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Fitting mobility 12volt AGM battery.

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

  1. SteveLee

    SteveLee Active Member

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    I do understand the initial reaction to stick with the tried and true, especially in regards to the things related to the Prius system, though the OEM 12v battery is not known for its robustness or longevity. The fact that the OEM and typical replacement batteries cost more than twice as much as typical car batteries is reason enough to be open to alternatives. So far I haven't seen anything to discredit these more robust AGM batteries that John has suggested for use in the Prius. The fact that he has used them for years in his mobility use with deep discharging and they have lasted, in addition to using one in his Prius for at least a year with no issues lends support for its viability. Without evidence to the contrary, at one third the cost of the OEM, this 12v used for Prius 12v use seems like a no-brainer to me.
     
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  2. mosesk

    mosesk Member

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    haha...
     
  3. Britprius

    Britprius Senior Member

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    Hi Monius, likely reason why the battery is specified as needing to be a VRLA is because it is carried within the passenger area of the car "under the boot/trunk floor". It is vented from the battery manifold via a small rubber tube to the outside of the car through the floor, something not really covered in the above posts or at leased only briefly.

    John (Britprius)
     
  4. ls40095

    ls40095 Junior Member

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  5. ls40095

    ls40095 Junior Member

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    I emailed and made offers to this guy for 2 battery's over the past 2 days and have heard nothing so I would strongly recommend finding them elsewhere.
     
  6. Britprius

    Britprius Senior Member

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    Is40095 there is a 125 amp fuse contained within the safety disconnect device on the HV battery. This however would not normally blow the fuse in an accident unless the HV cables from the rear of the car to the front, or the inverter were badly damaged. Water would not be likely to carry enough current to blow the fuse, but it is possible in that situation the HV battery ECU or the inverter could disconnect the HV battery by detecting a ground fault.

    There is as on most vehicles a switch that detects a sever impact and shuts down the engine, on the Prius this is mounted on the inverter to shut the hybrid system down.

    John (Britprius)
     
  7. Britprius

    Britprius Senior Member

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    Thanks again for your input. Here are some figures for you to work on, taken on my own Prius with a
    Ritar 55 AH at 10HR rate battery fitted a little over a year ago. The results are not as complete as I would have liked due to a sudden rain storm "working outside" and with an unexpected result to information previously gained from PC that is proven to be incorrect.

    The OEM battery in the UK from the Prius is indeed a S46B24R but the battery has no AH capacity marked on it.

    The Ritar battery voltage to begin with was 12.5 volts after sitting with a 26ma load for 48 hrs and then running the brake hydraulic pump "average 16 amps" for 8 seconds.

    The car was then put in ignition on mode (not ready) and lights turned on to give a load of 19.5 amps (measured with a Fluke 36 clamp ammeter) voltage under this load was 11.9 volts.

    The load was left on for 30 mins current fell to 19.4 amps and voltage falling to 11.65 volts. The load Was then removed the voltage was then measured at 11.98 rising rapidly.

    The car was then made ready charging the battery. The charge rate was showing at 43 amps. I stopped the charging thinking something was amiss with the measurement, so connected my DVM to read battery current.
    Restarting the charging gave 42 amps on the Fluke meter and OL on the DVM maximum current range 20 amps.
    After a little under 2 mins the Fluke had dropped to under 20 amps and the DVM confirmed this at 19.7 amps voltage unknown because I am now using the DVM for current.

    After 2 mins the current was at 18 amps
    After 3 mins the current was at 12.9 amps
    After 4 mins the current was at 10.5 amps
    After 7 mins the current was at 9.9 amps This is almost certain to be at 14.2 volts.

    At this point the project was suspended due to the rain.
    Two hrs later I had to use the car for a 1 hour run, so I monitored the voltage via the MFD. This started out at 14.2 volts and fell to 14.1 and near the end of the journey to 14.0 volts. I know normally it would run after a short period at a continuous 13.8 volts when the battery is fully charged.

    The Prius obviously does not have a current limit on charging of 4 amps, I do not know the upper limit but the DC to DC converter is limited 100 amps at a voltage unknown. This however is still well in line I believe with the charging specifications of the Ritar battery give as initial current unlimited up to 50 degrees C then 16.5 amps maximum. Float charge 13.6 to 13.8 volts.

