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Drop-In Lithium Replacement Pack, Design Discussion
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The main problem IMO is biting off more than you can chew with no experience.
Leaping in and going all out for a cheap commercial drop in Lithium solution from day one.
Insisting again and again it can be done easily for a modest amount of cash.
That's just going to annoy those who know that is highly unlikely.
Your pack contacts might still be very useful, but slow the heck down.
Take the whole thing in stages and build up some real world experience for yourself.
The people on here with lots of knowledge didn't suddenly acquire it.
It's taken 5-10-15 even 20 years with these cars/electronics/lithium etc to get us where we are.
Certainly build your own lithium pack now based on the advice you have already received.
Look at what others have done and have a go at an install.
We will assist in and be very interested in a well documented conversion or budding commercial prototype.
Ironing out issues in a real world conversion of your own will put the problems / costs etc into proper perspective.
None of us want cars going off to the scrapheap because of dead packs.
As soon as you say the magic word commercial you open up a world of serious litigious pain and suffering.
There are lots of ways to monitor and fit packs that I might try/use in my own conversions, or even help people to try in theirs on here.
But I would certainly not suggest or use them in a commercial product.
If owners do their own home brew conversions based on forum knowledge some level of risk/bodging/cludging etc is acceptable. There are also minimal liability issues.
But as soon as you offer to fit/do commercial packs and conversions your liability insurance better be up to date and your lawyer on speed dial.
Commercial ramps up the technical construction standards and price to warp 9.
Maybe for now concentrate on getting some sample packs into your car for testing and evaluation.
Build up some hands on experience...
Leaping in and going all out for a cheap commercial drop in Lithium solution from day one.
Insisting again and again it can be done easily for a modest amount of cash.
That's just going to annoy those who know that is highly unlikely.
Your pack contacts might still be very useful, but slow the heck down.
Take the whole thing in stages and build up some real world experience for yourself.
The people on here with lots of knowledge didn't suddenly acquire it.
It's taken 5-10-15 even 20 years with these cars/electronics/lithium etc to get us where we are.
Certainly build your own lithium pack now based on the advice you have already received.
Look at what others have done and have a go at an install.
We will assist in and be very interested in a well documented conversion or budding commercial prototype.
Ironing out issues in a real world conversion of your own will put the problems / costs etc into proper perspective.
None of us want cars going off to the scrapheap because of dead packs.
As soon as you say the magic word commercial you open up a world of serious litigious pain and suffering.
There are lots of ways to monitor and fit packs that I might try/use in my own conversions, or even help people to try in theirs on here.
But I would certainly not suggest or use them in a commercial product.
If owners do their own home brew conversions based on forum knowledge some level of risk/bodging/cludging etc is acceptable. There are also minimal liability issues.
But as soon as you offer to fit/do commercial packs and conversions your liability insurance better be up to date and your lawyer on speed dial.
Commercial ramps up the technical construction standards and price to warp 9.
Maybe for now concentrate on getting some sample packs into your car for testing and evaluation.
Build up some hands on experience...
Yes, I need to change my mindset a bit more. In my work, I put together teams of experts from different fields to solve problems. I know enough technologies to coordinate the experts to develop practical solutions. Most of the time, I'm one of the technical team members, as well. In this case, I only have 12-yrs of working experience and sourcing various Li-ion chemistries, so I thought I might still be able to add a little value or maybe different view-points to a team of Gen-1 Insight Li-ion battery conversion experts; but mostly in Li-ion cells at wholesale prices. While my communications skills can always improve, I apologize if I gave everyone the impression that I believe it will be easy to build and sell millions of fully developed conversion kits, just like stuffing a brand new 11.5 L "Twin Six" V12 ICE into a 1961 Austin Mini as a simple drop-in at almost no cost.
My hope was to develop an affordable and a much more convenient conversion kit for someone to do the conversion themselves or they can hire someone else to do it for them. There will be a very clear statement that says these kits were developed by those who successfully converted their own Gen-1s to assist the DIY'ers, and there are NO guaranties and warranties. It's similar to the homebuilt aircraft industry where the aircraft designer has successfully flown his own design, and is now selling the plans and some of the difficult-to-build parts. The designer is not liable for the builder's mistakes or alterations, but the designer will do his best to assist the builder to avoid mishaps.
I'm used to working on multi-technology projects with multi-experts on one team. Everyone contribute their expertise to solve a complex problem. This Li-ion conversion requires knowledge in HEV control systems, communication between subsystems, Li-ion chemistries, BMSs, and integration. I'm guessing at least 90% of those who thought about doing a conversion gave up after learning the difficulties. Everyday we wait to become better and more knowledgeable, more Insights go into junkyards. I guess I'm most concerned with waste. Now, I don't wash and reuse aluminum foil, but it is very wasteful to let these very efficient HEVs end up in junkyards when it's only the battery pack needing replacement while the rest of the car is in good shape.
