5 feet by 3 feet
Well if U had a slightly larger panel
63" x 38"
that would fit about 60x 6.25"x6.25" / 3.8 - 4watt solar cells
off the 'bay for around $150
The 1st question I would be asking myself how high current 8A or 16A ??
5 feet by 3 feet
That's a lot more reasonable size for charging expectations.auraslip said:errr.... 5 feet by 3 feet...... over the top of my trailer. I was out in the sun all day...I'm a little baked
5'x3' = 15 square feet = 1.3935456 square meters.
dermot said:I've built a little switchmode charger that I'll write up if anyone is interested - bits easily sourced from ebay or the component supplier of your choice and costs around $15 in total.
You can input anywhere between 8VDC and 30VDC and it will output a CC/CV up to 60V, but power limited to around 80W, but working on improving that. Efficiency is pretty good - in the 80s to 90s.
Based on the Nat Semi "Simple Switcher" and other similar ranges of chips - still a bit 'works in progress' and I've not yet decided which chip is the best to base it on..
It is a tiny circuit, hidden in the battery box - I use it so I can charge my bike from whatever low voltage DC I have available - laptop chargers giving 16 - 19VDC work very well - as do solar cells (had to borrow one for testing). It seems to cope very well with the changing voltage as the input from the sun varies - but only done brief testing.
Last piece of the puzzle is to interface it to Gary's BMS so that the HVC opto will switch the charger to a couple hundred mA when LEDS come on.
I also found 300W/hr of unused laptop batteries - they will make a lightweight trickle-charge range extender when I get some spare time.
dermot
dermot said:I've built a little switchmode charger that I'll write up if anyone is interested - bits easily sourced from ebay or the component supplier of your choice and costs around $15 in total.
You can input anywhere between 8VDC and 30VDC and it will output a CC/CV up to 60V, but power limited to around 80W, but working on improving that. Efficiency is pretty good - in the 80s to 90s.
dermot
dermot said:Pulling 350W off a 12V car battery would require over 30A - a bit unrealistic for long term charging. Why do you need such high charger power while on the move?
I have a good supply of 12 volt deep cycle batteries, and figure I could use 2 of them in series to charge 1 of the electrathon's cars batteries if I could somehow turn the 24V of the 2 batteries into 25A/15V CC/CV.
REdiculous said:Why not use an inverter and your normal 110v charging setup? A 600w 24v pure sine inverter can be found for $230 or a 300w for $140.
drewjet said:REdiculous said:Why not use an inverter and your normal 110v charging setup? A 600w 24v pure sine inverter can be found for $230 or a 300w for $140.
I have thought of that, it just seams a bit of a waste to take 12 volts and bump it to 120 just to bump it back to 15 volts
so thats 64-128 watts of power a day.. in winter.. how much is needed to charge a bomber?
drewjet said:What would be really cool is to then have solar panels to recharge the 4 deep cycles that became the charges of the car's batteries.
REdiculous said:... 2-6 hours of peak sun = 2-6 miles in the "tank". Not too bad I guess.
brisbanebikie said:REdiculous said:... 2-6 hours of peak sun = 2-6 miles in the "tank". Not too bad I guess.
you could almost go camping with your ebike and take a rollup solarpannel with you to charge it during mid day while you rest
Well I dropped the grid to my ride endpoint since it was costing US$7.5 a month just for the connection. The 75 watt panel there recharges my bike in about 2 hours. Admittedly it is at risk for being stolen, but it has already paid for itself. The less electricity you need, the more cost-effective is PV.mvly said:If I get it from the grid, I pay at most 20 cents per KWh. Thus, to charge my battery to full, it will cost 40 cents. Even if I inflate that to $1 for 2KWh to account for rise in energy cost in the future, it will still take a long time for me to make my money back on all the equipment assuming I use the battery once a day.