Insulating the battery may stop it from being drained but it won't stop the battery deteriorating.  To keep a battery in good order its needs charge and discharge. A battery optimiser would be a better bet.

 

'What is a car battery optimiser?

 

 

Car battery chargers plug into your mains electricity socket and attach to the terminals of your car battery. They can be used to charge up a battery that has run low, or to maintain a car battery that isn't being used - for example, if you leave your car in storage over the winter.'

 

https://www.halfords.com/motoring/buying-guides/car-battery-chargers-buyers-guide.html

5 hours ago, wombat said:

go the whole hog...cable inside inner tube inside pvc pipe.

Maybe one day.  I'm currently still only around a 7 out of 10 on the Howard Hughes scale. 

9 hours ago, Heng said:

9 hours ago, Anythingleft? said:

You could just use a piece of cardboard and it wont deteriorate in the heat like the plastic bag might....

Thanks.  Kind of concerned that that is fairly combustible though.   

You don't think that plastic bags are combustible?   Or all that other plastic, rubber, paint, insulation etc. under the bonnet?!

10 hours ago, Anythingleft? said:

You could just use a piece of cardboard and it wont deteriorate in the heat like the plastic bag might....

I think that would be the other way around.

15 hours ago, millymoopoo said:

And don't forget to reapply vaseline (petroleum jelly) to the post before reattaching lead.

Apply over the connected terminal, you want a clean and dry connection....

9 hours ago, MrJ2U said:

I think that would be the other way around.

Not with the thin cheap <deleted> out there, in my view anyway.. 

Best to pull the engine....taking the <deleted>, of course. This seems like a lying awake in the middle of the night type of worry. I get them. I would just wrap a cotton rag around the lead.

If I wanted to do as you suggest, I would use a piece of M/C inner tube, and use a zip tie to secure it. Mould on seats seems to be a problem here also so yes get them wiped down occasionally.

14 hours ago, Daffy D said:

https://th.rs-online.com/web/p/solar-chargers/7067918/

 

High-quality 4W solar cell for year-round 12V battery charging
Supports stand incorporated in the hard-wearing body
Suitable for indoor and outdoor use
In-built LED charge indicator
Cable and connections to attach direct to battery terminals and in car 12V socket
In-built diode prevents reverse battery feed.

 

User guide

Data Sheet

Well not sure about using the car socket as mine does not work like most cars unless the ignition is switched to accessary position. 

55 minutes ago, Anythingleft? said:

Apply over the connected terminal, you want a clean and dry connection....

Just apply it all over the terminal, inside and out, what remains between the post and terminal will squeeze out when terminal is tightened down making a good connection.

This prevents corrosion build up between post and terminal, which is were the connection will be lost if corrosion does build.

Corrosion on the outside of the terminal has no effect on the connection, it only serves to slowly leach away current from the battery.

I remove both and I wrap both battery terminals with black electrician's tape, a good amount.

2 hours ago, brianthainess said:

If I wanted to do as you suggest, I would use a piece of M/C inner tube, and use a zip tie to secure it. Mould on seats seems to be a problem here also so yes get them wiped down occasionally.

Well not sure about using the car socket as mine does not work like most cars unless the ignition is switched to accessary position. 

If you check the user guide it says that if your lighter socket is controlled by the ignition key use the clips provided to connect directly to the battery.

 

Connection:-

Decide whether the connection to the battery 
will be by an in-car, 12V socket using the cable 
and mating plug (A) supplied, or direct to a 
battery’s terminals using the supplied cable 
and crocodile clips (B). Then connect the selected 
cable to the battery.

 

NOTE – if using the in-car 12V plug, make certain 
that power can be delivered even if, for example, 
a car’s ignition keys have been removed. If in 
doubt use the crocodile clips.

 

I used to work on cars every day, I would have zip tied the negative terminal out of the way.

On 8/9/2021 at 9:53 PM, millymoopoo said:

And don't forget to reapply vaseline (petroleum jelly) to the post before reattaching lead.

Answered in a different post, so deleted my question.