170W Solar - Really though how many amps? 10? (1 Viewer)

[Chossy]

Hey everyone,

I am thinking of getting a 170w Eco Worthy solar kit from Amazon. A few folks have them installed looks pretty decent certainly for the price. I wondered if anyone has any numbers that could be reasonably or reliably assumed or even know for these kits.

I was thinking say 10-20amps a day? is that wishful thinking? The solar would only be used to top up / compliment the battery, I am not looking to run anything at all from it or expect anything other than a modest charge over a few days.

Does anyone have any real world figures?

Cheers,
Ross

 

[bigtwin]

I was thinking say 10-20amps a day?

I presume that you mean 10Ah to 20Ah per day

Depending on the level of sunshine, I think that your 170W panel could generate around 10 A. If it generated that amount for 6 hours then it would yield some 60Ah. Taking charging inefficiencies into account then your batteries ought to receive some 40Ah.

On that basis, your expectations would be met but perhaps others could be more precise than my estimates.

Ian

 

[68c]

Watts = volts x amps.

Amps = watts ÷ volts

So 170÷13.5 = 12.6 Amps. On a really sunny day at midday. If you are lucky, as your van roof is flat and the sun is never truly overhead out of the tropics.

 

[surreyhills]

Assuming a perfect solar system kit, on a sunny day the charging current should be about 14A but depending on the weather on other days it is likely to drop to much lower levels. If you have a large, 100Ah battery even a trickle of 2A for a 10 hour daylight day would keep it topped up provided you don’t use any equipment that draws a high current for long periods. You have already said that you will be careful so your system should be a great success. Obviously the main limitation would be long periods of really dull weather; we can all remember some weeks that were total write offs regarding sunshine.

 

[Chossy]

Thank you so much for the responses.

I did the old w/v calculation however there was a load of other info. like reduce it by 40% etc. nothing is efficient yadda yadda and you simply cannot make any decisions without someone with some cold hard truths . I just wondered if anyone had any field experience say "my 200W panel gives me about 40ah per day in the height of the glorious Scottish summer he he pretty reliably"

I would absolutely be happy with 20ah or more fed into my battery per day! so as you see I am not looking for much, anything above that I would be happy with.

Thanks again for all the valuable input.

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[dunnah01]

Hey everyone,

I am thinking of getting a 170w Eco Worthy solar kit from Amazon. A few folks have them installed looks pretty decent certainly for the price. I wondered if anyone has any numbers that could be reasonably or reliably assumed or even know for these kits.

I was thinking say 10-20amps a day? is that wishful thinking? The solar would only be used to top up / compliment the battery, I am not looking to run anything at all from it or expect anything other than a modest charge over a few days.

Does anyone have any real world figures?

Cheers,
Ross

In a UK Autumn, Winter, Spring you'll probably get between nothing and 20Ah/day. On a good summers day you could get up to 70Ah. This is pro-rata from our 360W setup

 

[Chossy]

In a UK Autumn, Winter, Spring you'll probably get between nothing and 20Ah/day. On a good summers day you could get up to 70Ah. This is pro-rata from our 360W setup

Awwwww Yeeeaahhhh

 

[sgl5gjr]

My better half purchased one of these kits for me....as a surprise... in October 2023.... I didn't fit it until Late January and cabled it in early February dodging the rain...lol.... the display was reading 13 + volts and 1.2 amps on overcast days in February when I finally commissioned it.
A pal and I went away to Belgium for the classic cycle racing at the end of February and we decided to go off grid for 2 days as an experiment. I have a 110ah leisure battery as a guide, we used lights (all led) water pumps, satellite, TV (18w) as well as the odd bit of streaming and we charged phones and laptop. After night one voltage was at 12.4v and the second day was overcast with rain and the battery was replenished during the day and the second night was similar. So for me it did the job well, for others it might be more restrictive due to their consumption needs. I was surprised how well it worked in February but before the MoHo we had a Bongo camper with 100w panel and compressor fridge which was on 12/7 365... but use on that was TV, lights and charging.
Hope that helps.....

 

[Raul]

Put your location on the map, then enter the relevant values on the right, by selecting off grid. This site never fault me on estimating solar harvest, it’s pretty much 99% accurate.

JRC Photovoltaic Geographical Information System (PVGIS) - European Commission

Photovoltaic Geographical Information System (PVGIS)

re.jrc.ec.europa.eu

 

[AdrianChen]

This might give a rough idea, defaults to 175w but you could change the spec and location. Graph is in KW so I used 12.8v to convert for Lithium.

