1. Attachments are working again! Check out this thread for more details and to report any other bugs.

'06 Prius battery upgrade to LTO 55Ah cells

Discussion in 'Gen 2 Prius Accessories & Modifications' started by T1 Terry, Jul 24, 2022.

  1. jakester21

    jakester21 Junior Member

    Joined:
    Aug 1, 2018
    35
    4
    0
    Location:
    usa
    Vehicle:
    2005 Prius
    Model:
    Two
    i cant wait till you test them can they charge below 32F?
     
    Isaac Zachary likes this.
  2. Isaac Zachary

    Isaac Zachary Senior Member

    Joined:
    Jan 20, 2018
    1,648
    798
    1
    Location:
    USA
    Vehicle:
    Other Hybrid
    Model:
    N/A
    I'm glad your experiments keep on going!

    Now, not for a Prius, but I am interested in a battery that's not big and bulky (so small and portable, like wallet sized or so) that is also freeze proof. Sorry for the derailment, but I'm just trying to figure out a good option.
     
  3. T1 Terry

    T1 Terry Active Member

    Joined:
    Jan 4, 2015
    584
    296
    0
    Vehicle:
    2006 Prius
    Model:
    Plug-in Advanced
    Charging appears to be limited to -10*C but discharge to -30*C, but that is not verified by lab testing and are from a well known chinese reseller of similar capacity and dimension cells ... but they also have a poor reputation for selling seconds and even factory reject stuff, so I don't have a lot of faith in anything I read on their listings regarding the accuracy of any specs, actually, I don't trust any specs I haven't personally verified .....
    As for -35*F, Google says that's around -38*C .... I don't thing our deep freeze goes that low, surely nothing lives in that sort of cold, surely it's kept warm inside or something?

    T1 Terry
     
  4. T1 Terry

    T1 Terry Active Member

    Joined:
    Jan 4, 2015
    584
    296
    0
    Vehicle:
    2006 Prius
    Model:
    Plug-in Advanced
    Define "freeze proof"? Water freezes at 0*C or 32*F .... it's a lot warmer than that I deem to be freezing cold, like anything below 10*C :lol: but then hot over here is anything above 45*C or 113*F ... so we live in a heat sensitive climate, not likely to see below b-10*C anywhere in Australia really ....

    T1 Terry
     
  5. Isaac Zachary

    Isaac Zachary Senior Member

    Joined:
    Jan 20, 2018
    1,648
    798
    1
    Location:
    USA
    Vehicle:
    Other Hybrid
    Model:
    N/A
    It's been under 0 °C / 32 °F for the past month with it dipping down to -12 °C / 10 °F. And it's only going to get colder. I was looking for a good battery for QRP operations in the winter. The Yinlong look good, but also look too big. I found these and they seem like a good option: LiFePO4 26650 Rechargeable Cell: 3.3V 2560 mAh, 50A Rate, 8.25Wh, ANR26650M1B (batteryspace.com)
     
  6. T1 Terry

    T1 Terry Active Member

    Joined:
    Jan 4, 2015
    584
    296
    0
    Vehicle:
    2006 Prius
    Model:
    Plug-in Advanced
    The data sheets don't all match the tech specs and there is no chart for cell operation at low temp, the lowest appears to be 23*C, but worth a try I guess ... no idea what QRP stands for, but as long as the 2.5Ah capacity with an end voltage of 2vdc will power what you need, then it looks as though they would do the job as far as low temp goes

    T1 Terry
     
    Isaac Zachary likes this.
  7. jakester21

    jakester21 Junior Member

    Joined:
    Aug 1, 2018
    35
    4
    0
    Location:
    usa
    Vehicle:
    2005 Prius
    Model:
    Two
    im thinking of getting my sodium batteries here looks really good im going to put 6 of them together in series for about 12v fully charged and 6v discharged per group of cells so the prius computer should except them. they are going to be a bit big so they will not fit in the original battery box

    ps they said they can charge at -4F and discharge at 140Amps and charge at 84amps so it should be fine for a prius

    im kinda worried about the 45c high temperatures rating but they say it is 98% efficient so there is less heat than lithium ion

    50,000 CYCLE BATTERY! 12v Sodium Ion 5.6Ah 25C 140A – Jag35

    this is the company that makes them
    Product - Natron
     
  8. T1 Terry

    T1 Terry Active Member

    Joined:
    Jan 4, 2015
    584
    296
    0
    Vehicle:
    2006 Prius
    Model:
    Plug-in Advanced
    Odd cell voltages for sodium ion, all that I've look into run at a very similar voltage range as LFP/LYP cells.

    The heating during charging and discharging is tied to the voltage at the max charging and discharging the cell will experience ... if the charging is faster than the ion intercalation into the negative graphite coating, the voltage climbs, if the load is greater than the ion release from the graphite, the voltage drops ..... the more abuse the cell suffers, the more extreme the heating/cooling cycle within the cell, the more elements within the electrolyte break down and coat the surface of the negative plate graphite coating, resulting is slower ion movement in and out of the graphite .... the death spiral.

    With LFP/LYP cells, keeping the cell terminal voltages above 2.5v and below 3.8v at all times, including charging and discharging, will not cause the electrolyte to heat and retain the C rating for the life of the cell .... yet to see just how long that is, 13 yrs and still retaining 100% of the advertised capacity under a 0.5C load, so far, so the 10 yr myth is certainly dead and buried, yet to fully understand just what a cycle is regarding to the LFP/LYP chemistry goes.

