back on the Lotus so questions arise: Battery tray

[TomMull]

finally found the reason that I could not remove the rear seat to be a seat belt bolt completely hidden under the upholstery, picture below. The hidden bolt goes through the rear seat "pod" and into the chassis, effectively locking the pod in place. I found the bolt by feel rather than sight. The bolt on the other side was missing.
That out makes the reinstall of the petrol tank a bit easier.

I
The next issue was the rusty battery tray and the tinfoil patch behind it. Looks like a bit of the Rotoflex might have come off and put a hole in the fiberglass. At least the PO apparently replaced the joints. There is a second bolt, apparently unused and circled (a bit hard to see) to the left of the bobbin that holds the tray, also circled. Any one know what that's for?

The tray itself is curious. It fits nicely in the recess in the boot sub-floor, it is cleverly and securely fixed with a single bolt. But it certainly doesn't seem right. I'd originally planned to duplicate it with new material but I have second thoughts now. I is made from 3.2 mm angle or larger. Hard to tell with all the rust but there is nothing I've yet found on the car that heavy. While the fit seems good, the welding dies not. Perhaps a poor heavy gauge replica of the original? Picture below also. I know there was a previous topic on the battery box and some ideas for replacements but not much on the originals, no part numbers, pictures or descriptions. Perhaps someone has this information?

Tom

[Bigbaldybloke]

The circled bolt is for the main earth connection from the battery to the chassis, ensure it is in good contact with bare metal on the chassis. That battery tray does not look original, my early transverse silencer car had what looked liked a short length of angle iron bolted to the inside of the wheel housing to located that side of the battery and a sort of hinged bracket that had a bolt through it that clamped the battery near the centre of the car. Sorry, no photos, that lot went rusty and was ditched years ago. My arrangement for my new modern smaller battery is shown in the attached picture. That?s an initial trial fitting, the drilling swarf is still there, the angles are alloy from the local hardware store and the top angle is attached with lengths of screwed stick, which then had some heat shrink put over the exposed threads to protect them and the battery.

[TomMull]

Thanks for the reply and the picture. It appears that your battery is mounted above the removable boot floor, nicely done by the way. Mine was mounted underneath (of course the top comes up through) in a recess in the fiberglass trunk floor. On yours, the bolt or stud I circled appears to come through the floor to provide a place for the earth and that in turn was connected to the frame with another cable. Is that correct? That avoids putting the cable through a hole. It also makes it appear that your mount is much closer to the original than mine.
Here is a picture of another car from the internet. The floor panel is missing but I'm guessing that earth connection would be made where the stud goes through it.

It looks like the battery is a BCI size 24 and the battery and plastic box seem to fit in the recess cast in the glass fiber section but a 24 does not fit in mine, hence the elaborate and heavy fabrication that came with my car. So why was the recess cast into the body if the battery goes above the floor?
I know this is all minutia but this sort of thing is why I have an old British classic.
Tom

[Bigbaldybloke]

If you look carefully, my battery is fixed to the fibreglass boot floor and is completely hidden below the wooden removable floor when it is in. You can see the floor support angle rail behind it. The area where my battery is fitted is completely flat, no moulded in fibreglass or metal tray. The earth wire from the battery secured to a long bolt that attaches the body to the chassis, it protrudes through the bobbin in the body by about an inch. Make sure the paint is off the chassis so this bolt makes good electrical contact with it. A good blob of copperslip or similar stoops any corrosion.

[JonB]

So why was the recess cast into the body if the battery goes above the floor?

It's because a smaller battery was fitted at the factory which did fit in the recess.

Nowadays we like bigger batteries because if you leave the Elan (or Plus 2) standing for a week, the fuel in the carburettor float bowls evaporates, so you have to turn the engine over for a while to refill them (via the mechanical fuel pump). A bigger battery helps with this - I suspect a standard battery would struggle, especially with 50 year old wiring and starter motor.

This thread details my efforts to fix down my own oversized battery: viewtopic.php?t=40916&p=286491

The best way to fix this fuel situation is to fit an electric pump (I have not got round to that yet!)

[TomMull]

Thanks to both. This is now making sense. Perhaps I'll be looking for a smaller or narrower battery with the same capacity. The BCI24 is actually not all that powerful. I'll post if I can come up with anything. If not maybe glass in a piece of foam to flatten the recess. Tom
Tom

[TomMull]

Assuming that the original battery was a BCI22 which fits the recess and the replacement battery is a BCI24 which is more powerful but does not fit into the molded recess (and I'm guessing at both), Here are some options along with specs.

I've tried to find batteries close to 5 inches in width, which is the only critical measurement and yet close to the power of the BCI 24. The BCI 22 and 24 are in the chart for comparison. The prices are in US dollars and are advertised prices but not from a common supplier so just ballparks for reference.
There are also AGM batteries that might work also but are a bit more expensive.
However Bigbaldybloke's solution still has merit and I appreciate his drawings and instructions in the link above and a hold down will still need to be made even if the battery is in the recess.
Tom

[2cams70]

Be careful when using modern batteries that have plates incorporating calcium. They have different charging requirements to old style plain lead/acid batteries and may therefore only have a short life in a classic car.

[TomMull]

Be careful when using modern batteries that have plates incorporating calcium. They have different charging requirements to old style plain lead/acid batteries and may therefore only have a short life in a classic car.

Good point. Disregard the comment I made about AGM. I believe that all the batteries listed in the chart are conventional lead acid batteries.
Tom

[69S4]

I've got an Odyssey in mine - is that an AGM type battery? If it is should I be keeping a more careful eye on the charging side of things? It's survived about 7-8yrs so far though without anything other than a glance to make sure it hasn't fallen out.

[TomMull]

I think Odyssey makes and markets AGM batteries only but I am no expert. I also know others who have used the AGMs in vehicles with antiquated charging systems without problems but the experts seem to agree that it is not recommended. I would certainly not worry about yours at this point.
Tom

[mbell]

I have an Odyssey in mine. They aren't AGM but require specific charging that is inline with a AGM. I think it's mostly they don't like high voltage (~15v+) charging, so should be fine with on car charging. Providing the charging system is working correctly.

While getting my car running again I flattened mine a couple of times and recharged it a couple of times with standard charger. It seems the battery hasn't liked this and despite having having a disconnect switch if I leave the car a few weeks it won't start. I just have it on a intelligent charger every so often ($25) that does the trick.

My brother had also had issues with one dying but again I think it was charged with normal charger and left on a basic trickle charger.

If still probably recommend one, as work well when they work. You just need to be careful with them and but a good charger when you get the battery.