Battery Upgrades are very possible

Daklein said:

Added pictures of the covers here: https://photos.app.goo.gl/tcVLm3SHCtozeLSa6

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Did you measure your clearance before and after battery swap? You definitely don't want to hit the battery on e.g. higher-than-usual speedbumps!

nlspace said:

Where would the heat come from--a stack of cold cells sitting all night?

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When you start driving, battery is heating up, don't you think? I'm not talking of getting warm air immediately - you don't have a choice except of turning AC in heat mode or use electric heater. But when you drive you can use heat from batteries, not just dissipate in the air, and stop using other heaters.

Andrey said:

nlspace said:

Where would the heat come from--a stack of cold cells sitting all night?

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When you start driving, battery is heating up, don't you think? I'm not talking of getting warm air immediately - you don't have a choice except of turning AC in heat mode or use electric heater. But when you drive you can use heat from batteries, not just dissipate in the air, and stop using other heaters.

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When the battery has excess heat, the odds are very good you don't need to heat the cabin. Almost no gain.

mux said:

I would HIGHLY DISCOURAGE blowing ambient air into the pack. Condensation will cause massive issues over time.

These battery packs are purged with super-dry air, often even just nitrogen/co2/argon to make sure that if temperatures drop, no moisture will condense inside the pack in inconvenient locations. This is an issue any time the battery comes close to the dew point, which can be any temperature under roughly 17C, depending on how much moisture is in the air inside the battery pack.

Once condensation forms, you can get rust on the compression frames, cause shorts or low resistance paths on contacts, etc. It's a major cause of battery fires in early EVs (although much less prevalent recently).

And you don't need to either. It's already a big help if you just mount a (fairly strong, it has to move air through tiny spaces) fan inside the battery enclosure, then reseal it and flush it with nitrogen or co2 and a bunch of silica gel packets. Circulating air inside the pack will even out temperature differences, which will even out the internal resistance of different cells and alleviate a lot of weak cell behavior.

We've been thinking about how to do a 'proper' thermal management system for the battery. Considering the battery already has heaters in most areas where the Leaf is sold, that part is easy. Cooling it is harder. It's probably inevitable that you would need to cut a large hole into the battery enclosure and weld/glue/bolt on a big extension piece that houses a heat exchanger and fan to cool the battery. Then add a separate controller for the heater pads inside the battery that doesn't suck balls. Not an easy mod to do, but the only way to do it properly.

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I don't recommend it either but where I am it's painfully dry with 15% to 50% humidity being normal. For the 20 or so wet days a year here I would have to have a way to seal the battery back up.
Or just leave it sealed and only hook it up to air conditioned air. I have a portable free standing air conditioner that could be used.
A closed system is ideal.

For the heaters I would just place stick on heaters on the outside under the pack with redundant temperature switches in the top of the pack that turnoff heaters at say 5 or 10 degrees C. Just simple, easy just sucks a little less than what the car already has. Wouldn't have to even open the battery case.
It's simple, quick, wouldn't have to take the battery appart and if I can the probably bad air circulation idea I can still do the heaters.

Needing more room for a cooling system take an empty 62kwh battery shell and refill it with 40kwh internals. I'm sure the 40kwh stuff won't just drop in to a 62kwh shell. But if it could be made to fit by relocating studs and brackets there would be lots of extra room.
No way I would ever have time to do it. Plus I dont think I could bring my self to butcher a perfectly good 62kwh battery.

If you could reprogram the BMS/LBC (or replace it with your own) for a more energy dense battery chemistry, then you could replace the batteries with something physically smaller, maintain or increase your capacity and have room for some form of cooling.

brunohill said:

If you could reprogram the BMS/LBC (or replace it with your own) for a more energy dense battery chemistry, then you could replace the batteries with something physically smaller, maintain or increase your capacity and have room for some form of cooling.

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Hmmm. So all you need to do is design and build your own BMS, assemble your own battery pack, and build a complementary battery cooling system. Ah, how many of us are likely to do those things in our garage (rather than buy a newer EV with more capacity)?

Dooglas said:

brunohill said:

If you could reprogram the BMS/LBC (or replace it with your own) for a more energy dense battery chemistry, then you could replace the batteries with something physically smaller, maintain or increase your capacity and have room for some form of cooling.

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Hmmm. So all you need to do is design and build your own BMS, assemble your own battery pack, and build a complementary battery cooling system. Ah, how many of us are likely to do those things in our garage (rather than buy a newer EV with more capacity)?

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Fenix power says they are going to.
:lol:

mux said:

I would HIGHLY DISCOURAGE blowing ambient air into the pack. Condensation will cause massive issues over time.

