by Burgerman » 28 Jul 2019, 01:32
Compare specs, you will see.
Better CCA, better CA, better MCA, better reserve time, better impedance, better Ah, and similar cycle life. Only downside is more weight. And the fact that they are a tiny bit wider than grp34 actually allows at the top edge only.
OPTIMA Internal Resistance (fully charged): 2.8 mOhms
ODYSSEY Internal Resistance (fully charged): 2.5 mOhms Lower is better! (less volt drop under load and less peukert, and more of the Ah usable before the chair stops)
MK 73Ah gel Internal Resistance (fully charged): 4 mOhms almost twice as bad as the Odyssey. Dont use for sport or fast charge etc.
OPTIMA Capacity: 55 Ah (C/20)
ODYSSEY capacity: 68 Ah (C/20)
MK Gel capacity: 73.6Ah But because of impedance does not offer more range unless driven like my grandma!
OPTIMA Reserve Capacity: BCI: 120 minutes (25 amp discharge, 26.7°C, to 10.5 volts cut-off)
ODYSSEY Reserve Capacity: BCI: 135 minutes (25 amp discharge, 26.7°C, to 10.5 volts cut-off)
MK GEL Reserve Capacity: BCI: 138 minutes Quoted as 145 mins in some places incorrectly I think. (25 amp discharge, 26.7°C, to 10.5 volts cut-off) At higher rates the Odyssey wins.
Optima CCA (EN-18°C): 765 amps
Odyssey CCA (EN-18°C): 850 Amps And 1500A for 5 seconds.
MK gel CCA (EN-18°C): A MISERABLE 410 amps.
ALL other batteries are inferior. Some very much so. The most important figures?
1. Impedance
2. CCA
3. Reserve time.
4. Ah
5. Cycle life at 80% DOD.
The order of these depends on your use, and priorities. But the optima always comes last.
For max range, longest service life on a slower chair with no hills or sport - most users - MK Gel wins.
For faster charging, sport, fast chairs, hills, highly lively programming, heavyweight users, and less weight and height, Odyssey wins.