Thursday, April 17, 2014

Personal power station

So, I have been shot voltage v v power recently. The Steve Harry presentation e voltage  versus is out of the water so I can't use its batteries & having just bought a new Van battery I am illogically precious about it.

So it felt like time to sort the situation out in time for the sun and as I need my pc now.

The funny thing about electricity is that to most people it's almost indistinguishable from magic. We have no idea how it works, can't see it and don't understand it. So I spent a while researching tech, reading a couple of books & understanding the science. stuff on his site really helped although doesn't sell exactly the same bits.

so here is what i came up with

here is al the kit. solar radio, ikea lamp solar battery unit, my goal zero which charges aa + aaa batteries

the orange toolbox is the original one i bought, then i found the smaller green toolbox in a skip at the marina 

everything just fits.. 

here is the kit in case anyone is interested. click on the links to buy from amazon. they dont pay me or anything i just thought it may help. you will also need wire, crimpers, electrical tape & a sense of adventure

to charge from the mains at Steve's house when the sun is shining
or in emergencies !
converts the 240v of the grid to 12v the battery needs, charges intelligently

Sizing the system, I wanted something portable that would give me 7-10 days of power.
charging my phone once a day uses 3a per day so 21-30ah . assuming a battery discharge of no more than 50% i needed a 42-60 ah battery
 shows battery charge level ie available voltage. approx 11v = dead, 12v = 50% full 13v =100% charged

this takes the variable power coming from the solar panel and charges the battery 
the multi power point tech is the key variable look for an mppt model for upto 30% more charge

for plugging in usb chargers, the voltmeter above or a car style inverter for getting 240v out of the battery
this gives you a normal plug socket (beware the wattage of the inverted and kit must match eg i cannot plug a 2000w hoover into my 150w inverter but a laptop, tablet etc is fine) 

i forgot these and had to get some from maplins. good to know they sell them !
just about the biggest truly portabe option.
65w pannel creates 65/12 (because you are going into a 12v battery system) = 5.4a so it puts 5.4amps per hour x 6 hours a day = 32.4amps per day into the battery. thus i can recharge the 50% of storage i use in 10 days in only 1 day of good sun ! 

note the high output. cheap usb chargers are 500ma this can run at 4200ma so more than 8 times quicker to charge your phone !! and its offers 2 usbs ! 

I put the kit together, then rebuilt it in the new smaller toolbox which has the same footprint as my laptop and yesterday it was sunny...yay

it charged the kit hard for the day and am now charging the boat batteries ! 

so far so good it works well.

update: here is the voltagee v %charged info from a steve Harris presentation 

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