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Post by 90GTVert on Jan 12, 2017 11:39:12 GMT -5
I've only ever used large caps in car audio. They work quite well there. It's nice when your battery gauge and headlights stop looking like they're dancing to the beat.
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Post by humanshield on Jan 12, 2017 23:29:34 GMT -5
Supercaps are cool. I worked with rather large banks of them extensively during the summer of 2010. They are sort of a niche item IMO. The only real thing they have going for them is they are able to be charged and discharged RAPIDLY without problems for many cycles. Otherwise they are rather large, heavy and expensive. Dont over charge them though not even a half of a volt. The organic electrolyte in them creates a dense choking black smoke when overheated/burning.  Hey, can't they put some over charge protection circuit on them like they do smaller batteries? |
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Post by humanshield on Jan 12, 2017 23:32:09 GMT -5
This is what I thought I know about car batteries and charging systems....but if wrong, "learn" me something lol The battery is mainly there for starting. Once started, the alternator does most of the work. If you disconnect the battery, the car will keep running. Todays alternators are precisely regulated to keep the voltage within a narrow range. And since batteries "can" and often do fail, modern alternators are usually internally protected against overload. The battery has been described as a power bank....the alternator makes deposits into it and the cars electrical system only makes withdrawals when the alternator either cannot supply enough voltage and current or during starting, before the alternator is spinning. You can verify this if you put your headlights on at night near a wall...bring the engine rpms up and if you look closely you will see a slight increase in brightness as the alternator output peaks...especially if you have a very low idle although most modern alternators are designed to put out their near peak voltage even at idle. If your car is relying too heavily on the battery, you have an alternator problem brewing because car electrical systems are designed so that the alternator whether 50amp, 80amp or 150amp can supply ALL the electrical needs of the vehicle ONCE it's running. Oh, and the alternator is rectified so the output to the battery is already DC (you can't charge a battery with AC current). Now if your alternator is marginal and you're at idle and you turn on a high current draw accessory like the headlights, the sudden spike might shut the motor off. That said.....the battery does act as a buffer to smooth out any voltage spikes (very much like a capacitor in an electrical circuit) so it's not good to try driving around without a battery. But that supercap thing is on the track I am looking for. That or building my own lead acid wet cell batteries. Lead should NOT be that expensive! I just confirmed with the electronics guys here at work and, a modern vehicle will not run without a battery. He did tell me something I did not know...he said that the older alternators would let you run without a battery so I was wrong about the generator/alt. being the difference. They run a fleet of service vans here and it has been tried and the very late model vehicles need the battery to run. Bill Do they mean 2016 - 2017 ? Or what do they mean by "very late model" because I tried it today on a 2014 camry and the camry didn't miss a beat. I haven't tried it on a 2015 - 2017 vehicle yet. So maybe they no longer do. Dunno. I will say that if the very latest cars DO turn off if the battery is disconnected, there are going to be some people who get killed because of it. Imagine going down the freeway at 75mph and a battery terminal breaks or the battery has some internal malfunction...sudden loss of power steering alone could be a disaster for many people. I would be surprised that they did that. Seems a dangerous move. Less liability in a blown electrical system than a carload of dead people due to loss of control. But I don't think it would necessarily "blow" the electrical system. I have a oscilloscope and I can tell you that the output from car alternators is VERY smooth and well regulated. Now if the voltage regulator or charge diode fails all bets are off. But you can check that before you disconnect the battery....if you know how. Even if it's not "likely" to happen in the new vehicles first few years, down the road it's going to get more likely. Most cars have vacuum reservoirs so that even if the engine dies you still have brakes for a few more stops. Power steering is different. Once the motor stops turniing...you better have the muscle to control it manually. |
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Post by Deleted on Jan 12, 2017 23:54:58 GMT -5
I just confirmed with the electronics guys here at work and, a modern vehicle will not run without a battery. He did tell me something I did not know...he said that the older alternators would let you run without a battery so I was wrong about the generator/alt. being the difference. They run a fleet of service vans here and it has been tried and the very late model vehicles need the battery to run. Bill Do they mean 2016 - 2017 ? Or what do they mean by "very late model" because I tried it today on a 2014 camry and the camry didn't miss a beat. I haven't tried it on a 2015 - 2017 vehicle yet. So maybe they no longer do. Dunno. I will say that if the very latest cars DO turn off if the battery is disconnected, there are going to be some people who get killed because of it. Imagine going down the freeway at 75mph and a battery terminal breaks or the battery has some internal malfunction...sudden loss of power steering alone could be a disaster for many people. I would be surprised that they did that. Seems a dangerous move. Even if it's not "likely" to happen in the new vehicles first few years, down the road it's going to get more likely. He didn't really say but the new vehicles in the fleet are 2016's. My 1995 Mercury will not run without a battery...pull off either terminal and it shuts right down. This may be something specific to certain manufactures maybe? The electronics fleet is Dodge and Fords. The way I found out about my minivan was, my + terminal broke while I was driving and it just shut off. I thought it was the fuel pump until I opened the hood and saw what had happened. I was able to clamp it to the battery post good enough to get to an auto parts place. And yes, I did lose lights, power steering and power brakes and wipers (it was raining)...it was exciting there for a minute. Bill Interesting discussion here about this at cartalk: community.cartalk.com/t/what-happens-if-i-disconnect-the-battery-while-my-car-is-running/82462Most of the concern seems to be with the electronics being fried from the alternators 14.6 volts thereby stalling the car after losing the fuel pump, computer, ignition module, or whatever. Some say their cars stops when doing this...others say no and no problems at all. Makes me wonder. |
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Post by luke611 on Jan 13, 2017 9:52:21 GMT -5
In my experience as a car shop owner, AC/Delco is very good quality. The case seals around the terminals very well.