Some people want the newcomers to go through the same hardship as they did to learn to convert their vehicle with a new Li-ion power pack. That's not a good role-model if we wanted to encourage more people to do the Li-ion conversion to keep more Insights running. That's why I suggested all of us put our heads together to try to come up with a more convenient kit for the less-informed to convert to Li-ion. Of course, I need to do my own conversion first to better understand the challenges, but preferably using new LTO or LFP cells; and to earn that merit badge for some of you who only recognize scarred faces. Once I get my own little Insight running properly on a Li-ion pack, then I'll be able to write that Li-ion conversion primer with more authenticity, but minor4326 might beat me to it. I suppose everyone can add to it to help the next person who has the motivation, but no idea where to begin, in the shortest and quickest manner.
I'm big on giving credit where it's due, so I will not take credit for anything I didn't honestly achieve or accomplish, and I'm guessing you all feel the same way.
My hope was to develop an affordable and a much more convenient conversion kit for someone to do the conversion themselves or they can hire someone else to do it for them. There will be a very clear statement that says these kits were developed by those who successfully converted their own Gen-1s to assist the DIY'ers, and there are NO guaranties and warranties. It's similar to the homebuilt aircraft industry where the aircraft designer has successfully flown his own design, and is now selling the plans and some of the difficult-to-build parts. The designer is not liable for the builder's mistakes or alterations, but the designer will do his best to assist the builder to avoid mishaps.
I'm used to working on multi-technology projects with multi-experts on one team. Everyone contribute their expertise to solve a complex problem. This Li-ion conversion requires knowledge in HEV control systems, communication between subsystems, Li-ion chemistries, BMSs, and integration. I'm guessing at least 90% of those who thought about doing a conversion gave up after learning the difficulties. Everyday we wait to become better and more knowledgeable, more Insights go into junkyards. I guess I'm most concerned with waste. Now, I don't wash and reuse aluminum foil, but it is very wasteful to let these very efficient HEVs end up in junkyards when it's only the battery pack needing replacement while the rest of the car is in good shape.
Some people want the newcomers to go through the same hardship as they did to learn to convert their vehicle with a new Li-ion power pack. That's not a good role-model if we wanted to encourage more people to do the Li-ion conversion to keep more Insights running. That's why I suggested all of us put our heads together to try to come up with a more convenient kit for the less-informed to convert to Li-ion. Of course, I need to do my own conversion first to better understand the challenges, but preferably using new LTO or LFP cells; and to earn that merit badge for some of you who only recognize scarred faces. Once I get my own little Insight running properly on a Li-ion pack, then I'll be able to write that Li-ion conversion primer with more authenticity, but minor4326 might beat me to it. I suppose everyone can add to it to help the next person who has the motivation, but no idea where to begin, in the shortest and quickest manner.
I'm big on giving credit where it's due, so I will not take credit for anything I didn't honestly achieve or accomplish, and I'm guessing you all feel the same way.
Now you are starting to sound like a "politician".
I accept your rationalization.
I accept your rationalization.
Oh, below the belt (politician part). Just want to work with a gentlemen team. No cynicism, all professional, all transparent, all for fun and to safe the Insight (while not losing money).
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Let us know your ongoing pack plans before you commit to buying some cells.
You have all the info you need now in these various threads.
You have all the info you need now in these various threads.
Thanks @Olympia-WA but I've already written a basic draft which I've passed to another member for feedback.
I can get two 40s2p (2.9Ah cell) LTO packs for almost the same price as two 30s5p (2.5Ah cell) LFP packs. The LTO pack is good for 20,000 cycles and the LFP pack is good for around 5,000 cycles. So, I am thinking going with the LTO packs. Both chemistries can handle the 50A in and 85A out. The LTO will be less stressed. On the low voltage side, the LTO pack can go down to 120V, and the LFP pack can go down to 150V. On the high side, the LTO can go up to 216V and the LFP can go up to 192V. Your thoughts?
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Try the LTO.
Yes, and if you are doing it just for yourself, use the Fit packs from Greentech. They are far more cost effective than using new stuff.
There are two practical configurations space wise, a 60cell and a 72 cell.
The 60 cell has the advantage of being very simple electronically. Since the pack number is divisible by 10, you can do without the fooler. The need for the interceptor is debatable, but it will help control the slight issue with overvoltage. It will also provide a gateway to help better manage the pack, as you gain experience.
