Couple of questions about DC-Dc charging
I've been thinking about adding a DC-DC charger now that I've added 400 amp hours of AGM batteries. There are lots of useful posts but I haven't run into a couple of things I'm curious about. One ...
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There is an easy way to do this but it's going to make the people who have never done it howl in anguish.
The feeder circuit from the alternator to the house batteries must be restricted. Restricted means resistance. The circuit must be made correctly. Professionally designed.
A charge division must be incorporated and the only one I have found to be reliable is a White Rogers 200-ampere capacity solenoid that actuated automatically. A smart solenoid that prefers chassis battery first then house battery. This system needs no switches. Both the Blue Seas and Sure Power solenoids are good brands. The bi directional allows automatic charging in the opposite direction as well. Preferable.
Amperes limiting is done via a fifteen foot length of FUSIBLE LINK wire. 10 AWG and ten to twelve feet in length. Fusible Link wire is tin coated but it's secret is in the insulation. Cross-linked polyethylene which can tolerate extremely high temperature.
USA auto manufacturers have utilized restrictive alternator output wire size for decades and of course they have utilized fusible link wire for gross amperage violations for the same amount of time. Decades.
For many years, GM used a 13 gauge alternator charge wire on their 10DN, 10SI, 12, 15, and 17SI alternators. Ford and MoPar did the same.
The issuse you face with a Ford 3, 4, or 6G, is the alternator has twin internal rans driven by the rotor. And underhood temperatures can read 240 degrees which is punitive for an alternator cooling inlet temp.
Fifteen feet of restricted gauge wire will limit ultimate amperage passage to around 60-70 amps. The preferential charge protocol of the "smart solenoid" inherently limits total amperage delivery.
The fusible wire must not be bundled or wrapped.
For over a decade General Motors avoided using a separate block resistor on their ignition system by using a STEEL CORE coil ignition wire. There was an override for starting booster voltage originating at the R terminal on the starter motor solenoid. Ford used this design as well.
Just make sure your wire is cross link type and is fifteen feet in length.
It would be light years more reliable than any electronic circuit.
The feeder circuit from the alternator to the house batteries must be restricted. Restricted means resistance. The circuit must be made correctly. Professionally designed.
A charge division must be incorporated and the only one I have found to be reliable is a White Rogers 200-ampere capacity solenoid that actuated automatically. A smart solenoid that prefers chassis battery first then house battery. This system needs no switches. Both the Blue Seas and Sure Power solenoids are good brands. The bi directional allows automatic charging in the opposite direction as well. Preferable.
Amperes limiting is done via a fifteen foot length of FUSIBLE LINK wire. 10 AWG and ten to twelve feet in length. Fusible Link wire is tin coated but it's secret is in the insulation. Cross-linked polyethylene which can tolerate extremely high temperature.
USA auto manufacturers have utilized restrictive alternator output wire size for decades and of course they have utilized fusible link wire for gross amperage violations for the same amount of time. Decades.
For many years, GM used a 13 gauge alternator charge wire on their 10DN, 10SI, 12, 15, and 17SI alternators. Ford and MoPar did the same.
The issuse you face with a Ford 3, 4, or 6G, is the alternator has twin internal rans driven by the rotor. And underhood temperatures can read 240 degrees which is punitive for an alternator cooling inlet temp.
Fifteen feet of restricted gauge wire will limit ultimate amperage passage to around 60-70 amps. The preferential charge protocol of the "smart solenoid" inherently limits total amperage delivery.
The fusible wire must not be bundled or wrapped.
For over a decade General Motors avoided using a separate block resistor on their ignition system by using a STEEL CORE coil ignition wire. There was an override for starting booster voltage originating at the R terminal on the starter motor solenoid. Ford used this design as well.
Just make sure your wire is cross link type and is fifteen feet in length.
It would be light years more reliable than any electronic circuit.
