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LiFePo Warranty

Posted: Fri, 30 Jul 2010, 18:30
by polo-ev
It has been mentioned by a certain vendor that batteries purchased in a bulk buy arrangement have no warranty.
That is just not the case.
The manufacturers and/or vendors offer a 12 month (sometimes more) workmanship & materials quality guarantee.

I did some checking on some US lithium battery vendor web sites in regards to their warranties they offer & this is what I found. I could not find any LiFePo warranty info on Australian sites.

All were limited warranties that warranted that the battery is free of defects in workmanship & materials & were worded along these lines.

Company XYZ will have no obligation under this limited warranty in the event the battery is damaged or destroyed as a result of any of the following events:

1. improper battery installation
2. use without an appropriate Battery Management System (BMS)
3. improper installation of a BMS,
4. use of a BMS in a manner other than BMS manufacturer intent,
5. damage resulting from BMS failure,
6. damage or destruction by improper charging;
7. damage or destruction by over charging;
8. damage or destruction by over discharging;
9. damage to to use of an inappropriate charger

10. theft or physical damage;
11.improper maintenance or mishandling of the battery;
12.natural forces such as wind, lightning, hail, etc.;
13.any willful or negligent act;
14.penetration or opening of the battery case in any manner.

Let's look at 1 through 9 in the event of a battery failure, given the lack of technical information from the LiFePo factories.

These are the problems that I could see arising.

1. Who determines what a proper battery installation actually is? Is it the battery vendor, the EV builder, the battery manufacturer or the certifying engineer?

2. What is an appropriate BMS? Is it the one being sold by the battery vendor, one you designed & built yourself, one you bought from a competing battery vendor or one you bought from a third party BMS vendor? Who determines whether it is appropriate or not?

3. Who is going to inspect & determine whether a BMS is installed correctly or not? The battery vendor, the BMS vendor or a third party? What if you built it yourself & no-one else understands it?

4. There are so many BMS's including home built ones so this would be impossible to determine.

5. This one is fairly self explanatory but difficult to prove.

6. What constitutes 'improper charging' & who determines whether a battery has been improperly charged? The battery vendor, the charger manufacturer, the charger vendor or a third party? How are they going test for it & use what standards?

7. Who is going to determine whether a battery has been damaged by overcharging? The battery vendor, the charger manufacturer, the charger vendor or a third party? How are they going to test for it & use what standards?

8. Who is going to determine whether a battery has been damaged by over discharging? The battery vendor, the charger manufacturer, the charger vendor or a third party? How are they going to test for it & use what standards?

9. What is an inappropriate charger? Is it any charger that is not sold or recomended by the battery vendor? What if a charger manufacturer says a charger is suitable & the battery vendor says it is not?

10 through 14 are fairly obvious.

It seems to me that a warranty claim could be somewhat problematic to prove.
It really comes down to us, as end users of these batteries, to take care of the battery pack & keep the batteries within the manufacturers voltage & operating specifications.

LiFePo Warranty

Posted: Fri, 30 Jul 2010, 19:08
by EV2Go
polo-ev I would consider all those points quite valid, unless the warranty adressed each of those points specifically.

Any warranty expressed or implied is virtually useless if it leaves huge gaps for the vendor to step not wiggle out of.

While it is easy to visually inspect a battery on the outside to say it has no defects, how does one say with the same level of certainity that there isn't a fault waiting to happen on the inside that shows up under charging and you get accused of overcharging it?

Good points when purchasing batteries off ANY vendor, of ANY technology type.

LiFePo Warranty

Posted: Sat, 31 Jul 2010, 03:48
by mcudogs
If only we (consumer & supplier) were all honest, we wouldn't need these overly protective warranties.

The end result is that the warranty is biased towards the supplier because they write the warranty and have to protect themselves from the vexatious or dishonest consumer.

While this protects the supplier it does nothing towards giving the consumer any confidence that the supplier will not rip them off.

All that we can rely on in the end is personal experience, which we can pass on to others in this forum.

LiFePo Warranty

Posted: Sat, 31 Jul 2010, 05:07
by EV2Go
Hear where you are coming from, you almost need to have several problems that are handled well to have confidence in future purchases.

Which is kind of crazy that you need to have things go wrong to establish a trust, but humans are complex creatures.

LiFePo Warranty

Posted: Sun, 01 Aug 2010, 06:22
by zeva
Warranties on lithiums are a tricky thing indeed because they can so easily be damaged through misuse, and in the absence of visible/external damage it can be hard to know if a warranty claim is valid.

