Antiscab's NWH10 Prius plugin Lithium conversion

Post up a thread for your EV. Progress pics, description and assorted alliteration
T1 Terry
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by T1 Terry »

I'm guessing all these figures are for the NWH10, The XW20 only has a max traction voltage of around the 240vdc mark, but that's a bit all over the place with regen over shoot, I've seen 280vdc on the scan gauge when the old traction battery was on its last legs yet officially it is rated at 201vdc. I've also seen the regen at 148 amps for a short period until the battery voltage started to climb rapidly, that long down hill run from the top of the Lofty Ranges into Adelaide on the freeway always exceeds the traction battery capacity unless I trick the system into draining the traction battery very deeply by switching the electric only just before the down hill starts. I feel that if there was more headroom in the traction pack the regen would remain stronger for the whole decent, so the capacity would need to be more than the capacity of the traction battery of 6.5Ah but I understand only around 50% of that is normally available to protect the battery from early degradation.

My thinking was, the capacitor pack acting as the traction battery and a constant drain of 40 amps once the voltage exceeded (?) volts and that fed into the 40Ah aux LFP battery in the spare wheel well. If the LFP cells were swapped out for LTO cells, could they be charged faster? I can't imagine any of the lithium chemistry cells handling the 150 amps recharge, so something would need to act as an interface.

T1 Terry
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antiscab
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by antiscab »

T1 Terry wrote: Sun, 19 Apr 2020, 14:22 My thinking was, the capacitor pack acting as the traction battery and a constant drain of 40 amps once the voltage exceeded (?) volts and that fed into the 40Ah aux LFP battery in the spare wheel well. If the LFP cells were swapped out for LTO cells, could they be charged faster? I can't imagine any of the lithium chemistry cells handling the 150 amps recharge,
100Ah NCM cells could probably handle it

more updates on the upgrade:

test fitting revealed I had 30-40mm of room between the original battery management components, and the battery. Now I know where I will be fitting the zeva EVMS:
IMAG1470.jpg
IMAG1470.jpg (499.64 KiB) Viewed 627 times
I didn't like how the batteries were restrained in the front/backward direction by the terminals. some 10mm polycarb roofing material used as spacers did the trick:
IMAG1472.jpg
IMAG1472.jpg (490.27 KiB) Viewed 627 times
Matt
2017 Renault zoe - 25'000km
2007 vectrix - 156'000km
1998 prius - needs Batt
1999 Prius - needs batt
2000 prius - has 200 x headway 38120 cells
Matthew100
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by Matthew100 »

How is the system performing now? What's the fuel /kwh consumption like?

I'm in Perth looking to add 20ah 98s LTO cells in my gen2 Prius.
antiscab
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by antiscab »

I still haven't got it going, too many other projects sadly.

Tbh, I don't think it will do any better than the last one I built in terms of energy efficiency. And the rego is nearly due.
Matt
2017 Renault zoe - 25'000km
2007 vectrix - 156'000km
1998 prius - needs Batt
1999 Prius - needs batt
2000 prius - has 200 x headway 38120 cells
antiscab
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by antiscab »

The gen 2 would probably do better, does yours have the ev button?
Matt
2017 Renault zoe - 25'000km
2007 vectrix - 156'000km
1998 prius - needs Batt
1999 Prius - needs batt
2000 prius - has 200 x headway 38120 cells
Matthew100
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by Matthew100 »

antiscab wrote: Sat, 10 Oct 2020, 08:02 The gen 2 would probably do better, does yours have the ev button?
It sure does.
antiscab wrote: Fri, 17 Apr 2020, 22:02
By using two current shunts, (a 75mv 200A and a 75mv 100A) only 1/3rd of the current should go through the original battery ecu current sensor, meaning the original battery guage should be rescaled to 19.5Ah
I really liked this idea about modifying the shunt to fool the battery computer. The LTO will have about a third to a quarter of the internal resistance, so the volt drop it would normally see at those currents would line up well. Plus being able to use that extra capacity without confusing it too much. It should look alot more like the stock battery to the computer.

I am still looking to find something to intercept the can bus signals to modify the perceived state of charge.

