40 amps of output from the DC-DC chargers could be 60 amps (or more) of input from the alternator. You may be hitting a hard limit on the circuit unless you have the two chargers wired directly to the alternator.
2 Victron Orion 30a dc to dc & alternator issue not enough amps
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grizzzman
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My DC to DC charger at 14 volts input draws 10 more amps when the output is 40 amps at 14.7 volts output. So 50 amps total.
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At first blush, this sounds like you're coming up with more power on the output side than on the input side. That doesn't sound right.
grizzzman
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Ya I can see that. does my correction meet with your approval or should i do a total rewrite?
Northstarjourney
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I have been more of a shadow on these forums but thought I may be able to add something to this issue.
It sounds like your rig is factory setup with dual alternators. Most up fitting has dedicated auxiliary power outputs as mentioned by someone else in the thread.
Where is you power feed for the DC to DC connected?
My thought is that the chassis/pcm/BCM monitors the starting battery with the shunt and current limits the charging based on what it expected for the starting battery. By adding your output cable between shunt and starting batteries the chassis thinks it's charging to much and limits current.
Most vehicles especially Fords have an aux power location. Usually they are in a fuse block or terminal block somewhere on the vehicle. Many times they have fuses, relays and dash switches depending on your models package.
Ford should be able to tell you what options you have and a wiring diagram detail where there located. Owners manual usually also outlined the locations and current the circuits are designed for.
If the chassis is as "smart" as I suspect it may be the only way. You may have to connect each dc to DC to a separate circuit to get enough output current.
Good luck, cheers
It sounds like your rig is factory setup with dual alternators. Most up fitting has dedicated auxiliary power outputs as mentioned by someone else in the thread.
Where is you power feed for the DC to DC connected?
My thought is that the chassis/pcm/BCM monitors the starting battery with the shunt and current limits the charging based on what it expected for the starting battery. By adding your output cable between shunt and starting batteries the chassis thinks it's charging to much and limits current.
Most vehicles especially Fords have an aux power location. Usually they are in a fuse block or terminal block somewhere on the vehicle. Many times they have fuses, relays and dash switches depending on your models package.
Ford should be able to tell you what options you have and a wiring diagram detail where there located. Owners manual usually also outlined the locations and current the circuits are designed for.
If the chassis is as "smart" as I suspect it may be the only way. You may have to connect each dc to DC to a separate circuit to get enough output current.
Good luck, cheers
The corrected version is better.
I have run a few tests today. I could be wrong but I think is the regulator on the actual alternator set to output 40a max. to prevent premature end.
Disconnecting shunt increases voltage from 14.65 to 14.78 but current remains the same.
Suppose smart vehicle, preventing human from doing something silly : )
And I guess, since Victron is trying to get max. current I can see the constant fluctuation of the current between 36-38 amps while accelerating vehicle, pressing pedal breaks etc.
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