electric vehicle and ultracapacitors

[michaeljayclark]

not cold in florida. I do see a capacitor pack is added to a starter battery to aid in cold freezing weather. looks like it is catching on in the trucking industry

I was wondering if the starter battery could be replaced by the capacitor battery.

deka is planning to produce batteries where the capacitor plates are in the battery with the lead plates. ultracapacitor technology is finally getting the attention it needs!

 

[peufeu]

deka is planning to produce batteries where the capacitor plates are in the battery with the lead plates. ultracapacitor technology is finally getting the attention it needs!

Well, the voltage on a lead acid element (~ 2V) neatly corresponds to a standard supercap voltage...

But not being able to vary the voltage on the supercap would make it rather useless as an energy storage tank... Would probably work very well for cold cranking though.

 

[adamey]

I don't see the point of capacitors in vehicle starting systems, even in cold weather. Good ole lead acid seems to work just fine. The biggest advance in vehicle starting isn't from battery or starter technology, but from fuel injection. A modern fuel injection ECU can determine very quickly the position of the engine and decide exactly how much fuel is needed and when to fire the ignition to get the engine to start right away. People take this for granted, but it's interesting to put a new car and old car side-by-side and compare cranking times until engine start.

Upcoming technologies like electrically operated valves will allow engine compression to be eliminated until the engine is cranking before finally enabling the valves/fuel/spark to let the engine run. This will require very small starters as the load to turn the engine over will be greatly reduced.

Ultracapacitors have their uses, but engine starting isn't really a good use for them. They are a solution to a problem that doesn't exist.

 

[michaeljayclark]

I believe the application is for diesel trucks. they dont have the advanced systems as of yet.

I know new cars crank up pretty much the first crank. if they dont that means its time for a tune up.

an electric motor could start an engine and not have that annoying cranking sound.

 

[tcmtech]

We have diesel equipment around the farm and I also work with many commercial diesel powered machines in construction and industrial settings all used at times in our cold -35 F North Dakota weather.

Starting diesels in cold weather is not really and issue now a days. The high compression engines along with the all electronic injection and automatic glow plug systems are for the most part trouble free in weather down to around -10 F or more.
Fuel jell up with diesel engines is more of the problem with cold climates not the battery's or starters and all the ultra capacitors in the world wont stop fuel jelling from happening.

Even with the older diesel equipment cold weather starting is not much of an issue if the equipment is properly taken care off. I have no problems starting our 1978 Massey Ferguson 2745 diesel tractor with its 540 cubic inch 18:1 compression and all mechanical injection system at -5 F with nothing more than a little starting fluid assistance when first cranking it and top that off its a 12 volt system too!
Ultra capacitors wouldn't do a thing for me being I need 12 volts at around 1200 amps for about 10 - 15 seconds which is no issue with a pair of 12 volt cold weather rated batteries good for 900+ CCA at 0 F each.

 

[michaeljayclark]

these ultra capacitors have an ESR of .29 milli ohms. with 52 in series does this esr add up or just stay at .29 milli ohms for the whole string?

 

[tcmtech]

Its additive so your total string resistance should be .0145 ohms. At a 144 volt input they would exhibit a natural current limiting of about 10,000 amps which is likely about 10 times what your batteries and cabling would even allow at a short circuit due to their own combined resistance in series with the capacitor banks resistance.

 

[michaeljayclark]

would need a very good control of how fast the caps charge from the batteries.

I am reading on wikipedia that lead acid batteries have a ESR of 50 milliohms. does this sound right? in order to keep the batteries at a 2C rate when filling the caps, I wonder what type of resister would need to be used.

if i bring the cap to zero and want to charge the cap at a comfortable c level before the battery starts to get hot from the battery. figure one ultracapacitor and one battery.

The numbers would be on a deka gel ev battery that has ratings of 92 minutes at 75 amps, 155 minutes at 50 amps. amp hours at 20 hrs is 180. I would like the batteries to only see 200 amps maximum discharge.

what would the C rating be then if the battery saw 200 amps discharge?

 

[tcmtech]

Would you mind explaining your logic and reasonings behind what it is you are trying to do and why?

Far to much of what you say shows you likely have a very limited knowledge of practical electronics principals and physics which unfortunately makes it very hard for those of us that are knowledgeable in those areas to follow your logic or reasonings relating to what you want to do or what you explain.

I don't get the point of pre charging the capacitor bank then using that to power the vehicle for accelerating purposes opposed to just pulling the power directly off the battery's themselves which are more than capable of supplying the amp requirement you need.

I also don't get the point of the concerns with the C ratings of your battery's in general being they are likely always going to be operating well within their intended designs charge and discharge parameters in the first place.

I am not trying to be rude here but at this point I am more lost than anything relating to point and goal of this project of yours.

 

[cowana]

One capacitor:
2.7v max
3000 Farads
0.29mOhms

52 in series:
140.4v max
57.7 Farads
0.015 Ohms

That 57.7 Farad number is a lot lower than the 3000 of one capacitor!