The 72 cell is a tight fit but achievable with a couple of layouts already tested. It provides a little more energy, but it definitely need both the fooler and the interceptor. My build thread points the way. I'd use the version 2 of the mounting plate, which stands the BCM and MCM on edge.
Good luck and have fun
There are two practical configurations space wise, a 60cell and a 72 cell.
The 60 cell has the advantage of being very simple electronically. Since the pack number is divisible by 10, you can do without the fooler. The need for the interceptor is debatable, but it will help control the slight issue with overvoltage. It will also provide a gateway to help better manage the pack, as you gain experience.
The 72 cell is a tight fit but achievable with a couple of layouts already tested. It provides a little more energy, but it definitely need both the fooler and the interceptor. My build thread points the way. I'd use the version 2 of the mounting plate, which stands the BCM and MCM on edge.
Good luck and have fun
Toshiba recommends 1.5-2.7V range for their LTO cells. Yinlong specs 1.5-2.9V for their LTO cells. 2.7V is the safest high end voltage if unsure of LTO cell source. Maybe the Chinese live on the edge more. Since we don't know when the FIT packs will get short on supply or have been abused, so I'm still leaning towards the new LTO cells; mainly for the future DIY'ers.
The Toshiba LTO 2.9Ah cells with a voltage range of 1.5-2.7V has a nom. cell 2.4V. Max charge rate is 65C, max discharge rate is 60C. At the vehicle's voltage range of 140-192V, the 140V would mean 94s on the low end, and 71s on the high end. So, 72s would have 194V at max and 108V at min.; which means it will never get fully discharged. The cost will be around $1000 for 72s2p. 960Wh pack. > 20,000 cycle life. I'll probably get more than 30,000 the way I nurse the car. Working Temp: -40℃~ 65℃ [-40°F ~ 149°F]. I'm in Olympia, WA, so the summer sun isn't very hot for very long. I plan to cover the rear deck with solar cells, so less direct solar heating and more solar fan cooling (batteries and cabin). In the winter, I'll use the solar cells to warm the batteries (and my seat).
With the above arrangement (2x36s2p), I should be able to hold-off on getting a BMS ($750) and just use Peter's Fooler. Peter?
Of course, I'll need to make sure all the cell voltages are equal and do manual balancing as necessary. Once this pack is working, then I'll get a BMS, which will make sure the pack stays within the 108 and 194V range, and do auto cell balancing. Once my professional revenue picks up again (and if COVID-19 doesn't get me), then I'll be able to buy/install Peter's other two systems.
Is driving around without the NMH pack bad for the ICE? My engine is starting to make more noises than before or is that the motor/generator grinding itself to pieces?. Thoughts?
The Toshiba LTO 2.9Ah cells with a voltage range of 1.5-2.7V has a nom. cell 2.4V. Max charge rate is 65C, max discharge rate is 60C. At the vehicle's voltage range of 140-192V, the 140V would mean 94s on the low end, and 71s on the high end. So, 72s would have 194V at max and 108V at min.; which means it will never get fully discharged. The cost will be around $1000 for 72s2p. 960Wh pack. > 20,000 cycle life. I'll probably get more than 30,000 the way I nurse the car. Working Temp: -40℃~ 65℃ [-40°F ~ 149°F]. I'm in Olympia, WA, so the summer sun isn't very hot for very long. I plan to cover the rear deck with solar cells, so less direct solar heating and more solar fan cooling (batteries and cabin). In the winter, I'll use the solar cells to warm the batteries (and my seat).
With the above arrangement (2x36s2p), I should be able to hold-off on getting a BMS ($750) and just use Peter's Fooler. Peter?
Of course, I'll need to make sure all the cell voltages are equal and do manual balancing as necessary. Once this pack is working, then I'll get a BMS, which will make sure the pack stays within the 108 and 194V range, and do auto cell balancing. Once my professional revenue picks up again (and if COVID-19 doesn't get me), then I'll be able to buy/install Peter's other two systems.
Is driving around without the NMH pack bad for the ICE? My engine is starting to make more noises than before or is that the motor/generator grinding itself to pieces?. Thoughts?
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For a first test you can just use a BCM fooler.
LTO has little capacity below 2V so that is really your bottom x 72 = 144V which is a quite good match for the car.
Peter - Can you post a simple diagram or sketch showing how your BCM Fooler should be wired to the Insight's wires or connectors? Also, can you point out the locations where the two 36s2p packs should be connected to the fuse that's mounted on the OEM's battery case? Thanks.
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14,379 Posts
I will do a video in the next week or so unless someone else answers first.
