Joined: Oct 2019 Posts: 46 Threads: 9
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Location: R o. Ireland
Car type: '34 RP ,'30 RF
I thought I'd heard of everything Austin 7 until up in the North of this Island at the Argory meeting of the Ulster pre-war Austin Club and Irish Austin Seven Club last weekend I was introduced to the use of sawn down 12 Volt batteries in Sevens. The example I saw, it was explained, had two cells physically sawn off the 12 volt casing, retaining the internal connection to the batteries terminal post resulting in an 8 volt version upon which the Seven apparently runs well without further mods. My informant was surprised I hadn't heard of this as it's apparently often used in the Irish Republic but I've not ever come across it in my wanderings in GB before.
Any comments ?
Ian C
Joined: Aug 2017 Posts: 1,647 Threads: 23
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Location: The village of Evenley
Car type: 1934 Austin Seven RP Deluxe
For a minute I thought this might be the latest delicacy offered in Glasgow’s finest fish and chip shops!
I’ve been around Sevens and all sorts of old cars for longer than I care to remember, but never heard of that. However, it makes perfect sense!
Joined: Aug 2017 Posts: 3,394 Threads: 106
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Location: Darkest Bedfordshire
It makes perfect sense but for the fact that correct size 6V batteries are readily available...
Joined: Apr 2018 Posts: 507 Threads: 129
Reputation:
2
Location: Staffordshire
Car type: Ruby mk 2
Should give starting a bit more whizz
Joined: Feb 2021 Posts: 292 Threads: 31
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3
Location: New Zealand
Car type: Austin 7 Ruby 1938
Any ideas about how the 8V battery might be charged without building a bespoke charger? Is a modern smart charger likely to figure out what voltage to charge at?
The 8V battery has some appeal to get a better performance out of many tired electrical items on my Ruby.
Graham
Joined: Aug 2017 Posts: 1,018 Threads: 53
Reputation:
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Location: The delightful town of Knaresborough, North Yorkshire
A modern home battery charger will measure the voltage (say 8.0) and assume it is a very flat 12 volt battery. I think it would charge the 8 volt battery ok, but rather quickly, and wouldn't know when to stop.
Also, when on the car and getting charged the voltage is likely to be around 10 volts, so 6 volt bulbs are likely to have a short life.
I can see the point, as 12 volt batteries are cheaper and available everywhere, but why not just use a 12 volt battery? I do, with a dynamo, and field windings fed through a resistor.
Joined: May 2018 Posts: 2,955 Threads: 558
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Location: Peak District, Derbyshire
Car type: 1929 Chummy, 1930 Chummy, 1930 Ulster Replica, 1934 Ruby
How exactly is the battery "sawn down"? Presumably by cutting through the exterior connections between the cells?
Joined: Oct 2019 Posts: 46 Threads: 9
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Location: R o. Ireland
Car type: '34 RP ,'30 RF
The example I saw Tony, was roughly sawn- the casing showed the saw toothmarks - the original internal connection to the terminal post was retained, poking out of the remaining block and turning upwards in it's original place. The cut down battery was being used in a Ruby which seemed to have adequate space for it.
I hope the acid was carefully removed and disposed of before attack with the saw!!
Joined: Apr 2018 Posts: 191 Threads: 76
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Years ago I was friends with Derek Chester who was a well known and certainly an "impecunious" owner. I'm fairy sure he did this by somehow testing old 12 volt batteries to determine which cells had failed then, having found one with three cells in good condition he cut off the rest.
In his case this was simply to get a free battery.
Out of interest, at one time he owned a French Blue "Ulsteroid" which he'd built to look very Bugatti like. He even had an elliptical country plate on the back carrying the letter "F". One day he pointed to a number of spare holes in the floor explaining these were from the sheet materials previous life as a street hoarding!
I miss that approach to owning a vintage car for very little money.