These battery packs are purged with super-dry air, often even just nitrogen/co2/argon to make sure that if temperatures drop, no moisture will condense inside the pack in inconvenient locations. This is an issue any time the battery comes close to the dew point, which can be any temperature under roughly 17C, depending on how much moisture is in the air inside the battery pack.

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Yeah, don't circulate outside air. Maybe just a fan to move air around inside to cool the air from the large surface area of the case.

When I opened my pack to replace the precharge resistor, https://www.mynissanleaf.com/viewtopic.php?f=30&t=28105&start=10#p568953, the weather was warm for late september in Michigan, and I didn't give much thought to humidity. I had to open the pack again about 2 weeks later to put in a proper precharge resistor, and I found condensation around the sealing flange, just inside the sealant on the lip of the lower case half. There was also some condensation tiny droplets on the underside of the top cover. I had take a fairly long trip on a warm day with multiple dcfcs, and then it got a bit cooler out overnight. I opened it the next day, a little water came out when I re-cut through the RTV sealant. The cells and the air had been warm, but the outer case would have been cool. I lowered the humidity where I was working to about 40%, as low as the dehumidifier could get it, and then I put in 1 pound of silica gel (contact adhesive attached to the case so it couldn't move around and chafe through the 2 packets)

For diy, I would pay attention to humidity and add desiccant for the volume of air inside, or purge the pack with dry air, if it's opened. Same for your car if you have it worked on by a small shop, there was someone on FB that had their pack opened in confusion looking for a HV interlock loop error. They just did it right in the garage bay, and humidity could have been a crapshoot, and I doubt a non-EV specialist shop would think about this.

See Prof Kelly's video on the Bolt battery pack resealing, smoke test and dry nitrogen purging.
https://youtu.be/VUvAW6skwrA?t=478 I wouldn't vote for using smoke to check for leaks, it must be some sort oil, which plugs up the pressure relief vents, so why would you want to get it in all the contactors. Careful if you pressure test for leleaks or to purge it. The cover has a large surface area and it oil-cans with pressure! 17:45 in that video, https://youtu.be/VUvAW6skwrA?t=1065 Whoa!

Andrey said:

Daklein said:

Added pictures of the covers here: https://photos.app.goo.gl/tcVLm3SHCtozeLSa6

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Did you measure your clearance before and after battery swap? You definitely don't want to hit the battery on e.g. higher-than-usual speedbumps!

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No, I didn't measure it before and after, beyond just taking pictures. We did talk about it as a family though, please pay close attention to high driveway entries, curb islands in parking lots, etc. Go diagonal as much as possible, go real slow, stop and back up if it starts to scrape. The covers take up an extra inch or so, they would scrape and deform a little first. I think my cowcatcher bar is strong enough that it would lift the car over a real obstacle.

In other battery upgrade news, today I completed my first QC at my favorite location. Thanks Nissan Tech Center!

It took a couple tries, not too much trouble, should be solved for anyone else now, that particular issue. Thanks mux and dala!
The code on the CAN bridge needed a change for the 62 pack, for those particular chargers. The charger's calculation of SOC, based on what the battery sends out, was off so it thought the battery was full at only 23% SOC. Other chargers nearby (only one tested so far) worked already.

Hyundai appears to be circulating cabin air through their hybrid battery.

That's the thing with water. You think something is sealed up well enough to keep water out, but only sealed up enough to not let it back out.

Today relative humidity is 14%. That's normal for winter.

I tried to search this thread, but apparently the words ''charging'' and ''charge'' are too common and the forum doesn't want to return a result.

I was just pondering, if we'd assume that the DC inlet, cabling etc is up to spec to receive more power than 50kW would it be possible to trick/hack the car to getting a higher charge rate if the charger can supply it? With a 50+ kWh pack the battery doesn't get stressed that much as it used to.

Oilpan4 said:

Hyundai appears to be circulating cabin air through their hybrid battery.

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True, many hybrid vehicles use smaller packs and it's nice (cost-wise) to have an air cooled pack inside the cabin. Batteries are comfortable in similar conditions as people, temperature wise. But they're designed have the air circulated through them. They could get condensation (some spring days where the vehicle & battery is cold from the previous time in the cold garage, and the outside air is now warm and moist), but it would not be on the terminals, wiring, controller, etc, it would be on the cooling channels and would shortly be removed by dehumidified cabin air. Some are high voltage like ~100V or less, but not usually 400V DC.

The eNV200 pack cooling duct that cools the rear bank of cells can be seen here: https://youtu.be/Oah-UB3d2_8?t=34 The video doesn't show much of the cooling heat exchanger and fan, but you can get the idea.

