charging toad with invisibrake brake setup

I found another type error in my original post. Should read connected to the ground wire on one side and the brown tail lite on the other side

It took me twice to follow your modification but I like it. My only concern is with the size of the charging wire when in the "lights off mode". The current available could be a bit high for the wires IF the toad battery is low for some reason. The Invisibrake only taps about 2 Amps which is enough to keep things going.

I know this sounds strange but if you add an inline 12 volt bulb to the relay supply line you will have a safety factor built in. The bulb will shine if the battery is low and slowly dim out as the voltage gets higher. If the bulb is placed somewhere you can see it (mostly hidden of course) then you have a visual as well. I put a bulb between the battery banks on my last RV until I installed the trik-l-start. It worked for several months.

On Edit, you could fuse the relay source to match the wire capability or add a thermal breaker. If the fuse pops then you need to charge the toad battery via running or other charger.

Two items come to mind....

My Rule number one is never do anything to your truck systems as it is the way you get home.. Item number two is you will only get a truckle charge at the end of your long 12VDC small gauge wire coming from your truck start battery. This Will not do any serious charging of your trailer battery per say...

Nose your truck up to the trailer battery bank and connect up using jumper cables and run your truck for three or four hours would be a better way to get some charge into your battery...

Consider these deep cycle battery charging rules put out by Progressive Dynamics. They don't even list how long it tales just using 12.2VDC - it will take a few days to re-charge...

"Progressive Dynamics ran this test on the amount of time it took a PD9155 (55-amp) converter/charger set to three different output voltages to recharge a 125 AH (Amp Hour) battery after it was fully discharged to 10.5-volts.

14.4-VOLTS (Boost Mode) – Returned the battery to 90% of full charge in approximately 3-hours. The battery reached full charge in approximately 11 hours.

13.6-VOLTS (Normal Mode) – Required 40-hours to return the battery to 90% of full charge and 78-hours to reach full charge.

13.2-VOLTS (Storage Mode) – Required 60-hours to return the battery to 90% of full charge and 100-hours to reach full charge."


Roy Ken