Super - Ultra Capacitors For Engine Starting

[krush]

Any long-term feedback on the KBI or Maxwell capacitors? I'm on decision time to buy new batteries or go for broke with new tech.

[Boatsb]

I've installed the northstar pure lead and the odyssey super cranking pure lead batteries on a few customers boats.

They are great for a burst to start engines. I'd bet a pair of grp 31 batteries from either (odyssey's owns northstar) will meet your needs. The cummins doesn't need huge bursts like the old detroits.

As for the caps I'd be wondering what will happen when you need to fire up an engine and theres a 3 minute recharge time.

[krush]

Maybe I will just build my own like this guy:

https://www.youtube.com/watch?v=GPJao1xLe7w


edit: and this guy improved on the design
https://www.youtube.com/watch?v=yWryYZFRot8

[Lmcruiser]

krush, I have a 1988 Viking 44 MY which original specs called for 2 8Ds in a box in engine room bilge. PO switched to 2 banks of 3 group 31 batteries. They fit sideways in the original box. I have 12 volt system and with 3 batteries paralleled I get more ah than 8D and a lot easier to get in and out. Had to change both banks last summer. The previous batteries were not special and lasted about 7 years.

[davidwigler]

Great idea! Let us know how it works.

[Boatsb]

The ECM may not like them. If the ECMs not happy nobody goes boating

[krush]

LMcruiser, your battery boxes must be wide. My boxes are from Todd (http://www.toddusa.com/battery-boxes.aspx) and and 21.5" x 11.5"


(all in inches LxWxH)
8d: 20 3/4 11 1/8 9 7/8
g31: 13 6 13/18 9 7/16

Group 24 and 34 will fit sideways
g24: 10 1/4 6 13/16 8 7/8
g34: 10 1/4 6 13/16 7 7/8

Did a lot of research and digging and my plan is now to go with one 24/34 per engine and build a capacitor deal...the Maxwell internal parts are easily available and it's a super simple device. It can be connected in parallel with the battery (I presume, like the maxwell generator power unit), or it can be used with a DC-DC converter to charge it to ~15 volts like the maxwell engine starting unit.

[Lmcruiser]

Boxes are probably custom built standard by Viking. I did not think about there being a difference in the boxes. Fortunately the PO had already made the conversion to the Group 31 batteries. Good luck with your project. Sounds like you have it engineered to work for your boat.

[spartonboat1]

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.

When you have $4.5Bn of the taxpayers money to play with and no requirement to pay it back, you can afford to buy stuff. Just sayin...

[krush]

To give an update to this thread, I haven't installed or sourced capacitors yet, but I did more research. I plan to put capacitors in parallel with a G31 battery. One set of G31 and capacitors for each engine. The capcaitors can be charged to 15V and connected directly to the starter, but I don't feel like doing this and it is unnecessary (read below).

I replaced the original starters on my cummins 8.3 with new designed gear reduction delco units: Delco Remy 39Mt 12V Starter - 8200433
https://www.jittruckparts.com/delco-...tarter-8200433

The original was a 38 size and I upgraded to the 39MT which is for engines up to 15liters. The physcial size of the starter was about the same. Around $340 each (memorial day 10% sale), brand new, official delco (now made in mexico instead of USA).

Original starters would draw over 1000 amps (my clamp meter only goes to 1000). New starters peak around 600-700 and crank the engine with no effort using one G31 battery. I replaced an 8d with one g31 and a newer starter and life is better.