100 Watt Portable Solar Panel

[Bruce H]

I went to a farm trade show this afternoon and this company was selling these:

Portable Solar Kit 100 Watt

Looked really well made. I will probably be a buyer.

[Mary Ann in MN]

I just bought this one on sale for 39.00. I very seldom run off the battery, but last summer the power went out in the camp ground and I didn't have any lights so a friend has one of these to keep the battery topped off. He said it works good. I just may invest in a larger one down the road, but if this will just keep the battery charged incase I need it, then that may be all I need.

[Bruce H]

About a year ago I was almost convinced to purchase one of these:

Amazon.com: Instapark PowerBox Mars100 Fold-n-Go Portable 100-Watt Solar-powered 12V Battery Charger with Built-in Charge Controller & Cooling Fan: Automotive

Then I read the negative user review from a user who had put a multi-meter on one and it was not putting out the advertized amperage.

I am still not sure about about this Kencove model. The vendor display was in a building thus no ability to test the display model with a multi-meter without purchasing and finding out the hard way.

Also assuming it would put out 7 - 10 amps in full sunlight would that be enough to effectively charge a 12 volt battery?

[Carol H]

Originally Posted by Mary Ann in MN

I just bought this one on sale for 39.00. I very seldom run off the battery, but last summer the power went out in the camp ground and I didn't have any lights so a friend has one of these to keep the battery topped off. He said it works good. I just may invest in a larger one down the road, but if this will just keep the battery charged incase I need it, then that may be all I need.

Mary Ann the 7 watt systems are commonly used for battery maintenance when a trailer is sitting for awhile (often in storage) unless you are camping in full sun and keeping your power usage to a real bare minimum, using only LED lights and a water pump sparingly I would not expect it if camping for a few days off the grid to keep my battery at a safe/good level of above 11.9 volts.

[jwcolby54]

Mary Ann, why didn't you have lights? If you have a battery and your unit has a built-in charger then it should keep at least some charge on the battery.

I'm with Carol on this, a small 7 watt panel will really only be good for a trickle charge.

[jwcolby54]

Bruce, expensive but portable and complete, ready to unfold and use. These things are really quite cool.

[Mary Ann in MN]

Carol. I usually don't use any battery power. I'm just hoping my battery stays charged up in case the power goes out again at the campsite. I don't always remember to charge it full before I leave home. I also have a Honda Generator 2000 with me. If the power is out, it's nice to be able to turn on a light in the middle of the night if I need it.

[jwcolby54]

Mary Ann,

A small solar panel works without anything else as a trickle charger. However you need to discover whether your battery is still functional. If it is then you also need to ensure that the battery charger functions correctly. A battery is one of three parts of a system. It just stores power. Something has to charge it. Then when it is time to use it ' various things will pull power back out. You mention lights, but if you have a propane furnace it will likely have a blower fan. If the ac goes out, and it is snowing out and you are stuck in your tt, you want to know that the battery will drive the furnace fan. Having lights isn't all that helpful if you have frozen to death

If you have a battery, then you should have a charger driven by the ac. The problem is that these built-in chargers may not correctly charge your battery. The sad fact is that they often don't and so your battery dies. Come time to use it, stuff will work for a few minutes then fail because the battery is simply dead. A trickle charger cannot charge a dead battery, it can only maintain the charge on a healthy battery.

In some circumstances a healthy battery literally keeps you alive, so get it tested. If you tried to use your battery and it didn't drive your lights you may well need a new battery.

Long term a small solar cell like this will also not keep your battery healthy. Your battery needs to be brought to a boil, with a large charge current. The boiling causes the battery acid solution to stay mixed. If this boiling does not occur then the solution separates and the bottom of the lead plates are exposed to pure sulfuric acid causing them to become crusted with oxide and... the battery dies.

Only a real, correctly functioning charger can provide the high currents required to boil the solution. A small solar cell like you bought will not do that.

In fact a small solar cell may trick a cheap built in charger into thinking that the battery is fully charged, causing the charger to go directly to 'float mode' when it powers up. If the built-in charger does not cycle through the stages, and does not have a de-sulfination stage, then your battery never boils and it eventually dies.

I hate to be the bearer of bad news but you are responsible for determining that your charger actually works correctly, and if not correcting the problem. There are aftermarket chargers which will periodically bring your battery to a boil for a few minutes, which all by itself eliminates that failure mode. If your charger doesn't 'de-sulfinate' then one of these widgets is the cheapest solution.

Also remember that a solar panel trickle charger doesn't work when covered with snow.

One thing I forgot to mention is that this does not affect AGM or gel cell batteries, which are fundamentally different from a wet cell (flooded cell) battery. These types of batteries do not need to boil to keep the solution mixed.

[deryk]

Bruce, this looks like a good deal, but there is no spec's to it... is it mono or poly crystal? what is the suggested optimal output? what is the warranty?

I like the idea of the folding panel, but this could be like Harbour Freights panels or they could be a good quality but they dont tell us anything relevant... so I wouldnt risk the money when I know in that same price range other companies sell similar panels.

[Carol H]

Originally Posted by Mary Ann in MN

Carol. I usually don't use any battery power. I'm just hoping my battery stays charged up in case the power goes out again at the campsite. I don't always remember to charge it full before I leave home. I also have a Honda Generator 2000 with me. If the power is out, it's nice to be able to turn on a light in the middle of the night if I need it.

If your Scamp is set up as most are with a converter, then every time you turn on a 12 volt light which most in the trailer are other than the large long one in the kitchen you are actually using the battery even when plugged in. As you use light power your converter is supply power via the battery. Your water pump & fan do the same assuming they are also 12 volt.

If your plugged into power at a campground & it goes out you should still be able to use your lights in the trailer for a few days without at solar panel or generator assuming your battery is in good condition. If you can't that suggested that perhaps your battery is no longer holding a charge which can happen if it been allowed to run right down more than few times. If that's the case then it's even more doubtful that the small trickle solar panel you posted the link for will do much for you even in full sun. The small panel would be ok for keeping the battery charged up at home when your not using the trailer so you would start each trip with a fully charged battery assuming the battery is in pretty good condition to start with.

If you don't already have a battery monitor which just plugs into a 12 volt plug in the trailer you might want to consider getting one to check what the resting voltage actually is in your battery. Charge up the battery then let it sit for a few hours before taking the reading. That will give you a pretty good idea as to the condition of your battery. Not uncommon for a battery of more than 4 years old that has been allowed to run down a few times to need replacing. You can pick up a fairly descent battery monitor for under $20.

[Glenn Baglo]

Interesting story on CBC's Quirks and Quarks radio science show. Story is about cheaper solar technology, but what I found interesting is that, it takes three to six years to recover the energy that it takes to make a solar cell. I suspect it takes much longer than that if the solar cell is only used from time to time on a travel trailer.

Story is here with link to audio:
Can You Catch OCD From Strep? * Orangutans Announce their Travel Plans * Solar - Smaller and Greener * Female Bug Masquerades as Male to Avoid Unwanted Sex * Quirks Question Period: What if the asteroid never hit? | Quirks & Quarks with Bob McDonald

baglo