The cells from ThunderSky and Sky/CALB both seem to be very reliable, I believe I'm yet to see a single cell that's been DOA or died from "natural causes" yet! In fact 99% of LFP failures I've seen or heard about can be attributed to over-discharging or over-charging, which can both spell instant death to lithiums and are unequivocally "misuse" in the eyes of the manufacturer - which is why having a BMS to protect every cell against these conditions is so critical. Having batteries die is sad for everyone. Image

I think it's largely the responsibility of vendors to make sure purchasers are properly informed about how not to murder their cells, and to ensure that the customer has an appropriate BMS for them. A few months ago I added a link to this Lithium Care Guide to every battery listing on the EV Works webstore in the hope of informing buyers and reducing misuse - but can we assume people will actually read it!?

PS: Any suggestions for changes/additions to that care guide are most welcome!

LiFePo Warranty

Posted: Sun, 01 Aug 2010, 10:01
by antiscab
polo-ev wrote: Warranty.
It has been mentioned by a certain vendor that batteries purchased in a bulk buy arrangement have no warranty.
That is just not the case.
My bulk buy supplier offers a 3 year workmanship & materials quality guarantee.

I'm curious as to how you were planning on managing that?

all the warranties from lithium manufacturers I have seen have required the cell be shipped back for testing before a new one is sent out.

unfortunately the cost of shipping one cell is more than the value of the cell.

having the majority of the pack fail would make using the warrantee worthwhile, however, thats rather unlikely.

not to knock the bulk buy business model.
the failure rate being as low as it is, its pretty much worth the gamble, as long as you know what you are doing.

as has been stated before, most failures are not natural (the QC at the factory takes care of that now).

heres the results of abuse I have seen:
increased self discharge and reduced capacity tends to be the result of over discharge. hot spots during charging at the cells internal high resistance shorts are also a sign of overdischarge.

cells that won't go above 0.6v OCV tend to have been reversed (btw - if you charge them anyway, eventually they burn)

increased internal resistance and reduced capacity tends to be the result of overcharge. as is bulging and leaking cells.

I have been in the position of acting on the warranty offered by a local importer.

in my case the battery was returned (to the importer). turned out I had miswired so the charger wasn't actually charging, and my battery was fine.
Without that technical support way back in 2006, I would have thought the battery was DOA.

I have also bought cells from overseas (via EV Components at the time).
There were no failures in that pack, and i didn't really need a warranty since the DOA rate is so low.

basically the 10-15% is technical support.

as far as chargers go, the only thing you shouldn't do is float charge for hours on end.
so if using a lead acid charger, a timer takes care of that.

other than that, any BMS worth it salt will sort it out.

damage the result of BMS failure will show up as either overcharge (not shutting down the charger when a cell voltage heads north of 4v) or overdischarge (say for instance a shunt failing full on).

from a warranty perspective, failure as a result of BMS failure wouldn't really come into it as the overcharge/discharge conditions are already stated.

from a technical perspective, you would of course look at why the cell as allowed to be overcharged/discharged in the first place.

I have actually killed a cell before due to number 4 (in my case, overcharge).
I used a 0.5A power supply to balance out a set of cells.
since the modules can shunt more than that continuously i didn't bother giving the BMS control over the charger.
at some point one of the cell modules failed, the BMS master module flagged the error but couldn't shut down the charger.
so the cell overcharged.

so basically points 1 through 6 are points 7 and 8 reworded a few times.


LiFePo Warranty

Posted: Mon, 02 Aug 2010, 05:06
by polo-ev
My bulk buy supplier requires the same thing. A failed cell would need to be shipped back for testing but given the high QA of LiFePo cells these days, a manufacturing failure would seem to be very rare indeed.

The point I was trying to make was there is no difference, warranty wise, between a private bulk buy group or a battery vendor.

At the end of the day it is really up to us, the EV end users, to be careful with the charging & discharging levels, use but not abuse the lithium battery pack and read information like the Lithium Care guide & follow its suggestions.

LiFePo Warranty

Posted: Thu, 05 Aug 2010, 22:05
by roddilkes
All of what has been said is true.

However do consider that Australian vendors usually carry stock and are in a position to quickly assess if a warranty claim is valid. On these terms a replacement cell would usually be supplied (as I have done in the past) immediately.

This can't be done if the vendor is in no position to make some income.

Please excuse me Ian B. for pushing my case. My livelihood is on the line here.

LiFePo Warranty

Posted: Thu, 05 Aug 2010, 22:10
by roddilkes
PS I hope the warranty disclaimer is not copyright. I couldn't have put it better myself ;)