1946-1949 6 volt Group 2 batteries

[conyankee2]

For those that it may interest/help - earlier today I just today received a "period correct" 6 volt battery (pictures below). Made to look correct (a somewhat outstanding question to me still - yellow caps don't seem correct?), but is a modern AGM battery inside. Jury is still out on how long it will last, but my initial impression is that it's well-made and is great for authenticity purposes. I am in a current conversation w/ the manufacturer regarding the caps. Per my question above, the caps in our 2nd edition authenticity manual shows black caps w/ 8 points equally space around them. This battery has yellow caps w/ 10 points, not equally spaced, as there are parts of the cap seemingly meant to place your fingers on when turning. Would be great if anyone could add to what the original OEM Cadillac batteries looked like (pictures preferred), which would either back up the authenticity manual or perhaps provide alternative context. The specifications on the battery are below in a picture as well. My suspicion is if you are after performance, you can't go wrong w/ an Optima red tops. If you are after 'period correct' then this may be a way to go.

[Jay Friedman]

I didn't see the specs in any of the photos. What brand of battery is inside the case? An Optima? Where did you buy it?

[conyankee2]

Sorry about that! Guess the photo didn't attach prior. See below (800 cold-cranking amps; 110 min reserve capacity). I don't know what brand of battery is inside other than its sealed AGM (would love it if it's an Optima, but not sure it is). Will try to find out and report back. Purchased from Battery Central Mall. 4-year warranty, 1st-year full replacement, then pro-rated the last 3 years. My main reason for purchasing was for appearance/authenticity purposes. Will use it for a bit and let folks how how it goes.

Tested it when received w/ a digital battery tester (pictures below) and it was approximately 62% charged. Put it on my Noco Genius 10 amp smart charger/maintainer and after 15 hours or so it was at 97%. I then used a carbon pile load tester on it. Put it through 2, 8-second load tests (which it passed) and that took the battery down to 70%.

For comparison sake (not apples to apples), I am showing the test results of my red top Optima that is 12 years old and still tests good (76% charged - dark photo) / is what I use in my '47 day-to-day.

[conyankee2]

Update: After 24 hours on the Noco Genius 10 charger/maintainer, results below (100% charge).

[TJ Hopland]

It is amazing now not that far off the modern tractor ones are.