Thursday, May 27, 2004 at 16:59
Hi Shawn,
I have used a 20 watt panel for 3 years to charge up a 27 amp hour battery set up to run lights of up to 3 amp current draw of a night. Longest stay on
battery power was 10 days with no problems.
If all you are running are lights and you are in an van (not a 25 foot motor
home where you might need plenty og light to find your way from one end to the other) then 50 watt should be ample to replace your nightly usage.
Wolud strongly suggest you wire in a good ammeter calinbrated up to 5 amps so you can read the draw. You will need to go to Jaycar or similar to get one. The ammeters sold in auto store do not give a fine enough read out.
That way you can monitor your current draw at night.
Also you should have a voltmeter installed to tell battery voltage. If the van does not come with one fitted, then a visit to Jaycar will see you fixed.
Lastly buy a good battery charger of around 2-4 amp output so you can put the rig on charge before you leave
home. Better to leave
home with a fully charged battery than not. If you go out with obe only 80% say then you will have problems as the panel may not bring your battery up enough after the first night.
Saw that just last week. Brand new off road rig. Flat battery after first day. Camper and wife, experienced too, hadn't charged it up before leaving
home. Wasn't me, but fellow camper had a generator so charged him up enough so they could stay the week provided they didn't run any lights at night.!!
And, yes, Solar panels do not put out the rated amperage except under ideal laboratory conditions. So, most people over solar rather than under solar.
Having said that, lights only, up to 3 amps draw, 50 watts should be ok.
Have fun
PS I assume you will also carry an emergency gas light. I use a small Gaz model with disposable cartridges. Takes up not much more space than a roll of
toilet paper but when you need it!! Like
Toilet paper, can't do without it.!!!!.
Cheers
Magnus
AnswerID:
60464
Follow Up By: V8troopie - Thursday, May 27, 2004 at 23:58
Thursday, May 27, 2004 at 23:58
Magnus, I second your suggestion re installing an Amp meter but, while you're at it, wire it in so that the solar charging current can also be read by the flick of a switch.
This will gove one a good idea how the panel is performing at any instant .
Klaus
FollowupID:
322121
Follow Up By: Magnus - Friday, May 28, 2004 at 09:47
Friday, May 28, 2004 at 09:47
Klaus,
You been sneaking round spying on my rig!! I can tell!!
Yep, that's what I have. Salvaged an ammeter from a defunct battery charger. Ammeter reads from zero to 5 amps on a 2 inch square meter mounted on a jiffy box from Dick Smith along with a 2 position switch labelled Draw and Charge.
This lot is right next to the voltmeter from Jaycar mounted inside a clear faced jiffy box also from Jaycar. Keeps voltmeter protected as the whole lot (voltmeter and ammeter) is mounted on the front of the trailer where I can see it during day and night. My trailer has the trailer drawbar in the kitchen. Back to front to most others.
Takes a bit of nutting out to get the same meter to show draw and charge, but sit down with a big mug of coffee and draw it up on paper first. Not very hard when you spend a bit of time planning the wiring.
a reminder, don't waste your money on an auto style ammeter. Spend the extra $ on a good one from Jaycar. Will be less than $50 if I remember correctly from their catalogue. The Voltmeter will set you back $40. So for less than $100 you should be set. They also have an on line
shop you can
check out.
Have fun
Magnus
FollowupID:
322146