What are your current challenges with the build?
antiscab
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by antiscab »

oh, so you're doing similar to me, replacing the original battery with a lithium one

sadly my one uses an obscure communication language called OBD-M or multiplexed OBD, so man in the middle adjustments for me

my main issue is how to the car from over charging, or overdischarging individual cells.

That, and the temp inside the battery I think will get too high, when the car is just parked in the sun with all the windows up
Matt
2017 Renault zoe - 25'000km
2007 vectrix - 156'000km
1998 prius - needs Batt
1999 Prius - needs batt
2000 prius - has 200 x headway 38120 cells
T1 Terry
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by T1 Terry »

Matthew100 wrote: Sat, 10 Oct 2020, 09:34
antiscab wrote: Sat, 10 Oct 2020, 08:02 The gen 2 would probably do better, does yours have the ev button?
It sure does.
antiscab wrote: Fri, 17 Apr 2020, 22:02
By using two current shunts, (a 75mv 200A and a 75mv 100A) only 1/3rd of the current should go through the original battery ecu current sensor, meaning the original battery guage should be rescaled to 19.5Ah
I really liked this idea about modifying the shunt to fool the battery computer. The LTO will have about a third to a quarter of the internal resistance, so the volt drop it would normally see at those currents would line up well. Plus being able to use that extra capacity without confusing it too much. It should look alot more like the stock battery to the computer.

I am still looking to find something to intercept the can bus signals to modify the perceived state of charge.

What are your current challenges with the build?
20 Ah v 6.5 Ah, interesting ..... maybe the control system from one of the add on battery kits that were around for yrs, I have one in my 2006 Prius that I bought from Jason. The problem is that only stops the contactors linking the 2 batteries when it senses a cell is low voltage or the combined pack voltage is too low.
I thought about the same thing, simply using the existing Prius BMS set up that monitors 12 Nickle metal hydride with a nominal voltage of 14.4v, 28 modules for a nominal 201.6v. Add this to a quality BMS that can monitor the voltage of all cells and balance as required.
The is a bloke of the Prius Chat forum (something or other toaster) that sells a drop in traction pack replacement that uses a different chemistry tubular cell pack and makes up a different cell harness to plug into the Prius battery computer. Might be worth looking at the cell voltages he uses and see if that can be adapted. I think Suziauto (sorry if I spelt that wrong) here on this forum also sells a similar pack.
There is a hall effect sensor in the original traction battery pack and it seems to use a combination of the battery computer that senses the module voltages and the coulomb count to set the display regarding battery state, not actually what has gone in or out. When the traction pack starts to fail the green bars just come up faster and drop off very quickly compared to a pack in good condition.

T1 Terry
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antiscab
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by antiscab »

I'm connecting the original prius BMS to every 5th LiFePO4 cell, which should have the same voltage range. I think partly what did my first attempt in, was I was continuously updating the SOC in the BCU to 100%, so it didn't stop discharging in time.

Doing this new setup with the shunt divider was to move away from driving with a laptop that was constantly updating the BCU SOC.

My problem, is at the moment, the battery that I have in the prius I think I would prefer to be in my focus, and I've lost motivation
Matt
2017 Renault zoe - 25'000km
2007 vectrix - 156'000km
1998 prius - needs Batt
1999 Prius - needs batt
2000 prius - has 200 x headway 38120 cells
T1 Terry
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by T1 Terry »

Sorry if this is dragging your thread off topic Matt, feel free to delete it or move it if you want.
Looking further into Mathew's post, apparently the LTO cells can handle a lot more current in both directions that the lithium ferrous cells.... or have I got that wrong?
The Gen 2 samples at every second module, so 14.4v nominal, the nominal voltage of an LTO cell is 2.4v so every 6 cells would give the same voltage reading. Top end voltage for the 2 Prius modules is around the 17v mark so the 6 LTO cells would suffer 2.8v per cell, not sure how well they would handle that on a regular basis, a low voltage cut of 2.14v and that looks to be within the LTO safe window.
6 x 14 = 84 cell groups in parallel, not cheap if the intention is to convert the Gen 2 Prius to electric drive, but certainly interesting .....

