Thread: DC/DC chargers, How do they work and do you really need one.

Originally Posted by drivesafe

Hi Barraman, just a guess but charging your batteries directly from the alternator gave you better results than charging with the DC/DC unit, regardless of what size the DC/DC unit was.

Sorry, I don’t understand your post, but you may have misunderstood mine.

My outboard is connected directly to the ‘start’ battery. The ‘house’ batteries (2 x 120 amph batteries in parallel) are connected to the ‘start’ battery via a 12v DC - 12v DC charger.

My point was that this appears to be more effective in keeping the ‘house’ charged than the VSR was.

I like to keep it simple on boats.
2 batteries connected to the alternator with a simple isolator so that I can run from either battery, both batteries or shut the power off.
The fridge runs on its own battery which not connected to the boats electrical system that is charged via a solar panel.

Given that I am running 4 x fishfinder combos, there is nothing simple about my boat!

Hi Barraman, then you would be draw very little power from any of the batteries.

When a small alternator is being use to charge a large bank of batteries, the last thing you do is use something that is inefficient to try to charge even moderately discharged batteries. There is just too much energy wasted by the DC/DC device that can not be made up by a small alternator.

So, as above, you are literally just topping the batteries up, or you had something not quite right with your original setup.

Originally Posted by Barraman

Given that I am running 4 x fishfinder combos, there is nothing simple about my boat!

I run 2x fishfinder combo's But they draw bugger all amps, The electric anchor winch however is pretty thirsty on power.

Originally Posted by trout1105

I run 2x fishfinder combo's But they draw bugger all amps, The electric anchor winch however is pretty thirsty on power.

Depends on the finder. Livescopes like the Garmin Panoptix Livescope are power hungry units. They can drain an N70 quite quickly if it isn't being charged. Far higher power consumption than sidescan, CHIRP etc.

Cheers

Originally Posted by ozscott

Depends on the finder. Livescopes like the Garmin Panoptix Livescope are power hungry units. They can drain an N70 quite quickly if it isn't being charged. Far higher power consumption than sidescan, CHIRP etc.

Cheers

Mine are only the 9" Lowrance and ray marine units.

I’m very conscious of hyjacking this thread. I made a simple observation that was relevant - I have replaced the VSR’s in both my boats with DC-DC chargers, and find them to be more effective. How do I judge that? Simply because the ‘low voltage’ warning doesn’t come onto my Humminbird Helix 12 mega sounders as often as used to be the case. Another motivation was that I know of two VSRs that have shorted out and burnt. All the commentary does not change my observation.