patrick_g
Elite Member
I suspect that being of above average intelligence the owner of the VERY NICE little dumper will not ordinarily start out with a discharged battery. If that is a reliable assumption then the solenoid/relay approach is the better choice by far.
In RV applications the diode isolator is typically better so that the users of the lights, heater fan, TV, etc don't run the vehicles starting battery down (you don't usually park overnight with the engine running.)
Normal ops with the dumper will work fine with a charge line significantly lighter in gauge than jumper cables. With jumper cables you could probably eliminate the dumper's battery. I still recommend 6 ga as able to handle enough current to help out a little (8 may be OK too and you will not have a self destruct mechanism at 10 ga but please use at least 8... multi strand of course) The 6 or 8 will be more than adequate for charging while driving from A to B and let the alternator and tractor batt help some during a lift.
You don't actually absolutely have to have the solenoid as there is no big penalty for just connecting the two batts in parallel with 6 or 8 ga wire. You will probably seperate the two and not leave the two batteries hooked up together all the time.
There is a small difference in final charging voltage between the normal starting batt and a deep cycle or maint free. For that reason the two batteries should not be left connected together when a batt maintainer (little wall wart I recommended) or other trickle charger is left connected for an extended period. For the times when the two are connected together and being worked and driven around there will be nothing to worry about regarding the different final charge voltage. I assume you won't be using the dumper for more than intermittent service for periods not to exceed 12-14 hours without a break!!!
Hope this has helped. If any of this is of further interest and not explained clearly, ask questions and I'll try to be more clear.
Oh, and one other thing... for completeness and to address some wrong info posted. Which ever batt is charged the most does NOT mean that it will supply all the power to run the system. The more fully charged batt will be discharged into the less charged and the result will be less power available than before the interconnection (batts are not 100% efficient.) In normal use (with the 8 or 6 ga interconnect) the batts will track each other in voltage quite closely, within a small fraction of a volt. A few feet of #6 can conduct MUCHO amps before it drops more than a couple tenths of a volt.
Reader's Digest version: When connecting the dumper to a tow vehicle, connect the tow vehicles 12 volt batt to the dumper's 12 volt bat (in parallel) using #6 or #8 multistrand wire for both positive and negative, avoiding using the hitch for a ground connection. Disconnect the interconnection when placing the dumper's deep cycle batt on a maintainer (wall wart.)
Pat
In RV applications the diode isolator is typically better so that the users of the lights, heater fan, TV, etc don't run the vehicles starting battery down (you don't usually park overnight with the engine running.)
Normal ops with the dumper will work fine with a charge line significantly lighter in gauge than jumper cables. With jumper cables you could probably eliminate the dumper's battery. I still recommend 6 ga as able to handle enough current to help out a little (8 may be OK too and you will not have a self destruct mechanism at 10 ga but please use at least 8... multi strand of course) The 6 or 8 will be more than adequate for charging while driving from A to B and let the alternator and tractor batt help some during a lift.
You don't actually absolutely have to have the solenoid as there is no big penalty for just connecting the two batts in parallel with 6 or 8 ga wire. You will probably seperate the two and not leave the two batteries hooked up together all the time.
There is a small difference in final charging voltage between the normal starting batt and a deep cycle or maint free. For that reason the two batteries should not be left connected together when a batt maintainer (little wall wart I recommended) or other trickle charger is left connected for an extended period. For the times when the two are connected together and being worked and driven around there will be nothing to worry about regarding the different final charge voltage. I assume you won't be using the dumper for more than intermittent service for periods not to exceed 12-14 hours without a break!!!
Hope this has helped. If any of this is of further interest and not explained clearly, ask questions and I'll try to be more clear.
Oh, and one other thing... for completeness and to address some wrong info posted. Which ever batt is charged the most does NOT mean that it will supply all the power to run the system. The more fully charged batt will be discharged into the less charged and the result will be less power available than before the interconnection (batts are not 100% efficient.) In normal use (with the 8 or 6 ga interconnect) the batts will track each other in voltage quite closely, within a small fraction of a volt. A few feet of #6 can conduct MUCHO amps before it drops more than a couple tenths of a volt.
Reader's Digest version: When connecting the dumper to a tow vehicle, connect the tow vehicles 12 volt batt to the dumper's 12 volt bat (in parallel) using #6 or #8 multistrand wire for both positive and negative, avoiding using the hitch for a ground connection. Disconnect the interconnection when placing the dumper's deep cycle batt on a maintainer (wall wart.)
Pat