Lightweight battery snobs...
#1
Boost Pope
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Lightweight battery snobs...
Cliffs: this guy has built a couple of replacement car batteries out of surplus Maxwell brand ultracapacitors.
Normally I wouldn't post stuff like this, as the source doesn't appear to be wholly credible (eg: his claim that he's getting these capacitors for $6 seems dubious), but it's an interesting concept for those folks who find LiIon batteries to be far too heavy and/or don't want to risk the possibility of killing one due to over-discharge.
That, and the manufacturer of the capacitors in question actually does product a couple of "battery" modules intended for automotive engine starting:
Maxwell Technologies Engine Starting Module
http://www.maxwell.com/images/docume...00552_EN_1.pdf
Normally I wouldn't post stuff like this, as the source doesn't appear to be wholly credible (eg: his claim that he's getting these capacitors for $6 seems dubious), but it's an interesting concept for those folks who find LiIon batteries to be far too heavy and/or don't want to risk the possibility of killing one due to over-discharge.
That, and the manufacturer of the capacitors in question actually does product a couple of "battery" modules intended for automotive engine starting:
Maxwell Technologies Engine Starting Module
http://www.maxwell.com/images/docume...00552_EN_1.pdf
#2
People in the comments say those caps are $60 a pop. It's hard to take the guy seriously when his reason for doing the conversion is saving 20lb for fuel economy (plus is awful glued together plywood). Also, caps in his engine bay without any kind of battery box? Seems like a great way to start a massive car fire.
#7
https://www.hobbyking.com/hobbyking/...dProduct=58820
Between this battery, my volvo electric power steering pump, and the geo tracker alternator (55amp at idle) it will pull this battery down to unsafe voltages in 20 minutes if I hold the power steering pump against the stop as hard as I can (80 amp in this case) while idling. In other words, its fine because I'm sure the pump would have problems in less time than that. Havent run it long enough to need to balance it. Another guy that I race with was running one in his daily driver civic as a test, he left his headlights on while at work one day and killed the battery, like it swole up and wouldnt hold a charge anymore kill, but thats a problem with all lipo batteries.
Between this battery, my volvo electric power steering pump, and the geo tracker alternator (55amp at idle) it will pull this battery down to unsafe voltages in 20 minutes if I hold the power steering pump against the stop as hard as I can (80 amp in this case) while idling. In other words, its fine because I'm sure the pump would have problems in less time than that. Havent run it long enough to need to balance it. Another guy that I race with was running one in his daily driver civic as a test, he left his headlights on while at work one day and killed the battery, like it swole up and wouldnt hold a charge anymore kill, but thats a problem with all lipo batteries.
#8
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Are you just using that 4S pack with no charge circuit? What prevents the battery from being over charged?
I only ask because I can get 4S lithium batteries through work....just concerned about safety over the course of several hours of running.
I only ask because I can get 4S lithium batteries through work....just concerned about safety over the course of several hours of running.
#11
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I do have a spare 4S that I use for jumping cars in case of emergencies, but maybe I'll give this a try, but just build a battery enclosure (just to be safe!).
#13
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I can take pictures of this tomorrow if you'd like.
#17
It stays balanced pretty well naturally. If you're really concerned you can buy a blinkly balancer for $40 and it'll automatically bleed amperage from any of the cells that over volt as it charges normally. Its not a big deal pretty much all of the LiFePO4 motorcycle batteries do not have internal balance circuits (ballistic, braille, anti-grav, etc), and they're fine I would take it off the car yearly and throw it on the balancer. This is way less traumatic to the battery than being run in an r/c car, it'll pretty much never see any sort of low charge levels. Oh, and dont use a normal LiPO, the voltage is too high it'll over volt the car and then it wont even come close to being fully charged. And LiPOs are the explody hydrogen batteries, LiFePO4 much less so.
Here's what it looks like in the back of the car for more size reference. Maybe I'll come up with something that doesnt involve a zip tie when I have more time in like 3 years. The battery weighs about as much as the tiedown hardware and tray from the stock battery.
Here's what it looks like in the back of the car for more size reference. Maybe I'll come up with something that doesnt involve a zip tie when I have more time in like 3 years. The battery weighs about as much as the tiedown hardware and tray from the stock battery.
#18
Is there any reason someone couldn't ditch all the wire to the trunk and just shove that little thing under the hood? If we are talking weight that should add up, plus better cranking volts with less drop?
I don't really agree with running it with no protection circuit though, I don't really know much more than 18650's and discharge rates though.
That wiring looks like the **** in my trunk. I burned the grey rubber positive boot cover. After that I kinda quit messing around with zip ties and all that to hold it down, actually bought factory hold downs.
I don't really agree with running it with no protection circuit though, I don't really know much more than 18650's and discharge rates though.
That wiring looks like the **** in my trunk. I burned the grey rubber positive boot cover. After that I kinda quit messing around with zip ties and all that to hold it down, actually bought factory hold downs.