Purpose of starter wire in a DC to DC controller
- Thread starter Arbee
- Start date
He indicated they were in parallel 99.9% of the time, so I assume that includes when the car is off, but that's a good point. Worth checking the two batteries to confirm they are at the exact same voltage.
In replying to your THIRD post on this subject, I realized I flipped the numerator and denominator in the current calculation. That's a serious shame on me because it support my conclusion almost 10X more strongly.
I reported the current as 2.7A when it's actually 4.5W/12V = 0.375A
Your trickle charger puts out almost 3X this amount, but your voltage is dropping to 12.3V overnight with a charger attached? Nope.
Your starter battery can power your dash cam for...
65Ah / 0.375A (1 day / 24 hr) = 7.2 days.
Please let that sink in. Your starter battery, when new and fully charged, can run your 4.5W dash cam for a WEEK.
I hope this convinces you that you have imagined a convoluted solution to a problem that has nothing to do with your perception of the situation.
Your trickle charger is either not working at all, or you have it connected to the wrong battery per @sunshine, or your batteries are shot and require so much current from the trickle charger, it can't keep up, or you're just never getting your starter battery fully charged for some unimaginable reason. A 3A battery tender should have your car fully charged in less than 2 days with the dash cam operating.
Your 100W panel and the 13.8V converter I linked you is OVERKILL by a factor of 3-4X for this situation IF your starter battery is reasonably healthy. Even if it's only 50% of rated, this solution is more than adequate.
IF you have allowed this vehicle to sit for several days at a time with the starter battery at a low state of charge, you have destroyed it. They EAT themselves at low states of charge and are permanently damaged.
PLEASE stop repeat posting about this just because you're getting pushback on a harebrained scheme.
I reported the current as 2.7A when it's actually 4.5W/12V = 0.375A
Your trickle charger puts out almost 3X this amount, but your voltage is dropping to 12.3V overnight with a charger attached? Nope.
Your starter battery can power your dash cam for...
65Ah / 0.375A (1 day / 24 hr) = 7.2 days.
Please let that sink in. Your starter battery, when new and fully charged, can run your 4.5W dash cam for a WEEK.
I hope this convinces you that you have imagined a convoluted solution to a problem that has nothing to do with your perception of the situation.
Your trickle charger is either not working at all, or you have it connected to the wrong battery per @sunshine, or your batteries are shot and require so much current from the trickle charger, it can't keep up, or you're just never getting your starter battery fully charged for some unimaginable reason. A 3A battery tender should have your car fully charged in less than 2 days with the dash cam operating.
Your 100W panel and the 13.8V converter I linked you is OVERKILL by a factor of 3-4X for this situation IF your starter battery is reasonably healthy. Even if it's only 50% of rated, this solution is more than adequate.
IF you have allowed this vehicle to sit for several days at a time with the starter battery at a low state of charge, you have destroyed it. They EAT themselves at low states of charge and are permanently damaged.
PLEASE stop repeat posting about this just because you're getting pushback on a harebrained scheme.
rin67630
Solar Enthusiast
I could imagine, that the MOS-FETs would else not survive a cranking current surge, so you need to protect them from the peak current.
rin67630
Solar Enthusiast
Not necessarily; it can even be badly under-dimensioned.
We know nothing on which location the OP parks his car. How long will it stay unattended?
How shady the place is, how much cloudy days he may have to deal with?
With winter days lasting only a few hours and a panel harvesting only 20% of its peak power, you will not reach the ~10Ah he needs to break even.
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This is the OP's 3rd thread on the subject, and those details are discussed in other threads. OP designated the 100W limit. Presuming the OP understands that solar doesn't work in shade or at night, or they wouldn't have proposed it as a solution.
The DCC50S will absolutely charge both the starting and service batteries .
"If the service battery is in float charge stage, the starting battery will be charged at the same
time. The charging voltage is limited at 13.8V. The charging amperage is limited at 25A."
"If the service battery is in float charge stage, the starting battery will be charged at the same
time. The charging voltage is limited at 13.8V. The charging amperage is limited at 25A."
..provided of course that it's daylight and that the starter battery is less than 12.7 V. And provided that charging has begun, the starter battery voltage remains at 13.2 V or less.
