Interaction of Solar and Alternator
My camper has a single 100W roof-mount panel, which meets my power needs (2 @ 6V batteries) when the sun shines. However, when camping among trees for several days it is easy to consume 70 to 100 Ah ...
Forum Discussion
The voltage the vehicle itself allows, and for how long it allows it, along with the circuit resistance, and battery resistance will dictate how many amps the battery will accept.
MOst vehicles might start out iun teh 14's, but quickly drop to mid to high 13's/
I regularly see 3x more amps flowing into my AGM at 14.7v compared to 13.7.
Since I can spin a dial and change vehicle voltage, i can change the rate at which my battery charges, but it is pretty much 14.7 anytime it is not full, and 13.6 to 13.8v when it is.
Many people who add secondary batteries use the starting battery as the + feed for the house battery, basically tacking the house battery onto the end of the starter battery charging circuit. The original alternator to battery charging circuit was never intended to carry the extra current of depleted house batteries.
Solution, Hook house battery to alternator dierctly through solenoid, rather than engine battery to house battery.
I have fairly thick copper between alternator and house battery and it was consuming 60+ alternator amps on start up and 59+ amps when I parked some 10 miles later, at 14.7v.
YOu cannot easily change the vehicle's chosen voltage so alternator charging is almost never saturation charging, bringing the battery to 14.5volts nearly instantly and holding it there.
I think a pair of healthy golf cart batteries at 50% can suck up 70 to 80 amps for a while before the voltage mearured at their terminals hits the mid 14s.
If youo vehicle is only asking for 13.7v then those same batteries might only require 25 amps.
So even if you were to wire your alternator directly to house batteries with fat copper + and - cables, the vehicles voltage regulator might decide 13.6v is just fine and dandy, and there is nothing you can do.
But the DC to DC chargers can remedy this, with some limitations and rather ridiculous price.
Some vehicles can have their voltage influenced.
I had to trick my engine computer into thinking my externally regulated alterantor is still connected to it, and I use an external adjustable voltage regulator, and can basically always charge my battery as fast as it is possible to do so.
The Solar just adds its amperage to what the alternator can make as I have its absorption voltage set for 14.7v too.
If I had solar set for 14.6 and vehicle for 14.7, then the solar would not contribute once 14.6+v was reached.
So a thick copper circuit can help only so much, you are still at the mercy of the vehicles voltage regulator. if you have a long thin house battery circuit, and your vehicle has decided to drop to 13.6v, you will be lucky to see 5 amps flowing into the gc-2's
MOst vehicles might start out iun teh 14's, but quickly drop to mid to high 13's/
I regularly see 3x more amps flowing into my AGM at 14.7v compared to 13.7.
Since I can spin a dial and change vehicle voltage, i can change the rate at which my battery charges, but it is pretty much 14.7 anytime it is not full, and 13.6 to 13.8v when it is.
Many people who add secondary batteries use the starting battery as the + feed for the house battery, basically tacking the house battery onto the end of the starter battery charging circuit. The original alternator to battery charging circuit was never intended to carry the extra current of depleted house batteries.
Solution, Hook house battery to alternator dierctly through solenoid, rather than engine battery to house battery.
I have fairly thick copper between alternator and house battery and it was consuming 60+ alternator amps on start up and 59+ amps when I parked some 10 miles later, at 14.7v.
YOu cannot easily change the vehicle's chosen voltage so alternator charging is almost never saturation charging, bringing the battery to 14.5volts nearly instantly and holding it there.
I think a pair of healthy golf cart batteries at 50% can suck up 70 to 80 amps for a while before the voltage mearured at their terminals hits the mid 14s.
If youo vehicle is only asking for 13.7v then those same batteries might only require 25 amps.
So even if you were to wire your alternator directly to house batteries with fat copper + and - cables, the vehicles voltage regulator might decide 13.6v is just fine and dandy, and there is nothing you can do.
But the DC to DC chargers can remedy this, with some limitations and rather ridiculous price.
Some vehicles can have their voltage influenced.
I had to trick my engine computer into thinking my externally regulated alterantor is still connected to it, and I use an external adjustable voltage regulator, and can basically always charge my battery as fast as it is possible to do so.
The Solar just adds its amperage to what the alternator can make as I have its absorption voltage set for 14.7v too.
If I had solar set for 14.6 and vehicle for 14.7, then the solar would not contribute once 14.6+v was reached.
So a thick copper circuit can help only so much, you are still at the mercy of the vehicles voltage regulator. if you have a long thin house battery circuit, and your vehicle has decided to drop to 13.6v, you will be lucky to see 5 amps flowing into the gc-2's
