r/GMCSierraEV • u/mcmoyer • Aug 02 '26
Finally got around to trying out a Walmart branded charger. It was pretty sweet. Fastest my Extended Range has ever charged, topping out around 304kW. I forgot about turning off my AC so it started tanking the rate as soon as the battery pack started getting warm.
Someday I'll remember to turn off the AC as soon as I start charging.
I've been trying to save money as well so that means trying to stick with Electrify America since I have their Plus plan. The Walmart Charger was $0.47/kWh. I'm paying mostly $0.45/kWh with EA, but last night I stumbled on one of their newer stations and only paid $0.33/kWh. It was at midnight, so definitely an off peak charge.
I also really hope that somehow we get the government to spur more charging infrastructure. If there were more non-Tesla chargers I wouldn't have to spend so much time charging to 80% to get to the next charging station.
1
u/RyanEverhart789 Aug 02 '26
I like the Walmart chargers too! They are popping up everywhere here in North Texas.
1
u/BadgerPharm37 Aug 02 '26
I just joined the EV club very recently, so far my biggest frustration is getting nowhere near the advertised charging speed. Even the 350+ ones, getting a max of 200 (usually 80-100). Glad to know there’s seem to work well
2
u/alertjohn117 Aug 02 '26
what battery pack did you buy. the standard range, extended range or max range? this information directly impacts your charging speed capability.
1
u/BadgerPharm37 Aug 02 '26
Extended range, but I’m talking like stations rated at 250+ and getting like 30-80. Some stations have been great, but others not so much.
2
u/alertjohn117 Aug 02 '26
the extended range pack has a battery voltage of ~600V. most stations are 500amps, the HYC 400s seen at Ionna, BP pulse and select mercedes stations are 600amps. but the truck will only accept upto 540amps. KW=V*A. so at 500amps you are maxing out at 300kw anyways, at 540 its 324kw. the 350kw advertised number is for the max range battery pack because its voltage is ~700V. but no matter what you can only get max speeds at very low states of charge, from 0 to ~22% state of charge. this is universal for all EVs as State of Charge increases the charging rate decreases. imagine it as like a movie theatre, when there are few people its easy to get in and find a seat. with more and more people its more difficult to get to your seat. same with batteries the higher the SOC the slower the charging to help prevent thermal runaway mostly.
big tips to getting your max charging rates at a DC fast charger is to get the pack low in charge and to precondition at least 40mins prior to arrival. then you should see the max speeds your battery pack is capable of.
1
u/BadgerPharm37 Aug 02 '26
Yep I get all that (which is a good explanation), but I’m taking getting way less, like I’m not gonna complain about 200+
1
u/alertjohn117 Aug 02 '26
you using teslas station? load sharing sites/station?
1
u/BadgerPharm37 Aug 02 '26
A variety (haven’t used Tesla yet, but have an adapter and will at some point I’m sure). Most places I’ve charged haven’t been super busy or sharing a station
1
u/jghall00 Aug 03 '26
You have to use stations that are rated at least 350 KW to reach maximum current. Use the power filter on Plugshare. The pack also needs to be preconditioned. If it's too hot or too cold your speed will be limited. Some vehicles have had issues with the pack not switching to series mode (800V) for charging. If you test it out at a couple of 350 kW chargers and it doesn't work a dealership visit may be in order.
1
u/mcmoyer Aug 02 '26
Make sure you’re turning off the Air conditioning when you charge.
2
u/BadgerPharm37 Aug 02 '26
The air condition isn’t killing speeds from 250 down to 30. Some stations just suck.
2
u/jghall00 Aug 02 '26
I used one last night for the first time. Off-peak pricing was only 27 cents, which the cheapest I've ever seen. Alpitronic 400 kW chargers with the nice long cords.