 

[nsaspook]

If the main usage for the large capacitor storage is to collect the energy from braking and then use that mainly as a starting boost charge instead of using the battery only, I can see how it would help. I would reduce the number of recharge cycles on the batteries (prolong life), reduce the starting currents needed from the battery (prolong life) and provide added power during starts. If the cap bank power was designed to be electrically in series will the battery voltage you could run the cap charge to zero to extract maximum energy. Just running them in parallel seems to be mainly a wasted effort.

 

[michaeljayclark]

If the main usage for the large capacitor storage is to collect the energy from braking and then use that mainly as a starting boost charge instead of using the battery only, I can see how it would help. I would reduce the number of recharge cycles on the batteries (prolong life), reduce the starting currents needed from the battery (prolong life) and provide added power during starts. If the cap bank power was designed to be electrically in series will the battery voltage you could run the cap charge to zero to extract maximum energy. Just running them in parallel seems to be mainly a wasted effort.

sorry for the last post, i read it over and yeah, it made no sense. sometimes I think faster than I type.

I believe that the caps need to be drawn down FIRST to zero to get the full energy from them. Maxwell assures me they can handle this with no problems or damage. In parallel they have given benefit to others that are experimenting with my same setup that I am trying to design. the battery temperatures have been nice and low and the damaging heat that is created when the batteries so a high rate, 600 dc amps, isnt created. Then after the caps are drawn to zero the batteries take over after the hard work has been done. The hard work being the starting the vehicle from 0 mph.

In order to have that design, I will not always get enough energy from regen, in fact in my dc system I wont have regen ;( that means I need to power the caps back up for the next launch of the vehicle. I can do that in two ways: the first being I can have a generator recharge the caps. the second I can have a controller control the amount of current that the batteries give to the capacitors. I have to have control of some kind, because when capacitors are at zero, and the batteries attempt to fill the capacitors, they will see enormously higher amperage then they were designed for and die slowly from heat or die quickly from explosion.

the option of the generator can be that when the caps are empty, the generator starts up and fills the caps, when the caps are full, the generator turns off. with an electric start generator this is possible.

I like the idea of putting them in series with the batteries. The controller I am using can operate with a battery pack voltage of 10 vdc to 300 vdc.

I would think that if I put the capacitors in series with the batteries with the capacitors first and then the batteries second, and I bought two more capacitors and brought my voltage for the capacitors up to 145.8 (54 capacitors) and put them in series with a 144 pack of batteries Ill have a total voltage of 289.8. I can then put the generator behind the batteries and through a bridge rectifier I could then push roughly (untested yes, I have the bridge rectifier and a 15000 watt generator) 200 volts through. the generator would only be a range extender, not on at all times.

when at home charging at the end of the day I can have a switch that i disconnect the battery pack from the capacitors and generator and charge them by themselves.

this entire setup would be based on if I could put the 145.8 capacitors in between the controller and batteries all in series. Ive actually be told by the controller engineer that this would work. BUT my research shows that all those trying to use caps in their vehicles have only put them in parallel.

 

[michaeljayclark]

If the main usage for the large capacitor storage is to collect the energy from braking and then use that mainly as a starting boost charge instead of using the battery only, I can see how it would help. I would reduce the number of recharge cycles on the batteries (prolong life), reduce the starting currents needed from the battery (prolong life) and provide added power during starts. If the cap bank power was designed to be electrically in series will the battery voltage you could run the cap charge to zero to extract maximum energy. Just running them in parallel seems to be mainly a wasted effort.

my thoughts exactly. This is probably the setup I will use, I thought of it yesterday and doubted how i can charge the batteries. as mentioned before this post, just a high current switch that I trun and disconnect the batteries from the capacitors and a switch that disconnects the bridge rectifier going to the generator.

this actually solves an issue that i had. the bridge rectifier is calculated to give 200 vdc. If my battery pack and cap back are both 145 vdc and under, how do i limit those 200 volts to 144? I know a dc to dc converter would do it, but i couldnt find one that operated fast enough at a high wattage to be of any use.

 

[tcmtech]

You are aware that at some point you will have to take the battery system up to around 173 volts and maintain it there for some time when its in the recharging mode.

I don't see the need for the concern with the battery's overheating during heavy load conditions that are momentary unless you have some seriously crappy battery's to start with. A good 180 Ah deep cycle will easily hold up a 500+ amp draw for a few minutes with negligible self heating or at least without creating any internal temp increases that would be worthy of concerns.

Its these simple things that cause me to wonder what you are thinking when you are apparently spending a great deal of time and money on aspects of what should be a rather strait forward and uncomplicated DC drive control system.

 

[michaeljayclark]

the peukart effect really hurts batteries. Batteries do get hot when they are delivering the amperage DC systems are taking from them. These temperatures may be just below the ratings given by the battery companies for maximum temperature but the temps STAY at the top of the scale the entire time the car is running down the road. We all know a system running at the top level of its specifications will fail prematurely.

Current experiments show with the help of capacitors batteries run cooler and ranges of electric vehicles are longer. I am one of the first to use ultracapacitors. A vehicle in Texas adds 10% more range when he added capacitors. these are not ultra capacitors, they are regular 3 dollar capacitors. he uses capacitors in his plug in prius and the temperature of the traction toyota batteries dropped as well as the add on batteries to make the prius a plug in.

