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Old 01-07-2017, 09:07 PM   #64 (permalink)
redpoint5
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Quote:
Originally Posted by serialk11r View Post

It is approximately 10Ah for 150 bucks, which is a great deal.
That price looks normal to me. I bought 4x 20 Ah prismatic cells for $140. It's in my Prius right now, with no balance circuit.


http://www.batteryspace.com/lifepo4-...assed-dgr.aspx

Batteryspace has the "lead-acid" replacement batteries with balance circuitry for a similar price.

http://www.batteryspace.com/Li-Ion-B...Batteries.aspx

Quote:
Originally Posted by Nautilus View Post
Standby drain leaves the supercaps dead after short time. Nippon 700F caps, if left alone and not connected to anything, drop from 14.8 V to 9.45 V in just 48 hours. They still drain even if connected to a battery, but very slowly, in weeks or even more. And this disregarding the consumers on the car: alarm, locks, ECU memory, gasoline pump, radiator fans which still run 5 to 10 minutes after engine shutoff and draw at least 16-17 amps.

So supercaps are not efficient if left alone, only if connected in parallel to a small, lightweight auxiliary battery.

Motorcycle batteries fit together with supercaps in the box and they're small and light enough.
There is a defect if you are experiencing that much capacity loss, either in the caps themselves, or in the balance circuitry employed. Even with constant light emitted from a crude LED and diode balance circuit, my caps go for months with just a volt or 2 of loss. Without the balance circuitry, they can go much longer.

The real issue, as you pointed out, is parasitic drain from the vehicles electronics. This should be measured before designing a battery replacement. Motorcycles are the perfect application because they are most sensitive to weight, and tend to have low parasitic draw. Combining with a small LiFePO4 battery will give the standby capacity needed.

Quote:
Originally Posted by teoman View Post
Redpoint,

would you have pictures of your 3400F setup? Especially the balancing circuit.

Also what would you recommend for an R1200GS?
I'll snap some photos later, but there isn't much to see. The 5 caps are just held together by aluminum bus bars and nuts in series. Then I put them in a styrofoam box I crudely built. No balance circuitry. I think I've got 4 awg leads.

I'm running 6x 400 farad caps alone on my CBR600, and it starts every time. You have very little time to waste in starting the bike once you turn the ignition on, and only 1 shot to start. I have no problem with this in daily use, but if the bike sits for more than 3 days, I have to put it on the trickle charger or else it won't start on the 4th day. I'm willing to put up with these limitations since bump starting is always an option if the caps ever did fail to start the bike.

The practical solution I would run on your bike is a 4.2 Ah LiFePO4 battery, perhaps in parallel with a 350 F capacitor bank. It would be good to know what the parasitic drain on your bike is, or perhaps what the capacity of the OEM battery is, but this should be adequate.

https://hobbyking.com/en_us/zippy-fl...epo4-pack.html

This is what I would build:
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Last edited by redpoint5; 01-07-2017 at 09:20 PM..
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