Im working on using capacitors as batterys to power a 12v inverter however the inverter only allow the caps to be charged to 13v because it shuts off if the input voltage is higher. Im looking for some way of charging the capacitors to 45v and having some sort of transformer convert to 12v and once the voltage drops below 12v have the transformer do a step-up conversion to 12v as long as it can. Would that be possible? Because currently I can only charge to 13v and run it down to 10v before the inverter shuts off. Capacitor bank is 14 69000uF electrolytic capacitors at 50V. (They are not supercapacitors so they are quite large)

You might be better off with a regular boost/buck voltage converter to take the 50V out of the capacitors and convert that to 12V.

Take a look at this part.

http://www.ti.com/product/LM5118

Dave

Thanks, I saw the part description and see that it would be great. However I am unsure how it would perform when the voltage drops below 12v because the inverter shuts off at 10v and from what I know, there is much more energy left in the capacitor that is wasted because the voltage is too low. I was thinking of a system with Relays that switches from voltage regulator to voltage boost when the power drops below 11 or 12 v

I also thought maybe its possible with zeners that change at 12v

The buck/boost topology could provide a steady 12V out with input voltages from 50V down to 3 V, all in one circuit. The Regulator will switch modes of operation automatically.

However, You've got less than a farad of capacitance, which isn't a lot of charge storage. What are you planning on powering with this?

Im planning on powering a CRT with this using the Inverter however im not sure how the buck/boost chip will handle the high amperage drawn by the inverter. Would it burn up?
And yes I understand its less than a farad of capacitance but that is all I can afford now but I will add more capacitors to the bank as time goes on.

You're planning on powering a CRT, which has a 120V input, from an inverter powered by a bunch of capacitors? it might work for a couple of minutes, but that's about it. Why don't you use batteries?

Because with batteries you have to use charge controllers and make sure you don't overcharge and all that stuff that I don't want to get into, besides Ill have to change them every couple of months with so many charge/discharge cycles I will be doing