[retepsnikrep]

Great John. Thanks..

Do they need compression?

 

[mudder]

Do they need compression?

Honda (Panasonic?) certainly made an attempt to compress these cells, but it's not a legitimate attempt because the plastic spacers in between each cell are quite malleable. In short, I'm not sure, but if compression is required, then certainly not much is required. Fortunately, each module is already compressed as shipped. If these cells are removed from the OEM mechanical enclosure, then I'd recommend at lease some compression. In general prismatic lithium cells should be compressed.

The outer mechanical components (which compress the cells) weigh 2.4 pounds on the smaller pack.

With the outer mechanicals, the 12S pack weighs 9.8 pounds.
Without the outer mechanicals, the 12S pack weighs 7.4 pounds.

Update:
After forcing this pack back together, yes, these cells are under compression as designed and should probably remain compressed in use. Note that this is how they come, so no additional work is required (unless you want to make your own for funsies). Here's a video with my findings, which show that the cells have already expanded slightly after not being under compression for a couple hours:

youtu.be/oCbw8HsPylw

Note that the plastic spacers between each cell are only contacting half of each cell's sidewall... so the force isn't applied evenly. This allows air to flow between each cell. I trust that Panasonic crunched the numbers and determined the compression is sufficient, even though it's not uniformly applied.

 

[minor4326]

Outstanding presentation. two longs and a short = G

 

[mudder]

Outstanding presentation. two longs and a short = G

Thanks John! You're correct: --. is Morse Code for 'G'. TIL.

 

[mudder]

FYI: To answer questions proposed earlier in this thread, the linked LTC6804 project has a readily-available PCB:

Arduino BMS Shield - 12 Cell - Share Project - PCBWay

However, it would be a bit clunky in the G1, as it only works with 12S cells as designed... you'd need QTY4 Arduinos, but it would work in a pinch. Note this limitation is of the PCB design, not the LTC6804 (which technically supports thousands of cells in series, via its isoSPI protocol. I recommend the community look elsewhere for an existing BMS design that can handle 48S natively.

 

[mudder]

Final post for this pack for today:

youtu.be/B1uSyRkeZzs

Key takeaways:
-the resistor in each wire harness is 12k on all four packs. This is almost certainly an "I'm here" resistor. It is NOT a temperature sensor.
-It appears these packs have zero temperature sensors. For G1 retrofit a sensor can be added, but I find it odd that Honda doesn't include one in the G3 Insight.
-Every QTY4 packs yields batteries for QTY5 G1 insights.

 

[retepsnikrep]

What are the exact dimensions of a bare cell please including the height to the top of the terminal studs.

I am wondering if they are short enough to fit inside a gutted G1 battery case.

Thanks

 

[mudder]

What are the exact dimensions of a bare cell please including the height to the top of the terminal studs.

I am wondering if they are short enough to fit inside a gutted G1 battery case.

Thanks

I'll measure these dimensions in a couple hours.

Update:
Here's a drawing. I make no guarantees that this is accurate. However, I believe all important features are modeled.

 

[retepsnikrep]

Thanks. Very interesting.

Studying the pdf and the insight case it is clear you can fit either complete modules or individual cells in almost any orientation inside the stock (de-webbed) G1 IMA case!

That's a massive plus for ease of mounting and installation..

I wonder how much cooling they actually need?

Two rows of 25 bare cells is doable for a 50S max voltage pack x 4.15V = 208V

Fitting them in is only limited by your ingenuity in providing some mild compression.

 

[mudder]

Looks like I might be coring out an OEM IMA core. I keep telling Lauren there's a reason I keep all these old Insight parts . Any coring tips?

.............................

In regards to cooling, I doubt they need any in most climates... I charged and discharged a single cell all day and it never got more than 10 degF above room temperature... that's equivalent to continuously charging (or discharging) a 48S pack at 5200 watts... for over 12 hours without pause.

I guess certain climates (Arizona?) might benefit from a cooling fan, but the fact is these cells have an ESR well below 1 mOhm, so they just don't generate much heat. For reference, the OEM NiMH pack's ESR can exceed 500 mOhm.

The fact that Honda doesn't monitor battery temperature (directly at the cell, at least) suggests that they're only turning on the fans (in the G3 Insight) when ambient temperatures are high (e.g. outside temp, and/or exhaust air temp, etc). Since the G1 Insight can pull considerably less current than the G3's IMA system, I'd venture a guess that these cells will never self-heat when used in any G1 setup. The only cooling benefit is if the car itself is stored in an area with intense heat (e.g. Arizona).

 

[retepsnikrep]

I'm probably going to remove my cells from the modules based on your temperature/charging tests.
I'll repack them like proverbial sardines in a gutted OEM case as that saves a bit of weight and space!

I just used a big sharp fine tooth wood saw to cut out the OEM case supports.
They are so cheap a new 10 TPI saw is only about $5

Magnusson 11tpi Hardwood Panel Saw 18

Order online at Screwfix.com. Fine cut wood saw with triple-ground, hard-point teeth for maximum cutting speed and durability. Bi-material, soft-grip handle for comfort and control. Blade with sanding polish displaying a clear water-based lacquered coating. FREE next day delivery available, free...

www.screwfix.com

Take it slow and you can get a fairly neat cut.

I then smoothed it off with a palm electric sander and coarse paper.

Maybe check what will fit with intact supports before removing. You never know..

 

[retepsnikrep]

Hmm.. I've just been quoted $1450 US for shipping one set of these packs to the UK.
This would be in addition to the purchase cost of $380..

On arrival they would then be subject to UK VAT 20% etc and customs duty on the total.
I'll keep looking for quotes but I might be out of the game..

Four sets would cost me $2205 shipping..

 

[mmdepace]

Is there anything we could do state-side to help? I'm wondering if it is just volume to weight ratio causing an issue with the quotes.

 

[KLR3CYL]

Peter,
Have them shipped to Jue Motors and we will figure out the least expensive way to forward them to you.

Scott

 

[retepsnikrep]

Thanks for the offers. Let me work on it for a bit yet..

Hazmat (Lithium) is an issue as are the current worldwide shipping problems.

 

[sharpmj]

One way might be if someone could get them here in the states and repack them in USPS priority flat rate boxes and ship them to you. Cost would be for under $200.
Sorry this wouldn't work due to Hazmat issues.

 

[mudder]

I'm probably going to remove my cells from the modules based on your temperature/charging tests.
I'll repack them like proverbial sardines in a gutted OEM case as that saves a bit of weight and space!

Keep in mind you'll need new bus bars if you remove the tab spacers... the battery terminal studs will get closer.

In regards to shipping these, it's possible the shipping is less if you open up the large outer box and then ship the two smaller inner boxes. The internal boxes are also correctly labeled for shipping lithium batteries.

 

[mmdepace]

Received:
Tap min = 3.573V
Tap max = 3.576V.

Nearly all rest at 3.574V or 3.575V

 

[mmdepace]

My first day of playing - Determine this balancing plug part number, has ended without success. More attempts will be made on another day.

 

[mudder]

Fantastic news gang: These modules fit in the OEM G1 IMA battery enclosure WITHOUT MODIFICATION:

youtu.be/-Yw_aFtO9JE

What does this mean? 48S (200 volts) with room to spare... you could even fit 54S (232 volts) )in the OEM bay (if you have QTY3 18S modules). This is the DREAM SOLUTION for a low effort aftermarket lithium in the G1 insight.

I just bought a few more sets. Ha, I tried to buy the rest, but owner wasn't interested . OK, fine, we'll just buy them all as a community.