Nickitoe
Posts: 2
Joined: Wed Jul 24, 2019 5:22 pm

Egolf Battery Warranty

If VW will replace a battery that goes below 70% total capacity (within 100k miles/8 years) , and we can expect around a 5% capacity loss per year, wouldn't they be replacing a ton of batteries? Has anyone actually warrantied a battery for having less than 70% capacity? Part of me thinks I could easily just go out of my way to always charge it to 100%, knowing this will degrade the battery faster, then just get a bran new one after a few years. I imagine a good number of people will unknowingly do things (like constantly charge to 100%) that will guaranty they'll ruin the battery before 100k or 8 years. Another part of me thinks I'm misunderstanding the battery warranty they offer.
manybees
Posts: 144
Joined: Sat Nov 17, 2018 5:08 pm
Location: Boston area, MA

Re: Egolf Battery Warranty

Where did you hear that the battery would lose 5% capacity per year?
2018 VW e-Golf SEL Premium (w/ DAP) - Silver White w/ black interior
Nickitoe
Posts: 2
Joined: Wed Jul 24, 2019 5:22 pm

Re: Egolf Battery Warranty

manybees wrote:Where did you hear that the battery would lose 5% capacity per year?
Anywhere between 1-5% per year is what I've been reading is to be expected. Now imagine I fast charged it every time, always charged it to 100%, and or let it get below 10%.
manybees
Posts: 144
Joined: Sat Nov 17, 2018 5:08 pm
Location: Boston area, MA

Re: Egolf Battery Warranty

Nickitoe wrote:
manybees wrote:Where did you hear that the battery would lose 5% capacity per year?
Anywhere between 1-5% per year is what I've been reading is to be expected. Now he imagine I fast charged it every time, always charged it to 100%, and or let it get below 10%.
We don’t have a large enough sample size to say for sure what will happen to the state of e-Golf’s battery pack over time, as we don’t really know how their BMS is managing the system over time, and we are not privy to any long-term, aggregated data. Anecdotally, I’ve heard some owners of 2015-2016 MY e-Golfs say they’ve noticed no degradation at all 3-4 years in, while others are seeing 1-2 percent degradation.

In any case, it’s nothing I personally will worry about. I’ll just drive and enjoy my car and roll with the punches if necessary somewhere down the road.

By the way, there are specific warnings in the owner’s manual about not doing frequent, back to back fast charging, so people who do so, do so at their own risk.
Last edited by manybees on Wed Jul 24, 2019 8:06 pm, edited 1 time in total.
2018 VW e-Golf SEL Premium (w/ DAP) - Silver White w/ black interior
f1geek
Posts: 1001
Joined: Fri Jan 23, 2015 1:18 pm
Location: SF Bay Area

Re: Egolf Battery Warranty

1. I believe that degradation is not linear, but is more likely hyperbolic ( from the data I’ve seen for Tesla packs), so while the initial loss rate may be high, the loss rate should decrease as time passes.

2. The e-Golf pack has both a top and bottom buffer, so 100% SoC is not equivalent to 4.2 Volts per cell, and you can’t fully discharge the pack, thus providing some protection.

3. Based on the names of some variables I have observed in OBDEleven, I believe the BMS is programmed to reduce the top and bottom buffers so that the net capacity can increase (at the expense of longevity) and help the pack to remain above 70% at the 8 year or 100,000 mile warranty limits.

4. I believe VW did heavy testing on the pack and has data (as well as the potential strategy in point #3) to give the company confidence in providing said warranty without needing to replace a significant proportion of e-Golf packs.

5. If the warranty is triggered, VW promises to NOT replace with a new pack, but with a pack at 70% net capacity.

6. Based on points 1 through 6, I believe the prudent owner will not deliberately abuse the pack as the chance of replacement with a new pack is low. Instead, accept that the pack will lose capacity, but probably no more more than 20 to 25% at the warranty mileage and time stipulations.
2017 e-Golf LE, Multi Coat White with Black Vegan Leather interior, purchased in early 2018
2015 e-Golf SEL leased for three years, returned in early 2018
Sparklebeard
Posts: 302
Joined: Wed Oct 03, 2018 10:45 am
Location: Bay Area, CA

Re: Egolf Battery Warranty

f1geek wrote:1. I believe that degradation is not linear, but is more likely hyperbolic ( from the data I’ve seen for Tesla packs), so while the initial loss rate may be high, the loss rate should decrease as time passes.

2. The e-Golf pack has both a top and bottom buffer, so 100% SoC is not equivalent to 4.2 Volts per cell, and you can’t fully discharge the pack, thus providing some protection.

3. Based on the names of some variables I have observed in OBDEleven, I believe the BMS is programmed to reduce the top and bottom buffers so that the net capacity can increase (at the expense of longevity) and help the pack to remain above 70% at the 8 year or 100,000 mile warranty limits.

4. I believe VW did heavy testing on the pack and has data (as well as the potential strategy in point #3) to give the company confidence in providing said warranty without needing to replace a significant proportion of e-Golf packs.

