How many Watts do you get from your solar panels? (1 Viewer)

Apr 27, 2008
11,842
14,071
Eastbourne East Sussex
Funster No
2,327
MH
Hymer low profile
Exp
Since 1972
Hmm. That's impossible because inverter loses are 15 percent so even if your solar panels produced a full 80w and you had zero losses through your wires or charge controller you would get 136w in perfect sunlight
Inverter losses are irrelevant surely, as he is measuring the power from the panels before the inverter, not the inverter output.
 
Sep 16, 2013
2,219
7,913
Horncastle, UK
Funster No
28,132
MH
Van Conversion
Exp
Since 2006
My system works a little differently to most, so instead monitors the actual amps going into the battery.

Due to being in the middle of changing my charger setup, I just have 2 x 180w panel hooked up at the moment.

I get between 20-25A on average (in sun of course :roflmto: ). I know when I had all 3 x 180w panel charging I was getting around 1.5 Kwh to the battery per day (again, with reasonable conditions).

Hoping to get the time to test a Votronic MPPT against a Victron later this week - although I suspect they will be about as good as each other (as far as actual charge goes).
 
Jan 17, 2010
262
348
Northants
Funster No
9,980
MH
Bailey Approach740SE
Exp
Since 2006
Why use an expensive and inefficient inverter to turn 12v dc into 240v ac just for the e-bike charger to turn it back into 39v (or similar) dc?

I installed a DC to DC charger unit for a few quid, with a variable output for charging a range of devices including an eBike. Works fine. And although I havenā€™t done the calcs, Iā€™m sure itā€™s more efficient.

Would be interested to know make and model as I hadn't considered that. I did buy a different bike mains charger that had a lower output as the original charger was not switched mode so buzzed due to the inverter not being as pure a sinewave output as they claimed.
 
Jun 2, 2018
448
1,010
Beautiful North Wales border
Funster No
54,207
MH
Carado T449
Exp
Since 2015
Would be interested to know make and model as I hadn't considered that. I did buy a different bike mains charger that had a lower output as the original charger was not switched mode so buzzed due to the inverter not being as pure a sinewave output as they claimed.

Will check later - it was an eBay purchase and I tried a couple before setting on the one I preferred.
 
Apr 27, 2016
6,870
7,984
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
Location, just north of Watford,
That's officially the frozen north then:giggle:. Panels are rated at 25 deg C, and the output is less when warmer, but more when colder. Obviously in strong sunlight the panels warm up, but if the air is cold exceeding the nominal rating is not surprising.

The voltage also goes up when cold, but for most motorhome installations (parallel) that's not a problem.
 
Dec 2, 2019
3,582
7,750
Amersham
Funster No
67,145
MH
van conversion
Exp
Since 2019
I know that temperature influences the output, but, not all panels are the same. Have a look at the Panasonic data for the temp coefficient, very stable and almost no change from 0C to as high as 30C. Itā€™s a hybrid cell 3 layers with heterojunction and amorphous is sandwiched by two monocristaline. Certainly the output was not due to temperature, but more to do with the irradiation exceeding 1000w/ m2 at the time, and, the incidence angle was close to optimum. The output will diminish once the sun descends.
 
Dec 2, 2019
3,582
7,750
Amersham
Funster No
67,145
MH
van conversion
Exp
Since 2019
Would be interested to know make and model as I hadn't considered that. I did buy a different bike mains charger that had a lower output as the original charger was not switched mode so buzzed due to the inverter not being as pure a sinewave output as they claimed.

Victron Orion dc-dc converter. You can chose a buck boost, or just boost,(for your particular needs), isolated or non isolated, and adjust it before use to your perfect voltage output requirements.

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Mar 30, 2019
2,775
5,143
Cardiff, UK
Funster No
59,476
MH
Coachbuilt
Exp
Since 2016
Had my 12v coffee machine on and saw 142w from my 140w panel, it was only a spit second as the sun came out from behind a cloud and settled at 130w and over when the sun was bright
There's a 12v coffee machine? Is it any good?
 