    Your thoughts and observations would be welcome.

    John (Britprius)
     
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  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Correct, the DC/DC converter regulates voltage on the 12V bus to be ~13.8V. Whatever current the battery wants to take given that charging voltage (up to 100A) is what it will receive.
     
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  9. Britprius

    Britprius Senior Member

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    With an OEM battery fitted and only discharged for 5 mins with the headlamps the voltage will go up to 14.6 volts on the MFD It may go higher with a larger discharge but have not tried this yet.

    John (Britprius)
     
  10. css28

    css28 Senior Member

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    I had wondered about your 4 amp assertion before, given threads I'd read about people powering substantial inverters for emergency home power.
    Very interesting report to be sure.
     
  11. bobodaclown

    bobodaclown Member

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    Just to clarify somewhat to compare to a hose and what not.
    The voltage is the pressure, amps is the flow rate (gallons per minute). The battery will only accept/draw so many amps, but the voltage has to be high enough (greater than the battery charge). For a gel or deep cycle battery the max is usually no more than 14.1 volts, it sounds like the charging system is more than capable of charging/maintaining Gel or AGM batteries. The flow of electrons doesn't care.
     
  12. Britprius

    Britprius Senior Member

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    The charge rate may be to high for gel batteries initialy, "this does depend on the battery fitted and it's initial maximum charge rate" to high a charge rate with a gel battery causes gassing that lifts the gel away from the plate. The gas cannot escape and therefore reduces the area of acid gel in contact with the plates, reducing capacity.

    I have measured charge voltage of 14.6 and it is possible it could go higher (no proof of this) but this dropped quickly to 14.2 volts this level seems fine for AGM in my opinion but would welcome conformation from Monius, "two heads are better than one" but still stand behind my conviction that these batteries are fine for the Prius application.

    The fact that my battery had been in use for over a year and had a voltage of 12.5 after standing with some use for 48 hrs and the only fell to 11.65 volts measured with a near 20 amp load for 30 mins then recovered rapidly. In my book this bodes well.

    John (Britprius)
     
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  13. ls40095

    ls40095 Junior Member

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    Does this switch shut down all power making the dash inoperable?
     
  14. R-P

    R-P Active Member

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    So what price is reasonable for an AGM deep-cycle one?

    Here's one for under 100 euro (UK)
    And another one for under 110 euro (US)

    Yet I can't for the life of me find anything under 170 euro here... And I've called electrical wheelchair companies, battery 'manufacturers', large battery-sales points, etc.

    Am I (due to false advertising?) mistaken stand-by batteries for cyclic ones like one of the sales persons warned me about?
     
  15. Britprius

    Britprius Senior Member

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    To be honest I do not know how many of the systems it shuts down, but I would be very surprised if it did not cut power to the HV DC relays thus disconnecting the HV battery.

    John (BRitprius)
     
  16. Britprius

    Britprius Senior Member

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    The first of the two batteries is much the same as the one's I have fitted, the second is the same type of battery with flat lug type terminals. These batteries can be used for standby or cyclic use, the difference is in the voltages on charge. Standby use a maximum charge voltage of around 13.8 volts, for cyclic use this can go up to 14.8 volts dependent upon the battery used.

    John (Britprius)
     
  17. ls40095

    ls40095 Junior Member

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    Thank You
     
  18. ls40095

    ls40095 Junior Member

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    I bought the Power-Sonic 12V 35Ah (Battery Replaces 33Ah Ritar RA12-33) should get it tomorrow and install over the weekend. It cost $70 delivered. I will keep everyone updated. Here are the specs..


    Product Description



    The Power-Sonic valve regulated sealed lead acid batteries are maintenance free, easy to handle, rugged and economical. It has a characteristic of high discharge rate, wide operating temperature, long service life and deep discharge recover.
    • Dimensions (LxWxH): 7.7 '' x 5.2 ''x 6.1 ''
    • 12V 35.0 Amp Hour
    • Absorbent Glass Mat (AGM) technology for superior performance.
    • Valve regulated, spill proof construction allows safe operation in any position.
    • Power/volume ratio yielding unrivaled energy density.
    • Approved for transport by air. D.O.T., I.A.T.A., F.A.A. and C.A.B. certified.
    • U.L. recognized under file number MH 20845

    RELIEF VALVE - In case of excessive gas pressure build-up inside the battery (usually caused by abnormal charging) the relief valve will open and relieve the pressure. The one-way valve not only ensures that no air gets into the battery where the oxygen would react with the plates causing internal discharge, but also represents an important safety device in the event of excessive overcharge. Vent release pressure is between 2-6 psi; the seal ring material is neoprene rubber.


