Eyetattoo wrote:
westend wrote:
Eyetattoo wrote:
Zacvv wrote:
Thats a good thing to hear i was starting to feel like i may have made a bad purchase. How much do you use your 12v system and for what things?
eye tattoo
We power our sound system during the day and usually a 21 inch LED TV. At night the TV and lights get used. I used to run the generator for 6-8 hours a day, now roughly 4 hours. I do plan on adding 1 more 20w panel so it can keep up a little better.
There is no possible way that a 20W solar module will equate with two hours of generator run time even with the smallest RV converter. You are either running the generator too long or have misjudged the amount of charge the module can deliver.
If can you state how many AH's you are using in a day, I'll retract my previous statement.
No I cant state my actual AH's, don't know how to calculate it, but I have no reason to lie. Maybe its because we camp at Pismo where we get a good 10 hours of sunlight, who knows. All I know is that the 20w panel does a great job for our usage. Once I convert to LED lights and the temps rise(which means no need to run the heater at night) at the beach I might not need to run the generator at all. I still want to add one more panel just for good measure though.
I don't think your honesty is in question. I hope you didn't get the impression that I was questioning it. I do question whether you have accurately estimated the contribution of the 20W solar panel. That's important not so much to me or even you, but may be important to someone shopping for solar modules and reading this thread or to the OP.
If someone thought that a 20W solar panel would take care of their battery charging needs and at the end of a 24 hr. cycle that battery State Of Charge (SOC) would be near 100%, they may be disappointed or feel that they were misinformed.
Maybe breaking it down a bit would help: A typical RV'er will use 40-100 AH per day off their 12V system. The OP will be at the lower end of this (maybe lower), since he doesn't have alarms, a working furnace, or an inverter. For the sake of this discussion, let's say his use is 40AH (maybe he uses a radio).
Let's also say that he has a brand new 12V marine/deep cycle battery that has a 20hr. rating of 90 AH. We need some type of battery to compare since drawing the battery below 50% SOC will limit the longevity and we need some type of threshold to compare. The threshold amount in this case means the user has 45 AH of usable power, just a bit more than the daily usage estimation.
Our user goes to the beach on a nice sunny day and parks. At the end of his first 24hr period he has used 40 AH and the 20W panel has returned 5AH back into his battery. He is now down 35AH and in the next 24 hr. period, without a generator, will draw his battery down below 50% SOC. Somewhere in this second day his battery will not be above 11V and typical 12V devices won't run. If someone leaves a light on during the first 24 hr. period, he'll be down to 11V in short order. Repeat this scenario a handful of times and a new battery will be needed.
For the sake of this discussion lets say the above is what actually happens and now the user is contemplating a new battery. Maybe he's getting smarter and buys 2 x 6V GC2 batteries this time. This allows 105-115 AH to the 50% SOC mark. If his use and solar system remains the same, he'll now be able to use his 12V system into a third day but will be at the 50% SOC threshold at the end of that time. The 20W panel will only return 5AH/daily back into the battery at the maximum.
