Tiaan

I saw a video once (somewhere on youtube i suppose) of a guy who stripped the wires off a laptop charger and screwed them into a solar charge controller. Those "laptop bricks" (as they are called) puts out anywhere between 13/14 up to 19 volts depending from which laptop it comes from - typically what a 12volt solar panel would put out during peak sunshine. End result is he kept frying the laptop bricks. He had quite a few spare and kept replacing them, but they wouldnt last. I cant remember the video, but in the comments section someone explained why the solar charge controller would keep on frying the laptop bricks. For whatever reason the charge controller can distinguish between 12-19 volts coming from a solar panel and 12-19 volts coming from a laptop brick, and it didnt like the latter.

So, I finally will have a few hours available on Saturday, and im planning to buy the thicker wire, switches and fuses i might need for this project. Just a quick question. Superdiy suggested right at the beginning that i put a SPDT switch between the A/C battery charger and the solar charge controller, to ensure that both cant be switched on at the same time by accident. Since im substituting the a/c charger for remote terminals, i am wondering what route some of you might take. Would you still install a SPDT switch? It would be a good idea, since i would still use the remote terminals to charge the battery. The one drawback is that if i want to use the terminals to DRAW power from (like connecting an air mattress pump for example), i wont be able to draw power from the terminals and charge via the solar panel at the some time.... what to do, what to do.... Im curious as to what route you guys would take.

Mark, that is a very nice example of what i intend to do with this project. Your photos are an inspiration for me to get started! Silvernodashi, The idea is to start small and cheap. hence the modified sine wave. I would like to build a unit, and use it before i throw more money into it. By using it, i would be able to determine how many times a month/year it has helped me, and also how much of a necessity/luxury it is. by using it, i would best be able to determine if it is worth spending extra money to "upgrade" it with more/better features. I said in the beginning that this is going to be a "learning project" for me, to allow me to "ease into" solar. Im hoping that through using (and later expanding) this project, i would gain enough knowledge to maybe later have a more permanent off-grid system in my small house.... one has to start somewhere.. Thank you to everyone that has replied to this thread - it is most valuable, i feel that i have learned something from every post. All very positive tips and suggestion. Many threads that i have read in the past (on other forums relating to other topics) quickly turns into negative comments where each poster is trying to show (in his mind) his superior knowledge, and doing so through derogatory comment. My experience on this site has been very positive thus far

Thanks for all the replies regarding fuses, again, it gives me a "starting point" from which to experiment further. Last night another thought crossed my mind though... I was thinking that instead of a "built in" charger, it might be better to install "remote battery terminals" that leads to the outside of the box. This solves a number of problems. First, it "free's up" the charger, allowing me to either connect the charger to the remote terminals should i need to charge the box, or i could use the charger elsewhere, like on my car if ever that needs recharging. Secondly, it gives me the option of connecting different chargers, like a trickle charger for example during long periods of non-use. There are also other advantages like weight reduction and the ability to connect ANY appliance through the use of crocodile clips. (i cant tell you how many times i wanted to pump up my air mattress, just to find that the flimsy cigarette socket was stepped on or damaged in some other way. Truth be told, ive long since replaced the air mattress pump's socket with crocodile clips) Speaking of weight reduction, i have wondered around the geewiz site (thanks to Terrible Triplett's tempting) and came across this: http://www.geewiz.co.za/geewiz-inverters/6019-500w-inverter-built-in-8a-battery-charger.html Not a pure sine wave inverter-i know, but maybe a good "stepping stone" inverter before i decide to trough serious money into this project. i love the fact that its so small and light. Plus, the fact that it has the ability to charge (albeit probably a very basic charger), is what turned my thoughts towards remote terminals...

lol... OK, consider me tempted - job well done. On the topic of fuses.. What size fuse would i be looking at next to the "master cut out switch"? For the inverter and A/C charger it would be pretty self explanatory, since each of those components would already have a fuse of the correct size, but im a little unsure what size fuse i should be looking at that protects the whole system right at the battery's positive terminal.

Thank you terrible triplett, as you said, this is a "learning project" for me, a point to "get started" and learn while at the same time expanding both my knowledge and equipment as my experience and knowledge broadens... an MPPT controller and pure sine wane inverter is definitely on the bucket list, but for now, i would like to build the most cost effective (read: cheapest) system up and running so i can test and play and learn

Thanks for the quick reply superdiy, Regarding your first point (secondary 12v outputs on the charge controller), I already have a temp setup minus the battery charger and the inverter as a "proof of concept", and my CC (charge controller) have the additional 12v outputs, so no problem there. Also, the wiring and my current equipment (PV panel, CC, battery and wiring) have been correctly sized for each other, although i should mention that im considering a larger battery with a bigger AH rating - hence my intention to add the battery charger (at least until i have acquired n bigger PV panel to keep the bigger battery topped up). But even if/when i DO get a bigger PV panel, the charger is a nice addition to get the battery topped up quicker if and when conventional power is available Regarding all your other points... thank you VERY much - that was exactly the answer i was looking for. Your suggestion about a SPDT switch between the Battery charger and CC is an excellent idea that i have not thought of. This will ensure that one can never (by accident) have both switched on.

Hi, First of all, this is a great forum which i have visited many times in the past as n guest and have received lots of info and answers as a result. It is because of this that i have decided to join in the hopes that more knowledgeable people out there can help me with a little project i would like to do. In order to "ease into" solar power, i have decided to build myself a little Portable Solar Generator. Youtube and the internet are full of examples of people who have build similar generators that they install in a plastic tote/Pelican case/ammo box. Basically a container that holds the battery, charge controller and inverter with various plugs on the side to accommodate one's power needs. All this gets replenished with a portable/camping solar panel that also plugs into the side of the box. Since I intend to use this for both camping and power outages i would like it as versatile as possible, and im contemplating to also add a automotive battery charger should the solar panel not keep up, or during extended periods of use (i.e. longer camping trips where the PV panel might not keep up) I am including a crude wiring diagram to better explain my intention. My question is regarding the placement of fuses and switches. Assuming all the equipment and wiring have been sized correctly, were would one put fuses and switches? I was thinking 3 switches, 1 switch to switch the inverter on and off independantly (to be able to switch it off if i only use 12 volt appliances) Another switch for the charger And a third "Master cut-off switch" to use when the unit is transported to and from camping sites, and should i wish to store it for extended periods of time. I have not yet bought the inverter or battery charger, and i assume they come with their own switches and fuses. Is this assumption correct, and would said fuses/switches be sufficient, or would i need additional switches/fuses in my wiring? So, to re-capp 1. Could I use the existing switches and fuses in the battery charger and inverter, and if not, where in my wiring diagram should i place these? 2. Where in my wiring diagram would i need to install a "master cut-out switch" and fuse?