www.jec.org.uk

Hi

Thanks for looking at this topic - I wasn't sure what to write in the Subject line to give people a clue as to what I am inquiring about. Hopefully the photo below will speak a 1,000 words!

Anyway, I changed the battery in my car recently. The specification is 68Ah - but the choice that I had was either 60 Ah or 75 Ah. Intending to err on the side of caution, I went for the 75 Ah one.

However, when I came to install the battery, I found that the “tent peg” bolt used to secure the cage that fits across the top of the battery to the base of the battery storage space is too short for the new battery.

Has anyone else come across this? Interestingly, I can still refit the plastic cover over the whole battery - so it’s not as if the new battery is ridiculously big.

Any thoughts on 1. Whether I need to worry about the tent peg bolts (please feel free to supply the proper technical name!) and if I do, 2. How to obtain replacements.

I am quite happy faffing about - finding a fabricator to build a couple of longer bolts - I love workshops and all that - but if there is a consensus of people saying don’t bother (because the battery cover fits) - then maybe I’ll save my time and money for the next little project.

Thanks for anyone’s thoughts

Peter

Hi Peter,

Your car won't pass an MoT if the battery isn't secured properly, so you're going to have to resolve this one way or another.

Ideally, I think I'd just get a battery of the correct size, however there's nothing wrong with measuring how much longer the retaining bolts need to be for your new batery and then having a pair made up.

It's totally up to you!

Hi Simon

Yes - the plan is definitely to secure the battery then. Looks like I’ll be looking for a local fabricator!

Thanks

Peter

Hi Peter, simple solution is to go to B&Q or a similar hardware store, together with the wing nut from the existing bolt and purchase a piece of screwed bar that is the correct over length you need for the new height battery and obviously the correct thread for the wing nut - probably something like 8MM. Then you simply put the bend in the bottom of the bar to mimic that of the existing bolt, clamp it in a vice or similar. You may need a bit of heat on the new bar to get it to yield properly. Job done - not as pretty as the original, but will do the task.

Jim Mann

Peter,

The XJS battery size changed during the life of the model. Sadly, many battery suppliers quote tehw rong size battery for the XJS, particularly for the late facelift models.

I'm not sure what size your year car should have, but the pre-HE uses an 075 size battery.

I presume you obviously didn't buy the same size as was previously fitted to your car?

If I were you, I would return the battery as being the wrong size for the car. But if you do want to keep it, you must get it securely fixed with a longer fixing bolt.

Good luck

Paul

Hi Peter, simple solution is to go to B&Q or a similar hardware store, together with the wing nut from the existing bolt and purchase a piece of screwed bar that is the correct over length you need for the new height battery and obviously the correct thread for the wing nut - probably something like 8MM. Then you simply put the bend in the bottom of the bar to mimic that of the existing bolt, clamp it in a vice or similar. You may need a bit of heat on the new bar to get it to yield properly. Job done - not as pretty as the original, but will do the task.

Jim Mann

Jim

Good suggestion - I’ve already measured the current bolt (and worked out its thread pitch) - so I will try your excellent suggestion first. maybe I was just looking for an excuse to get into a fabricator’s workshop - but I’ll try B&Q and such routes first. Thanks.

Peter

Peter,

The XJS battery size changed during the life of the model. Sadly, many battery suppliers quote tehw rong size battery for the XJS, particularly for the late facelift models.

I'm not sure what size your year car should have, but the pre-HE uses an 075 size battery.

I presume you obviously didn't buy the same size as was previously fitted to your car?

If I were you, I would return the battery as being the wrong size for the car. But if you do want to keep it, you must get it securely fixed with a longer fixing bolt.

Good luck

Paul

Paul

Yes - maybe I should have returned the battery - but I didn’t want the same as the 60Ah one that was in the car already given that the spec is 68 Ah. Maybe I should have been more conscious of the physical dimensions of the battery - I’ll have to chalk that down to experience. I’m minded to stick with the battery and obtain suitable bolts - time will tell if that’s a good approach to this challenge!

Thanks

Peter

Always use Tayna for batteries. www.tayna.co.uk

They give all the dimentions, details and a good choice.

I think what I'd do would be to obtain 6 nuts of the same thread as the 'tent pegs' a couple of lengths of steel tube of the correct internal diameter for the pegs and length for the new battery height, and two bolts of the same thread.

For each peg, screw a nut all the way down to the end of the thread, and get a fabricator to weld the other two onto either end of the tubing. You can then screw the down onto the tent peg, cinch up the two free nuts to hold them firmly in place at the correct height and use the bolts screwed into the top to clamp the battery holder into place.

That way you get your bit of fabrication done and don't need to alter your existing parts at all in case you end up with the correct-sized battery next time.

I think what I'd do would be to obtain 6 nuts of the same thread as the 'tent pegs' a couple of lengths of steel tube of the correct internal diameter for the pegs and length for the new battery height, and two bolts of the same thread.

For each peg, screw a nut all the way down to the end of the thread, and get a fabricator to weld the other two onto either end of the tubing. You can then screw the down onto the tent peg, cinch up the two free nuts to hold them firmly in place at the correct height and use the bolts screwed into the top to clamp the battery holder into place.

That way you get your bit of fabrication done and don't need to alter your existing parts at all in case you end up with the correct-sized battery next time.

Hi Simon

Good idea - I had actually been thinking about seeing if I could find some “extension bolts” and overcome the challenge that way. I’m back home tonight so I’ll have a good think about it all tomorrow. Thanks very much for the suggestion.

Peter

Hi All

I’m pleased to report that this issue is now resolved - in a way that I think is technically sound and keeps the old part in the car.

In case it helps anyone else - this is what I did:

1. I worked out that the existing bolt was an M6 with a 1mm pitch.
2. I went on the internet looking for what I thought would be called a “connector bolt” or an “extension bolt”. Fortunately, this threw up an image of what I was looking for - and a name. What I needed were called Standoff Spacers.
3. I ordered a mixed bag of M6 standoff spacers from a well known online retailer.
4. They turned up today. I fitted the 10mm standoff spacers to the original bolts - which gave them sufficient extra length to allow me to secure the battery using the original washer and wing nut on each bolt.

Hopefully the pictures below illustrate what I did.

Thanks to everyone who contributed to this thread to help me solve this problem - I appreciated the ideas and support - it’s a great example of team work. As I said, I’m pleased with the solution because it is simple, cheap, technically sound (I believe), sympathetic to the original parts and reversible should the next battery be less tall.

All the best

Peter

Looks good, Peter!

Well done!

Paul

Hi Peter,
Glad you got it sorted,will keep the MOT tester happy.
Take care.
Andy

Paul & Andy

Thanks - I’m glad it’s sorted too - in an away that is easily reversible should I replace the battery with a physically smaller one next time.

All the best

Peter