Alternator Charging ? Again
I need to use the truck to recharge the batteries for the truck camper when off grid because there is no room for a generator, and solar can't always keep up.
I know you are supposed to upgrade to fatter wire instead of using the existing 7-pin. However, I am not sure what that really means for connecting wires from where to what. I have read here that you should by-pass the truck battery and use the alternator connections. It is a 105a it seems, and it has a lug for the positive wire that goes via some sort of little box which is wired to the battery pos, and the alternator is marked GRD where it is bolted on to its bracket. I do get about one more DC volt by taking the voltage from the alternator's pos lug instead of the battery's.
I just can't understand what people are doing to get their reported 60 amps or whatever from using their alternators. What is the secret?
Thanks.
So far, I have been playing with my long jumper cables, 25 ft of #1 cu/al which have fairly low resistance. Results so far:
A. 7-pin. Gets 10 amps at first then tapers to about 6 amps within four minutes. Truck at idle 600 revs, going to 2000 revs makes little diff.
B. Jumper cables from truck battery to house batts. Gets about 20 amps at first then quickly tapers. Higher revs make little diff.
C. Using the long set of jumpers from truck battery to 2000w MSW inverter, to run a 35 amp (gets 33 amps max) Vector smart charger to the house batts. Gets 33 amps nice and steady, truck voltage holds at around 12.2 volts steady at 600 revs idle.
D. Same as C, but using adjustable voltage modified PowerMax PM3-55 converter. Runs ok, but where it gets 57 amps on shore power, on the MSW inverter on this long wire set, it gets about 50 amps. The truck has a hard time holding its own battery voltage at near 11.7 volts. Amps taper a little as truck starts losing the fight. At 49 amps, revving the truck to 2000 revs from 600 at idle did make a diff. Amps rose from 49 to 51 and truck voltage stopped sliding away.
So it looks like I can somehow run cables back to the truck camper to an inverter to run a charger, solving a few physical layout problems, and it will work, especially if I use the 35 amper. If I use the 55 amper, it will mean putting a brick on the gas pedal or something to hold the revs up for an hour instead of idling with no complications as with the 35 amper. Means 33 AH vs 50 AH for an hour of idling (batteries would be low so no tapering amps then)
Some time ago I used this method with the 35 amper and idled the truck for an hour no problems at all. That was working outside and not having the inverter and charger and wiring all inside so it could be done without going out in the dark and rain. (Which is likely to be the case, since otherwise the solar would keep up, and this charging from the truck would not be necessary :) )
So before I do some renos on the truck camper's set up for all this, is there an easier way to get those good amps from the truck to the house batts? (Where the amps won't taper like crazy from whatever they start out as. I get constant amps with the Vector or the PowerMax chargers, which is the big advantage of using them)
BTW, not related, but the Xantrex MSW inverter will not run the VEC1093DBD at all. It shows code OPP, which means incompatible device (that code is not in the owner's manual, I got that from tech support) It does run the Vector 1092A though. I wonder if the 1093DBD needs PSW. No matter, I can do 33 instead of 40 since I have one of each.
I know you are supposed to upgrade to fatter wire instead of using the existing 7-pin. However, I am not sure what that really means for connecting wires from where to what. I have read here that you should by-pass the truck battery and use the alternator connections. It is a 105a it seems, and it has a lug for the positive wire that goes via some sort of little box which is wired to the battery pos, and the alternator is marked GRD where it is bolted on to its bracket. I do get about one more DC volt by taking the voltage from the alternator's pos lug instead of the battery's.
I just can't understand what people are doing to get their reported 60 amps or whatever from using their alternators. What is the secret?
Thanks.
So far, I have been playing with my long jumper cables, 25 ft of #1 cu/al which have fairly low resistance. Results so far:
A. 7-pin. Gets 10 amps at first then tapers to about 6 amps within four minutes. Truck at idle 600 revs, going to 2000 revs makes little diff.
B. Jumper cables from truck battery to house batts. Gets about 20 amps at first then quickly tapers. Higher revs make little diff.
C. Using the long set of jumpers from truck battery to 2000w MSW inverter, to run a 35 amp (gets 33 amps max) Vector smart charger to the house batts. Gets 33 amps nice and steady, truck voltage holds at around 12.2 volts steady at 600 revs idle.
D. Same as C, but using adjustable voltage modified PowerMax PM3-55 converter. Runs ok, but where it gets 57 amps on shore power, on the MSW inverter on this long wire set, it gets about 50 amps. The truck has a hard time holding its own battery voltage at near 11.7 volts. Amps taper a little as truck starts losing the fight. At 49 amps, revving the truck to 2000 revs from 600 at idle did make a diff. Amps rose from 49 to 51 and truck voltage stopped sliding away.
So it looks like I can somehow run cables back to the truck camper to an inverter to run a charger, solving a few physical layout problems, and it will work, especially if I use the 35 amper. If I use the 55 amper, it will mean putting a brick on the gas pedal or something to hold the revs up for an hour instead of idling with no complications as with the 35 amper. Means 33 AH vs 50 AH for an hour of idling (batteries would be low so no tapering amps then)
Some time ago I used this method with the 35 amper and idled the truck for an hour no problems at all. That was working outside and not having the inverter and charger and wiring all inside so it could be done without going out in the dark and rain. (Which is likely to be the case, since otherwise the solar would keep up, and this charging from the truck would not be necessary :) )
So before I do some renos on the truck camper's set up for all this, is there an easier way to get those good amps from the truck to the house batts? (Where the amps won't taper like crazy from whatever they start out as. I get constant amps with the Vector or the PowerMax chargers, which is the big advantage of using them)
BTW, not related, but the Xantrex MSW inverter will not run the VEC1093DBD at all. It shows code OPP, which means incompatible device (that code is not in the owner's manual, I got that from tech support) It does run the Vector 1092A though. I wonder if the 1093DBD needs PSW. No matter, I can do 33 instead of 40 since I have one of each.