T1 Terry
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Matthew100
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by Matthew100 »

antiscab wrote: Sat, 10 Oct 2020, 12:38 sadly my one uses an obscure communication language called OBD-M or multiplexed OBD, so man in the middle adjustments for me

my main issue is how to the car from over charging, or overdischarging individual cells.
I was looking at orion bms with the simulated virtual battery function to take care of soc. let it spoof high SOC until the pack got low than it is set to maintain that level of charge.
http://www.orionbms.com/manuals/utility ... rofile.png

But they are so expensive, I would only consider second hand. same with my batteries i'm trying to repurpose stuff before buying new. I even got an entire 1kw solar system- panels, inverter, etc second hand for $200 to recharge the batteries in the car. An arduino and a can bus shield might get ok results too to automate the process. I know what it is like driving and data logging with a laptop.

The cells I was looking at were the scib 20ah 2.3v LTO. https://www.scib.jp/en/product/cell.htm
I saw pallets of them for a really good price but I may struggle to import them.
T1 Terry wrote: Mon, 12 Oct 2020, 09:07 LTO cell is 2.4v so every 6 cells would give the same voltage reading
With this flavour of LTO you would want 7 not 6. Between 2.5v-2v is where most of the energy is anyway and leaves a nice safety buffer. That's still 16.5ah usable per cell. or about 3700 watt hours ( 98s1p config) compared to the 500watt hours usable range of the nimh oem battery. Realistically tho, most of that isn't going to be used. without a dedicated bms to take advantage of all that extra energy. BUT that's not to say it doesn't have merit, They will outlast the car. They are good for 25 years. Plus that 98s1p configuration has a power output rating of 117KW watts as opposed to the oem batteries 36KW.
antiscab
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by antiscab »

I have an Orion BMS in my shed if you're interested
Matt
2017 Renault zoe - 25'000km
2007 vectrix - 156'000km
1998 prius - needs Batt
1999 Prius - needs batt
2000 prius - has 200 x headway 38120 cells
Matthew100
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by Matthew100 »

antiscab wrote: Thu, 15 Oct 2020, 19:16 I have an Orion BMS in my shed if you're interested
I'll send you a message :)
T1 Terry
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Re: Antiscab's NWH10 Prius plugin Lithium conversion

Post by T1 Terry »

Matthew100 wrote: Thu, 15 Oct 2020, 17:48
antiscab wrote: Sat, 10 Oct 2020, 12:38 sadly my one uses an obscure communication language called OBD-M or multiplexed OBD, so man in the middle adjustments for me

my main issue is how to the car from over charging, or overdischarging individual cells.
I was looking at orion bms with the simulated virtual battery function to take care of soc. let it spoof high SOC until the pack got low than it is set to maintain that level of charge.
http://www.orionbms.com/manuals/utility ... rofile.png

But they are so expensive, I would only consider second hand. same with my batteries i'm trying to repurpose stuff before buying new. I even got an entire 1kw solar system- panels, inverter, etc second hand for $200 to recharge the batteries in the car. An arduino and a can bus shield might get ok results too to automate the process. I know what it is like driving and data logging with a laptop.

The cells I was looking at were the scib 20ah 2.3v LTO. https://www.scib.jp/en/product/cell.htm
I saw pallets of them for a really good price but I may struggle to import them.
T1 Terry wrote: Mon, 12 Oct 2020, 09:07 LTO cell is 2.4v so every 6 cells would give the same voltage reading
With this flavour of LTO you would want 7 not 6. Between 2.5v-2v is where most of the energy is anyway and leaves a nice safety buffer. That's still 16.5ah usable per cell. or about 3700 watt hours ( 98s1p config) compared to the 500watt hours usable range of the nimh oem battery. Realistically tho, most of that isn't going to be used. without a dedicated bms to take advantage of all that extra energy. BUT that's not to say it doesn't have merit, They will outlast the car. They are good for 25 years. Plus that 98s1p configuration has a power output rating of 117KW watts as opposed to the oem batteries 36KW.
You would need to limit the upper cell voltages if using 7 cells rather than 6, so they would never fully charge, how do you know what capacity the cell is actually at? Or do LTO cells behave differently to LYP cells? The only time voltage means anything in an LYP/LFP cell is at 100% SOC and drained, the voltage anywhere in between doesn't really reflect SOC.

Next question, how do you plan to get around the 80km/h speed restriction when driving on electric only?

T1 Terry
Green but want to learn
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