I want an "always on" USB port(s)

[Biaviian]

Is my only or best option to do a direct connection to a single 12v battery so that it bypasses the switch? How much draw will hurt the battery? I am looking to run a Bluetooth speaker and potentially charge a phone, but only 2 hours max between cart charges.

EDIT: The dealer ran the power from a single battery to the headlights so I guess I should not use that battery for the USB ports or I should get a reducer and rewire the headlights.

[orangeman6]

You “probably” shouldn’t run anything off of one individual battery. To know how much extra strain you’re putting on that one battery, and therefore reducing the life of the whole pack, you’d need to know how much your accessories are drawing. But, again, it’s not the best way to do it.

I use the stereo in my cart quite a bit when I’m working in the garage. Turn the key to the accessory position, reducer comes on, stereo comes on. Two steps as opposed to one, but definitely not an issue.

[Biaviian]

Originally Posted by orangeman6

I use the stereo in my cart quite a bit when I’m working in the garage. Turn the key to the accessory position, reducer comes on, stereo comes on. Two steps as opposed to one, but definitely not an issue.

Will the cart drain the battery if it is as the on position? That was my concern. Do you have a reducer that you suggest?

[Denntt]

Agreed, pulling 12V from one battery reduces the life of the battery pack as a whole. Wiring a voltage reducer of 36V/48V to 12V to a relay on the accessory position of the keyswitch is the best bet as it will draw power equally across the entire battery pack, and only use the power when you 'call' for the power at the BT speaker or USB plug port, etc. using the accessory function of the keyswitch.

It is a fairly straightforward install, but would require additional purchase plus wiring & installation. Further, installing a fuse bank would also let you separate the electrical loads (lights, USB charger, BT Speaker, etc.) all of which are typically on a 12V circuit. You can find a reducer, relay and fuse bank at an online retailer.

[Biaviian]

Originally Posted by Denntt

It is a fairly straightforward install, but would require additional purchase plus wiring & installation. Further, installing a fuse bank would also let you separate the electrical loads (lights, USB charger, BT Speaker, etc.) all of which are typically on a 12V circuit. You can find a reducer, relay and fuse bank at an online retailer.

I have a 20 amp reducer coming Sunday. I like the idea of a fuse block.

[mgas]

Really? Lets look at the math. A typical Trojan 105 6V is basically rated at 225 AH over 20 hours. They say it will produce 250 AH if you discharge it over 100 hours. That's 2.5 amps for 100 hours. Say the 12V one is only 100 AH battery. That means it can produce 100 Amps for one hour, or 1 Amp for 100 hours. Your Bluetooth speaker probably draws a whopping 100 mAH or 0.1 Amps. Lets multiply that by 10 and say it really draws 1 full amp (no way but...). So if you play it for 2 hours between charges, you have used 2% of that battery. That's noise in the power world. If it bothers you, move the wire to a different battery once a year. I suspect the actual draw is closer to the 100mAH which means your 2 hour BS session will actually use 0.2%.

A simple multimeter inline with your USB port will tell what its drawing.

[Biaviian]

Originally Posted by mgas

Really?

No, it was a joke.

Sent from my Pixel 4 XL using Tapatalk

[mgas]

I'm sorry. That was really directed at the comment about reducing the life of the battery pack as a whole. I get people want to sell reducers, relays, etc. I also get people want to justify why they bought reducers, relays, etc. Hook your USB up to a convenient battery and enjoy your toy. If it worries you, move the wire once a year. The math should have more value than opinions and urban myths.

[Biaviian]

Originally Posted by mgas

I'm sorry. That was really directed at the comment about reducing the life of the battery pack as a whole.

I'm just trying to understand the best practices. It would be great to ask the questions without the snarkiness. Have a great day.

[orangeman6]

Originally Posted by mgas

I'm sorry. That was really directed at the comment about reducing the life of the battery pack as a whole. I get people want to sell reducers, relays, etc. I also get people want to justify why they bought reducers, relays, etc. Hook your USB up to a convenient battery and enjoy your toy. If it worries you, move the wire once a year. The math should have more value than opinions and urban myths.

Chill out. Without knowing which Bluetooth speaker he has you have no idea how much current it’s drawing. The myth is that all Bluetooth speakers are small and underpowered. Another myth is that the OP won’t find he wants some other 12v accessory sometime soon.