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MG TD TF 1500 - TD No start, dead bat???

Last year, after I put on my spare generator, and topped the battery off with distilled water, I found that I got a lot of sulfating on the battery and surrounding metal. I had the orig generator bushings replaced and installed it last weekend. Every thing seemed fine, it initially started ok and the ammeter indicated a slight charge as it always has. Then, once, the starter didn’t operate when the knob was pulled. Tried again, and it started fine. It started up a number of times until Monday, when the starter worked for just a split second and then nothing. The starter never turned slower and slower as it would with a dead or dying battery. I immediately thought that it was the starter switch, replaced it, still nothing. AND, the horn just gives one click. All indications of a dead battery. I tried to charge the 4+ year old battery, but it wouldn’t take any charge. The meter on the charger hardly moved.
I’m taking the battery to get it checked at lunch time. Should I have polarized my starter before I installed it? (Only the bushing was replaced) Did this cause the battery to possibly fail? All of the grounds and connections are clean. Maybe the belt is too loose? Would the sulfating kill a battery? The ignition light comes on, but gets dimmer as the headlights are turned on, and even dimmer still when the high beams are turned on.

SPW
Steve Wincze

Hi Steve, I would start by replacing the battery, especially if it won't take a charge as you indicated. This will probably solve your problem, If not then further tests would be required. You do not have to polarize your generator everytime it is removed from the car for a quick and simple repair, as their is enough residual magnetism left in the field poles to renergize correctly. In fact, the generator is actually disconnected by the cut out relay, everytime you turn off the ignition, by the cut out relay in the control box. Good luck Phil
Phil Atrill

Steve,

A generator can sit for years and not need polarizing; you polarize it to get the field coil correct to send out a charge, but it still turns in the same direction. A starter is an electric motor which will turn the correct direction regardless of the polarity, and does not require a field coil charge because energy is supplied to the coil to turn the armature, not the other way around.

You can have a belt as loose as one inch on the top and still charge the battery.

I think your battery just failed, probably dropped a cell. It happens. If you can remove the dust covers from the cells, check to see if any are low. If they are all 'up' you are not overcharging and boiling off the electrolyte.

I like to store batteries fully charged in the coldest place I can find. A fully charged battery will freeze at something like -90F. I recharge it in mid winter, and again just before I place it in the car. Batteries and fuel love cold storage, and it helps promote a long life. Now days, a lot of people swear by battery maintainers, as it keeps the battery in a charged state, just like driving it regularily... but I'm still not totally convinced.

warmly,
dave
Dave Braun

Problem solved,,, I think,,,

Even though the starter didn't give the gradual slowdown that a dying battery would make,,, it seems like the battery is the problem ,,, it tested out at 4 volts, with NO cranking amps,,,

Thanks,
SPW
Steve Wincze

Steve: Glad you fixed your battery problem. Do me a big favor and be very careful when you back up that TD, I would not want you to hurt that pretty baby standing in the back of your car.
Louis
Louis Levin

Steve - Your battery is probably sulfated, which happens when it sits for long periods of time without going through periodic charge/discharge cycles. Sorry Dave B. but there is a good reason to use a battery maintainer when the car sits over the winter without being started on a regular basis. What happens is that the plates in the battery build up a coating of lead sulfate on them, which insulates them from current flow. You might be able to rejuvenatory your battery by taking it to an auto electric shop that can run sufficient current through the battery to break the lead sulfate coating loose, but I would just go for a new battery. Cheers - Dave
David DuBois

I'm sorry Dave D. It gets a lot colder here than it does in Washington State. We rarely have daytime highs during the storage season greater than the low 20s, and often are much, much lower. I routinely get 9-10 years from my batteries by storing them fully charged and very cold. The Sulphation process is not much of a threat when the battery is fully charged, stored cold, and recharged in mid-season. But we aren't talking six months here, because I'll drive the car regularily right up to Thanksgiving, and take it out again in early to mid-March.

warmly,
dave
Dave Braun

This thread was discussed between 01/06/2010 and 02/06/2010

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