question

kajones99 avatar image

Preventing Alternator Burnout with DC-DC Charger

I have purchased a Smart DC-DC 12/24 15 amp charger for use on a small boat.

The alternator on the 60HP outboard puts out maximum 21A.

The start battery will be a 75AH Li.

The plan is to charge a 24V 200AH Li battery (used to power a trolling motor) while the engine is running.

I am concerned about overheating the alternator when the motor is running at idle and producing less amperage than the rating of the DC-DC charger.

If the alternator is only producing 5A at idle but the 24V trolling motor battery is discharged and the charger is trying to pull its maximum of 15A, do I have a potential problem?

If I use a Lead-Acid start battery do I avoid potential problems?

Thanks for your help.

battery chargingOrion DC-DC Converters not smart
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
kevgermany avatar image
kevgermany answered ·

The problem isn't the Orion, it simply takes what the alternator provides, steps it up to 24V and feeds the battery. With a max of 15A at 24V, i.e. 30A input to the Orion at 12V. Lithium, as you're aware, takes all it can get in a system like this.

This means your alternator potentially runs at full output continuously, depending on how much you take out of the lithium battery.

Best bet would be to upgrade the alternator, based on the power needed. Changing to lead acid may help, but...


2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.