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MG MGA - 2 sixes to 1 12 volt

What wiring other than the cables must I change to install one 12 volt battery. The amp gauge ? I have ckd Barneys web page which show plenty of battery types and mods to the tray only.
Bill Mason

quote "The amp gauge ?"

There is no Amp gauge on a factory MGA. If you have one, then it was certainly installed as an aftermarket.

No changes to the wiring are required except to remove one battery (the one that presently has one wire to ground) and its associated battery wiring. Wire from starter switch goes to first battery, normally the neg terminal. The wire to the opposite terminal (the post term) now goes to ground instead of going to the 2nd battery. That is it. This would be a good time to think about neg ground conversion. In which case you would reverse the heavy wires on the new battery, starter switch wire to B+ and B- to chassis ground. Check your fuel pump to see if it is polarity sensitive. If it is then you must take appropriate measures. You can find them in the archives.
Chuck Schaefer

On this topic I noticed the battery cradles on my two. Mga were different.
One was 6 inches square and the other half an inch bigger.
Needless to say the smaller one was much harder to find a 12v battery to fit.

One of my cars has a factory tiny amps gauge fitted, it's much smaller than the normal 2 inch gauges
I could fish out a photo if required ?


Mark Hester

Mark, is your car an Australian built car? Reason I ask is that the factory schematics show no such gause. The workshop manual does show other optional equipment such as high note horn, fog light(s) and high beam flick switch. Never seen a amp gauge in any of my ref books either. Is yours a Jaeger meter? A photo might be nice if you can.

Undoubtedly the pPO had extended one battery box. Not an uncommon thing due to the things you noted.
Chuck Schaefer

I have placed a piece of approx half-inch particle board over the battery cradle on both of my MGA's (coupe and roadster) and used the original clamp to hold down a single 12volt battery. I do not think that any "factory" options were available on Autralian-assembled MGA roadsters.
Barry Bahnisch

Hi chuck,
One us and one uk.
Both replaced from original. The us car with battery replacement metal from moss uk.
The uk car may have been done by bob west in uk and has the smaller battery boxes which was very hard to find a 12v battery that was only 6 inches long

Not sure what is original
6 or 6.5 inch inside diameter ?

Mark Hester

using this same principle, is it possible to replace one pianoforte with two twenties? Sorry, couldn't resist it!
Lindsay Sampford

This thread was discussed between 01/08/2011 and 04/08/2011

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This thread is from the archive. The Live MG MGA BBS is active now.