    PRODUCT FEATURES SEALED MAINTENANCE FREE - The valve regulated, spill-proof construction of the POWER-SONIC battery allows trouble-free, safe operation in any position. There is no need to add electrolyte, as gases generated during charging are recombined in a unique "oxygen cycle".
    EASY HANDLING - No special handling precautions or shipping containers - surface or air - are required due to the leak-proof construction.

    ECONOMICAL - The high watt-hour per dollar value is made possible by the materials used in a sealed lead-acid battery: they are readily available and low in cost.
    LONG SERVICE LIFE - Under normal operating conditions, four or five years of dependable service life can be expected in stand-by applications, or between 200 and 1000 charge/discharge cycles depending on the average depth of discharge.
    DESIGN FLEXIBILITY - Batteries may be used in series and/or parallel to obtain choice of voltage and capacity. Due to recent design breakthroughs, the same battery may be used in either cyclic or standby applications. Over 50 models are available to choose from.
    RUGGED CONSTRUCTION - The high-impact resistant battery case is made either of non-conductive ABS plastic or styrene. Large capacity batteries frequently have polypropylene cases, all of these materials impart great resistance to shock, vibration, chemicals and heat.
    COMPACT - Power-Sonic batteries use state of the art design, high grade materials, and a carefully controlled plate-making process to provide excellent output per cell. The high energy density provides superior power/volume and power/weight ratios.

    HIGH DISCHARGE RATE - Low internal resistance allows discharge currents of up to ten times the rated capacity of the battery. Relatively small batteries may thus be specified in applications requiring high peak currents.
    LONG SHELF LIFE - A low self-discharge rate may allow storage of fully charged batteries for up to a year at room temperature before charging is required. Lower storage temperatures enhance shelf life characteristics even further.
    WIDE OPERATING TEMPERATURE RANGE - Power-Sonic batteries may be discharged over a temperature range of -40 ºC to +60 ºC (-40 ºF to +140 ºF), and charged at temperatures ranging from -20 ºC to +50 ºC (4 ºF to +122 ºF).
    DEEP DISCHARGE RECOVERY - Special separators, advanced plate composition, and a carefully balanced electrolyte system have greatly improved the ability of recovering from excessively deep discharge. CONSTRUCTION PLATES (Electrodes) - Plate construction is the key to producing a good battery. Recognizing this, POWER-SONIC utilizes the latest technology and equipment to cast grids from a lead-calcium alloy free of antimony. The small amount of calcium and tin in the grid alloy imparts strength to the plate and guarantees durability even in extensive cycle service. Lead oxide paste is added to the grid to form the electrically active material. In the charged state, the negative plate paste is pure lead and that of the positive lead oxide. Both of these are in a porous or spongy form to optimize surface area and thereby maximize capacity.
    SEPARATORS: POWER-SONIC separators are made of non-woven glass fiber cloth with high heat and oxidation resistance. The material further offers superior electrolyte absorption and retaining ability, as well as excellent ion conductivity.
    ELECTROLYTE Immobilized dilute sulfuric acid: H2SO4.

    CONTAINER - Case material is ABS, high-impact plastic resin, styrene, or a polypropylene-polyethylene copolymer with high resistance to chemicals and flammability.
    LEAKPROOF DESIGN & OPERATIONAL SAFETY - POWER-SONIC batteries have been approved for shipment by air, both by D.O.T. and I.A.T.A. U.L.'s component recognition program for emergency lighting and power batteries lists POWER-SONIC under file numbers MH14328 and MH14838.

    TERMINALS - Depending on model, batteries come either with AMP Faston type terminals made of tin plated brass, (post type terminals of the same composition with threaded nut and bolt hardware.
     
  19. 2009Prius

    2009Prius A Wimpy DIYer

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    No outlet to connect to the vent tube?
     
  20. SteveLee

    SteveLee Active Member

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    Do you have a link? Yes, the vent tube is a must have.