I am still curious why Nissan didn’t try to put at least a fan with the 62 pack. Admittedly, even running hundreds of miles on very hot days and fast charging didn’t hit an issue. I just don’t know yet whether it will lead to a faster battery decline.

DougWantsALeaf said:

I am still curious why Nissan didn’t try to put at least a fan with the 62 pack. Admittedly, even running hundreds of miles on very hot days and fast charging didn’t hit an issue. I just don’t know yet whether it will lead to a faster battery decline.

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It's so tight in there, it would require ducting to circulate it evenly, a little power to run the fan (maybe 40-100 watts based on what a squirrel cage blower on my woodstove can use), for benefit just some times. The bigger thermal mass of the batteries, and the better cells. I respect Nissan for keeping it simple, and not giving in to the 98th or whatever percentile use cases. The little 24kWhr battery with no cooling works great 95% of the time. Now I feel a little guilty dragging this heavy sled around, just to have enough range for some longer trips.

The van, with likely more extended daily driving use cases, apparently warranted the still minimal cost system; chilller in the a/c refrigerant circuit, fan & ducts inside the battery. Still avoids the likely higher cost of cooling plates to touch all the cells, plumbing and risk of leaks, extra cooling pumps, service procedures to fill the system without any air bubbles left, etc.

Hyundai runs 270v on their hybrid air cooled pack.

That's why it would have to be easy to seal back up air tight for rainy days.

As muxsan showed us Nissan can cool the pack. The NV-200 has liquid cooling and fans in it.
I always thought it looked liked the gen 1 pack had the modules packed in there loosely.
Turns out if the modules are packed in tight the back hump is free to house a heat exchanger and fans.

Oilpan4 said:

Hyundai appears to be circulating cabin air through their hybrid battery.

That's the thing with water. You think something is sealed up well enough to keep water out, but only sealed up enough to not let it back out.

Today relative humidity is 14%. That's normal for winter.

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Kia does the same thing. There is quite the difference between ambient air and forced air circulation. Even modest positive pressure is good. Granted Kia has a fan to help but its still cabin air. TBH; It would be the most helpful in Summer as many EVs do not have the cold weather fits that plagues TMS. Its heat and you would be pushing conditioned air thru the pack which is naturally lower in humidity anyway.

DougWantsALeaf said:

I am still curious why Nissan didn’t try to put at least a fan with the 62 pack. Admittedly, even running hundreds of miles on very hot days and fast charging didn’t hit an issue. I just don’t know yet whether it will lead to a faster battery decline.

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No room. It was already a challenge getting the 62 kwh pack to fit (this is why they were released late.) So adding more stuff w/o a complete redesign would not have happened. I am guessing they "could" have done it to the 40 kwh pack with the advanced cell design but felt that is was a different driving segment and I agree on that point.

Rodriguez said:

I tried to search this thread, but apparently the words ''charging'' and ''charge'' are too common and the forum doesn't want to return a result.

I was just pondering, if we'd assume that the DC inlet, cabling etc is up to spec to receive more power than 50kW would it be possible to trick/hack the car to getting a higher charge rate if the charger can supply it? With a 50+ kWh pack the battery doesn't get stressed that much as it used to.

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Ssshht, I've been doing this since last sunday and it's not going quite as planned yet, but don't blow my cover, I want to make a big video where it seems like everything just worked first try!

Haha I'll keep an eye on my YouTube feed.

DaveinOlyWA said:

DougWantsALeaf said:

I am still curious why Nissan didn’t try to put at least a fan with the 62 pack. Admittedly, even running hundreds of miles on very hot days and fast charging didn’t hit an issue. I just don’t know yet whether it will lead to a faster battery decline.

Click to expand...

No room. It was already a challenge getting the 62 kwh pack to fit (this is why they were released late.) So adding more stuff w/o a complete redesign would not have happened. I am guessing they "could" have done it to the 40 kwh pack with the advanced cell design but felt that is was a different driving segment and I agree on that point.

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You can't just put in a fan into the battery. Physics won't work.... Heat moves from hot to cold... To cool, you don't ADD cold, you take away heat and send it somewhere.

If you put a fan pumping outside air into the battery, there will be many instances where the outside air will be HOTTER than the battery, and the fan will actually heat the battery. Also, if the air is very cool outside, then the cold outside air of the fan will take away heat from the battery and freeze the battery, which is also NG.

A cooling fan needs to blow air (or fluid) that will ALWAYS be cooler than the battery, but will turn off if the battery is too cold.