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Post by humanshield on Jan 13, 2017 10:47:36 GMT -5
Bill,
It seems "Some" cars will keep running others won't.
Good thing battery "disconnects" while cruising down the interstate are rare.
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Post by Deleted on Jan 13, 2017 10:57:41 GMT -5
Bill, It seems "Some" cars will keep running others won't. Good thing battery "disconnects" while cruising down the interstate are rare. Well, what if they are not that rare? What if there is not enough left of the vehicles for them to figure out that is what happened? I totally agree with you it is not a safe configuration to be set up this way. I mean, you can buy a new computer, or whatever but...if you are dead...you are dead. I was only doing about 45 when my event happened...had I been doing 75 on the interstate it might have turned out very differently. Bill |
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Post by FrankenMech on Jan 14, 2017 18:41:03 GMT -5
Battery disconnects while the vehicle is running will cause large transient voltage spikes called 'load dump' transients, they can reach over 500v with a large amount of amps behind them. Most small well engineered automotive electronic devices will have transient suppressors built in.
Alternators today have a large surge capacity but they have a very low continuous power capability. Newer small frame alternators will not charge a dead battery without releasing magic smoke. The older pre ~80's large frame alternators will charge a dead battery. The difference seems to be the heatsinks. larger alternators have larger heatsinks. The move from large frame to small frame alternators seems to be in the 1980's depending on manufacturer and vehicle models.
Supercaps often refer to the large capacitors used to help power stereo systems. They don't work well for that but opinions vary. Kind of like many 'bigger is better' fads. Supercaps also refer to small high capacity devices used to back up power in electronic devices. The supercaps in electronic devices can not be charged or discharged rapidly. They have a high internal resistance but have shown improvement over the years.
As far as batteries go, I just go to a battery recycle place about a half mile away and buy recycled batteries for $25-30. They have done well for me for many years. I usually bring in collected cores for a few bucks off. Speaking of such, I will need two batteries soon.
There are videos on YouTube about recycling your own batteries. YMMV
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Post by ryan_ott on Jan 14, 2017 21:49:13 GMT -5
Car batteries I use Deka, only because I get them through work for cost but a very well made battery that will last. It's the same battery NAPA's supply with a different sticker. Cycles I use Yuasa, oem to Honda, finally had one go dead after 8 years.
Never tried the caps but I'll be going battery-less on my RD so I'll be looking into them some more.
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Post by humanshield on Jan 15, 2017 14:02:17 GMT -5
Car batteries I use Deka, only because I get them through work for cost but a very well made battery that will last. It's the same battery NAPA's supply with a different sticker. Cycles I use Yuasa, oem to Honda, finally had one go dead after 8 years. Never tried the caps but I'll be going battery-less on my RD so I'll be looking into them some more. RD ? As in 350 or 400? |
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Post by jaga4life on Jan 15, 2017 16:48:17 GMT -5
Almost all batterys now a days are manufactured in the same place then sold to the company who put their name on them and sell them.
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Post by ryan_ott on Jan 15, 2017 21:05:06 GMT -5
Car batteries I use Deka, only because I get them through work for cost but a very well made battery that will last. It's the same battery NAPA's supply with a different sticker. Cycles I use Yuasa, oem to Honda, finally had one go dead after 8 years. Never tried the caps but I'll be going battery-less on my RD so I'll be looking into them some more. RD ? As in 350 or 400? It's a RD200, with some massaging I think I'll be able to get around 30 hp for a 270 pound bike. When I was looking I couldn't find any of the others for a reasonable price. Random internet pic:  upload image free |
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Post by humanshield on Jan 16, 2017 10:27:23 GMT -5
Dang Ryan THAT is a beauty !!! I wouldn't object to seeing more info that magnificent 2 stroke  I sold my last RD 2 stroke twin last year, a '77 RD400 |
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