I perhaps was not clear. When engine is cold estimate how much effort is required to turn it by hand. This is in the fall. A duplicate test just before attempting to start next spring. You will have to have a lot stiffer manual turn over present to make a starter notice it. It will be enough differance for you to mentally compare after that length of storage. If it is engine or accessory related. Or the battery.

As for my own experience. If you have been doing this with that battery for 4 years. If it were my car and battery. I would immediatly suspect the battery.

This is a diesel starter. My load tester heats up as well. The starter may even be a heavier load than the load tester. So it may not reflect the service the battery is really required to deliver.

You will know the situation better next spring. If the engine is no worse to turn over by hand. Then it cranks even harder then you can almost assume the battery is suffering damage sitting each year.

Depending on climate and perhaps a few other things. An average car battery lasts no more than 6-7 years usually in regular service. If it is deep discharged many times. Or you leave it sitting idle for long periods of time. The overall useful life will usually be shorter.


There are exceptions but in general these factors have caused me many issues with the newer batteries In the last 25 years or so. It has not been unusual for me to visit private car collections and this area in conversation comes up time after time. Many try things like trickle chargers and other things. We all seem to lose batteries quicker than we like.

The United States navy uses the only real approach that does work. They also get many more years of service out of a battery. When the battery is to be out of service for quite some time. They drain the battery and store the eletoylite until they want to put the battery back into service. This is hard to do with our car batteries. Not impossible but harder. Their batteries would have individual cell drains.

You would have to drain a car battery into a large pan using a full mask and other protection from battery acid. Wash the surface of the battery off after putting the cell plugs back in. Store the chemical it in a non metal sealed container and reinstall it next spring.


You then add the length the battery was drained to the average lifespan.
So a car in use six months a year and stored six months. The battery might last 12 to 14 years. As soon as you put the acid mix back in you have a battery at the same level of charge as when you drained it and no sulphating issues have occurred with the plates.


There are specific high tech chargers that claim to give you the average lifepan. Like many things I have no ideal if they really work. The only certainty is in a case like I describe they will not give you the 12-14 years of service.

This is just some food for thought as I cannot see people draining their batteries for storage unless they become substantially more costly. Also if you look at batteries for sale they will have a date that they are not supposed to be retailed beyond.. They used to come in dry and the acid was added at the time of sale. Now they come in wet. So always look at the back of the rack for any that may have a later date than the ones up front. I still do this but our battery type for these cars is no longer usually stocked in any form of depth anymore where I live.


Since big chains probably do not pay for product until it is sold. What happens to the batteries that exceed the date and are pulled back off the shelves by the suppliers. Although I guess they are cautious in trying not to supply stocking levels that create this issue. Are they then sold as seconds by independent vendors? I do not know.