MPPT Calculator - Victron Energy

MPPT Calculator - Victron Energy

www.victronenergy.com

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[Chossy]

My better half purchased one of these kits for me....as a surprise... in October 2023.... I didn't fit it until Late January and cabled it in early February dodging the rain...lol.... the display was reading 13 + volts and 1.2 amps on overcast days in February when I finally commissioned it.
A pal and I went away to Belgium for the classic cycle racing at the end of February and we decided to go off grid for 2 days as an experiment. I have a 110ah leisure battery as a guide, we used lights (all led) water pumps, satellite, TV (18w) as well as the odd bit of streaming and we charged phones and laptop. After night one voltage was at 12.4v and the second day was overcast with rain and the battery was replenished during the day and the second night was similar. So for me it did the job well, for others it might be more restrictive due to their consumption needs. I was surprised how well it worked in February but before the MoHo we had a Bongo camper with 100w panel and compressor fridge which was on 12/7 365... but use on that was TV, lights and charging.
Hope that helps.....

Yessssss!!! thank you very much indeed!

 

[Chossy]

I have installed it now and I am very happy, pretty consistent 5a on an average march day. Really chuffed, thanks again for everyone's input and help. I need to neaten a couple bits up but all good.

 

[Boldly]

I think you will get a much reduced yield because of shading from the roof bars. Maybe remove them if not in use?

 

[headlight]

I think you will get a much reduced yield because of shading from the roof bars. Maybe remove them if not in use?

The roof bars are only going to have a shading effect when the sun is very low when there is not much solar production anyway.
If it was my set up I wouldn't worry as the effect on what is produced will be minimal.

 

[Chossy]

Indeed, although the bars at the back will have some shade it won't make any impact on my intended results.

For anyone who wants to know it was £159 from amazon and it is the 170w eco worthy kit. Hopefully it lasts a long time.

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[Tombola]

Don't leave your canoe up there will you..

I used to have just 200w at one time..and living up north with it sat on my drive my batteries never dropped below 70%

Some.days virtually nowt...other days decent winter yeild

 

[Boldly]

I was parked next to a very tall single stemmed tree in onil and even in Spanish full sun got less than half of what I got the day before.shadow only about 2 inches wide across the middle of the panel.

 

[Tombola]

I was parked next to a very tall single stemmed tree in onil and even in Spanish full sun got less than half of what I got the day before.

Oh yeah..even a finger width of shading can cut solar a lot.

 

[TheBig1]

The rough rule of thumb is a minimum of watts of solar panel to match the battery bank, better is more. So minimum 100w of solar per 100ah of battery. The 170w ecoworthy panel is an excellent choice if married to a half decent mppt solar controller

As others have said, any shadowing on the panel will drastically reduce the output

 

[Chossy]

Hey,
I thought I'd give an update with some real world info. My wife and I dodged off for 6 days late April 20th - 25th North West Scotland. We have a 200ah Renogy Lithium hooked up to the 170w solar panel mentioned in my original post.
We ran a 65l fridge freezer continually, tap, extractor fan, charged mobile phones etc. telly usb films 10 hours, diesel heater 6 hours. The battery dropped to 89% one morning and each day at around 6pm the battery was sat at around 96-98% we had cloudy days and a couple of full sun days. This setup performed beyond what I had hoped. I would fully recommend all of my purchases.

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[Tombola]

Hey,
I thought I'd give an update with some real world info. My wife and I dodged off for 6 days late April 20th - 25th North West Scotland. We have a 200ah Renogy Lithium hooked up to the 170w solar panel mentioned in my original post.
We ran a 65l fridge freezer continually, tap, extractor fan, charged mobile phones etc. telly usb films 10 hours, diesel heater 6 hours. The battery dropped to 89% one morning and each day at around 6pm the battery was sat at around 96-98% we had cloudy days and a couple of full sun days. This setup performed beyond what I had hoped. I would fully recommend all of my purchases.

you sure you go the numbers right, and your monitor is working ok.....seems very good considering the fridge was on or did you drive a lot

 

[Chossy]

My numbers are correct and I have no charging other than the solar. As you can see it was putting 7a in at one point. Several times what the fridge was pulling.

 

[Raul]

That type of consumption per day equates to about 50ah per day. Only the fridge alone will be 28-30ah daily, at least.
Now, the 50ah will need about 650wh minimum put back. A 170wp can harvest 1-1.5 sun/hr per day in Scotland that time of year, not 3.8 sun/hr. Further south, and towards midd summer yes 3-3.5 sun/hrs is achievable, even with a flat panel.

