Baffling Battery

[AustinWood]

I have always assumed that the ignition light going out & nothing happening when operating the starter are symptomatic of a bad connection somewhere. Often dirty battery terminals, but any of the connections, including earths. When this happens the offending connection gets hot, often Very hot.
This happened to us recently. It was where the earth from the battery was joined to the frame. In this case the engine turned over but wouldn't start and I burnt my finger on the earthing bolt.
Do other circuits, eg horn, work?

[John Cornforth]

Thanks to all for the replies.

Just to summarise, the battery has been on long term float charge at exactly 6.9 volts (2.3 volts per cell), which from what I can glean is close to the recommended float voltage for a flooded lead acid battery.  It isn't a smart charger, just a fixed voltage stabilised power supply. Once settled the charging current drops to about 100 mA for weeks on end. Despite this, the battery gave all appearances of being "dead" when any appreciable current was demanded.  Nothing wrong with any connections, and after charging for 24 hours all is well and the starter turns vigorously.

The only things I can think of are:   1.) Maybe the battery should have been given a full charge after the car was last run, before putting it it bed.   2.) Maybe the cells have slightly different characteristics, so although the total float voltage is 6.9  the individual cells deviate from 2.3 and one or more therefore aren't being held at the correct float level.

The lesson here is to ignore government "stay home" rules and get on and use it from time to time !

[David Stepney]

No car likes to be idle for long periods of time. Running them regularly keeps them in good condition I have found. I try and use my Seven at least once a week, although, during this winter, it was sometimes longer between runs out. Those of you who have seen my various posts scattered across this forum will be aware that my little car gets out and about quite a bit, doing exactly what is was built to do - provide transport.

Consequently, I have never (in over 2 years of ownership) had a flat battery, relying solely on the car's charging system to keep the battery charged. Only once have I actually had to charge the battery, and that was my own fault when I was getting to grips with the mysteries of the use of the 'half charge' facility. I don't know what make the battery is, as itis the one which came with the car, but it has never failed to start the car.

[Bob Culver]

A colleague has a very flash Corvette which is very seldom driven. To counter the constant drain he maintained with some expensive modern smart charger. When he went to start the car the $350 (L170) battery exploded , the whole end blew out and acid everywhere but fortunately largely contained by the battery housing. I cannot recall the figure but i was surprised at the voltage it maintained. now runs through a timer.
A charger I use on the very rarely used inherited "modern"' Jazz pulses at 13.2 volts and settles to 13.1, lower than its claimed 13.7 performance. Other makes claim to float at 13.6 but all are primarily for Ca batteries.
The advent of Ca batteries, now often not distinguished, has complicated everything and rendered much older advice practices and voltages obsolete.
i dunno what present 6v are, but Ca batteries with their 14.6/7.3 or so limit seem unsuited to original Sevens reliant on in car charging.
In the days of the cap type battery connectors I have had mysterious effects due intermiitent connection on 1960s car. Did in two bulbs on a tour but did not twig. Only months later did it suddenly fail to crank