Upgrading to 12V batteries on an MGBGTV8
Several useful V8 Workshop Notes has been contributed by various members of the V8 Register which set out ways of improving the power and reliability of the type of batteries in an MGBGTV8 when compared with the 6V batteries originally fitted to the model. The suggested modifications are not difficult for most enthusiasts to undertake and the cost is less than replacing tired twin 6V batteries with another pair of the same 6Vs. So in many ways the case for an upgrade is clear - but what are the various upgrade choices? Here we set out the various V8NOTES which have developed members' approaches to a batteries upgrade.

Fitting a 12 volt battery to a chrome bumpered MGBGTV8
Gordon Hesketh-Jones from Cornwall has changed from the original twin 6 volt batteries to a single 12V 065 battery and describes how to carry out this modification. (10.3.02)
"Some twelve years ago I decided to replace the pair of 6 volt batteries in my V8 with a single 12 volt battery and found that with a little modification to one of the battery trays, a standard "065" battery would fit. The "065" refers to the physical size of the battery as defined by UK standards, and all manufacturers fit different sets of plates - for example medium-duty, heavy-duty, caravan-duty etc into these standard cases. The 065 case is no higher than the standard 6v battery, but is longer so I had to modify the battery tray by flattening the forward retaining cross-member part of the tray. One standard battery clamp was fitted to the rear of the battery and a second was modified so that that it sits across the centre of the battery ." (Gordon Hesketh-Jones) V8NOTE250

12 volt battery conversion

New battery clamping "pegs" will be needed.

Converting the twin 6 volt batteries to a single 12

volt unit has a number of advantages - one single 12 volt is less expensive than two 6 volt batteries and 12 volt battery technology seems to have moved on so more powerful sealed units are now available, but also you can remove those wretched "top-hat" battery terminal connectors which are a cause of many difficulties. Now this conversion is by no means original but here Victor Smith describes how he carried out the change using a single 12V 063 battery. (15.6.05) V8NOTE329

Another 12V battery conversion!

Twin BOSCH 4FNs wired in parallel provide improved starting performance and have a near original look. V8NOTE357

Kai Knickmann from Germany looked at the options for replacing his old 6 volt batteries and an offer from a local trader produced another 12 volt battery conversion using two new 12V batteries installed in parallel. BOSCH offered a good choice for me with a battery called 4FN which is identical in footprint with the old standard 6 volt ones using silver technology for a longer lifetime,
being service free and sealed for life and as an additional plus, having a nice black case as well. Of course, the electrical values due to the reduced size are less impressive with 360 amp cold start and 40Ah capacity. (1.6.06) V8NOTE357

Fitting an 065 12 volt battery in an MGBGTV8

Comparison of the original 6v battery with the new 065 Bosch 12v battery.
The topic of 12 volt battery conversions for the MGBGTV8 has been covered in V8NOTE250 by Gordon Hesketh-Jones who installed the larger 065 battery and then later the installation of the marginally smaller 063 was covered in a detailed installation note, V8NOTE329, by Victor Smith. At the turn of the year 2006/07, Malcolm Venables decided he wanted to make the change and obtained a 12 Volt Battery Conversion Kit, but then began pondering over which battery to fit - an 063 or an 065? His contacts with Gordon provide a useful sequel to the earlier V8NOTES. (12.1.07) V8NOTE364

Fitting two 12V batteries in parallel

View of new 12V batteries fitted in parallel from the front. The isolator switch is lower left; new earth strap is upper right of the driver's side battery compartment. Original earth strap used in the nearside compartment.

Kai Knickmann developed the idea of upgrading to more modern 12V batteries a stage further by using two 12V batteries - one in each of the existing battery boxes - but installing them in parallel as V8NOTE357. Later Bob Owen developed the idea as a way of curing difficulties he had experienced with poor starting with a hot engine as V8NOTE390. (12.10.08)

Battery replacement and 12V conversion
Peter Spurrs found his CTEK battery conditioner indicated that the twin 6V batteries were not holding their charge. So he carried out a 12V battery conversion. V8NOTE617 (210110)

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