Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Replacement battery

Thanks Paul
I have an acumate thats meant to condition as well. Problem was I hadnt got round to fitting it. Its on now.
We use a lot of dryfit type batteries at work and we use a yuasa capacity checker to test them.
Its effective surface area of the plates that determine real capacity and as yu know a duff battery can still read ok on a volt meter. However I have checked the recharged battery using an old style( looks like a ray gun) current type checker and it tells me the battery is ok. Still only turns the old girl over for a few seconds and then flat however. To be honest three years aint bad considering the intermittant use of the car in winter.
I am still perplexed by the instant start I got on the charger/ starter. Will try a big battery in parallel also and see what ocours.

Matty I expect a battery to last longer than 3 years. The Varta battery on my 1930 Sunbeam is 19 years old & considering there is no voltage regulation just on/off charge switch it has a very hard life. I'm keeping it staggering on with a battery minder.
My kettle just packed up after 38 years, nothing lasts these days.

Tim

Have you got an immobiliser fitted? If so it could be that the battery voltage drops below the immobiliser threshold whilst cranking and hence the engine won't fire.

I had the same on another car - clipped up a booster pack and it fired first time. A new battery cured it immediately.

I'm curious that the battery loses voltage on the car - wonder what is draining it? No interior light / radio etc that are the usual culprits in these circumstances. I don't remember ever having problems on Caterham 7(s) in the past.

It's shocking. I hope you take it back & complain.

You may not have much of a drain on your battery, but if it's more than just slight, this is what I would try.

If you don't have a 12v test light, you can make one up easily with most any small wattage 12v bulb and two wires. Solder the one wire to the bulb lower brass case and the other to the lead in the center. This would be like a bulb for a dash light etc. Little alligator clips on the two ends would be helpful. If you place the two wires from terminal to terminal it will light up the bulb. If this is what it does, you're able to the test.

Once you have the test light, disconnect your ground post cable from the battery. Connect either wire to the unhooked negative cable and the other to the battery negative post.

If you have more than just a "little" draw, the light bulb will light up probably dimly.

If it doesn't light up, there's not much more for you to do.

But if it does light up just a little, start pulley out one fuse at a time until the light goes out. You can put the fuse back in as you move to the next fuse.

Like I said, if it's enough to light the bulb, albeit just a little, pulling fuses like this will give you he circuit that has the draw. If you are getting a slightly lit bulb, you should fix the problem.

I'm not sure on the M3W if the ECM stays "hot" when the key is turned off. If it does stay hot, that's probably where you're drawing the loss. If so, there's not much you can do about it.

Good luck with your search.

Nice simple idea. Have an ammeter though.
Yes there is an immobiliser and thats what gently pulls the battery down. Should have fitted acumate before this winter. Last year I drove the old girl all through winter but the salt played havoc. Interesting about threshold on immobiliser.
New battery it is then. Will crank her over with voltmeter attached and see what the volt drop is like.

Matty, how long did you keep the optimate on once the battery had discharged.

I'm sure you've already tried and are well aware - It can take a couple or three days to restore from dead. - I have to do this constantly with the Harley's moving it between bikes but to date have not experienced an issue with the M3W.

Looking fwd to getting out in the country around your way soon mate😊🍻

Some "battery tenders" will not charge a battery from dead, but only maintain from a normal operating state, or just a few volts below normal.

You will need to use something like a 10 amp charger to get it "up" and then use some type of battery tender to maintain between drives.

I keep my battery tender on my '76 Shovelhead as it's a lead acid battery and seems to drop a lot quicker than my '09 Roadglide AGM battery. Just a quick startup and idle every couple weeks seems to keep it going okay.

Topped up today with about 200ml - will see next week if it makes any difference.

I was trying to think when I last topped up a car battery - I reckon it was a good 30 years ago....