The last section we left off with LEAF needing 50 amps at 12 volts to power the band. Now amps are per hour so when you say you need fifty amps, in technical terms you mean "50 amp hours." Now batteries are conveniently rated by using... wait for it.... Amp hours!
So, if you have a fifty amp hour battery, in theory it could run the band for an hour. IN THEORY. But in reality you won't get that much out the battery. Here's why. As a battery discharges it works harder and harder to maintain constant current levels. Think of it like this. A battery is like a water balloon, as when you first open the hole on the balloon it squirts out water fast, but then slowly tapers off. In order to get all the water out of the balloon you have to squeeze to get it out. YOU CAN'T SQUEEZE BATTERIES.
Now it makes sense to simply increase the battery size/capacity to allow a steady 50 amp current without draining it down more than 50% or half. And draining batteries down to half capacity is not going to make them last too long. Like the balloon, we would need a huge ass balloon to squirt a stream of water for an hour, but a big enough balloon could squirt all day without going low.
So 50amp hours would require around 400 amp hours of battery capacity to run for an hour.
A 400amp balloon... lol This allows us to mess up and use 200 amp hours and still not go below 50% capacity on the batteries. My batteries are all about 90 amp hours each, and luckily I have five old ones that together should get LEAF to around 400 amp hours.
5 x 90 amphours = 450 amp/hour capacity
Now how many solar panels do we need?
It all depends on how fast you want to recharge the battery bank.
"Battery Bank" is just jargon for the whole group of batteries you use. My battery bank consists of 5 90 amp hour deep cycle marine batteries.
For this system, if I can generate 200 watts per hour, then I will be golden. Now this 200 watts only counts as 16 amps per hour or so, or in other words... 16amp hours per hour. If we charge for 20 hours:
20 x 16 = 320 amphours for or battery bank!
Lets say we get 5 good hours of sunlight every day on average, and we charge monday-friday 5 days:
25 hours per week x 16 amp hours = 400 amp hours!!!
Well all you need is an inverter but lets wait till next time... Let all the math sink in and go order your solar cells and or panels. I make my own panels out of broken solar cells purchase from these guys Silicon Solar they are rad.
So next time we will look at inverters and such... Scroll down for the next blog.
One Love from LEAF Leaf Music
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