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Re: Traction battery going bad or something else?

Posted: Wed Dec 06, 2017 8:11 am
by Aerowhatt
RobbW wrote:Anyone know if replacing the main battery pack resets the warranty on the battery? Or do you only get the remaining life of the warranty?


As with most warranty replacements, or repairs you only get the remainder of your original warranty on the new traction battery.

Aerowhatt

Re: Traction battery going bad or something else?

Posted: Wed Dec 06, 2017 9:14 am
by Aerowhatt
kiev wrote: The i909 from icarsoft will do everything except programming also, and it is much less expensive--but i don't need another data-reader, i want all the functions so i can do cell smoothing on my own time...


Cell smoothing may also include charging to a higher voltage. But certainly it's main function is to enhance the balancing function. As you stated previously the balancer function has a very small power "bypass" making the amount of balancing per full charge pretty small. That's part of why I advocate frequent charges to 100% SOC (but that's another conversation).

You can increase the balancing function time per full charge without much in the way of equipment. What ends the charge while balancing is the highest cell(s) tripping whatever the high voltage limit on the BMS is. That's why a full charge to 100% on 8 amps of 120 volt AC will give you a longer more effective balance than a faster charge at higher power. The balancer bypass on the high cells is a larger percentage of the total amperage fed to the pack. So it takes longer to trip the end of charge and lower cells catch up more.

Taken a step further. With Canion you can see just what is going on with a charge cycle. So using it, you can use the power used by accessory drains to pull down the charge current to the main traction pack. Thereby significantly holding off the end of charge signal from the highest cells. The charger in the car can only produce a fixed amount of power based on what is supplied to it. By sending the right amount of this power to the DC converter to run lights and cabin fan etc. A single end of charge balancing cycle can be drastically extended by only providing to the traction pack for charging approximately what the balancers can bypass. This will provide a similar activity to whatever the voltage smoothing cycle is that the dealer can do with their programing equipment.

Aerowhatt

Re: Traction battery going bad or something else?

Posted: Wed Dec 06, 2017 8:22 pm
by kiev
The only way i can see for smoothing to be effective is to turn on all the balancers except for the lowest cell and try to bleed them down to the target value. This could be done at any SOC while the car is stationary and not charging.

If there were any charging currents greater than 0.1 Amps, then the cells would continue to be charged even with bleeders on.

Re: Traction battery going bad or something else?

Posted: Mon Dec 11, 2017 12:28 pm
by adam
RobbW wrote:Anyone know if replacing the main battery pack resets the warranty on the battery? Or do you only get the remaining life of the warranty?


I called today and the dealer don't know if the new battery pack is brand new or refurbished. He confirmed that the warranty period is not reset though.

Re: Traction battery going bad or something else?

Posted: Mon Dec 11, 2017 1:51 pm
by phb10186
adam wrote:
RobbW wrote:Anyone know if replacing the main battery pack resets the warranty on the battery? Or do you only get the remaining life of the warranty?


I called today and the dealer don't know if the new battery pack is brand new or refurbished. He confirmed that the warranty period is not reset though.


This question has come up before, and essentially, no warranty would be reset by a replacement part/ product, it's effective from the purchase date of the vehicle (all warranty terms are somewhat different, but it's almost always from the date of purchase/ delivery).

RE: whether the packs use recycled cells or not, that's also been debated, but who knows. It would certainly make sense on cost and environmental grounds to not dump the entire pack for one or two bad cells... They are going to need a couple of packs at the ready for dispatch at all times to cover failures in-warranty, but who knows what processes are happening behind the scenes, RE cell reuse to the point packs are made for dispatch. Seeing as there is no common source of used cells for our cars, I would assume some that pass specific test marks are reused, and those that are not are destroyed, but there would be no way to know that. It's as probable that they are all new, as it is that some are re-used... i'd like to know the answer to that question though.

Does the ah/h quoted on the recently replaced new pack on the other post equate to 88 brand new cells... anyone?

Lastly, does anyone know if there have been any other pack replacements for items other than bad cells - i.e. circuitry - I've always thought that one of the balancing boards could fairly easily get a dry joint and pack up...

Re: Traction battery going bad or something else?

Posted: Mon Dec 11, 2017 2:00 pm
by Don
It's only been a short time that we end users have had a way to measure capacity. I think most who have measured replacement packs are reporting 44 or 45 Ah - Who knows what the supposed 50 Ah packs actually measured when they were brand new?

I would *assume* that replacement packs are put together using used cells - Why would they even consider using brand new ones when more than half of the warranty is already expired and they only need the replacements to last another 4 years or so . . . . ???

One could even make the argument I think that a replacement made up of well tested cells with 10 or 15K miles on them might actually be less likely to fail than a brand new pack

Don

Re: Traction battery going bad or something else?

Posted: Mon Dec 11, 2017 9:37 pm
by kiev
i remember reading in the service manual that the old battery pack is flooded in a bath of salty water before being sent back--a safety measure for shipping. So i don't believe that any are remanufactured.

To get 50 A-Hrs from a new cell requires discharging to 2.75 volts after charging to 4.1. Mitsubishi doesn't let them discharge that low, so nobody will ever see a value that high.