads 185 watts @ 21VDC from the combined, parallel output of the three 160 watt panels feeding the 150' cable at the head end. At the far end of the 150' cable, the reading is 165 watts at 20 volts. Note: the Blueettti was at 40% charge at the time of testing.

Specifications of the RS-P-160 Rich Solar Panels as follows:
* 160 watts max power
* Minimum Power Voltage (VMP) 18.2 volts
* Maximum Power Current (IMP) 8.79 amps
* Open Circuit Voltage (VOC) 22.4
* Short Circuit Current (ISC) 9.35
* Maximum System Voltage (VMAX) 1000 VDC
Designed in Cali,. made in Nam.
Click to expand...
If your Bluetti limits to 10A charging then the best you will get for parallel connection will be around 10A * 18.2V = 182W. No real mystery here.

If you connect 2 series 2 parallel you will still be limited by the Bluetti. The panels will be trying to produce 17.58A at 36.4V, but your Bluetti will limit to 10 A so you will get around 364W, plus or minus. WIth a 10A limit you have to go series given your panels are 8.79A. And the most you can go in series is 3 due to the Bluetti 68V limit. You should get 480W (3 * 18.2V * 8.79A) which is under the 500W rating of your Bluetti.
 
offgriddle said:
THANK YOU MBR and everyone for responding:
2) The cable is 8 gauge stranded copper, new. The Bluetti's wattmeter reads 185 watts @ 21VDC from the combined, parallel output of the three 160 watt panels feeding the 150' cable at the head end. At the far end of the 150' cable, the reading is 165 watts at 20 volts. Note: the Blueettti was at 40% charge
Click to expand...
Even with 8AWG you are losing a lot over 150 feet at that low 21 volts and even restricted to 10 amps.
About 9% loss.
Also three 8.79A panels in parallel would be 26A

You can change the inputs in this calculator to see how it works.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.
www.calculator.net www.calculator.net

3 panels in series at 54 volts and 8.79A will have a much lower voltage drop of about 3% which not great but tolerable.

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.
www.calculator.net www.calculator.net
 
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