Accessory Battery question

[rraquib]

Hey all, I have a 2020 EG-Go RXV with a Lithium pack. Since I got the cart I added a bunch of 12-volt accessories off of a voltage reducer (big power draw from a subwoofer). Since I have enough space under the seat, I was thinking of adding a second 12v 8ah lithium battery to power the accessories. Adding the battery is easy but I was hoping it could be charged off of the main 48v. Any thoughts and ideas?

Thanks.

[JohnnieB]

An 12V-8AH battery only stores a max of 96Wh, so tunes with heavy bass will deplete it quickly.

I suspect the amp feeding your subwoofer is greater than 100W, so the runtime will be less than hour for each 100W of amp power.

[rraquib]

Originally Posted by JohnnieB

An 12V-8AH battery only stores a max of 96Wh, so tunes with heavy bass will deplete it quickly.

I suspect the amp feeding your subwoofer is greater than 100W, so the runtime will be less than hour for each 100W of amp power.

I can go with a 20ah battery and I think that is more than sufficient. I would rather have the cart running than listening to music. Since the battery pack has built in bms, is it safe to have it charge with a dc to dc converter off of the main battery? I would add a relay in the charging circuit so the secondary is only charging while the main battery is being charged. TIA

[sigfla45]

I would just shoehorn in one of these and call it a day with a trickle charger. Odyssey PC1200 battery. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[JohnnieB]

Originally Posted by rraquib

I can go with a 20ah battery and I think that is more than sufficient. I would rather have the cart running than listening to music. Since the battery pack has built in bms, is it safe to have it charge with a dc to dc converter off of the main battery? I would add a relay in the charging circuit so the secondary is only charging while the main battery is being charged. TIA

It'd probably be better to ask this question in the Lithium EZGO forum.

I know you cannot successfully charge a 12V lead-acid accessory battery with a DC to DC converter because the voltage needed to charge a 12V lead-acid battery is considerably greater than the output of the DC to DC converter. (See attached chart fro Trojan Battery) What happens is the lead-acid battery is chronically undercharged and doesn't last long.

On the other hand, the charging process for a Li battery may be different and charging a 12v Li battery from a 12V source might work. Like I said, the guys over in the Lithium EZGO forum might know.