Battery Care and Maintenance
From Practical Motorist and Motor Cyclist March, 1955

Whilst this article is not specific to the pre-war Austin Seven it may provide extra information, and/or clarify, that which is available from other sources.  Articles specific to the Austin Seven are in sections of The Austin Service Journal; and those written by our members are in Technical Articles.

NB:  Most 'Sevens' are fitted with a 56amp/hr battery, type 421, ie the poles are diagonally opposite.  The Big Seven is fitted with a 63amp/hr battery, also type 421.  Be careful to connect with the correct earth.   Although modern batteries are much improved, and usually last longer, they still require regular care and maintenance; these notes may help.

Battery Care 1

Battery Care 2

Hydrometer readings denote the specific gravity for a 12v or 6v battery as follows: 

State of Charge Specific Gravity Battery Voltage
12v 6v
100% 1.265 12.7 6.3
75% 1.225 12.4 6.2
50% 1.190 12.2 6.1
25% 1.155 12.0 6.0
Discharged 1.120 11.9 6.0


Please note: The technical advice and information given in this article is that of the original author and the publication cited.  The Cornwall Austin Seven Club, its officers and members do not necessarily endorse the advice given in this article, and do not accept any liability for loss, damage or injury from persons acting upon that advice.  Anyone following the advice given in any of these articles, shall be deemed to have accepted this statement.

Our technical members are only able to answer questions relating to the Austin Seven (1922-1939) and may not be able to answer any questions arising from this article as they may have developed their own method of undertaking the work.

See also:

The Lead Acid Battery