- #31
Jslaughtskies
- 1
- 0
The last two posters seem pretty cool (and recent) so I thought I would contribute what I have gleaned from contemplating the exact same type of project for some time now.
1: Maxwell does make larger voltage rated ultracapacitors
2: These higher voltage rated ucaps typically have much lower capacitance, hundreds of Farads compared to the 3000F 2.7v ucaps they sell.
3: This is because of a tradeoff that necessarily occurs due to the electrolyte solution found on the inside of the ucaps. Basically, with that much energy at that voltage, the stuff breaks down if you go any higher.
4: As you use a ucap, or even as you just let it sit there, the voltage at which it is operating and the total capacitance reduces.
5: The way that ucaps function is like a copper tube with a big magnet being dropped through it. The magnet, while it is in the tube, slows way down, and represents stored energy in my little analogy, but it does continue moving towards the ground/a zero energy state. The analogy does break down at this point however: ucaps drain more slowly the more depleted they become. I.E. a ucap charged to 2.7v will deplete faster than one charged to about 1.5 volts.
6: The number one benefit of taking a series of ucaps and placing them in parallel with a series of lead acid batteries is that the lead acid batteries will expend relatively little energy to maintain the charge of the ucaps and prevent them from parasitically draining over time.
7: Alternative uses of these types of batteries in conjunction with one another is to let a regenerative breaking system charge ucaps which happily and easily accept charge instantaneously and then allow them to recharge depleted lead acid batteries very slowly because lead acid batteries do not like to charge or discharge quickly.
8: If you are using lead acid and ucaps in conjunction, and this is true even if you only use one or the other type as well, you would do well to get a power controller that will permit much larger input voltages than it will ever export to the motor. For instance, some controllers will supply 144v at up to 1000 amps, but let you feed 300v into the controller. This is particularly useful when using ucaps because ucaps deplete in voltage as you use them. Realistically you aren't going to charge a 2.7v ucap past 2.4 or 2.5 volts anyways, and, as you use it, its going to operate at lower and lower voltages. But, that motor still needs that 144v, and the power controller probably needs about 150v at the minimum to supply that 144v, so you want to have many more volts worth of ucaps than is actually needed. You could defeat this problem with some type of gizmo that dynamically upscaled the voltage of the caps as needed, but that is beyond what I understand how to do.
9: Other than speaking about maintaining capacitance of a ucap with lead acid, or using a regenerative breaking>ucap>battery setup, it is silly to talk about charging one type of battery with another because doing so necessarily creates an energy loss. You would do better to supply power in parallel.
10: I think the idea of using a manual switch or one that works more like a relay is a good idea in terms of switching the ucaps out of the circuit once you reach a certain speed, like 30mph. The desire here is to preserve the ucaps for when they are needed, which is acceleration because they can supply the energy necessary to accelerate much more efficiently than lead acid batteries can. Drawing a large amperage at a steady voltage from ucaps creates surprisingly little heat, which represents lost energy, but doing the same from lead acid batteries creates quite a bit of heat, and results in something known as voltage lag or sag, where there will be a notable drop in the actual output voltage of the lead acid batteries.
11: Maybe you are thinking about incorporating a solar panel on the roof of the car. Let me tell you, with energy densities like we are all talking about here, that solar panel won't even make a dent in RECHARGING these battery arrays. But, it might supply a very useful but small current which would put a sizeable dent in the parasitic drain that constantly occurs in the ultra caps, but you would need to be sure that current went to the caps, and ONLY the caps, possibly by using diodes as previously discussed.
12: The clever thing about using ucaps and lead acid batteries is that the lead acid batteries determine your range, while the ucaps determine the number of starts and stops you can make on the way to work. At that point, your best bet is to plan a route with the least amount of signals, or the least amount of signals which cannot be timed.
13: If anyone isn't aware already, the desire to use ucaps in an ev car comes from the fact that if you developed a good and safe charging method/device, you would only need to carry a long extension cord with you in your car. You could get out, plug in, and fill up at an external outlet found on most business buildings before anyone bothered to come out and tell you to stop what you were doing lol. You can find these outlets on gas stations and even buildings at the ends of strip malls.
14: despite how amazingly fast it is to charge ucaps, even if you build an ev that runs only on ucaps, you need to seriously think about how you are going to charge these things without blowing the power at wherever you are when you plug in. Ucaps typically present themselves as giant shorts when they are empty, so you need a way of stuffing power in that won't blow your mains/the mains of the building you are now stealing electricity from. This probably means extra wiring that will let you charge just one cap at a time. To do this right, the system will need to charge them each to a set voltage one at a time, and then go through and do it all over again. Each complete cycle will reduce the differences between the charges of the first cell and the last cell you do this to. I suppose if you have a full set of those charge balancing boards they sell between every two ultra caps then you would only need to hook your charge lines up to a single ucap and you could let the boards even out the charges, but I would experiment with that theory before I implemented it.
