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Fast Charging the NiMH battery - COOL TIP

Discussion in 'Gen 2 Prius Main Forum' started by Stocky, Mar 9, 2005.

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  1. Stocky

    Stocky New Member

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    Oh wow - picked up my new baby about 5 hours ago – now I am a real Prius owner - WUHU!!!!

    I read with interest that there is a lot of concern over running down the NiMH battery in various forums. I think I found an easy fix.

    To FAST CHARGE your NiMH Battery.
    1. Start the car
    2. Put it in Drive
    3. Depress both the brake and gas pedal simultaneously to the floor.
    4. The car will recognise that you want to charge the battery and move into a special "fast charging" mode.
    5. This can take up to 5 minutes depending on the charge state of your battery (you can even get it up to 100% - FULL GREEN)
    6. The car will NOT overrev and will adjust the engine speed back as the battery charges.

    I suggest you do this only once in a 3 or 4 day period, because despite statements to the contrary, the NiMH does have a memory and I am not sure what the fast charge will do.

    Save it for emergencies, better to be safe than sorry.
     
    #1 Stocky, Mar 9, 2005
  2. KTPhil

    KTPhil Active Member

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    What is your source for this method?
     
    #2 KTPhil, Mar 9, 2005
  3. V8Cobrakid

    V8Cobrakid Green Handyman

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    yeah.. and the engine automaticaly stops turning as fast when it's full.. i found that parto be kinda cool when i found this out several months back.. it's completely full. good if you are doing autocrossing at the time and, not worried about your mpg or enviromental impact.. but bad for most people on this site. It drops your overall mpg by a decent amount. that's a lot of 0's going into the mpg calculation that would normally be at least 15s..... punching it and riding the car at max speed for about a min is the same amount of fuel it uses.

    I would also believe that doing this on a regular basis might possibly shorten your battery life. needless to say, i don't do this anymore

    Stocky: unless you have text, i don't think the system goes into a smart mode to charge. I wouldn't put it too far past Toyota to incorprate this.. but from i notice in normal electric motor/generator behavor, time and constant speed is a factor that usually results in a quick charge.
     
    #3 V8Cobrakid, Mar 10, 2005
  4. naterprius

    naterprius Senior Member

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    This is actually very, very useful if I have a mountain climb ahead.

    Thanks much!

    Nate
     
    #4 naterprius, Mar 10, 2005
  5. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(naterprius\";p=\"71067)</div>
    And that is the only reason I can think of to do this. Otherwise it's exteremely inefficient use of the ICE and battery and creates a ton of emissions for no reason.
     
    #5 efusco, Mar 10, 2005
  6. DaveG

    DaveG Member

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    Someone on the Yahoo Groups list had also mentioned that this may cause extra wear with components overheating as the car is stationary.

    I have no information either way, and am just repeating what I've read.

    Needless to say, as Evan has mentioned, it's not something that needs to be done because the battery will recharge itself during regular driving, and unless you are racing (in which case it was foolish to buy a Prius), there's no reason to force-charge your battery.

    Dave
     
    #6 DaveG, Mar 10, 2005
  7. V8Cobrakid

    V8Cobrakid Green Handyman

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    i've never had the prius fail me with a mountain climb. it would be more efficient to just drive up the mountain instead of charging. either way, the car will probably give the electric motors priority when going up the hill (utilizes electric as much as possible) and the battery will last the same amount of time. just take it easy up hills and cruise down the other side. it will at least be a natural charge and drain on your battery.

    poor battery. always taking the beating for our poor driving habits.

    :) better it instead of gasoline :)
     
    #7 V8Cobrakid, Mar 10, 2005
  8. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(V8Cobrakid\";p=\"71086)</div>
    That's an excellent point V8...the improvement in climbing ability with a force charged battery over one at mid-level is going to be negligible.
     
    #8 efusco, Mar 10, 2005
  9. Stocky

    Stocky New Member

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    I never said that it was good for gas or the emissions. I just said that if you get into a bind with your NiMH battery going flat when climbing hills or whatever, then this will get you out of it.

    Actually, I found it surprising that engine was just running at a real fast idle when I did it, then dropped away to a normal idle, so I don't believe the impact on MPG is as great as you would first surmise.

    The Toyota dealer told me that the car DOES go into a special mode, he specifically called it "fast charging mode". However, someone with the set of manuals may be able to post a confirmation or rebuttal.

    When I took delivery of my Prius this afternoon (WUHU), I spoke with the Toyota Service Manager. He confirmed that it is the way the service guys charge the battery when they have problems. Go figure.

    Again I reiterate, I don't know the "real" impact on the battery, so caveat emptor - use at your own risk.
     
