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

Fitting mobility 12volt AGM battery.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Britprius, Mar 3, 2013.

  1. 2007blueprius

    2007blueprius Member

    Joined:
    Dec 26, 2012
    461
    30
    0
    Vehicle:
    2007 Prius
    Model:
    N/A
    1.5 Watt Solar Battery Charger
    this would probably solve the low voltage drain situation regardless of which battery one decides to use aproximately 100 ma for say 5 hours on a clowdy day, too bad I tinted the back window
     
  2. Britprius

    Britprius Senior Member

    Joined:
    Jun 14, 2010
    5,194
    1,914
    0
    Location:
    Herefordshire England
    Vehicle:
    2008 Prius
    I was trying "with real world figures" to show that even a plus .5 volts charge over the battery voltage can produce large charging currents. It is not the voltage on it's own that makes for a high charge rate, you have to take into account the internal battery resistance. This resistance also "not withstanding any other limitations" limits the output current even with a dead short across the output.

    John (Britprius)
     
  3. 2007blueprius

    2007blueprius Member

    Joined:
    Dec 26, 2012
    461
    30
    0
    Vehicle:
    2007 Prius
    Model:
    N/A
    this is a bit beyond my comprehension I guess, bottom line does the 12v see such 100 amp draw? I read some other post claiming a suitable replacement must be able to withstand 100 to 150a currents, christ it says right on top never charge more than 4.2 a I am assuming that is the max it ever sees from the car, same on the discharge how much can a 12v output, 100 amp sounds ridiculous.
    my concern is if I build a 40ah pack rated at 1/2 c continuous, 2 c bursts it will be capable for 80 amp max, in traction batteries that is not unheard of but to run a fan or a remore receiver, unlikely
     
  4. Britprius

    Britprius Senior Member

    Joined:
    Jun 14, 2010
    5,194
    1,914
    0
    Location:
    Herefordshire England
    Vehicle:
    2008 Prius
    The DC to DC converter in the Prius is capable of 100 amps output. It is most unlikely the OEM Prius battery would ever see this sort of figure unless it had one or more shorted cells.
    The maximum charge rate on the top label of 4.2 amps is possibly why it does not stand up well to being deep discharged and then recharged on the Prius system. Having done some testing on the Prius charging system I can state that at 50% discharge of the OEM battery it will be charged at at least 10 times that figure. This is probably why it is fitted with a vent as at that rate of charge it will gas.

    John (Britprius)
     
  5. 2007blueprius

    2007blueprius Member

    Joined:
    Dec 26, 2012
    461
    30
    0
    Vehicle:
    2007 Prius
    Model:
    N/A
    so you have seen 50 amp charge current? oau that is quite a bit, that is a little over 1/c for those cells I was planning to use, is that a short initial burst? or stayed there for some time.
    I noticed when charging the oem it likes amps, I hooked up a car charger on the 2 amp setting just to open the trunk and it was spiking to 7 amp, sure enough while charging it afterwards, I am using an adjustable PS, the initial voltage was about 7 I set my ps at 9.5v and it was taking in 7 amps or so, I tuned the voltage down to get the 4 amp rate, and slowly been increasing it since, it has been charging over night I am up to about 13 v now still taking amps no problem,
    should I stop at about 13.6 or charge it to 14v or so? this is the original battery 6 years old now so there's not much to destroy, figured I'll topp it offand see if it holds
     
  6. Britprius

    Britprius Senior Member

    Joined:
    Jun 14, 2010
    5,194
    1,914
    0
    Location:
    Herefordshire England
    Vehicle:
    2008 Prius
    AGM batteries charge to a slightly higher voltage than normal flooded batteries, so charge to about 14 volts providing the current does not go to high.
    You have basically discovered what I found with the Prius charging system that in the absents of a current limit the battery takes what it can. Float charge voltage for an AGM (continuous standby charging) is 13.8 volts.

