Dual battery setup

[XP 787]

Is it safe to use 2 battery tenders at the same time on each battery if the switch is set to the off position? 99 Speedster.

 

[BoLongo]

I would take a multimeter and see if you have continuity between the positive posts on the batteries. If there is no continuity you should be fine but if there is continuity I would not use both at the same time.

Both batteries will share the same ground.

 

[BoLongo]

You want to find out of the batteries are isolated with the switch off. If they are isolated (no continuity), you can charge both at the same time. If you have continuity, you can use one battery tender which should charge both at the same time.

 

[XP 787]

Ok thanks for the input

 

[BoLongo]

Also look to see if your battery tender has a desulfurizing mode. If it does; once a year, I would disconnect the battery and let it spend a couple of days on the battery tender. The desulfurizing mode will not work if it senses any load, so that is why you need to completely disconnect the battery to activate the desulfurizing mode.