Using 555 charge pump to boost the 11.1v lipo to 15 possible?

[amateur_25]

Hi Guys,
I know the 555 can be used as a charge pump to obtain a higher voltage. What I need to do is boost 11.1v @ 4A (2  3 cells lipos) coming from my lipo to 15v so I can drive my leds properly. They're wired as 4 columns ( in series)  by 7 rows ( in parallel) hence I need at least 12.4v to give each led equal power.   Also AFAIK the 555timer isn't designed to power such a big load. How would I get more current at the higher voltage? Also can you safely wire 2 lipos in parallel. Prefer it not to blow up in my face.

I have already built the matrix on veroboard it works. I just need a portable power source as it's a work light. The work light I have used very cheap leds. I also think the power source they've thrown together is lethal. No mains isolation and the capacitor/resistor combo used to reduce the voltage isn't a y capacitor. Not only that it's on the neutral side and not line. Isn't that dangerous? I think I'll convert it to a power brick instead. At least  that will have a switch mode transformer in it.

[amateur_25]

not too bothered about efficiency.  Well I would like around half an amp since I may make it bigger.

So how do I wire this up to the timer? Sorry I have no experience of this sort of thing.
Is the the arrangement in the image what am after?

[Zero999]

A charge pump isn't the best option for 500mA. A boost converter is a better option.

[amateur_25]

ok Just out of curiosity if you were to use one, how many milliamps  would you expect it to be good for? Just so that I know for next time. I've opted for a simple lm257 from ti.