[Kevin Cranick]

I am awaiting the build and delivery of an SE tomahawk sidecar. I have a 2017 Indian chief vintage. Currently I have a Kuryaken Road thunder and a small set of under glows attached directly to the battery. The sidecar will have a USB charger, Additional under glow lights and I’m considering another pair of Bluetooth speakers. Should I purchase and install an additional battery for the Sidecar support for the additional amp draws? If yes is it just a direct connect from battery to battery?

 

[K9F]

If you tour, do long haul trips or camp a second battery is a great idea but not 'necessary' for the extra items you have listed. I used to run a leisure battery in my Land Rover. Do NOT connect battery to battery directly in parallel. If one battery was to fail the other would be dragged down too. Both batteries ideally should be of the same make, same age and same ampere hour rating. What you need is a simple split charge system. This would allow you to use the secondary battery as a leisure battery when you wish to run small consumer items such as lights, a cool box etc. etc. even a small inverter when parked up without affecting or draining your primary battery or putting undue strain on your motorcycle charging system.

Do your research but here is a starter, whilst it is campervan oriented the principle of battery care, maintenance and charging is exactly the same when running two batteries, the split charging systems be they automatic relay operated or manual are quite small and with a sidecar you will have more room anyway:

Campervan Split Charging: A Helpful Illustrated Guide | VanLife Adventure