You either drove and alternator contributed quite a bit, or/and, your shunt is out. It drifted. Renogy bms is prety poor for accuracy as it will not detect small currents. There is no way you are 95% charged at 13.55v and over 7A going in.
If it was true 95% SOC, then in the next 10ah charged, it should reset to 100%. I think it drifted and will take more than 10ah to full, so your fuel gauge is not accurate.

 

[Ian_H]

That type of consumption per day equates to about 50ah per day. Only the fridge alone will be 28-30ah daily, at least.
Now, the 50ah will need about 650wh minimum put back. A 170wp can harvest 1-1.5 sun/hr per day in Scotland that time of year, not 3.8 sun/hr. Further south, and towards midd summer yes 3-3.5 sun/hrs is achievable, even with a flat panel.

You either drove and alternator contributed quite a bit, or/and, your shunt is out. It drifted. Renogy bms is prety poor for accuracy as it will not detect small currents. There is no way you are 95% charged at 13.55v and over 7A going in.
If it was true 95% SOC, then in the next 10ah charged, it should reset to 100%. I think it drifted and will take more than 10ah to full, so your fuel gauge is not accurate.

Hi Raul
What is a sun/day in aH or wH? Not heard of it before.

 

[Raul]

Sun hr is the amount you can harvest of any given array in wh/kwh.
If you have a array of 100w you harvest 100wh per day, thats 1 sun/hr. If you harvest 300wh with same array, thats 3 sun/hr.

Its a term used mainly by professionals to estimate solar harvest taking the solar irradiation data for that time and place.

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[Ian_H]

Sun hr is the amount you can harvest of any given array in wh/kwh.
If you have a array of 100w you harvest 100wh per day, thats 1 sun/hr. If you harvest 300wh with same array, thats 3 sun/hr.

Its a term used mainly by professionals to estimate solar harvest taking the solar irradiation data for that time and place.

Raul
Thanks for that. Are the figures you quote as achievable averages or maximums? I'm asking because my 250W of panels were giving me over 1KWh (4sun/hr?) in a day 2 weeks ago in South Wales.

 

[Chossy]

It's correct. The fridge is only consuming energy at night, there was a net contribution from the solar at around 8am or earlier each day, which at around noon was several times the consumption of the fridge. My consumption is nowhere near 50ah a day. I'm not sitting there with the heater on for 6 hours a day and watching 10 hours of telly jeeso those are totals. My figures are correct and there is no other charging in place.

 

[AdrianChen]

This is todays forecast for my area, and the actual for so far in blue - batts will be full very soon so wont get the forecast, but it's surprisingly accurate normally. The forecast potential for today is 0.7kWh and tomorrow 0.8kWh - of course if the weather forecast is wrong then..... Today is overcast with 2 hours of clear sky, tomorrow is overcast rainy and no clear sky. We have 550w. So with slightly better weather we would be similar to you I guess. PS. South Coast - 10miles inland.

 

[Guigsy]

To reemphasise a few points:

Even a tiny finger of a shadow across your panel can have a large impact. It depends on the panel arrangement and where the shadow is, but halving performance when the shadow of a wire is over the panel is possible.

If your battery is full (or even over about 75% with lead acid), then you're going to see disappointing yields from your solar app. The only way to see how many photons you can harvest is to start from a discharged battery (or have a good amount of load).

Solar is very dependent on time of year and weather. You might only get a tenth of the yeild in the winter months, even on a nice day. And even a summer's day can be poor. Last August, by brother's 400w panel he takes tent camping (yes, it powers his friends temporary canvas commune) only gave about 20Ah per day for several days running because the weather was so bad. I was up the other end of the field in the van with a hook up, and he was dragging his batteries up to me to charge them overnight. The next week, he was making ice cubes all day because the batteries were full by lunch and there was power to spare.

 

[Raul]

Raul
Thanks for that. Are the figures you quote as achievable averages or maximums? I'm asking because my 250W of panels were giving me over 1KWh (4sun/hr?) in a day 2 weeks ago in South Wales.
View attachment 890136

Average, as maximum without a tracker can achive 7-8 sun/hr. A tracker can do 10 sun/hrs.

Yours its doing very well, cold panels I see 266w out of a 250w if you say its a 250w, then you have a good efficient system.

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