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.


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: