Toad Battery Charger

We have a 2012 Honda CRV which we tow behind a 2004 Jayco Granite Ridge MH. Prior to a long trip we had asked to have a charge line installed between the MH and Honda as well as a toad charger. At the end of day 2 the Honda battery is dead. When we took it to another technician, the charge line is in and working but no toad charger.

So, what toad charger are you using, do you like it and why? We have another cross country trip planned and do not want a dead Honda battery.

Thanks and safe travels.