You won't get the package for at least a week or more anyway.
You won't get the package for at least a week or more anyway.
KOK Power (my cell supplier) will be laser welding the aluminum cell connectors onto the 2.9Ah LTO cell terminals similar to what's shown below. 2mm is the thickness of the connector plates. The 72 cells will weigh around 11 kg or 24-lbs.
![86155]()
Each cell is 63Wx97Lx14Tmm or 2.5"W x 3.8"L x 0.55"T. They won't fit the stock battery frame, but the open space is around 20"x14"x8" high. The 2 x 36s2p will occupy a space around 20"x10"x4" high, roughly.
At 85A current flow (15C) for 2-4 seconds each gear for 3-gears will not heat up the cells. So, air gaps between cells will not be needed. However, thermistors will be installed for the cooling fans, in any event.
I plan to have around 100W of solar panels in the rear deck. A separate set of thermistors in the new battery area to turn on the cooling fans when the ambient temperature exceeds 100F (38C). Otherwise, it will just charge and balance the pack. No charging more than 85% SOC. Need some room for regen. Any excess energy will operate new mini-fans to remove hot air in the cabin.
The reverse happens when ambient temp drops below 50F (10C). A heater will help to warm the battery space until it's up to around 70F (21C). Other times, it will warm the cabin to about 70F (21C) if power is available. During extreme cold nights/days, grid power will help to warm the ICE and the cabin. I've lived in -55F (-48C) regions for many years, so this should be easy.
This cell's datasheet is attached.
Each cell is 63Wx97Lx14Tmm or 2.5"W x 3.8"L x 0.55"T. They won't fit the stock battery frame, but the open space is around 20"x14"x8" high. The 2 x 36s2p will occupy a space around 20"x10"x4" high, roughly.
At 85A current flow (15C) for 2-4 seconds each gear for 3-gears will not heat up the cells. So, air gaps between cells will not be needed. However, thermistors will be installed for the cooling fans, in any event.
I plan to have around 100W of solar panels in the rear deck. A separate set of thermistors in the new battery area to turn on the cooling fans when the ambient temperature exceeds 100F (38C). Otherwise, it will just charge and balance the pack. No charging more than 85% SOC. Need some room for regen. Any excess energy will operate new mini-fans to remove hot air in the cabin.
The reverse happens when ambient temp drops below 50F (10C). A heater will help to warm the battery space until it's up to around 70F (21C). Other times, it will warm the cabin to about 70F (21C) if power is available. During extreme cold nights/days, grid power will help to warm the ICE and the cabin. I've lived in -55F (-48C) regions for many years, so this should be easy.
This cell's datasheet is attached.
Peter - any chance this BMS will work with the 2x36s2p LTO packs? If it has MOFSETs, then can you develop a "fooler" to compensate?
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155.0US $ |168s 12s 36s 48s 96s Li-ion Lipo Lifepo4 Lto Battery Management Bms Active Balance 200a 485 Can Communication Protection Board - Battery Accessories & Charger Accessories - AliExpress
Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com
Thanks very much for compiling all this information. It will save more Insights from the junkyard. I'm waiting for the BCM Fooler to arrive from Peter and the two LTO packs from KOK Power (China). From the brief review of your Guide, I will likely need to call you for some clarification once I get started. I'm guessing you used 3 FIT power packs (?).
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We know nothing about that linked BMS and it would require major software work and wiring effort. $$$$$Peter - any chance this BMS will work with the 2x36s2p LTO packs? If it has MOFSETs, then can you develop a "fooler" to compensate?
155.0US $ |168s 12s 36s 48s 96s Li-ion Lipo Lifepo4 Lto Battery Management Bms Active Balance 200a 485 Can Communication Protection Board - Battery Accessories & Charger Accessories - AliExpress
Smarter Shopping, Better Living! Aliexpress.com
The price on that link is $136 for 1 x 12S unit. (You would need 6 units with a multitude of interconnects, cables etc)
So that would would be $817. More expensive than the Orion2 price you got.
We can already talk to the Orion2 and are familiar with it. (I even have one sat on my bench.)
That's a much better choice for your 2x36S pack.
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@Olympia-WA you won't be able to design a newbie-friendly drop-in kit. What's going to stop you is the fact that many elements of the stock design have to be heavily modified.
Working the hand-built items I just mentioned takes a LOT of time and shouldn't be attempted by anyone with limited mechanical skill.
- Cooling fan replacement needed
- Usually IPU case gets cut up
- Junction Board usually requires a whole bunch of modifications
Working the hand-built items I just mentioned takes a LOT of time and shouldn't be attempted by anyone with limited mechanical skill.
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