    Sodium ion is a whole new minefield, so many electrolyte and negative plate coating combinations ... and none of the true cell manufacturers are saying what combination they are using in what product number cell

    CATL are already on their second generation mass production run with hundreds of combinations still at the lab/testing stage, hundreds and hundreds abandoned, who knows what combinations the minor manufacturers are using and how exhaustive their testing is prior to production ......

    I see even more pain navigating this newest chemistry, the basic chemistry is the same, so it can't be determined using that criteria ...... hands on testing will be the most reliable method, not simply trusting the reseller to tell the truth ... or even knowing the truth ......

    T1 Terry
     
  9. jakester21

    jakester21 Junior Member

    Joined:
    Aug 1, 2018
    35
    4
    0
    Location:
    usa
    Vehicle:
    2005 Prius
    Model:
    Two
    I think it's the perfect voltage if you want to replace the old cells in the Prius I just installed them wish me luck I'm a bit worried about how they will do since they are only rated at 72amp charge and I haven't figured out how to balance a 1.8v cell
    thanx for the reply I guess I still can't upload pictures
     
  10. T1 Terry

    T1 Terry Active Member

    Joined:
    Jan 4, 2015
    584
    296
    0
    Vehicle:
    2006 Prius
    Model:
    Plug-in Advanced
    Hmmm.... the Gen 2 Prius can pump out more than 180 amps on regen under heavy braking, you would need three sets of these battery configurations to handle that, so you are going to need to retain the original traction battery as well so it can at least absorb the high current, then some sort of current limiting to the extended range battery you are adding.

    With the 15Ah sodium ion cells I'm about to test (too many projects already) they are spec'ed to handle between 1.8v and 4v, 4 cells in series would handle 160v, but the Gen 2 Prius can belt out close to 200v sometimes, so I'll be building 5 cell in series strings to handle the high inrush voltage and hopefully the 10C charge rate is actually possible for 1,000s of cycles, or I'll have to build 2P5S strings to reduce the C rating to a peak of 6C (180 amps)
    A series string of 5 of these 15Ah cells is slightly smaller than 2 modules of the original NiMh cells (12 cells), so 14 strings will build a battery with 3 times the capacity, yet fit in the same position as the existing battery .... if the cells can actually handle the charge current ...

    T1 Terry
     
  11. jakester21

    jakester21 Junior Member

    Joined:
    Aug 1, 2018
    35
    4
    0
    Location:
    usa
    Vehicle:
    2005 Prius
    Model:
    Two
    I'm not to sure on your 180amp charge rate I use Dr Prius all the time and I only see maybe 100amp and the main battery fuse is 120amps.

    Do you have a like to the sodium cells your going to use

    I've noticed that the 12 nickel metal hydrate cells the Prius does monitor does hit 20v sometimes so that's 20x14 that will give you the volts you want to have your battery at so if the sodium can go 4v and you have 5 being monitored then that would make it to the 20v you need but I would maybe have some wiggle room so you don't over charge the sodium maybe 6 in series but you also have to consider you don't over discharged them 1.8x6 that should be fine
     
  12. T1 Terry

    T1 Terry Active Member

    Joined:
    Jan 4, 2015
    584
    296
    0
    Vehicle:
    2006 Prius
    Model:
    Plug-in Advanced
    Yet another thing to determine during these battery tests, is the charge voltage linear and relates to state of charge in each cell. Lithium ferrous phosphate (LFP and LYP) chemistries don't, so to get the cells fully charged, the max charging voltage must be very close to the fully charged voltage, there is only 1v between 100% SOC and 0% SOC, yet 0.5v above 0% SOC does not equate to 50% SOC, it just equates to not fully discharged or fully charged.

    That 180 amps was measured using an independent shunt and recording logger at the battery terminal. The majority of each brake application is in the form of regen until the wheel speed is below 6km/h, Dr Prius only sees an average of what the computer interprets to be the charging current, it allows a Peukert exponent related to the charging efficiency of the NiMh chemistry and the voltage it senses at the battery to alter the current very rapidly to guard against module over voltage causing a cell to go bang, the peaks are blurred over, but they do briefly show up using a Scan Gauge 2

    T1 Terry
     
  13. jakester21

    jakester21 Junior Member

    Joined:
    Aug 1, 2018
    35
    4
    0
    Location:
    usa
    Vehicle:
    2005 Prius
    Model:
    Two
    i still cant find any sodium batteries that have more than 1c charge rate
     
  14. T1 Terry

    T1 Terry Active Member

    Joined:
    Jan 4, 2015
    584
    296
    0
    Vehicle:
    2006 Prius
    Model:
    Plug-in Advanced
    That is why you need to do a lot of research, then buy samples and do your own testing to identify just what the ability of the cells you have chosen ..... If you could get your hands on genuine CATL gen 2 cells you will find they can handle better than 20C in both directions, but you and I are not a big enough enterprise for the likes of these companies to even return an inquiry. Fortunately, I have someone who can get access where many can't, but it is still a trial and error thing to get what you need, these days, factories don't do the lab testing any more, that is up to the purchaser and feed back between the two develops the battery the purchaser needs ..... China is a very strange market to work in, just about any product you can find on the market that sells direct to the public is a secondary reseller who is selling factory rejects, none of them have the $$ to do factory testing, half of them don't even know what they are selling, just look at the number of them that seem to end up with lithium ion somewhere in their product description .....
    At the moment, sodium ion is a very new product with very little genuine information available .... LiFeP04 was that way 12yrs ago when I started testing those for various load applications, there is an absolute flood of them on the market now, but only 1 or two brands that are the real thing, the rest are relabelled factory rejects .... the good manufacturers don't sell their rejects, they break them down to find out why they didn't reach the minimum requirements, then they reprocess the materials ..... that is why quality lithium cells are still very expensive ...

    T1 Terry