Solar panel

Submitted: Friday, Apr 18, 2003 at 17:30
ThreadID: 4451 Views:3651 Replies:10 FollowUps:5
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We are trying to work out what size solar panel we will need to run our Engel 40l fridge (new), when we are camping in one spot, (travelling around WA in July-Dec). We have looked at the files and tried the formula.

We have a 130amp/hr deep cycle battery. The place we bought the battery said that a 60W panel would be ok to keep us going say 4 days without starting the car. But at another place the advice was that we would need at least a 150W panel to keep the battery charged.

The formula in the files section seems to tell us that the 60W won't even keep us going for 2 days.

Can anyone give us some advice?

Jo & Adrian
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Reply By: Martin - Friday, Apr 18, 2003 at 19:40

Friday, Apr 18, 2003 at 19:40
You will need a minimum of 120w of solar panel and preferably 150w to keep you going in mid-winter. With a 120w panel you would need to be particular about shifting it three to four times during the day and have the panel at the correct angle. With a few inclement days in a row, or if the sun dips behind a mountain early, you will not have sufficient power with a 120w panel. 2 x 75w BP Solar panels should give you sufficient power with enough spare to run fluro light and TV for a couple of hours a day the majority of the time.
Previously I relied on 2 x 75w panels and the large majority of the time it was sufficient. Now that I need to use a laptop and charge the satellite phone I had to go to 3 x 75w panels.
AnswerID: 17904

Follow Up By: Jo Day - Friday, Apr 18, 2003 at 21:32

Friday, Apr 18, 2003 at 21:32
Thanks Martin,

We also posted this question elsewhere and the answer was the same as yours.

What size battery are you running?

Adrian & Jo
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FollowupID: 11233

Follow Up By: Martin - Friday, Apr 18, 2003 at 23:16

Friday, Apr 18, 2003 at 23:16
A standard 90 amp hour deep cycle wet cell. They are the only cost effective practical solution. Spending more on batteries is not cost effective. A 90 amp hour is light on for 3 x 75w solar panels, but is ok for 2 x 75w solar panels. If this was a stationary fixed application the batteries used would be completely different.

You would have been well *.*ed off if you had bought the 60w panel and found it useless. Was this a well known 4WD outlet that gave you that incorrect advice?

We buy our solar panels from Bias Boating.
http://www.biasboating.com.au/solarpanels.html
Solarex is now owned and made by BP Solar.
Majority of solar panels have a guarantee to last for 25 years so are a great investment.
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FollowupID: 11234

Reply By: Jo Day - Saturday, Apr 19, 2003 at 13:09

Saturday, Apr 19, 2003 at 13:09
In regard to the 60W panel, we were at a solar energy shop in Melbourne and the advice they gave was that by having the 130 amp hour battery, a 60W panel would be able to give us about 4 days power.
AnswerID: 17923

Follow Up By: Martin - Saturday, Apr 19, 2003 at 18:03

Saturday, Apr 19, 2003 at 18:03
Jo that is possibly just possible provided you moved the solar panel 5 times during the day in autumn or spring. That would also mean that at the end of the 4 days your battery would be flat. If you flatten a battery below 50% of capacity the battery life is seriously cut short and should not be done.
A solar energy shop should know better.
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FollowupID: 11247

Reply By: Member - Topcat - Saturday, Apr 19, 2003 at 13:19

Saturday, Apr 19, 2003 at 13:19
Hi Jo Day, I went through this exercise quite a few years ago with solar panels & since I run a 60ltr. Trailblazer fridge & camp in places for weeks at a time, I have found that the ideal setup [taking weather
conditions into consideration] is 2 x BP585 85 Watt Solar Panels coupled to 2 x 190 amp 6 volt Deep Cycle batteries connected in series is more then adequate for me to run all my accessories [comms gear, laptop computer, lighting + 240 volt inverter ect].
In varied weather conditions the charge rate is anywhere from 2amps
up to 9amps & running a pulse charge setup keeps the batteries topped up & in good condition.
Have Wheels Will Travel
AnswerID: 17924

Reply By: Bob Y. - Qld - Saturday, Apr 19, 2003 at 18:48

Saturday, Apr 19, 2003 at 18:48
Jo,

I've mentioned this before on this forum, but last year I saw a bloke in town with 2 panels, obviously 120 watt by their size, on roof bars on his tarago or similar type of people mover. Didn't manage to talk to him, but feel he must have towing a camper or trailer to require that much power. This may be overkill for what you want.

