Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Exide AGM 12-31 reliability

If it was there would be a considerable amount of smoke!

Sounds like the issue is internal to battery. Even then considerable heat would be likely.

If that was the case wouldn't all the rectifiers would have been faulty? It is only these particular Exide batteries that are failing in this way.

Dont know much about M3Ws but only made the comment as I believe the rectifiers are a known issue and also thought that maybe these batteries were in common use…so just putting two and two together….maybe making 5!

Thinking further about it an internal short(s) to a bad batch of batteries would have a 10 or 8 remaining voltage battery charged as a 12 volt, quickly putting paid to any good remaining cells.

I've certainly seen this happen on a boat with one cell shorting in a battery that's part of a bank. The others then try to charge the faulty one resulting in heat, fumes and battery case expanding. Thankfully the easily identified faulty one was isolated, although if left an explosion would have been a possibility

Just to add to the confusion here... my car died post IoM trip while en route to Lancaster for Phil to sort out the Centa spline issue. I had assumed it was the regulator but in the rain / Liverpool traffic I had not noticed any warning light (or monitored the charge). Power loss was total (all electrics, engine).

After a while on the hard shoulder the battery had recovered enough to run the hazard lights for a short while.

Phil reports the regulator (original) is working OK with a slightly low (<14v) output, and the battery charged up fine on the Li CTEK (starting the engine a few times without a run).

The battery is a Li based one, so can't blame Exide or lead acid issues! The mystery continues...

It's the battery that loads the alternator output if not near fullly charged, so a measured voltage below the regulated 14.3 or so volts is entirely to be expected given the situation. I do wonder if the regulator has become intermittent though so it may happen again!

Once battery is fully charged suggest keeping a regular eye whilst driving on running battery volts. Expect no less than 14.2 -14.4 volts. Hopefully the Li-ion battery is of the type with internal regulation to adjust to batteries differing charge needs.

Thanks Richard - I'm wondering if something like https://www.amazon.co.uk/Victron-Battery-Monitor-Bluetooth-BMV-712/dp/B07SG6NKV4 might be useful for seeing what is going on? When I bought my Li batter there was a logging version that you could connect to to get data but it has been discontinued...

The battery behind the oil tank suffers from the temperature enormously, it is best to put the battery at the passenger footwell, moreover if you make a support you can fit a 50AH there at a lower cost and it lasts a long time without problems.
The only thing is that you have to do it yourself and extend the electric cables.

That's a premium device more suited to large boat battery banks Paul.

All you need is to keep an eye on running battery volts. There is a stalk controlled option built into your M3W that displays on one of the instruments.

If it is running at something less than 14v I would suggest it's not running 100%. The system usually seems to run at a pretty constant 14.2v -14.4 v when all is well and no load (headlights). Keep the display on Volts and check it occasionally, you really don't need to know the time, your total or trip mileage so "volts" is the useful display to show when driving.

The spate of problems with batteries have been exclusively with Exide AGM 12-31 batteries. I would suggest the problem is the battery, not it's environment. Total and quick failure has not been a problem up to now and is limited to Exide batteries. If you are running an Exide AGM 12-31, particularly fitted in the last two years, maybe you are on borrowed time and should replace it?