battery load test 2002 xc70

[fauteux]

I recently bought a 2002 xc70 with 103k miles. The battery dies rather easily. For example, keeping the tailgate up for a couple of hours killed it. Is there a way I can perform a load test on the battery? I have a multi-tester. The alternator is putting out around 13.8. What should the battery be showing if it is fully charged?

Is it ok to charge if from under the hood, or do I have to put my charging contacts on the battery itself, which is located in the rear?

It has a new new looking volvo battery. The fluid levels are fine. Anyway to know how old the battery is?

Thanks.

[sjonnie]

Your alternator output voltage should be measured when the car is at operating temperature and with the engine doing 2,300rpm. Then the output should be (depending upon operating temperature) between 13.75V to 13.9V min to 14.2V to 14.4V max.

The Volvo batter #9459947 has a stand-by voltage of 12.72 when fully charged. It should have a month and year stamp on it if it's a genuine Volvo battery.

Your Volvo dealer has a battery tester to check the condition of the battery, I'm pretty sure Autozone run a similar test. To perform your own load test on the battery make sure it is fully charged, after fully charging let it sit for 30mins. Attach a multimeter and check the voltage. Switch on the main headlights for 6 mins and monitor the voltage while listening to a couple of your favorite tunes, it shouldn't drop below 9.8V at any time during the test and should bouce back to >12.3 as soon as the load test is completed.

[fauteux]

Thanks for the information. Do you know whether I can charge the battery by connecting my charging leads to the positive terminal and ground under the hood, or does that need to be done at the battery in the back of the car?

[sjonnie]

Generally you should always remove the battery from the car before charging it via a remote battery charger although last time I did it I just opened the trunk, disconnected the terminals and attached the charger clips overnight and left it like that.

[fauteux]

Thanks for the info. Much appreciated.