Power sliding door works but needs a nudge

[August West]

A fully charged battery should be above 12.7V when the car is off. 12.5V is slightly discharged. Charging the battery with a charger is more reliable than charging it with your alternator (driving the car). Other than voltage, a sign of a fully charged battery is that it cranks the engine much faster.

A sign of your battery affecting the door is that it opens/closes easier downhill than uphill. If not, it may be the door contacts/limit switch alignment.

[August West]

Here is a chart of battery voltage vs charge level.

[slow_runner]

A simple measurement of volts across the terminals will not give you anything near accurate assessment of your battery condition.
Best to measure volts with a decent voltmeter under cranking conditions' anything under 9V is suspect.
Better to have the battery tested under constant load at a auto electrical shop. Down this way, this service is usually that, a free courtesy service.
My battery charger is an Endurant 'intelligent' (?) charger that has a float function.
As the recent battery is a sealed 'maintenance free- long life' unit ( read : for the lazy or ill informed ) (AND an efficient charging circuit is more critical than that of old)
It will be interesting to see how long this newer battery lasts. I was informed that if it drains down it is no longer a simple matter of hooking up the battery charger; they need a jolt of some description for them to accept a charge(??).

[automation]

A simple measurement of volts across the terminals will not give you anything near accurate assessment of your battery condition.
Best to measure volts with a decent voltmeter under cranking conditions' anything under 9V is suspect.
Better to have the battery tested under constant load at a auto electrical shop. Down this way, this service is usually that, a free courtesy service.

You also want to be testing on the cable connections (not the battery posts) if you're interested in how the "system" is performing. Testing on the battery posts can indicate a "good battery" yet the slightest bad connection will drop VOLTS between the post and the connector. If you have probes with sharp points, also try jabbing them into the cable insulation -- in case a bad connection between the cable and the connector!

[Had this problem with the battery in a forklift a few weeks back. Battery looked good while cranking but only a few volts at the starter. Walked back up the cable to the battery connectors to notice that all of the voltage drop was happening within an inch of the battery posts!]

[Andy]

Especially on a 25 year old vehicle...no telling how corroded the junction of the crimped-on connectors and terminals are on the wires

[slow_runner]

You also want to be testing on the cable connections (not the battery posts) if you're interested in how the "system" is performing. Testing on the battery posts can indicate a "good battery" yet the slightest bad connection will drop VOLTS between the post and the connector. If you have probes with sharp points, also try jabbing them into the cable insulation -- in case a bad connection between the cable and the connector!

[Had this problem with the battery in a forklift a few weeks back. Battery looked good while cranking but only a few volts at the starter. Walked back up the cable to the battery connectors to notice that all of the voltage drop was happening within an inch of the battery posts!]

Yes, not only battery condition.
It brings to mind an occasion years back when the shop mechanic replaced a Ford Falcon starter motor because it appeared to be stuffed- the problem lay with a poor earth contact due to oil/crud between the starter motor face and the bellhousing.
Simple things.

[August West]

A simple measurement of volts across the terminals will not give you anything near accurate assessment of your battery condition.

A no load test won't confirm if the battery is good. But it may confirm if the battery is bad or needs a charge. Because there is a minimum voltage a battery should have even without a load. Having said that, it's not a true no load test unless at least one of the terminals is disconnected. Because there may be some parasitic load.

As the recent battery is a sealed 'maintenance free- long life' unit ( read : for the lazy or ill informed ) (AND an efficient charging circuit is more critical than that of old)
It will be interesting to see how long this newer battery lasts. I was informed that if it drains down it is no longer a simple matter of hooking up the battery charger; they need a jolt of some description for them to accept a charge(??).

My BMW battery has caps but it says "do not open" so is that sealed? It's lasted 13 years with zero maintenance. My Battery Tender chargers says it works on all lead-acid batteries, flooded or sealed maintenance free batteries (AGM and gel cell)

[slow_runner]

A no load test won't confirm if the battery is good. But it may confirm if the battery is bad or needs a charge. Because there is a minimum voltage a battery should have even without a load. Having said that, it's not a true no load test unless at least one of the terminals is disconnected. Because there may be some parasitic load.
My BMW battery has caps but it says "do not open" so is that sealed? It's lasted 13 years with zero maintenance. My Battery Tender chargers says it works on all lead-acid batteries, flooded or sealed maintenance free batteries (AGM and gel cell)

13 years? Good grief August, that must surely take the cake and first prize for longevity. Congratulations [IMG]/forum/images/smilies/smile.png[/IMG][IMG]/forum/images/smilies/smile.png[/IMG]

[August West]

I guess I've gotten lucky. I owned my Monte Carlo for 18 years and had only 2 batteries (10 years on the OEM battery and 8 years on the replacement battery from Interstate). That was without using a charger. I had a bad ignition switch that would stay on and drain the battery, which lead to several jump starts, which is bad for the battery. Without all those jump starts and/or using a charger, I suspect I would have gotten longer battery life. So I'm a bit surprised to hear people expect 3 years.

I'm more educated now. With a van, I need to be. Will be charging and load testing the battery on a schedule and replacing it once it's ability to hold a charge degrades. I just don't see the sense in replacing a battery solely based on age. Because if you do that, eventually you'll replace a perfectly good battery with a bad one.