blueroomelectronics
Well-Known Member
Have you ever built an inverter before?
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Have you ever built an inverter before?
Power handling and stuff not a problem. finding the parts to make it, not a problem either, All that integration and handling stuff is outside of my area!
Someone else has to field those questions!
One of my previous posts pointed to a Chinese supercapacitor I found online. It was a module rated at 2200 Farads and 2.7 Volts, for about $20 or so. The energy stored in a capacitor is E=0.5*C*V^2. So if a charged cap drops to half voltage, it has lost 3/4 of its energy. Fully charged to 2.7V the cap above will hold about 8,000 Joules, or Watt-Seconds. It has a max charge/discharge rate of over 1200A, so it can transfer energy FAST. I'd say it would make sense to run it between 1 and 2.5 Volts or so. Not much energy left below 1 Volt and getting too close to comfort above 2.5.I do need someone elses input on this.
As I understand it one farad is one amp for one second. So, one amp for 3600 seconds is one amp hour right?
what do big ultra caps have for real world values right now?
what volts and what farads capacity?
And what dischsrge rate do they work up too? Amps per second or something like it.
And what actual cost?
They seem like interesting devices but how big do they need to be to match a small battery in terms of usefull energy.
Say physical size per theoretical amp hour of an ultra cap bank Vs different battery types.
Any Ideas out there?
I don't want a supercar, there are several of them already and they are way too expensive. I want to build something that is universal and inexpensive. I want flexibility most of all. This system seems to fit the bill. I love the idea of starting small, with two slaves and a few batteries so a car can drive around town. More power and/or range could be added at any time with a major redesign. Right now and EV will replace a whole string of batteries if just one is tired because replacing the one will unbalance the string. With this setup the batteries could be used until they were truly near the end. Also, the idea of adding different types of batteries is VERY appealing! I'd love to build all NiMH but there is no way I could afford it. With this type of system I could add NiMH incrementally, slowly replacing over time as the older LA batteries wore out.hmm... theoretical super EV car. I put much thought into that one myself!
Remember that supercap would be tied to only one slave controller. With each additional controller there would be another supercap bank. 1200A at 13.5V is good. With 6 slaves you get the total equivalent of 1200A at 80V. Now that could really move you!usefull info on the super caps. but still 13.5 volts is very low for driving any decent size car. My old EV was 96 volt and ran at 250 amps regulated. It had good power and could do normal road cruising at 65 mph most of the time. but the 16 6 volt 220 amp hour batteries still did not go that far. for real wolrd driving I would go double that voltage and amp hour and double the motor amp limit as well. 96 volts at 250 amps gave me 24 kw or about 30 hp at the wheels. With a bigger motor or multiple motors I could get 120 hp to work with.
given 3 electric hp is considered the same as 5 gas hp that would be like having a 200 hp engine. Or about like driving my mercury grand marquis.
But then to do that I get the same delema as you, battery type.
My brother plays with the lithium polymer batteries alot in hobby RC stuff. Given the average cell size he uses and 3.7 volt 5 ah capacity plus the 50 amp draw capability.
We sized up to that of a 12 100ah deep cycle battery and we came up with a theoretical cappacity of 14.8 volts and around 1000ah per battery block. With a discharging rate of well over 1500 amps! In theory of course!
Now High output EV with good real world driving range is doable.
( with a $30,000 battery pack!)