"Battery boost" question

Ivylog wrote:
Rarely do I disagree with Doug so here goes. Using the boost switch on a DP is like trying to jump a car with a cheap set of jumper cables. Will not start the car at first but after several minutes of putting some amps into the dead battery the combination has enough amps to start. Unfortunately the boost system on a DP is like a set of cheap cables as it can only supply less than 200amps which mainly goes into the dead batteries from the house batteries. Trying to start a minute later has done a quick charge on the dead batteries so now there is enough combined amps to turn the engine over. Doubt the OPs charger was more than 20 amps so even after an hour on two batteries that are 900+ amps each has not done much. I 'm actually surprised that it started after just one minute as the cables going to the bird are much smaller than the starter cables.
I have 00 welder jump cables that plug into the front of my truck(do not have to raise the hood) which can handle the 2000 amps from my two diesel truck batteries and rarely do I have to wait to start anything unlike the cables on a DPs boost circuit .

Sorry, I have had more than my share of DEAD/LOW chassis batteries on our service lot over the years. Just pushing and holding the battery boost for even 5 minutes is NOT going to transfer needed power to extremely low or dead chassis batteries. NOT GOING TO HAPPEN. You MUST have any type of external charging going thru the system. Either the Coach charging system or an external battery charger. YES, the battery boost SOLENOID and the cables usually going thru it are usually not large enough to get the needed current to the starter. I HAVE used jumper cables between the coach and chassis when they are close enough to start an engine when the battery boost would not, even tho the boost solenoid was operating. WE also have a battery boost cart that has 2 31 series chassis batteries and we keep it plugged in with a battery maintainer for a full charge and sometimes the chassis batteries are so dead, that even those 2 extra batteries will not start the engine until we get a small boost charge on the chassis batteries. It appears from my experience that completely DEAD 31 series batteries will actually pull any current into them before it can be pushed to the starter circuit. Once we get a short(30 minutes or less) small charge on the dead batteries the Start boost will then operate and the coach batteries will give enough power to start the engine. Doug

PS, There is a BIG difference between "theory" and what actually happens in the REAL world.