1: Maxwell does make larger voltage rated ultracapacitors
2: These higher voltage rated ucaps typically have much lower capacitance, hundreds of Farads compared to the 3000F 2.7v ucaps they sell.
3: This is because of a tradeoff that necessarily occurs due to the electrolyte solution found on the inside of the ucaps. Basically, with that much energy at that voltage, the stuff breaks down if you go any higher.
4: As you use a ucap, or even as you just let it sit there, the voltage at which it is operating and the total capacitance reduces.
5: The way that ucaps function is like a copper tube with a big magnet being dropped through it. The magnet, while it is in the tube, slows way down, and represents stored energy in my little analogy, but it does continue moving towards the ground/a zero energy state. The analogy does break down at this point however: ucaps drain more slowly the more depleted they become. I.E. a ucap charged to 2.7v will deplete faster than one charged to about 1.5 volts.
6: The number one benefit of taking a series of ucaps and placing them in parallel with a series of lead acid batteries is that the lead acid batteries will expend relatively little energy to maintain the charge of the ucaps and prevent them from parasitically draining over time.
7: Alternative uses of these types of batteries in conjunction with one another is to let a regenerative breaking system charge ucaps which happily and easily accept charge instantaneously and then allow them to recharge depleted lead acid batteries very slowly because lead acid batteries do not like to charge or discharge quickly.
8: If you are using lead acid and ucaps in conjunction, and this is true even if you only use one or the other type as well, you would do well to get a power controller that will permit much larger input voltages than it will ever export to the motor. For instance, some controllers will supply 144v at up to 1000 amps, but let you feed 300v into the controller. This is particularly useful when using ucaps because ucaps deplete in voltage as you use them. Realistically you aren't going to charge a 2.7v ucap past 2.4 or 2.5 volts anyways, and, as you use it, its going to operate at lower and lower voltages. But, that motor still needs that 144v, and the power controller probably needs about 150v at the minimum to supply that 144v, so you want to have many more volts worth of ucaps than is actually needed. You could defeat this problem with some type of gizmo that dynamically upscaled the voltage of the caps as needed, but that is beyond what I understand how to do.
9: Other than speaking about maintaining capacitance of a ucap with lead acid, or using a regenerative breaking>ucap>battery setup, it is silly to talk about charging one type of battery with another because doing so necessarily creates an energy loss. You would do better to supply power in parallel.
10: I think the idea of using a manual switch or one that works more like a relay is a good idea in terms of switching the ucaps out of the circuit once you reach a certain speed, like 30mph. The desire here is to preserve the ucaps for when they are needed, which is acceleration because they can supply the energy necessary to accelerate much more efficiently than lead acid batteries can. Drawing a large amperage at a steady voltage from ucaps creates surprisingly little heat, which represents lost energy, but doing the same from lead acid batteries creates quite a bit of heat, and results in something known as voltage lag or sag, where there will be a notable drop in the actual output voltage of the lead acid batteries.
11: Maybe you are thinking about incorporating a solar panel on the roof of the car. Let me tell you, with energy densities like we are all talking about here, that solar panel won't even make a dent in RECHARGING these battery arrays. But, it might supply a very useful but small current which would put a sizeable dent in the parasitic drain that constantly occurs in the ultra caps, but you would need to be sure that current went to the caps, and ONLY the caps, possibly by using diodes as previously discussed.
12: The clever thing about using ucaps and lead acid batteries is that the lead acid batteries determine your range, while the ucaps determine the number of starts and stops you can make on the way to work. At that point, your best bet is to plan a route with the least amount of signals, or the least amount of signals which cannot be timed.
13: If anyone isn't aware already, the desire to use ucaps in an ev car comes from the fact that if you developed a good and safe charging method/device, you would only need to carry a long extension cord with you in your car. You could get out, plug in, and fill up at an external outlet found on most business buildings before anyone bothered to come out and tell you to stop what you were doing lol. You can find these outlets on gas stations and even buildings at the ends of strip malls.
14: despite how amazingly fast it is to charge ucaps, even if you build an ev that runs only on ucaps, you need to seriously think about how you are going to charge these things without blowing the power at wherever you are when you plug in. Ucaps typically present themselves as giant shorts when they are empty, so you need a way of stuffing power in that won't blow your mains/the mains of the building you are now stealing electricity from. This probably means extra wiring that will let you charge just one cap at a time. To do this right, the system will need to charge them each to a set voltage one at a time, and then go through and do it all over again. Each complete cycle will reduce the differences between the charges of the first cell and the last cell you do this to. I suppose if you have a full set of those charge balancing boards they sell between every two ultra caps then you would only need to hook your charge lines up to a single ucap and you could let the boards even out the charges, but I would experiment with that theory before I implemented it.