May 7, 2013
845
1,353
RUK
Funster No
25,884
MH
C Class
Exp
On our 2nd MH now a AutoTrail Savannah which we're absolutely delighted with
I get more when it is sunny, less when it is dull and practically nothing when it is dark...


JJ :cool:
My God how does that work???????? LOL

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Oct 25, 2016
5,586
31,621
Hartford Cheshire
Funster No
73,061
MH
Bailey Autograph 79-
Exp
Lots but slow learner.
Got panel/s on our MoHo roof and a switch inside that say's "ON", that's as much as i know about them. But willing to learn so reading and not understanding :eek: :sun:
 

Joynel

Free Member
Aug 12, 2020
5
10
Funster No
74,324
MH
Adria SLplus
Exp
since 2016
I started reading this because I was really interested in the solar results (we have 200w Renogy, I'll note the outputs this weekend).... but ended up searching Amazon for 12v coffee machines and 12v Ebike chargers LOL :)
 
May 5, 2015
1,939
5,687
Sussex
Funster No
36,204
MH
C Class
Exp
Since 2010
I started reading this because I was really interested in the solar results (we have 200w Renogy, I'll note the outputs this weekend).... but ended up searching Amazon for 12v coffee machines and 12v Ebike chargers LOL :)

I'm ok, I don't drink coffee and haven't got an e-bike. šŸ˜‚

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SuperMike

Free Member
Apr 28, 2010
2,477
7,593
St Albans
Funster No
11,285
MH
Winnebago Sightseer
Exp
11yrs, but many years a tugger.
My thread from a while back .................................................... :gum:

 
OP
OP
TobyQuest
Jul 8, 2019
277
109
Funster No
62,280
MH
Jap Import Nissan4x4
Exp
Semi-newbie to motorhomes
I started reading this because I was really interested in the solar results (we have 200w Renogy, I'll note the outputs this weekend).... but ended up searching Amazon for 12v coffee machines and 12v Ebike chargers LOL :)
Id be interested to hear what you get. What charge controller do you have?

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Duckato

Free Member
Sep 15, 2018
83
110
North Shropshire
Funster No
56,218
MH
Van Conversion
Exp
Newbie
The angle of the dangle makes a huge difference to output especially in winter.
The SOC of the battery bank makes a huge difference to the observer output all the time.

In ideal conditions midday on 21st June providing battery was so discharged it was pulling max current in bulk mode you might see 80-85% of the rated output for a very short period from a flat panel

The reality is on average they produce a lot less though and without a tilting panel close to only 5-10% of rated output in the winter. trying to compare result even for an identical setup parked next to each other is virtually meaningless without some exact controls being in place.

Tilting panels are so easy to do especially if you used to play with Meccano!

 
OP
OP
TobyQuest
Jul 8, 2019
277
109
Funster No
62,280
MH
Jap Import Nissan4x4
Exp
Semi-newbie to motorhomes
Yes that's exactly as I would have thought, but then it's strange that multiple people even using inverters are getting more or less full rated power from their panels
 

PeteH

Free Member
Nov 22, 2007
6,853
9,030
East Riding of Yorkshire
Funster No
900
MH
Rapido, 999M.
Exp
18+yrs plus 25+Towing
Just a bit of an update on this "theme". The `van had been on solar only, off EHU now for over a week. The meter which shows Solar Panel out-put was showing 15.5v to 16.5vish on what is a dull day here with no current (amps) showing, out of curiosity I put some load on the system. and watched the battery level(s). They had been holding at approx 13.1V, as the load dropped the Voltage slowly at about 12.8V the current from the Solar panels started to come up, which suggest the solar charge unit is functioning as it should.

One curious thing though, is that the hab AND chassis batteries show the same movement of voltage. Something which concerns me, in that it suggests they are linked but without any protection against reverse current?, which means the Chassis Battery could be drawn down if the hab drain was great. something I think will bear investigation.

The photo's show the sequence.

IMG_6291.JPG
IMG_6292.JPG
IMG_6329.JPG
IMG_6331.JPG


Just been back in, to put some clean gear back. and I note the Batteries are back to 13.v and the output from the Solar`s is back to Zero. (y)

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