Trucks 12 volt power lead to trailer battery
How many amps can I expect to recover during a 8 hour drive. Say I use 30 amps per night boondocking and then hit the road again. I have a 150 amp alt. I have 2 twelve volt deep cycle batteries. The o...
Forum Discussion
RoyB wrote:
Some folks have beefed up the truck start battery lead back to the 7-way trailer connector to get more DC amps back to the trailer...
It is not that simple any more ! About 10-15 years ago, most auto manufactures went to "smart" charging systems. The short version of this, you are likely to have insufficient voltage at your TT batteries to completely recharge them. They probably will not discharge further, but don't expect them to be "topped off".
With lead acid batteries you need greater than 13.2V AT THE BATTERY for it to charge. The ECM will want to keep the voltage at 13-14V (the voltage immediately after you start the engine will be higher, but it will drop withing a few minutes) and after the voltage drop through the wiring to the TT battery you will be lucky to get that 13.2V !
Expecting your vehicle charging system to do most of the bulk charging after using your inverter to make your morning coffee and toast your bagel, even after 8 hours on the road, is going to leave you disappointed.
There are some DC-DC chargers out there, but make sure that they will work down to about 10V. For best results, make sure it does a 3 stage charge.