I imagine with panels on vehicle, it could be parked in full sun, while camper, van etc can be parked in whatever shade is about. Know when we were vanning, for work, the rating of campsite, was always judged by the size ot trees that the van could be parked near. Hooroo...
AnswerID: 17933

Reply By: Flash - Sunday, Apr 20, 2003 at 21:09

Sunday, Apr 20, 2003 at 21:09
It all depends on what you want.
I'd go for for 120 watt for normal use ---- if you want to stay put for less time you may get by with 80watt, but you'd have to be a bit careful.!! You could go 2 days with 60 watt!!! (if you then drove for a good charge!!)
With 120 watt you wud be right for normal frig use- with 150 watt you could be extravagant!
How much power do you want??
Lights gas or electric???
extra generator or not???
How long is a piece of string????

AnswerID: 17974

Reply By: Flash - Sunday, Apr 20, 2003 at 21:14

Sunday, Apr 20, 2003 at 21:14
ALSO
I would rather have TOO MUCH power rather than TOO LITTLE!!!!
Life is more fun when you are not worried about little troubles!!
very few people complain about TOO MUCH POWER!!!!!
(dont think I ever met one!!!)
AnswerID: 17975

Reply By: GOB vic - Monday, Apr 21, 2003 at 19:09

Monday, Apr 21, 2003 at 19:09
jo while at melb caravan show last week we looked at a different product called a light energy panel
blurb states
"light energy panels are recommened for mobile applications because of their superior performance inthe shade and incresed performance in high temperatures .they have an addittional advantge of being repairable in the field.unlike the glass panels the light energy panels will still work if punctured and is repairable by sealing with the punture hole with silicone.while glass panels have better performance in direct sun light the light energy panels work in partial sunlight or shade and as such have a superior performance over glass panels in a mobile application .free standing frames either pole or roof mount are available "
only thing we found was as with all technolgy its dearer than glass panels
i have nothing to do with this mob other than i picked up a sheet from there stand if you want more info try www.12voltccma.com.au
ps prices on application nothing on the sheets steve89 nissan looking foward to august and more travelling
AnswerID: 18026

Follow Up By: David N. - Tuesday, Apr 22, 2003 at 12:18

Tuesday, Apr 22, 2003 at 12:18
G'day GOB- I'd like to think you were on to something- BUT
As an (ex) electrical engineer I'd be VERY sceptical- there is no "free lunch" ie: power has to come from somewhere. Solar panel technology has come a long way- but none of them work worth a damn in the shade- true some are slightly better than others but we are talking fractions here. I'd do my homework very well before parting with my hard earned dollars....
Cheers
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FollowupID: 11334

Reply By: Jo- Tuesday, Apr 22, 2003 at 16:38

Tuesday, Apr 22, 2003 at 16:38
Thanks everyone for all that input. We now think we'll go for a generator as pricewise, to get large enough solar capacity, it is too expensive.

Jo
AnswerID: 18103

Follow Up By: Flash - Wednesday, Apr 23, 2003 at 11:04

Wednesday, Apr 23, 2003 at 11:04
Only downside is you cant use a genne in most national parks, and even where you can you ll upset your neighbours.
If you go down the genne path have a good battery and only run the genne in the day.
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FollowupID: 11405

Reply By: twandy - Tuesday, Apr 29, 2003 at 23:37

Tuesday, Apr 29, 2003 at 23:37
We have just purchased a panel etc., from the Rainbow Power Company in NSW. Gave us all the information we needed and good backup service. And had it delivered in double quick time to Vic.

http://www.rpc.com.au
AnswerID: 18766

Reply By: twandy - Tuesday, Apr 29, 2003 at 23:38

Tuesday, Apr 29, 2003 at 23:38
We have just purchased a panel etc., from the Rainbow Power Company in NSW. Gave us all the information we needed and good backup service. And had it delivered in double quick time to Vic.

http://www.rpc.com.au
AnswerID: 18767

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