storing a van - how do you do it?

[wildebus]

You might want to do some experimenting on this, I have and found it isn't the case. I my case 'shading' reduced the output by the amount of shading, totally blocking light to a cell (say as per some leaves on it) can have dramatic effects depending on how the cells are connected.

Actually I HAVE done some experimenting on this and what happened is EXACTLY as I described.

There are also numerous youtube videos demonstrating the same effect.

So if it is ok with you, I will stick with what I personally found to be the case.

 

[GeoffL]

[...]
Re your solar panel... does it maintain your battery at a decent level for longish periods - my 3 batteries seem to slowly reduce in voltage if i dont have the van on charge - even though i have a solar panel.

I just spotted this question, the answer to which is "Yes". We've been on a CL for a few days without EHU. Didn't watch any telly yesterday but I did use the laptop for an hour or so. System voltage was 13.1V at 09:30 this morning and was 13.7V last night. So my solar panel certainly maintains a decent battery level during summer.

Last winter, the solar panel couldn't top up the battery bank to a system voltage of much more than 12.8V, but I suspect the difference between that and 13V+ in terms of amp-hours is relatively small and battery condition is being maintained at 12.7V to 12.8V. That said, we did several 100+ mile drives last winter (takng the van back to the dealers for warranty repairs) and so didn't leave the van solely on solar for long periods. BTW, I don't leave the solar on all the time the van is in storage -- only if the "at rest" battery bank is below 12.5V. HTH, Geoff

 

[delicagirl]

Collette, I am going to sound brutal stop asking 101 questions on subjects you clearly don't understand when on occasion given transparent answers. then find a man with second hand info here.Your not helping yourself

The question that needs to be asked is there any member that has first hand experience of an electrician that know what he is doing. That you can use ,most of your problems seem historical the 110 v malarkey etc

Let them go through your system with a fine toothcomb and advise as necessary. I think that is what it needs it is apparent you seem to have a patchwork quilt of a system.

I do hope you take my post in the spirit intended I have no desire to intentionally offend and for what its worth I cant help with electrics but it seems

Friendly Yorkie or not (im one) you need proof that a workman can do the job the reason the good ones are in business is they can diagnose and do things us lesser mortal can weeding them out from the chaff the difficult part which is why you need good recommendations
Channa

Channa i have been looking for an expert in 12v/110v/240v auto electrician who knows his trade for 4 years now..... several auto-electricians have just looked at my van and said they did not want to work on it. i respect their integrity in saying that. You haven't seen my van. Yes it is a hotchpotch. I have also moved house twice since i bought the van and that has not helped me in finding garages willing to work on it.

i frequently know more about my van than any of the men who have worked on it.... mainly because i have asked so many questions on here and i have learned a huge amount from posters here.

even on this thread i have learned a lot of new stuff about solar which i will be discussing with the Highbridge company which has been recommended to me - they have auto electricians there - and i will take the van over to them this week and have a chat.

i do appreciate all the help i have received here and can well understand some members thinking "oh god not another delica-question!!!"

i amaze myself with how much i now know about my van, and i will continue to learn more about it as long as i own it.

if you find my questions tedious then don't engage with my thread Channa - there's lots of other threads to read !!

 

[jann]

Van is always in use!!

 

[delicagirl]

It depends what n how the panels are arranged. Each cell gives about half a volt. Typically, a panel is made up of about 36 cells wired in series, so you get about 18v open circuit, but less when you draw current (because of their internal resistance).

Each cell that isn't getting sun isn't helping, so it is easy to drop the output voltage below what is adequate to provide a worthwhile charge.

However, you may have multiple panels. If so, you can wire them in parallel or you can wired pairs in series. That means that the voltage may drop from 36v with a bit of shading, but it is unlikely to drop below the 15v "useful" threshold. (I have never seen a solar controller that can boost voltage)

The drawback with this setup is that even with an MPPT controller, you get less efficiency from the controller (it has to do more conversion). But it does cope with partial shade a bit better and it does work a little in poor light conditions.

i am going to give my solar panel a bit of a dusting off today - i suspect it may be covered in dust and dirt. in this hot weather is it too hot to touch?

later


interesting - the solar panel is on my sloping roof above the cab and it was Perfectly clean - there's one good thing about this van then !!!

 

[wildebus]

It depends what n how the panels are arranged. Each cell gives about half a volt. Typically, a panel is made up of about 36 cells wired in series, so you get about 18v open circuit, but less when you draw current (because of their internal resistance).

Each cell that isn't getting sun isn't helping, so it is easy to drop the output voltage below what is adequate to provide a worthwhile charge.

However, you may have multiple panels. If so, you can wire them in parallel or you can wired pairs in series. That means that the voltage may drop from 36v with a bit of shading, but it is unlikely to drop below the 15v "useful" threshold. (I have never seen a solar controller that can boost voltage)

The drawback with this setup is that even with an MPPT controller, you get less efficiency from the controller (it has to do more conversion). But it does cope with partial shade a bit better and it does work a little in poor light conditions.

Very good points there.
You can get individual panels that are not impacted by individual cell shading but these are pretty rare and considerably more expensive so I feel it is a fair assumption that the panels fitted to the typical motorhome is the standard design.

Yes, series connection is best for voltage, but parallel is best for 'protection' against the shading effect. This is one reason why I went for a larger multiple (4) of smaller (100W) panels so I could do a series-parallel combination. Best of both worlds

There is a controller that deals very well with the issue of do you go parallel or series however. That is the Amperor Associates Power Integrator (PI/25C).
This is an MPPT Controller which has two seperate inputs and manages the voltages to give the highest possible voltage as well as minimising shading effect. I would see 100W per panel from my pair of 100W panels from this controller.
It also was a B2B charger and was able to generate a recalibration voltage from either the Solar Input as well as the Alternator, so this was one of the rare devices that had an integrated DC booster. Highly recommended with the main limit being max of 200W solar so was not suitable for my new install.

 

[delicagirl]

As it happens, I checked the temperature of the panel on my van roof yesterday afternoon. It was around 57°C according to the infra red heat gun. But it was a very hot day.

The checkerboard alloy panel on the roof seemed even hotter: far too hot to touch.

As for dust on your panel, think of poor Opportunity in that Martian dust storm..

mmmm .... puzzling ... i touched my solar panel briefly and it was not at all hot

 

[bobj808]

I keep my mh parked on our tar drive completely inside the car port which is sheltered on 3 sides. Perfect. I leave the handbrake off and connect it up to a 240v socket when we aren't using it. Their is an outside caravan storage area near us which charges over £600 a year with restricted access daily. Gulp. Glad I don't have to stump up for that.