I wonder if anyone with an experience of solar panels could take a look at the following links and advise which (if any) is the better solar panel to go for. Both seem to be reputable companies and the specs seem to be very similar, but one the Renytek version is £35 cheaper!
We do a lot of rallies with the DA and so are final biting the bullet and looking to buy a solar panel. I have done a calculation of our daily use (Worst case scenario) and found we would use 290.5wh (24.2ah) per day so the 60w panel would cover this.
Does anyone have or used either of these. Is there any difference other than the price?
I would doubt that a 60W panel will meet your demands, except on sunny days - try looking for either 100 or 120W panels that can be fitted to your roof.
Those portable panels have been known to "walk" if you forget to put them away whilst you're not at your van
the fixed panels do not really meet our needs in that anything on the van would reduce an already depleted payload and is something we could take with us as and when we outgrow our current outfit. With the folded option this can be put in the car, the van or left at home dependant on our destination. In terms if it being stolen, yes this is a valid point and something we would have to consider further although those we rally with we trust to look out for the kids so i wouldn't be too concerned, but yes, always a risk.
would you consider 60w too low, i have heard people getting by with 30 or 40w panels?
We only really do weekends in the winter except a 5 day stint at new years
Would a 100w fixed panel get enough day light for a 5 day outing in Jan?
Last/this year we survived for 4 days with a 85ah battery and an approx 1x3hr top up using a friends generator (i should point out that every night at new year we spend in a hall reducing our light usage etc)
Maybe I'm calculating my usage wrong. My initial 24ah per day was based on a worst case scenario (chilly, rainy day in march for example) so 6h x 12v tv, water pump x30min 6x 1.5w led lights x 4.5h a day, charging iphone/ipad, even went as far as to calculate standby light on aerial amp being left on all day (x24hr = 1a and the same with the water heater (= 1ah).
Being more realistic, and based on our use last bank holiday weekend i would say we run at more like 10ah / 120wh. In fact we arrived with a fully charged 85ah battery on Friday night and on arriving home on Monday I read the battery with a multimeter at 12.4v (no charge from the car on the way home).
With only 3hours sunshine I'd get 180wh back from an 60w, in addition this would be relative cheap to buy, only 7kg in weight and quite compact. But obviously I don't want to shell out only to find it doesn't meet our needs.
PS I do plan to upgrade to 110ah battery very soon which will help
You can get an 80w Renytek version for cheaper than the 2nd link. Check their ebay page for options. If you are going to spend that much and you are worrying over what usage you are using, why not just spend an extra £20-£30 on a higher rated one and then you will be fine.
Regarding thefts, you could get a chain for it but like anything you leave outside, there is always a risk, you just have to trust people you are with.
I would also change to led lights Because these do reduce your power consumption.
I think that it difficult to accurately calculate both your consumption of electricity and the solar panels production of electricity. For what its worth this is my experience. We used to use a free standing 40w panel and that seemed to keep up with our consumption between March to November. In the depths of winter my feeling was that the battery was a little less full than ii was at the beginning of the weekend.
About two years ago I fitted a 135W panel to the roof. My impression is that it keeps the battery fully charged for the same period as the old panel I think this illustrates how relatively inefficient a panel flat on the roof is compared to one angled to face the sun and moved a couple times per day. The big advantage for us of a roof panel is that even in the depths of winter the battery is being charged while the van is siting in storage and is always fully charged when we go away.
Thanks Boff, Yes that is useful. I have already made the jump from Halogen to LED on all but the under counter one which we never use anyway.
Alpiner, thanks but the only portable panel there is £260 and a little outside our price range.
I'm inclined to go with the photonic universe 60w panel. On further examination between the two the Bosch solar panel has an efficiency rate of 19%. Even Renytek were good enough to say their solar panel would not match this. When I asked if there would be a noticeable difference between the two I was told margonally but I was still paying more for the Bosch brand rather than increased performance. I am tempted by the 80w Renytek panel for the same price, but at 11kg as opposed to 7.5kg this is getting fairly heavy.
If I was convinced the 60w panel would be sufficient for our needs id get the Photonic one, but there is so much conflicting information out there.
A lot depends on your needs. If you have a 12v on 8 hours per day then maybe a 60w panel will struggle. We never struggled in the past even with the 40W panel even in the winter or it we went away for up to a week in the summer. But then again we don't watch that much TV and I don't have some huge 3000W invertor so the OH can dry her hair.
As a point of pedantry the panels you have linked to claim to be 60W or whatever they are not they are 2 30W panels hinged together and connected in parallel. There is nothing to stop you buying a single panel and adding to it if it is not adequate for your needs
We've got an 80w portable kit made by Baird, the reason we went portable is because we also have a canal cruiser that we use it on. We had 2 nights on the boat last weekend and it fully charged the battery in no time after watching tv all the previous evening and that was a bright cloudy day. The first trip in the van was also a success over easter but no tv as no signal which was a shame as I really wanted to give it some grief!
I now thinking on not booking ehu pitches and saving the money as I dont think I need the charging function, although no hair straightners for the mrs is still a tricky one!
Our solar panel is a free standing 85 Watt Kyrocea unit, charging the van's 90Ah battery and a 60Ah, portable battery for the TV, via a Morningstar "Duo" controller.
The Morningstar controller has the optional meter so I am able to see the Ah yielded by the panel each day, I zero it on going to bed.
The daily yield is typically 13 to 15 Ah, somewhat less than the OPs usage estimate.
Of course the solar panel can only put in AHs where the batteries have "room" before being fully charged, the meter allows me to see when they are full and the controller has switched off the panel.
In summer the 85 Watt panel is a gross over-kill and both batteries are fully charged a few hours into the morning, leaving all the midday afternoon and evening sun untapped.
It is a very different situation in the winter and typically the panel does not cope. The winter yield can be exceptionally high as it is cold and the sub zero temperature leads to crystal clear skies, but that is not typical. More typical is a string of overcast or even wet days when the cell can't replace the usage and the batteries begin to be depleted to too low a value. We can do a week-end but not have unlimited time autonamy.
And even to get the best yield in winter means the panel needs constant "tracking", and tree shadows become more of a nuisance. So winters days have to be invested in panel tracking, not holidaying. In summer I can simply place the panel at 15 to horizontal on a south azimuth bearing and go out enjoying the day, the loss of efficiency being of no relevance in that the 85 Watt panel is way oversize for the room in the batteries.
I get the general opinion is that an 80w panel would be overkill in the summer so I could get away with a 60w (the maths agree too). A 60w won't be of much help in the winter, but typically nor would an 80w!
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Topic: Solar Panel - 2 options, but which one?
