I run a 14-30 on a 30A breaker in my garage, and I’m wondering if installing a HPWC on that breaker would be overkill, or if it’ll improve my charging rate.
I don’t mind using the 240/14-30 receptacle, but i have a referral reward to cash in on and I already got my nephew the Radio Flyer, lol.
You're getting a lot of half-opinions. Since you have the referral award, it would be irrelevant for all those who are citing a $500 cost for a HPWC. Your HPWC would be free.
Now once you have your HPWC, you can either install it onto your 14-30 or even have it hard wired to the existing breaker and wiring. But that do much and won't be able to increase your charging rate. At best, you get a shorter cord to manage.
If you were going to hire an electrian to install it anyway (or perhaps willing to try it yourself,) then it may very well cost you $500-$1000 to get it installed. But if you did that, it would be the right time to get that wiring updated to handle more amperage. In this case, yes there will be cost involved; but you will also be getting an improved charge rate.
If you went that route, your 14-30 is most likely giving you a charge rate of ~20mi/hr. Depending on what car you have, you will either have a 48amp charger or 72amp enabled charger. This could be a 70% improvement (48amp = 34mi/hr) or a 160% improvement (72amp = 52mi/hr) of your charging rate. Whether or not that cost is worth it...that depends on your situation and needs.
PS. Keep in mind you could also sell the HPWC or the Radio Flyer and make some money too..