Solar panel - Charging Lithium while Discharging to motor?

[everest]

Can this be achieved

Thinking of trying to charge my 48v 10AH pack with solar.

Mount a 100 or 200 watt panel, I have room on my bike , 100 watts weights in a 1.9kg for a flexible panel

I don't know if my 'poor' calculation are correct but

48v * 10AH = 480 Watt hours in my pack.

8 (number of hours of full sunshine (optimistic) ) * 100 watts Panel * 0. 85 (system/batt losses) = 680 watt hours.

probably only get half of this due to weather, shading, and non-optimum position of a solar panel.

So, if i was stationary and had a full day of of sun , I could charge the pack from flat to full in approx. 6/7 hours ? correct?

Is it possible to run a 12volt lipo charger from a panel, i presume the panel volts/amps is going to is going to vary as the sun goes in and out, shading, bad weather , etc etc. I presume the lipo charger will just freak out with a variable voltage/amp source such as solar.??

Is there a circuit i can build to do this?

is it possible to charge the pack while discharging the pack via the motor? , that means i can ride a get the benefit of a little extra watt hours as i ride along, rather having to be stationary and the motor disconnected to charge?

is this going to make my pack explode, or unbalanced or worse?

anyone doing this? are my calculation completely wrong?

I checked out http://www.solarpoweredbike.com/2009/07/best-solar-panels-for-your-solar.html

but he doesn't mention anything about the charging system he is using.


Now to find some 'satellite solar modules', for maximum efficiency and lightest weight! anyone work at nasa?

Cheers,

Everest

 

[dogman dan]

It's doable if you have the money. I like the idea of the RC charger, but you will need a 12v buffer battery to go between the panel and the RC charger.

So panel, 12v charge controller, 12v battery, RC charger. You won't be able to charge at 100w, but 50w might work. Two 8s chargers each set to 1 amp? Or inverter and one 2 amp 48v charger.

100w panel sounds light enough, and should charge it in one day.

But every time I do calculations, if a plug is available, it just comes out better to carry more battery, and a faster charger.

 

[everest]

Is it possible to be charging the pack while discharging? Or should i have just have two packs, one for discharging, and one charging?

 

[jonescg]

Having two packs and using them one then another is exactly as useful as having both of them wired up in parallel and enjoying the extra amps on tap. Both will weigh you down, so you might as well use both as much as possible.

Charging while you ride could be an option, but you would need at least twice the incoming power as the outgoing, otherwise you will have to wait another day while both packs are charged.

Try to check out as much of the Darwin to Adelaide solar race as you can - they have some neat systems going.

 

[Tommy L]

You might find that using a Bank Of Super Capacitors prior to the charger might be more efficient than
a battery. Maybe a LiFePO4 might give good results too. Lead is probably too resistance.

On the second vid, Pats Cat almost takes a full discharge from his Capacitor bank.
He's got some great videos that might get your brain thinking

Tommy L sends......

[youtube]we88Rcum4V0[/youtube]
[youtube]3LzcGXHjpdM[/youtube]

 

[doovalacky]

How about 2 panels, 24v each 50 or 100w. There's plenty of small dc to dc buck/boost regulators that would handle 100w. Charge pack and either have a balance module or cell monitor to keep an eye on individual cells. When you're riding the panels will provide all they can to the motor then.