Odyssey 12 volt dry cell battery

For MGA owners, the most important point of this article may be that we find a 12 volt battery which will fit nicely into the original MGA battery tray with no modification required. It drops right in. The picture below shows two 12 volt Odyssey batteries nested nicely in the original 6 volt battery trays. You must not connect two 12 volt batteries in series for 24 volts. Also consider general advice warning against connecting batteries in parallel (see next page).

One of these batteries will do the job for an MGA (marginally). Cold cranking current capability is a modest 326-CCA. This is similar to the original twin 6-volt batteries, which were not very good in cold weather. Total electrical storage capacity is moderate at 27 AH (10-hr rating), which is less than half of the storage capacity of the original twin 6's. This is why one person was installing two batteries in parallel. The original twin 6-volt batteries had storage capacity of 58 AH. So if you install one Odyssey 12-volt battery, don't expect real strong cranking ability in cold weather. If you leave the headlights on when parked it will be dead in an hour or so. If the generator fails when driving with lights on you will have a similar short period of time to get off the road before the car is dead.

The following photos are compliments of Mac A in Tehachapi, California, USA.

The battery shown above is the Odyssey PC925T, with the "T" being for the SAE type terminal posts. This is smaller in height than you may be used to seeing in a car battery being less than 5 inches tall (not counting the terminal posts). These are zero maintenance sealed dry cell batteries which will not leak if punctured. They can be mounted in any orientation and have very long life and excellent vibration resistance.

For more information see the Odyssey Battery web site.

Installation of an Odyssey Group-26 battery in my car, November 23, 2016. The Groupe-26 battery size requires extending one of the battery carriers 1-1/2-inches longer, or making an adapter to raise the battery above the edge of the carrier frame.
Summit Racing claims the PC1200-A battery is superseded by PC1200 plus a top post screw-in kit. Otherwise they also have a PC1200MJT which has top posts and a steel outer shell all around. This is a "Jeep" battery for off road use, very rugged. Looks like a good idea to me, considering that the MGA battery resides about six inches from the road, exposed near the rear wheel and always very dirty. I'm sold. This is to be joined by a Braille BRL-6188 hold-down clamp. I really like this one made from FRP (Fiber Reinforced Plastic), corrosion proof, adjustable for battery width, and very strong. I had one of these on my Mazda RX7 for more than 10 years and it holds up well.

Out with the old, and in with the new. Very happy to get rid of the corroded hold-down clamp. Also notice corrosion on the cable connector which was replaced on July 20, 2016, just four months earlier. This was so bad that the screw tips were completely corroded away, and electrical connection between the wire and terminal was so bad as to prevent cranking the starter motor (even though it was so tight you couldn't pull it out with a mule). The close-up picture was after wire brushing. I expect this new sealed battery will be a huge improvement. Also found a broken connector on the ground cable (to be replaced later), temporarily secured with large Vice-Grip.


Addendum June 8, 2017:
Six months on I am happy to report this battery is doing well, entirely corrosion free and maintenance free. With adequate storage capacity I could leave the lights on for an hour when parked, and it still starts the car. CCA=540. Reserve Capacity = 76-minutes.

Addendum September 6, 2021:
Someone reminded me to do an update. The Odyssey battery is still hanging in there, almost 5 years years and 130,00 miles since 11/23/16. Pretty sure I have never lifted the battery cover, not needing to ever clean the terminal connections with the sealed "dry cell" battery. That alone is worth the purchase price. No degradation of performance that I could notice.