Ultracaps, Is this it?

[TheMonolith2001]

I agree, I would rather have the passive as well. I am definitley interested but it won't be for a little while. I have to travel out of state for my son's open heart surgery in a couple weeks. (Hey I'll be in St. Louis again!) That is going to take at least a couple weeks more, and then im going to be broke for awhile from the whole ordeal. If you are still doing this by the time I get some money together I will definitley be shooting you a PM. If I had to guess 1-2 months but who knows. This type of thing is pretty unpredictable and I am just going off a smooth operation and quick recovery like he has had in the past. This time might be more complicated than usual beacause he has excess fluid where it should not be but I am hoping we caught it early enough. Poor lil' basshead He is only 7 but he loves this stuff already! I probably sound pretty nonchalant about the whole ordeal which is because he has had an open heart surgery every year since he was born. You just try not to think about it too much and hope everything is okay like last time. He IS showing a lot of improvement though and once he is old enough/big enough he is probably going to get an artificial heart or transplant depending on technology at the time. He already has a few cow parts in him!

[SnowDrifter]

You know.... That's one of those things where I can math it out, but at the end of the day it's going to very from car to car. Different cars have different draws on their own, then there's your battery bank, plus whatever else you have plugged in. Amps consume a little bit of power even when they are off.

It's less of an issue with the car not being able to start. Mine has no trouble starting after a week of sitting, but the resting voltage after that long sucks. Having the battery constantly sitting in a partially drained state can kill it's longevity.

For what it's worth I don't treat my car any different with the cap bank than I did without. Any time it's going to be sitting for more than a week, it stays on the charger. I also charge my car about twice a week.

[Bump4life]

Snow can you visit the parisitic draw thing again?

If you have batteries front and rear and you had a smaller sized bank of caps, not like AMI or bump4life, how many days could your car sit with out starting or being on a charger? Obviously an estimate.

Days

Week

Weeks

Month...?

Wouldn't the batteries hold the voltage up high enough for a unassisted start even after a few weeks? Asssiuming its 12v batteries. Say a d2400/3400 up front and a d3100 or two in the back.

I figured that would cover most smaller builds electrical.

Also, would that parisitic draw if left for weeks with out a charger or start damage the batteries and / or lower the resting voltage?

if you have batteries in parallel with caps the caps will hold the voltage of the highest potential which would be the batteries since car is not on. as long as batteries are good and holding charge the caps leakage would be replaced with energy from the battery. thus until battery was discharged (11.9 or lower) you could start your car. with caps since the amperage is constant at all voltages, whatever voltage your starter can function at it would turn the engine over, but this would streess the alt a ton to recharge the caps, and if you did drop into 6-8 volt range your battery woul dbe dunzoos. this could take months , all depends how many banks of capps you have and how many batteries you have.

i personally ran 1 banks of caps with 2 d3100s and never had any voltage issues. rested at 12.9 all the time. i daily drove the car. at most it sat for 5 days.

this brings me to the time constant. look up RC time constants.

here is a general graph for a RC circuit. i have calculated each time constant to be about 20 hours for these caps.

that means it would take approx 100 hours or just over 4 days for the caps to drain to near 0 volts (10% of full) with passive balancing.

when you add batterys, this leakage is overcome by supply of battery. but this does put wear and tear on batts but the gain you get with the car on might cancel ou tthat effect.

im tired. i hope this makes sense

[Swordlordboy1234]

Understood sir... I was just thinking incase I had to leave for 2-4 weeks and didn't have my car to start it if stuff would be all effed up when I came back (for knowledge reasons of course) Both for my info and for anyone else thinking about caps here in the future.

Are there any ways to prevent them from hurting batteries in this situation? Like a nice battery charger w/float mode..? Disconnect them before vacation? Have neighbors / gf / family start your car every couple days?

Good info on the amps drawing current even when off..... Didn't know that but it makes sense. I'm sure its a crazy small amount.

[Bump4life]

once again caps will hold the highest potential. if you left a charger on them, they will hold 14.xx volts or whatever the charger charges at. thus batteries would be getting charged.

you could disconnect the bank of caps but you would have to recharge with a resistor when you got back. thats what i would do if you are letting it sit for an extended period of time.

[TheMonolith2001]

That IS a very real concern, especially for those with competition dedicated vehicles that don't get driven a whole lot. The most I ever let mine sit is probably 2 days, but I think I will install a quick disconnect/bypass system just in case.

[Bump4life]

That IS a very real concern, especially for those with competition dedicated vehicles that don't get driven a whole lot. The most I ever let mine sit is probably 2 days, but I think I will install a quick disconnect/bypass system just in case.

be careful if you install a disconnect/bypass. first of all, can it pass all the current from caps safely. second, you need to be careful because if you disconnect caps, have them drop down and try to reconnect, they will try to draw a ton of current which can melt wire ro your bypass system.

[Bump4life]

I agree, I would rather have the passive as well. I am definitley interested but it won't be for a little while. I have to travel out of state for my son's open heart surgery in a couple weeks. (Hey I'll be in St. Louis again!) That is going to take at least a couple weeks more, and then im going to be broke for awhile from the whole ordeal. If you are still doing this by the time I get some money together I will definitley be shooting you a PM. If I had to guess 1-2 months but who knows. This type of thing is pretty unpredictable and I am just going off a smooth operation and quick recovery like he has had in the past. This time might be more complicated than usual beacause he has excess fluid where it should not be but I am hoping we caught it early enough. Poor lil' basshead He is only 7 but he loves this stuff already! I probably sound pretty nonchalant about the whole ordeal which is because he has had an open heart surgery every year since he was born. You just try not to think about it too much and hope everything is okay like last time. He IS showing a lot of improvement though and once he is old enough/big enough he is probably going to get an artificial heart or transplant depending on technology at the time. He already has a few cow parts in him!

wow. i hope all is well with him. and with you. ill be here. just shoot me a pm whenever.

[TheMonolith2001]

Hey thanks, I appreciate it, really I do.

I wonder if I could use something like those bigass breaker switches to do it instead of actually having to disconnect things. Those can get pretty expensive though.

[alaskanzx5]

If you have a fused connection going to the cap banks couldn't you take the fuse out if the car is going to be sitting for a while then do as snow suggest and charge the battery using a turn signal bulb before replacing the fuse to reconnect it to the batteries for use.