Is it ok to charge the 12 volt battery with a 15 volt battery? My car sat for four months and needed to be charged which i did with a portable 3 in 1 (charger, compressor, work light) charger. It charged and ran normally for five days. After that, when i turned the car off the dashboard light stayed on and flickered crazily. Thanks for any insights.
Some questions to know: How old is your car's battery ? If its life exhausted then must be replaced. Is the Battery Charging System in your car working properly ? If system is not working as per its rated out put, then repair or replacement is required.
The maximum voltage that should be used to charge a 12V AGM battery is 14.4V. Once the battery has been charged, if it fails to hold the charge over a reasonable period of time, then it needs to be replaced. The 14.4V charging voltage should be stopped when the charging current no longer drops as time passes. If desired, a trickle charge to maintain the battery charge can be applied at ~13.2V. Measure the voltage across the 12V battery when the Prius is IG-OFF. A new, fully-charged 12V AGM battery will measure ~13.0V. If the voltage measurement is ~12.0V, the battery is near-discharged. An intermediate measurement value will show you the approximate % charge - for example, 12.5V would be ~50% charged. Then, measure the voltage across the 12V battery when the Prius is READY. The voltage should measure ~13.8V which would indicate the DC/DC converter is working OK. If much lower, the 100A DC/DC fusible link has blown or the converter has failed which means the inverter needs to be replaced.
Didn't you already ask this question in another thread ?? Where do you get a 15 volt battery and why is that part of the question ?
