Re: How much battery can I charge off of ont 65amp alternator?
If the maximum current that your battery charging circuit can produce is 65-Amperes, that will be the most charging current that can be provided. In order for a battery to accept 65-Amperes of charging current, the internal resistance of the battery must be very low. Typically only premium-quality batteries will have an internal resistance low enough to permit 65-Amperes of current to flow into them.
If you push 65-Amperes for one hour, you will have pushed 65-Ampere-hours of charge into a battery. Of course, in order for that to occur the battery must have a capacity to store at least 65-Ampere-hours of charge. Most batteries cannot store that much charge.
As a general rule, with 65-Amperes of charging current available, the battery itself will be the limiting factor in deciding how much charge can be absorbed. Also, as a battery is re-charged, its terminal voltage rises. As the terminal voltage rises the difference in voltage between the battery and the charging source becomes lower. The lower the difference in voltage, the less current tends to flow. This behavior also will limit the ability of the battery to absorb charging current. It is unlikely that 65-Amperes will flow for more than a few minutes of the charging period.
