diy solar

diy solar

Installation of Lithium, DC Charger, AGM with a Boat Switch assistance

Typically stock alternators are set to about 13.8v , so let’s say you set the set point at 13.5V , fine

But when the engine stops you will tend to discharge the AGM until the cut off point is reached. AGMs hate partial discharges. It reduces their life considerably.

A better way is to establish a engine run stop signal and switch the Victron dc dc on off ( it’s has that ability )
I’ve generally seen a pretty quick falloff on lead acid batteries when they go into rest. If you stop holding them at the 13.8 float and just let them rest, they drop to 13.5 or less within minutes.
 
Like been mentioned several times it also shuts off automatically when the start batt voltage drops below whatever setting you want so not really a concern if I set that at 12.6
 
Like been mentioned several times it also shuts off automatically when the start batt voltage drops below whatever setting you want so not really a concern if I set that at 12.6
Except the battery will discharge partially into the dc dc
 
I didn't read the whole thread so forgive me if info is irrelevant. On my boat the start battery does nothing except start engine. The house batteries charged from solar power everything. I have a 9 amp DC to DC charger so I can charge start battery or any other battery from the house batteries. I mostly use the DC to DC charger to charge my smaller portable lithium batteries. I do have a shore power charger that can charge any type of battery. I've only used it a few times in two years. This works well for me on my sailboat. My engine is 14 HP diesel with a 30 amp alternator so charging house batteries from alternator is not an option. 200 amps of solar runs compressor cooler, fans, TV ,lights etc. Good luck with your boat.
 
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