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

And for those of us still using the OEM Banner battery, it's worth pointing out it's not sealed or maintenance free . So you do need to top it up with distilled water from time to time. Mine tales about a cm per cell every couple of thousand miles.

I also have to frequently top up my Varta battery.

I ditched the Exide AGM 12-31 battery after 2 Months for an original Banner Battery. On a run with the Exide battery fitted I would get dashboard readings of 14.4volts when starting but after a few miles would drop between 13.3 and 13.7 volts and remain at that for remainder of the drive. The Exide battery never got to full capacity which overtime could shorten the life of the battery. I came to the conclusion that perhaps the M3W charging system may not be suitable for AGM batteries.

On a run with the Banner battery fitted constant reading of 14.4 volts may dip to 14.3 volts when idling and the Banner up to full capacity.

I appreciate that there will owners who have had no problems with the Exide battery, just sharing my experience.

That's interesting SBP and maybe ties in with my thoughts earlier in this thread of a shorted battery cell.

Given a working alternator regulator, the only factor that could drag down alternator voltage that much would be excessive load from equipment or battery itself. If you intially saw the normal regulated 14.3 -14.4 volts then equipment can be excluded so battery is failing in some intermittent way to cause it to draw excess current, despite being fully charged referenced to its current state. Since this excess current can only be dissipated as heat, l would expect it to get hot quite quickly. Has anyone noticed this prior to the full failure?

I guess the open cockpit of an M3W dissipates attendant smells which would be another tell-tale sign of imminent failure.

When I bought the 3 wheeler over a year ago the dealer had replaced the battery with a Yuasa battery which had only a 180cca which would cause temperamental starting, although when running was ok and all voltage readings were normal. I changed to the Exide AGM 12-31 to overcome the starting issues as this battery has a higher capacity. However, it never performed well always needed to be connected to the battery conditioner after a run to ensure the engine started the next day. I still have the Exide battery and have tested it and as far as I can see there is nothing wrong with it, but it doesn’t perform well in my 3 wheeler.
With the Banner battery I can leave the 3 wheeler a few days without connecting it to the battery conditioner and it will start with no issues.
My theory was as AGM batteries require a higher voltage to charge, perhaps my 3 wheelers system was not suitable for this type of battery.

We have used the Exide battery for 4+ years without problem...when the car is not in use, it is normally hooked up to a CTEK set for motorcycle AGM but it has perfomed fine on long trips where we have not had the CTEK with us

We have however taken note of the failure reports (even through those seem to be among recent manufacture) and changed to a Westco Platinum as we are shortly heading off for the Treffen. Hard to know if this is a good call...Exide was fine....new one will not have long to bed in and get past the early part of the bathtub failure curve....

My boat has munched through three Victron 12v 90ah starter batteries in 9 years. By rights these high quality low internal resistance batteries should last 7 or more years. The battery is mounted on a shelf immediately above the engine and it gets pretty hot in there. Enough is enough and I’m moving the battery despite the complications. When they fail the voltage display still reads 12.8v but it can’t deliver enough power to crank the engine and operate the electronics interface. Interestingly when it has failed to start the voltage drops to 12.4 / 12.5 and after a short time creeps back up to 12.8 without any charging current. So voltmeters are no indicator of real health in these batteries. My Victron AGM 12v 165ah batteries are lasting 10 or more years but they are away from the engine heat.

My money is on a temperature problem with the M3W AGM batteries. I use a standard Varta on my M3W but have to top it up regularly otherwise it’s spot on.

If it was the installation that was the problem there would be several different types of battery failing, there isn't.

I have recently returned from a touring holiday around Northern Spain with 4 other M3W's. One of them had an Exide AGM 12-31 battery that had been fitted 3-4 years ago and had caused no issues in that time. Following reports of problems he had it checked by the Morgan workshop that he had do a pre-trip service, it got a clean bill of health.

A few days into the trip the indicators and tacho failed, along with some hesitant engine running. We disconnected the Turn Signal Module, no indicators or tacho but the engine ran better. The engine cranked over and started easily every time. We tried but failed to find a replacement battery, so set out on the trip to the next hotel in convoy.

Almost at the next hotel the engine cut out and there was no electrical power other than the chattering of the fuel pump relay when ignition was turned on. A power pack battery across the battery terminals confirmed the battery had failed by restoring full function. We got the stranded M3W back to the hotel with a battery robbed from another M3W. A replacement was found eventually at a Stihl garden machinery dealer who had 5 in stock! They are used on mowers and small tractors, worth remembering if you need a battery. This worked perfectly for the rest of the trip.

I would suggest that if you have one of these Exide batteries fitted, no matter what age, replace it. I am not sure if the failing battery took the TSM out but some have had rectifier failures at the same time as battery failures, so some electrical power spikes are likely causing secondary damage.

It amazes me that MMC fit such a tiny battery into a substantial vehicle in which there is ample space for a larger automobile battery. The electrical demand from a lawn tractor is VERY different from that of a small sports car.
I'm not sure what sort of test a Workshop can do: I'd view these batteries as consumable, to be replaced after 2 or 3 years.