Originally Posted by sail2liv
How much help does tow vehicle battery give the battery in the trailer when it is connected? Some TV have place for second battery under hood....if that will help support the one in the trailer.....but TV would have to be connected....
Not as much as you would think. The construction of truck starting batteries is significantly different than a deep storage battery.
The truck battery has thin waffled surface plates to give up electrons easily in order to provide a LOT of power for a few minutes of starting; then recharge quickly. They are rated in Cold Cranking Amps (CCA).
Dual Purpose (Marine) batteries are usually installed as OEM and are a compromise between cost and performance as a house battery. They normally have their rating in CCA but also have an RC rating on it somewhere. This stands for Reserve Capacity in Minutes at a 25 amp load and is calculated differently than the Amp Hours of a Deep Storage battery which is the hours a battery can deliver a 20 amp load. To convert RC to AH for comparison, multiply RC by 0.4167 and the result is AH. So a 200 RC battery has the same battery capacity as a 83 AH storage battery.
The Deep Discharge (House) storage battery has thick solid plates with minimal surface waffling in order to pack as many electrons into the same battery volume as possible and release them at a low rate for a long time. They are rated in Amp Hours.
Since it is easier to give up electrons from the starting battery without the truck running, the trailer battery will be constantly trying to charge the truck battery.
Read the attached PDF and graph on the Peukert Effect. It shows how a storage battery's ability to deliver electrons at a given rate is reduced as that demand increases. If you ever plan on using an inverter, the high demand requires multiple batteries in order to keep the load on any one battery from exceeding the optimum discharge rate.
See the attached PDFs for more information and there is a great FAQ in that area of the forum.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
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