# question

## Orion-Tr Smart 12/12-18 charging current greater than 23 amps

On my boat is installed Orion-Tr Smart 12/12-18 (220W) Isolated DC-DC charger ORI121222120.

It is used to charge the Lifepo4 battery. The outboard motor has a 35 amp generator. I bought an 18 amp charger to limit the load on the generator. I watch the charging current with my battery meter. When charging, the current is not limited to 18 amps, and can exceed 25 amps.

How can I fix the charging current limit ?

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Justin Cook - Bay Marine Supply USA answered ·

@koh, are you watching the charge current or the supply current being pulled from the start battery? To output ~18A of continuous current to the house bank, the charger will pull ~20-21A continuous current from the start battery. As noted in the user manual, the 12/12-18 is 87% efficient, so take 18A continuous output and multiply it by 1.13 to get the approximate continuous input current required: ~20.34A.

Then take into account that the 12/12-18 can surge to 25A output for up to 10 seconds to supply the demand of the house battery, and it will not be out of the question (using the same math) to see ~28.25A of current being drawn from your start battery for ~10 seconds.

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Justin , thank you for your answer! The current of 25 amps I see at the input to the LiFePo4 service battery = output the charger more than 10 seconds. I have to use the victronconnect app to lower the charge voltage to 13.5-13.7 volts so that the output current of the charger is no more than 20 amps

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