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Battery charging?

I own 2005 Ford Escape, 3.0L engine with 71,500 miles on it. This morning I wont start, no cranking, nothing so I assumed its battery so I checked battery with multimeter result 12.47 volts sound 75% charged. I jumped cable it with my 97 Plymouth Voyager and it started right up. So I disconnected battery cables of Escape so I left my Van running so it’s charging to Escape up to fully charge about 20 minutes. I tested the battery and it was 12.90 sound full but about two hours later I tested again and it was 12.60 volts. I will check again in couple hours. The question is charging battery using jumper cable with other vehicle and running idle to feed the weak battery will be enough? Or do I need to have it new one?


What you are seeing is expected. When a battery is fully charged it will have an overvoltage that will wear off on sitting. However, if the voltage drops below 12 volts in 12 hours, you can suspect a bad cell. The best check of a battery’s condition is a load test or what the battery voltage falls to under starting load. If you have a VOM monitor the battery voltage as the engine is cranked. If the voltage falls below 9 volts, the battery may be low on capacity.

Hope that helps.

How about checking that battery voltage while the engine is cranking,let us know what figure you have.

Charging with jumper cables off a running vehicle is not adaquate.

The battery will show 12 volts even when it’s too weak to start the engine. You need amperage to start the engine. I suggest you have the battery and charging system tested. If the battery is the original it’s probably on its last legs. Ask to have the battery “load tested.” This will tell you the true condition of the battery.

It would be difficult to fully charge the battery just using a vehicle’s alternator. You need a battery charger if you want to fully charge a battery.

True, any battery must be tested with a load. You can try with the headlights on first. Often you don’t even have to try the crank test because the voltage will drop significantly with only the lights on and you know you have a bad battery.

This morning I tested the battery and was 12.5V so I decided to go to Oreilly auto parts to have load tested from them as a result same but shown it is bad battery so I had replaced. The question is the old battery had CCA 590 but I bought and installed a CCA 650. Is 650 ok or may harm to starter due to higher current amps?

CCA 650 is fine. It won’t hurt anything. The starter will draw only the amperage it needs. You’ll just have a little more reserve power for starts on cold mornings. Enjoy.

Thank you you all!!!:slight_smile: