Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Determining the age of the battery

My MGB battery defies all logic. I've drained it completely at least 5 times in the last 20 months - so much so that there is not enough juice to light the interior LED light. Jump start and it's back up to strength by the time I get to work.

It's usually the heated rear window - the car has had a badly wired new aftermarket fusebox fitted by a previous owner, and as a result most of the switches are permanent live rather than switched live. I have a 'routine' when I park up to check that all the switches are off, but if I'm in rush, or get distracted when I stop I forget and pay the price the next morning!

I'll get round to fixing it one day, and possibly need a new battery at some point, although it got through last winter with no problems and she lives outside 24/7.

I'm guessing it is a lead acid one. The newer styles especially the AGM ones die without warning. On my CX it failed in just over 2 years but before I got it the car did 1900 miles in 2 years including sitting at a dealers for 11 months. Central Morgan the dealer swore it was on a conditioner.

On the Wed it was fine on Sat I got the overseer warning light.

I really didn't suspect the battery & got the AA out. Their technician said it was quite common to fail after 2-3 years for AGMs if not used.

Welcome Bob,

Good info here and around the rest of the forum as well! I find google search will usually flag up what you are looking for on the site far better than the forum search engine which I find is next to useless!

Morgan's Mmm! Well they are really bitsers, Lot's of borrowed parts and with the 2006 plus examples they have more electronics and in the Morgan it doesn't have the go to sleep technology of it's donor vehicle so tends to drain the batteries, a good battery will get to the non start stage after about three weeks. Most of us just don't use them regularly enough to avoid this happening. When I first bought my 2010 plus 4 I was always suffering from this issue. I'd charge the battery up and then a couple of weeks later it was again to flat to turn the engine over! So I thought the battery was duff and changed it out for new. Same thing again although it did last a little longer being new and at the start of the summer season occurred less as I was driving more often!

I'd left the old battery on the garage floor and one morning my son's VW polo wouldn't start and the battery wouldn't charge so on the off chance I stuck the old MOG battery on, that was four years ago and it's still going strong with no problems whatsoever!

Upshot, I bough the ctek battery conditioner/charger, The 10 model without looking I think but it also reconditions the battery automatically and allows voltage drop and recharges to mimmick a more natural use. I had a lower spec model that I used on my lawn tractor but this one knocks it for six! The current battery has been on for 4 years now with no issues. As richard says there are no ideal solutions but a high spec Ctek conditioner seems the best solution for me as I take my car off the road in winter. Living in the wilds of Wales it's almost unsuitable for the Defender and ithe Morgan certainly wont like a sub surface role!

The original factory battery of mine 2009 +4 Anniversary (Banner UniBull) after 15 years and 20000km still starts the engine well and keeps 12,5V voltage after 5-6 months winter pause. Almost a miracle...

I got 13 years from my Roadster battery, but as John says, will fail without warning. Mine failed in the garage from a full charge.

Well if you go down to the motor museum at Beaulieu there are cars from the early 1900's with original batteries that still work, BUT....... they weigh almost as much as a Morgan! Yet their functionality is poor when at their best. Modern batteries are always evolving to produce better cold cranking amps, better amp hours etc. yet fit into smaller places and weigh , well, not too much!
So, something has to give and that is in effect quality or in the lead acid battery world, HEFT! so things are more fragile and don't tolerate the things we tend to do to them like running them flat by leaving them to drain, fast charging them or not checking the electrolyte if not a sealed unit! In an ideal world they last pretty well. Those who report good results from their battery have looked after it, they must have! In your daily drive the modern car is doing just that for you, it monitors the battery state and demand on it and adjusts the charge to suit, so in effect its looking after your battery for optimum performance and subsequently its longevity.
So, for the Morgan owner who is probably driving a later classic which has a limited brain and a constant drain on the battery when all alone in the garage, the battery will drain unless action is taken. You can isolate the battery with a switch on the negative battery terminal ie. isolating the chassis earth to everything in the car. Alarm would be lost, if fitted, unless alternative feed was run direct to battery! The PCB (board) fitted in these cars is both fragile and unsophisticated and installed in a poor environmental location without protection and owners have reported that isolating switches have on reconnection fryed the electronics/electrics.
As we don't have an alarm system ,only an immobiliser ,the isolator switch in effect becomes an Immobiliser if you want to go that way!

As I said earlier I chose to use a fairly technical battery conditioner/charger And pound for pound I feel that it is the best option available for me, Look at the CTEC MX-S 10. they seem to retail about £175, think I paid about £150. I fused and wired it directly to the battery connecting it to a plug in the rear wooden bulkhead for easy access in the car. This is where I connect my CTEC charger, I can also fit a splitter lead to this and connect a trailing power socket to provide for phone charging etc whilst driving. You can in theory charge the battery through the car power socket at the dash and CTEC provide an adaptor for same but that gives me the willies, however when I'm out and about I do connect the battery state indicator here which flashes a traffic light colour state every couple of seconds and when parked up, to the uninitiated it looks like the car is very well protected! If we are away and just walking for the week I can instantly check the battery state and take action early if needed. You can buy and use that lead without the CTEC unit .

In conclusion, modern batteries like to be used constantly and in conjunction with technical cars that protect them, otherwise they are compromised or stuffed in the vernacular! Why Morgan didn't choose to either not install a part modern system or rather not just some of it and stick to manual switching which they were pretty good at I cannot fathom, Surely after bragging about just how long Morgan's last and that people enjoy them generationally they could have at least made replacement parts both available and affordable having chosen that route!

My experience with lead acid batteries is very similar as previously mentioned. I forgot twice to disconnect the battery in one of my cars and the battery was useless/destroyed after one year. On the other hand, a car I bought new it survived for more than ten years. In regular use (every few days) it should last at least 5 years.
Sometimes I do a battery capacity measurement (i.e. full charge then discharge with constant 5 Amps down to 10.8 Volt and measure the Amp*Hours).
Lead Acid degrade most, AGM are only marginally better, LiFePo4 are best. After 5 years, lead acid have lost half of their capacity, but are still good enough to start the engine if not longer cranking is required.
When buying a new battery, buy one from the big dealers, they have more throughput and batteries don't spend life on the shelfs...(and mark the date on it).
If you rarely use your car, you can install a battery cut-off/protection switch. This device disconnects the consumers from the battery to protect the battery from deep discharge which really kills a battery.

Good advice apart from the capacity check. As you say and have proven for yourself "deep discharge really kills a battery". There are dedicated thick plate deep discharge or traction batteries which fair far better under such regimes. With a starter battery, as a minimum, a full discharge takes a chunk out of its service life.

Treat it like your wife (partner boyfriend trans whatever) a good run out and airing does them both nothing but good and prevents things seizing up..