    #9 Stocky, Mar 10, 2005
  10. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(Stocky\";p=\"71091)</div>
    Actually, you said nothing of the sort...you didn't say anything about the utility except about concern by posters on other forums of the 'battery going flat'. Anyway, there 'may' be some utility in getting over a particularly steep 'hump' on a climb if the battery is really drained, but those times, I assure you, will be very very rare...maybe while climbing Pike's Peak or something.

    He made that up. Others with battery monitoring equipment can rebutt that, but I assure you it isn't true.

    Yea, ok, so maybe they left the car in neutral for a long time and it got down low and they have more work to do on the car in that state so they rev it up to get the SOC back up so they can continue their work. This is still not something routine or something the lay person should need to do or worry about....if the SOC is low just drive your car.
     
    #10 efusco, Mar 10, 2005
  11. Stocky

    Stocky New Member

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    Thanks for that efusco.

    Well, I didn't say anything about gas or emissions and I did say "Save it for emergencies, better to be safe than sorry." in my original post To me that implies extraordinary circumstances, at least that is my definition of an "emergency".

    Be that as it may - I certainly don't advocate that this should be done as a matter course, I am merely pointing out an additional feature of the car.

    I will investigate the "fast charging" claim further, I would hate to think that the Dealer Manager was telling lies, I see no reason why he should, he already had my money - LOL.
     
    #11 Stocky, Mar 10, 2005
  12. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(Stocky\";p=\"71094)</div>
    Ok, nothing we need to debate in depth. My point, vague though it is, is that there really are no such 'emergencies' that I can imagine. If the HV batt is so low that it can't start the ICE your the forced-charge won't work b/c your ICE won't be running. If the there is enough charge to start the ICE then all one needs to do is drive and the computer will do the rest.

    The force-charge is as much parlor trick as anything else. The techs might do it b/c it's easier than driving around, but unless you're doing a lot of your own technical work and also don't like to drive around you shouldn't need to do it.
     
    #12 efusco, Mar 10, 2005
  13. jtmhog

    jtmhog Member

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    Is this fast-charge one of those "mal-operations", "abuses," "parlor tricks" that the computer will remember and the dealer/toyota can download to refute your claim for premature HV battery failure.
     
    #13 jtmhog, Mar 10, 2005
  14. Tempus

    Tempus Senior Member

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    <div class='quotetop'>QUOTE(Stocky\";p=\"71094)</div>
    I sincerely doubt he was lying, because to lie you have to know the truth.

    He was most likely repeating second hand what the techs had told him, with some degree of distortion.

    You will find in relatively short order that after a day or two of reading the available Prius Sites you will know far more about the car than most any normal Service Writer or Dealership Sales/Management personnel. You will probably also know some things that the Prius Techs aren't aware of, though they will also know many things you don't :)
     
    #14 Tempus, Mar 10, 2005
    AllenZ likes this.
  15. Ray Moore

    Ray Moore Active Member

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    I read this entire thread and didn't see the main reason for doing this posted by anyone. You should always do this just prior to getting the green light at the track. I intend to take mine to the drag race in Houston on Friday night when you can run the timed quarter mile for ten bucks. I've always wanted to know what a stock Prius can do in the quarter with a full charge. I'll let you know what happens the next time I'm down there. Well, not the next time; because, that will be for the Nationals and I just don't think they're going to let my Prius out on the track that weekend.
     
    #15 Ray Moore, Mar 10, 2005
  16. Stocky

    Stocky New Member

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    Tempus

    Yes I agree, I have already decided that I know far more than he does after reading and research. Hey - you're keen to get your new car, so you go to any lengths to learn about it, simple! There is so much to discover, little things like the interior light coming on when you walk up to the car with SKS. These are not possible when you are waiting for delivery, so I will be on a discovery weekend.

    Ray

    Well done that man!!!!!! If you frequent the drags enough you may have to revise your plate - LOL.
     
    #16 Stocky, Mar 10, 2005
  17. rick57

    rick57 Member

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    "Fast charge in a special mode"? :roll: That is a new one on me,never heard of that.
     
    #17 rick57, Mar 10, 2005
  18. mikepaul

    mikepaul Senior Member

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    So, say I was climbing up a mountain, and started to lose speed when the battery was nearly drained. The best solution is to pull over (safely), "speed-charge", then start going again?...
     
    #18 mikepaul, Mar 10, 2005
  19. Tadashi

    Tadashi Member

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    I am curious to know how your track times are with full charge or normal charge (1/2 - 3/4 change), but too chicken to do it with my Prius. :D
     
    #19 Tadashi, Mar 10, 2005
  20. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(mikepaul\";p=\"71205)</div>
    That might be 'a' solution, though I'm not sure it would be the 'best' solution. I don't think it would have any great effect, though it might give you some added boost for a short while.

    Someone should try it that lives on a really steep mountain and often drains the batt down to 1 pink bar and see if they find it helps much for any length of time.
     
    #20 efusco, Mar 10, 2005
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