5. If the warranty is triggered, VW promises to NOT replace with a new pack, but with a pack at 70% net capacity.

6. Based on points 1 through 6, I believe the prudent owner will not deliberately abuse the pack as the chance of replacement with a new pack is low. Instead, accept that the pack will lose capacity, but probably no more more than 20 to 25% at the warranty mileage and time stipulations.
Would you mind sharing any of your OBDeleven findings? I've been tracking battery info via a spreadsheet for my vehicles in an attempt to figure out the data (because I love me some data). Would be mega interested to know some more
⚡️2016 e-Golf SEL in Deep Black Pearl⚡️ (The Handsome Boy 1.0)
⚡️2019 e-Golf SEL in Indium Gray ⚡️ (The Handsome Boy 1.1)
2016golfse
Posts: 258
Joined: Tue Jul 11, 2017 10:56 am

Re: Egolf Battery Warranty

Sparklebeard wrote:
f1geek wrote:1. I believe that degradation is not linear, but is more likely hyperbolic ( from the data I’ve seen for Tesla packs), so while the initial loss rate may be high, the loss rate should decrease as time passes.

2. The e-Golf pack has both a top and bottom buffer, so 100% SoC is not equivalent to 4.2 Volts per cell, and you can’t fully discharge the pack, thus providing some protection.

3. Based on the names of some variables I have observed in OBDEleven, I believe the BMS is programmed to reduce the top and bottom buffers so that the net capacity can increase (at the expense of longevity) and help the pack to remain above 70% at the 8 year or 100,000 mile warranty limits.

4. I believe VW did heavy testing on the pack and has data (as well as the potential strategy in point #3) to give the company confidence in providing said warranty without needing to replace a significant proportion of e-Golf packs.

5. If the warranty is triggered, VW promises to NOT replace with a new pack, but with a pack at 70% net capacity.

6. Based on points 1 through 6, I believe the prudent owner will not deliberately abuse the pack as the chance of replacement with a new pack is low. Instead, accept that the pack will lose capacity, but probably no more more than 20 to 25% at the warranty mileage and time stipulations.
Would you mind sharing any of your OBDeleven findings? I've been tracking battery info via a spreadsheet for my vehicles in an attempt to figure out the data (because I love me some data). Would be mega interested to know some more
Regarding point #3, refer to this post:

https://www.myvwegolf.com/forum/viewtop ... y&start=53
2021 Tesla Model 3 SR+, Pearl White Multi-Coat, Black interior, 18" aero wheels, no FSD
2019 e-Golf SE, Pure White w/ DAP and deAutoLED H7RC HID's (SOLD)
2016 e-Golf SE, Pure White w/ Ed's Golf R Replica HID's (SOLD)
Spektre
Posts: 137
Joined: Mon Jun 13, 2016 8:14 am

Re: Egolf Battery Warranty

f1geek wrote:1. I believe that degradation is not linear, but is more likely hyperbolic ( from the data I’ve seen for Tesla packs), so while the initial loss rate may be high, the loss rate should decrease as time passes.

2. The e-Golf pack has both a top and bottom buffer, so 100% SoC is not equivalent to 4.2 Volts per cell, and you can’t fully discharge the pack, thus providing some protection.

3. Based on the names of some variables I have observed in OBDEleven, I believe the BMS is programmed to reduce the top and bottom buffers so that the net capacity can increase (at the expense of longevity) and help the pack to remain above 70% at the 8 year or 100,000 mile warranty limits.

4. I believe VW did heavy testing on the pack and has data (as well as the potential strategy in point #3) to give the company confidence in providing said warranty without needing to replace a significant proportion of e-Golf packs.

5. If the warranty is triggered, VW promises to NOT replace with a new pack, but with a pack at 70% net capacity.

6. Based on points 1 through 6, I believe the prudent owner will not deliberately abuse the pack as the chance of replacement with a new pack is low. Instead, accept that the pack will lose capacity, but probably no more more than 20 to 25% at the warranty mileage and time stipulations.
f1, can you provide any sort of reference/evidence for point 5? This seems like an interpretation. Their warranty is very vague in this regard.
Hers: 2021 Tesla X Long Range Plus
His: 2015 eGolf SEL Premium
Lucky kid: 2019 Mazda CX-9 Touring
f1geek
Posts: 1001
Joined: Fri Jan 23, 2015 1:18 pm
Location: SF Bay Area

Re: Egolf Battery Warranty

For point 5, please read the battery warranty section in the warranty booklet included with the car. I haven’t read it recently, but I remember a statement about pack replacement with another pack having at least 70% net capacity. I suppose VW could be generous and provide a brand new pack, but per my memory of reading of the warranty, VW is not obligated.
2017 e-Golf LE, Multi Coat White with Black Vegan Leather interior, purchased in early 2018
2015 e-Golf SEL leased for three years, returned in early 2018
msvphoto
Posts: 196
Joined: Mon Nov 20, 2017 12:30 pm

Re: Egolf Battery Warranty

f1geek wrote:For point 5, please read the battery warranty section in the warranty booklet included with the car. I haven’t read it recently, but I remember a statement about pack replacement with another pack having at least 70% net capacity. I suppose VW could be generous and provide a brand new pack, but per my memory of reading of the warranty, VW is not obligated.
The bigger question is where would a replacement pack come from? It is highly unlikely VWofA will have used ones laying around (unless they purchase them from wrecked cars from Copart or the like...which by the way will likely be a good out of warranty source for battery packs). There may be (should be but who knows?) an inventory of replacements to accommodate the forecasted warranty replacement requirements.

Has anyone here had a battery replaced under warranty yet? (The one 2019 that appeared to die right away after nothing but DCFC doesn't count.)
2015 e-Golf SEL my wife's daily, shared on weekends
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1986 Audi 4000 quattro "the cockroach" my alternate daily
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