I have sources that show how capacitors help. DEKA has even informed me they are integrating capacitors into their batteries for power companies. these batteries will weight 70 pounds each, so can be used in electric vehicles. so if the battery industry is going to having capacitors in their batteries then they believe that caps help batts.

I pay attention to all angles of the argument. The problem I am having is that when I am being told it wont work, save your money, I meet someone who is making it work and sees the difference and tells me the cost is worth it. The biggest factor that makes me believe that caps helps batts is the argument for the caps comes from people that are using them and have successful experiments. The majority of the people telling me it wont work are looking at formulas.

The first experiment I can find was with a capacitor pack that costs $100. this was done a few years ago. It took some digging to find it within diyelectriccar.com. The results of the experiment was that the cap pack eliminated the voltage sag that the person was seeing from his battery pack on starting from zero. this is proof that the peukart effect was essentially eliminated in his vehicle. this means the batteries will operate at their Ah rating. drawing massive amounts of amps from a battery will lower its Ah rating. we see this in the different amp hour vs. time vs. amps tests that the battery companies publish about their batteries.

 

[4pyros]

peukart effect really hurts batteries

The peukart effect can be reduced by macanical means as well. Does your car still have a transmission?

 

[adamey]

Sorry to be blunt, but I call BS on that guy in Texas claiming 10% increase from just adding capacitors. That simply goes against the laws of physics - you can't get more energy out of the batteries than what was there in the first place.

I have done studies with Transport Canada regarding mileage of various aftermarket products. People will claim increases of mileage as high as 10% when in fact the accessory makes no difference in fuel consumption (asproven by data acquisition equipment monitoring the actual fuel flow to the engine). What has changed is their driving profile. They so much want to believe their newly purchased "gadget" improves mileage that they alter their driving habits, which can have a profound impact on mileage.

I bet that's what has happened with the guy in the Prius. That or he's fudging his numbers. Do you have any links to all these people and their vehicles showing data to support their position?

You say he's using a Prius. The Prius electric controller takes braking energy and uses it to recharge the batteries. This controller would have no idea that a set of capacitors were added to the circuit and therefore the controller would not dump additional energy into the batteries. - it's going to dump the same energy as before since it's programmed to do so. So I don't see how he can get any extra range from adding capacitors since the controller is working the same as before.

Unless he claims to have modified the Prius controller, which I highly doubt since I'm familiar with how it works and how it's integrated into the vehicle.


And as I mentioned before, adding capacitors to a battery pack in a vehicle that doesn't use regenerative braking is going to do nothing to help you with range. You could prolong your battery life better by using a transmission (as mentioned) and a properly designed controller that delivers power smoothly to your motor and only draws power at a rate that your batteries are designed to support.

Just because DEKA is designing batteries with built in capacitors doesn't mean that capacitors are a good idea in all situations. I'd bet cold hard cash that DEKA will only recommend these batteries to be used with a controller that is specifically designed to work with the unique parameters of their battery, and that they would not recommend them as a drop in replacement for conventional batteries. I think you're drawing a huge conclusion that capacitors help in all situations simply because a battery company is integrating them into batteries.

 

[4pyros]

adamey; You mentioned nothing about the so called Peukart effect. As far as I can tell this is what the OP is basing his capacitor advantages on. Andy

 

[HarveyH42]

This sound a lot like the Stan Meyers fuel cell argument... And that was quite a few years ago, so many enthusiastically swore it worked flawlessly, and should of been standard equipment in some cars by now, or available any local automotive store. There are a lot of factors that influence fuel economy, proper tire inflation, acceleration (saves on tire rubber too).

With anything new, there will always be people looking to cash in on things not well understood. I don't claim to understand all this battery, capacitor stuff, but sounds a little off to me. Maybe the capacitors would allow you to user cheaper constructed batteries, which are likely going to be needing replacement in 3-5 years anyway. I'm waiting for a solar powered car, we get an excessive amount of sun here.

 

[nsaspook]

The "Peukart effect" of effective total available power loss with increase current in a lead Acid battery is easy to manage and to account for. What causes problems long term for SLA/FLA batteries when there is limited recharge power available is the non-constant CEF "Charge Efficiency Factor" First, if you really want them to last you don't discharge more than 50% routinely. During the charge cycle in BULK mode where you can recharge a typical cell with a C20 rate (40A for a 200Ah thick plate traction battery) the CEF will be above 90% until somewhere about 80% charged. At this point the CEF will drop off very rapidly to below 50% at full charge. So at the top 90% of battery charge your losses will be about 50% just because of the chemistry limited power conversion. If you don't fully charge them to 100% then the total capacity will be rapidly reduced. This last 10 to 15% is where large capacitor storage systems can help. If the CEF of the cap bank is 90%+ when being recharge across it's entire range and you can use all this energy instead, keeping the battery as fully charged as possible, you have a net gain in usable energy because of fewer losses. Making a controller that does this is not a trivial thing.