Is adding a second battery possible?

Discussion in 'Prius PHEV Plug-In Modifications' started by hyp3rmil3r, Dec 22, 2019.

  1. dingaling007

    dingaling007 Junior Member

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    Id be very interested in your results. From my understanding there is a benefit but its around 10% better fuel economy and more peppyness. but I'm only going on Dr Prius Nextcell Lithium cell upgrades. What you have may be completly different with LTO. Something ive wondered about myself. Fluid cooling is also of interest and a huge challenge in itself!

    Ah yes Ian Hooper of Zeva, i used to use a lot of his 8S BMS boards on various systems. Still use them! A shame he hung up his hat. But glad he opened sourced it all. I just don't have the time or fortitude at the moment to try and create his BMS from the source files.

    Ah and Rodney Dilkes of EV power! yep i love those cell balancers! what a great solution they've been! only recently did i discover those cell balancers have a that 1 wire loop to turn things on/off if any cell goes into the danger zone! was great as a backup when my BMS failed.

    But Rodney said to me just a few weeks ago, he wont sell me those Cell balancers for my Prius project as they are not designed to see100+ Volts... I wasn't aware that would be an issue.

    That sounds like an interesting cell monitoring solution by that member. I certainly would be interested in it also. As there really isn't a great deal available out there without spending a lot of money. I'm looking at around $2000 with shipping with the Orion BMS2, and I'm on a wait list due to parts shortages :/
     
  2. dingaling007

    dingaling007 Junior Member

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    I should of hit reply instead so you would get an alert.
     
  3. T1 Terry

    T1 Terry Active Member

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    Hopefully I will see him tomorrow and tell him there is export market interest as well ..... maybe that will get him re-inspired to get back into the production stage.
    The original set up used optic fibre links but issues with getting and keeping a good connection had him switch to single wire canbus instead. He is a very clever bloke, unfortunately his talents are well sort after so big $$ jobs keep getting in the way as well

    Nearly finished pack 3, broke a terminal off in one of the cells getting a bit heavy handed tightening them, so 5 down now ..... these are pricey eggs I'm breaking to make this omelette :lol:

    T1 Terry
     
  4. dingaling007

    dingaling007 Junior Member

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    Hopefully you had some luck re-inspiring your friend. And yes Optic fibre would be no good for a car in my book. I have enough trouble in my job with optic fibre issues!

    Bugger, yes, LTO are not cheap! Something I've not been able to find solid information on is how LTO compares to NIMH with energy density?
     
  5. T1 Terry

    T1 Terry Active Member

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    Energy density is a bit like Ah and Puekert factor and charging efficiency, it doesn't tell the full story and is really just a number resulting from basic maths with half the equation missing.
    The real measurement should be something like "full load watts per kg", so the voltage drop under load is added to the equation along with internal resistance causing losses to heat and chemical reactions and then the return cycle losses till the same full capacity is reached.
    The module pair might have a nom. voltage of say 14v, but under load that drops to less than 12v but goes as high as 18v when recharging. Those are the numbers that really should be used when multiplying the load amps and recharge amps. A battery built from cells that neither drop their voltage under load or suffer voltage rise when high rate recharging can provide a lot more energy on the full cycle and that would give a far better indication of the weight penalty compared to the "usable" energy storage .... then you have to factor in the safety aspect and the cycle life

    T1 Terry
     
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