Marinepower
Solar Enthusiast
- Joined
- Apr 24, 2020
- Messages
- 220
I'm trying to design a system to charge a 12v -280ah LFP bank from a high output alternator as well as charge and isolate an engine start battery.
DC-DC charger seems a good way to go but there are 2 issues I'm trying to understand before committing to this route.
First, do I need to size the DC-DC charger to be less than the out put of my alternator at idle RPM?
For example in this video
(see 5 min and 45 seconds in) I see that the poster's starter battery is being drained by the DC-DC charger because his alternator cannot keep up to the demands of the DC-DC charger at idle?
I would ideally like to size my DC-DC charger to take advantage of all the current my alternator can put out. But if i'm limited to the idle output, then I may have to look for another solution.
Are others using starter battery isolation (like a Victron Argofet https://www.victronenergy.com/battery-isolators-and-combiners/argo-fet-battery-isolators ) in addition to a DC-DC charger to avoid this issue? Or is this an issue specific to the Renology DC-DC chargers and other brands have input voltage sensing protection or some other built in isolation to protect the starter battery?
Sorry if this question has been asked and answered before. I did search this forum without luck.
MP
DC-DC charger seems a good way to go but there are 2 issues I'm trying to understand before committing to this route.
First, do I need to size the DC-DC charger to be less than the out put of my alternator at idle RPM?
For example in this video
I would ideally like to size my DC-DC charger to take advantage of all the current my alternator can put out. But if i'm limited to the idle output, then I may have to look for another solution.
Are others using starter battery isolation (like a Victron Argofet https://www.victronenergy.com/battery-isolators-and-combiners/argo-fet-battery-isolators ) in addition to a DC-DC charger to avoid this issue? Or is this an issue specific to the Renology DC-DC chargers and other brands have input voltage sensing protection or some other built in isolation to protect the starter battery?
Sorry if this question has been asked and answered before. I did search this forum without luck.
MP