    John (Britprius)
     
  7. 2007blueprius

    2007blueprius Member

    Joined:
    Dec 26, 2012
    461
    30
    0
    Vehicle:
    2007 Prius
    Model:
    N/A
    wonder if that solar panel would do the trick, granted my driveway faces east and it is a bit shaded, but it seems the larger size is for extended standby, but even that would eventually run out, I think on the new ones they have it incorporated in a spoiler, whish I thought of this before I tinted the windows, I could put it under the windshield I guess, thou not sure about those solar panels if they ever reach 13.8v I'll have to look into it
     
  8. Britprius

    Britprius Senior Member

    Joined:
    Jun 14, 2010
    5,194
    1,914
    0
    Location:
    Herefordshire England
    Vehicle:
    2008 Prius
    Most solar panels off load reach about 18 volts so you should have no problem beneath the screen. If you go this route and use the Prius power outlet make sure the output is permanently on. We only get one outlet in the UK and that is ignition controlled.

    John (Britprius)
     
  9. 2007blueprius

    2007blueprius Member

    Joined:
    Dec 26, 2012
    461
    30
    0
    Vehicle:
    2007 Prius
    Model:
    N/A
    allready thought about that, I was not even considering it I would wire it directly into the batery
     
  10. R-P

    R-P Active Member

    Joined:
    Dec 6, 2011
    804
    288
    0
    Location:
    Netherlands
    Vehicle:
    2009 Prius
    Model:
    II
    Blueprius, have you checked fluid levels on your battery before starting your charging?

    Mine had one cell that was obviously less full than the others.
    BTW, it is still working 1+ year later, but I plan to get a new one (possibly a 90Ah one :) if it will fit)
    [​IMG]
     
  11. Britprius

    Britprius Senior Member

    Joined:
    Jun 14, 2010
    5,194
    1,914
    0
    Location:
    Herefordshire England
    Vehicle:
    2008 Prius
    I had looked at the 90 AH cell power battery but it is to big from back to front at 168 mm. The largest you can fit in the OEM space is about 140 mm, but there is no reason why it could not be moved.

    John (Britprius)
     
  12. 2007blueprius

    2007blueprius Member

    Joined:
    Dec 26, 2012
    461
    30
    0
    Vehicle:
    2007 Prius
    Model:
    N/A
    hold off a second, I thought those were some sort og gel bateries, glass matt or something, mine is all black doubt you can see through , says right on the top do not add watter, are these floded?
     
  13. R-P

    R-P Active Member

    Joined:
    Dec 6, 2011
    804
    288
    0
    Location:
    Netherlands
    Vehicle:
    2009 Prius
    Model:
    II
    Yes, maintenance free, yet they have a vent... So they apparantly CAN loose something. And if they HAVE lost something you can either do nothing or at least make sure the plates are submerged. I chose to do the latter, as the part of the plate that is not submerged, does nothing to help the capacity of the battery.

    I did not have a specific gravity tester back then, so all I could do is add some demineralized water.

    Flooded cell:
    [​IMG]

    Partially empty cell:
    [​IMG]

    Battery after removing plexi window-strip revealing the rubber caps (they act as vents, note if they are all meniscus-shaped and all the same, that would be the normal situation, in case of gassing they buldge until some gas escapes while the plexi-window prevents them from being blown off completely)
    [​IMG]
     
  14. 2007blueprius

    2007blueprius Member

    Joined:
    Dec 26, 2012
    461
    30
    0
    Vehicle:
    2007 Prius
    Model:
    N/A
    so there are caps under that label? I never considered it, I have tore apart several bateries one is not supposed to, was not sure weather this one is flooded or some gel type funny stuffhow hard is it to get to the caps? some I opened were rather tuff, I have no problem tinkering with it the way I look at it is no good now not much harm I can cause.
    lately came across this Alum reconditioning process , this might just be a good candidate for an experiment
     
  15. R-P

    R-P Active Member

    Joined:
    Dec 6, 2011
    804
    288
    0
    Location:
    Netherlands
    Vehicle:
    2009 Prius
    Model:
    II
    I probably already forgot that I removed a label to get to the plexi strip (on the right next to the battery). You should be able to do the back-light-test without even removing the label. I think I used a flashlight, so the other levels weren't all the way up to the black part of the battery, but significantly higher than the white plates, which I assume are the glass matts in A(bsorbed)G(lass)M(att) (AGM) batteries.

