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  1. #1

    Super - Ultra Capacitors For Engine Starting

    I need to replace both port and starboard 8D starting batteries. I'm considering installing an ultra capacitor system with a group 31 battery to start both engines.

    Does anyone have experience with the Maxwell, KBI, or other ultra capacitor system?

  2. #2

    Re: Super - Ultra Capacitors For Engine Starting

    How long to restart after a failed attempt? Ho long until you bv can fire up an engine in an emergency if you lose it and cant immediately restart it?

    I'd not look at it as a replacement for a marine engine. Maybe something on land.
    Scott
    41C117 "Hattatude"
    Port Canaveral Florida.


    Marine Electronics and Electrical Products Distributor.

  3. #3

    Re: Super - Ultra Capacitors For Engine Starting

    Pm me if you want, I had a Maxwell on my last boat, maybe the best thing I have ever had on a boat. Mine was about the size of a group 32 battery and I was able to get rid of 2 8D’s and a group 24 battery. Was able to start 2 300 hp diesels and an 8 kwgenerator easily. The test they do on them is to start a 600 hp diesel at minus 40 degrees 3 times. The internal charger will recharge the capacitor in about 10 minutes with 10 volts. Amazing piece of equipment unfortunately not made in 32 volts or I would have one on my Hatt. John
    Mahalo V
    1974 53 Motoryacht
    Hull Number 406
    San Diego, Ca. Ready 32 Nordic Tug, Brunswick Ga.

  4. #4

    Re: Super - Ultra Capacitors For Engine Starting

    Quote Originally Posted by Scarlett View Post
    Pm me if you want, I had a Maxwell on my last boat, maybe the best thing I have ever had on a boat. Mine was about the size of a group 32 battery and I was able to get rid of 2 8D’s and a group 24 battery. Was able to start 2 300 hp diesels and an 8 kwgenerator easily. The test they do on them is to start a 600 hp diesel at minus 40 degrees 3 times. The internal charger will recharge the capacitor in about 10 minutes with 10 volts. Amazing piece of equipment unfortunately not made in 32 volts or I would have one on my Hatt. John
    Unless your boat has it’s original starters you have 24v units. I’ve been told that replacement 32v units haven’t been available since well before the turn of the century. I know mine are 24v and have been for a very long time: long before I bought her. It’s a very intermittent cycle motor, not continuous duty.
    Michael & Beth
    Hull Number CV312
    63’ Cockpit Motor Yacht
    1986 model launched in August 1987

  5. #5

    Re: Super - Ultra Capacitors For Engine Starting

    Quote Originally Posted by Scarlett View Post
    Pm me if you want, I had a Maxwell on my last boat, maybe the best thing I have ever had on a boat............... The internal charger will recharge the capacitor in about 10 minutes with 10 volts. Amazing piece of equipment unfortunately not made in 32 volts or I would have one on my Hatt. John
    I did some research on these and saw that truck fleets had good reviews. I'm glad to hear real world boat experience. I'm not happy Maxell got bought by Tesla, but that's just a grumpy old man reason. https://www.maxwell.com/

    I'm ditching my 8ds and going with something else. I was pondering the Maxell, but they were $800 a piece I think? I want one for each engine (cummins 8.3). I guess they last a long time, but batteries are $100 +/-a pop (2 per engine) Group 31 or 34.
    FTFD... i drive a slow 1968 41c381

  6. #6

    Re: Super - Ultra Capacitors For Engine Starting

    I fyou have the original Hatteras cases, for 8Ds, three Gr 24s will fit right in there, sideways. Perfect fit. I use to in parallel to fire the engines, and the third one the generator.

    Incidentally I think I got 11 years on the previous set of Deka Marine starting batteries...

  7. #7

    Re: Super - Ultra Capacitors For Engine Starting

    Cummins did a great job lowering the needed amps for starting. A single grp 31 can spin the 5.9, 6.7 and 8.3 engines but 2 are always better.

    Ive sold a bunch of the super duper starting agm batteries (low resistance and high cca) for starting but theres not a good solution in that technology for house banks.
    Scott
    41C117 "Hattatude"
    Port Canaveral Florida.


    Marine Electronics and Electrical Products Distributor.

  8. #8

    Re: Super - Ultra Capacitors For Engine Starting

    Quote Originally Posted by jim rosenthal View Post
    I fyou have the original Hatteras cases, for 8Ds, three Gr 24s will fit right in there, sideways. Perfect fit. ........
    I have 3 plastic (with top) 8d battery boxes. I can't remember the brand. They are not original Hatt fiberglass. I will have to measure and see if G24 will fit sideways (but I do like the idea). Eventually I may move the battery location to outboard each engine, now that I'm not using 8d's.

    My RV is an 8.3 and uses two group 34's. I couldn't fit g31 (better battery) in the holding tray.
    FTFD... i drive a slow 1968 41c381

  9. #9

    Re: Super - Ultra Capacitors For Engine Starting

    I bet they will fit. The Hatteras cases fit a standard 8D. Let us know. I am happy with my multiple Gr24 rig.

  10. #10

    Re: Super - Ultra Capacitors For Engine Starting

    I've decided to replace the two 8Ds with two paralleled Deka Group 31 AGMs (800 CCA, 105 20 Ah Cap) and a KBI super capacitor. This setup will be used to start both engines.

    KBI is more expensive than Maxwell, but has a higher max ambient temperature rating so less chance of high engine room temperature causing a problem. More importantly, it recharges in a couple of minutes instead of the Maxwell's 15 to 20 minutes.

    I've been told that Tesla has eliminated Maxwell's super capacitor line. Don't know if that's true.

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