Solar panels a question (1 Viewer)

[Reallyretired]

I am thinking of getting some more solar panels on the van (currently 1x85w panel).

I know some funsters have quite a lot of solar (I know Jim has) and I wondered what output you get from them in practice, particularly in the winter.

I was thinking of going for around 400w in total, which I would expect would probably meet 50% of my requirements in the winter, and about 300% of my requirements in the summer.

What do you use the excess summer leccy for? I could run hairdryer, kettle, toaster, steamer (all mains via inverter) We hardly ever watch TV and our little LCD TV only uses about 1-2A on 12v anyway. We removed the microwave as we never used it.

The aim is to avoid EHU (except when free or included)

 

[pappajohn]

i have a 170w panel flat on the roof feeding a MPPT controller and expect around 14amps mid-day in summer.

 

[Reallyretired]

i have a 170w panel flat on the roof feeding a MPPT controller and expect around 14amps mid-day in summer.

What about in the winter though. On a reasonably bright day I get around 1A from my 85w panel, enough to keep the batteries topped up if I'm not using anything.

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[vwalan]

to be honest i think in winter in the uk best just think of topping batteries if you just use a light and radio cassette . normally i winter in spain/maroc . we have 240v fridges washing machines . etc . even the inverters dont really like powering anything that heats things up like micro wave , kettles etc.... hair drier can be ok. but not for too long . i have 6x80wt and 800amp of batteries. i used to just have 3x80wt and 600amp of batteries and found in darkest winter even in spain and portugal sometimes we had to turn things off early in the morning as the inverter started to squeal its low volt alarm. i run a lead into the house and power my fridge and seperate deepfreeze in summer . take the freezer off in september . by oct even the fridge is only powered for 2-3 days a week. at the moment batteries are full but arent using anything as it could take days /weeks to recharge them . they are good but there just isnt enough sun here in uk in winter. as i say normally in winter they are great. havent used ehu for the last 10yrs. hardly use campsites so never get the chance . but solar is great.

 

[Wildman]

1)It is more the low angle of the sun in winter than the perceived light level so a verticle panel aimed at the sun gives the best results.
2) The apparent output of the panel cannot be measured at the regulator unles a heavy load is put on as the regulator will hardly show any charge at all on a fully charged battery.
3) a one amp charge from an 85W panel in the summer (given middday and sun) is very low but see above, it should be around 4.7 amp if the batteries can take it.
poor quality regulators and small dia cable swallow a lot of the available power. Upgrading the cables WILL in most cases double usefull the output.
No need to worry about producing too much in the summer, your total battery storage limits its useability anyway.

 

[dave newell]

We'll see how we go at the Wrenbury New Year meet and I can then give a better response. We have 3x110 Elecsol batteries and a 155Watt solar panel, I'm also taking a 900Watt genny as backup for charging but hopefully we won't need it, we'll see how we get on.

D.

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[pappajohn]

What about in the winter though. On a reasonably bright day I get around 1A from my 85w panel, enough to keep the batteries topped up if I'm not using anything.

never really checked in winter as the controller is inaccessible due to being behind the slide out wall when it's in.

in summer, long after the sun has gone in, i get around 1amp from dusk light.

 

[Reallyretired]

1)It is more the low angle of the sun in winter than the perceived light level so a verticle panel aimed at the sun gives the best results.
2) The apparent output of the panel cannot be measured at the regulator unles a heavy load is put on as the regulator will hardly show any charge at all on a fully charged battery.
3) a one amp charge from an 85W panel in the summer (given middday and sun) is very low but see above, it should be around 4.7 amp if the batteries can take it.
poor quality regulators and small dia cable swallow a lot of the available power. Upgrading the cables WILL in most cases double usefull the output.
No need to worry about producing too much in the summer, your total battery storage limits its useability anyway.

Sorry, I seem to have not been clear, the 1A charge is midwinter, thin cloud.

 

[Jaws]

Well to put this in to perspective...........

On the house we have 12 panels delivering a max of 3kW..
Today it was bright but zero sun.. Was getting very little really.. In fact fact just checked and we got .2kW all day !!

That equates to..
lets say 7 hours daylight
200W over 220v = 1.1 amps.. and that over the 7 hour period so about .15 amps per hour generated with 12 panels

Now at the other end of the stick, on a sunny day last week we managed 7kW = 4.5 amps pers hour ( though that is at 220 v of course... )

What I am saying is, the delivery is so variable no one can really put any figure on it with any surety ..

The best plan is to go for as much panel coverage as you can afford, thereby giving the best possible performance in any given scenario.

I have about 180W worth of panels and two 110Ah batteries.. I can usually last 10 days using all functions with moderate sunshine

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[Snowbird]

I think Jaws hit the nail on the head. As no 2 vans are the same,no 2 persons usage are the same and no 2 days are the same,whatever you have will be different than your neighbors. I have not had hookup for years as have always had good solar and battery systems. BUT my needs are not great as I watch little TV,am in my playpen early and have LED lights. Its no use having a roof full of solars and then wasting what you have produced by running a 1000 watt inverter to charge your mobile phone. This may sound daft to some but believe me SOME do it.

 

[Jaws]

And as a follow up.. today, so far, we have generated almost 7kW in the 6 hours of sun we have had.. and THAT equates to about 32 amps !

 

[JJ]

IMO, Solar panels are like cold beers in the fridge...

... you can never have too many of them.

JJ :Cool:

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[Hayleylulu]

IMO, Solar panels are like cold beers in the fridge...

... you can never have too many of them.

JJ :Cool:

IF you put any more on you will have to make your van longer