    As for the Alum process, that doesn't ring a bell, but I have seen many miracle battery reviving pocesses, but for every success storu, there is at least one horror story. Then again, if a battery is toast (like an old 170Ah which appears to have a shorted cell that I have lying around) or when you are prepaired to buy a new one anyway, what do you have to loose? (Apart from the investment in the chemicals, the potential spill of battery acid over clothing/marmor tiles (yes, from experience...), hours of your time, etc... :D )
     
  16. 2007blueprius

    2007blueprius Member

    Joined:
    Dec 26, 2012
    461
    30
    0
    Vehicle:
    2007 Prius
    Model:
    N/A
    That is my thought process as well, I charged it for now, I am not using the car at the moment so I got time to tinker, I had it up a little over 13v, it settled overnight at 12.89v, I checked it later that evening it was at 12.85v, right now I am waiting to see if it holds voltage, not sure if backlight will work, mine is all black, those caps can be reinstalled? some batteries I tore up could not put back, had to make caps, but yes once I determine I can't get any more use out of it it will certainly get tore, I know it is weak but at the same time we had it parked for a while so it may be a combination SKS draw, maybe we left a light on, who knows.
    I charged 8 x 20 ah lifepo4 cells that are somewhat questionable for ev traction use, they were loosing quite a bit of voltage at rest no secret there I knew they were questionable, I am kind of tinkering to see if I can use them, same concept there they are already questionable so I don't mind to try them, just hope if any damage occurs it's to the cells and nothing else.
     
  17. getwellsam

    getwellsam Junior Member

    Joined:
    Jul 8, 2010
    22
    0
    0
    Location:
    Pittsburgh
    Vehicle:
    2010 Prius
    Model:
    II
    Hello.
    I got the Ritar 12-55 battery from BritPrius ' link in this thread. While I have been pretty excited about the thread (I have spent a few late nights reading this), I have run into some installation issues: (disclaimer: im not too knowledgable about cars, or the prius)

    1) I thought that as I have a Gen II with a MFD, I would have a bigger 12v battery size. But when we placed old battery next to the Ritar 12-55 , the Ritar was about half an inch wider. makes me think the smalled size is in there- (maybe like BritPrius wrote about some US prius' with smaller battery size?). but the mechanic guy said it might be able to be dealt with.
    2) posts- I didnt get the posts, didn't piece that together till i saw the top of the ritar.my battery has an overhanging thing (see attachment) from the tops. It doesn't seem compatible with the layout of the top terminals. I have afeeling I rip off the overhangy things and would screw on the posts I buy to the top= just want to get a confirmation i'm on the right track.

    3)/white circuit board thing:i think i talked ot the mechanic guy about 'well ok, what if the posts were on top' and The mechanic guy says that while one of the terminals can be just hooked on to a post (positive terminal?), but the other terminalcan;t because it has a white retangular circuit board-thingy that has to attach to it, and that 'it needs to attach the way the previous battery did." I do not fathom this issue, I said why not just tag it onto the post anyways, but the mechanic guy says "if we 'just attach to the post, it won't be connected the way it was previously, all those important things that the circuit board replays for, won't get powered"

    ok , gotta go to bed, at least this is a start. any help would be appreciated-
    Sincerely,
    Sam
     

    Attached Files:

  18. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,627
    3,848
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    Your "overhanging thingies" are a different type of terminal that are called (I think) side posts. I doubt you can just "rip them off". Are you able to take the battery back and exchange it for one with M6 terminals? Then you could just purchase a set of M6->Japanese pencil post converters.
     
  19. getwellsam

    getwellsam Junior Member

    Joined:
    Jul 8, 2010
    22
    0
    0
    Location:
    Pittsburgh
    Vehicle:
    2010 Prius
    Model:
    II
    Dolj, I got the battery online; I'm guessing the store would let me exchange it, though I may have to pay for shipping, at least one way.

    But mechanic guy also said 2 posts won't do the trick because the negative terminal needs to supply power to the white circuit board. I will look at the white circuit board connection to see what he means, but is anyone on here familiar with the concern of : "the terminal with white circuit board attached can not be hooked up with a post terminal ?"

    my apologies for any circuitry/connection inaccuracies. I am a beginner with cars and circuits- slept through most of physics (and drivers ed).

    any guidance appreciated,
    Sincerely,
    Sam
     
  20. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,627
    3,848
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    I'm not exactly sure what your mechanic is getting at, but if suitable converters are attached to the battery, it is then no different from a standard JIS pencil post automotive battery, so the post clamps should just attach straight on. Make sure your battery has the positive terminal on the left-hand side as you look at the battery with posts nearest to you.