CTEK Multi US 7002 for charging 12V battery

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by srivenkat, May 30, 2012.

  1. srivenkat

    srivenkat Active Member

    Joined:
    Feb 28, 2011
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    Location:
    IL
    Vehicle:
    2021 Prius Prime
    Model:
    XLE
    Folks,

    A few weeks back I saw the "Check Hybrid System" message which went away after
    3 restarts of the system. The dealer was able to get to the codes when I took the car
    in for an oil change. The issue was some sort of a communication failure with the
    12V battery typically caused by the 12V battery charge momentarily being low
    sometimes. He didn't mention I should replace the battery so I assume the 12V battery
    is still good. When I check the voltage at the terminals using a cheap non-digital multimeter, it
    shows up as slightly below 12V. My daily commutes are about 3.7 miles each way.

    So, now I am looking at the CTEK Multi US 7002 charger and one question I have is
    would it be OK to connect it to the jump terminals in the hood? The manual recommends
    not exceeding 4.2 Amps and this charger says it will supply a "7A max". Does that mean
    it will not generate more amps than necessary or demanded by the battery/system?

    The reason I am interested in the 7002 Vs the 3300 is that the former has an 8-phase
    charging process while the latter has a 4-phase process.

    Also, another question I have is, once the Hybrid System is on (Ready), do the
    accessories continue to be powered by the 12V or does the traction battery power
    these in addition to charging the 12V battery?

    Many thanks.
     
    #1 srivenkat, May 30, 2012
  2. tumbleweed

    tumbleweed Senior Member

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    Eastern Oregon
    Vehicle:
    2010 Prius
    Model:
    V
    When the car is in Ready the HV battery supplies the 12V system charging the 12V battery and supplying power to everything. The charger you mentioned will only supply 7 amps if the battery voltage is pretty low but to be on the safe side why not look for a charger with a lower rating.
     
    #2 tumbleweed, May 30, 2012
  3. szgabor

    szgabor Active Member

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    Location:
    Oceanside NY
    Vehicle:
    2012 Prius
    Model:
    Two
    If the 12V battery is depleted 3.7 miles normally will NOT be sufficient to fully recharge it. Especially in the winter. If the 12V battery stays extended period undercharge or really deeply discharged it may suffer damage Prius' battery more susceptible because it is relatively small.

    Check your manual, it has a table on off load voltage levels and state of battery ... you would need to wait an hour or more before measuring.

    Unless this is a smart charger 7A steady will damage the battery.

    Sounds like a smart charger but you should check the specs ... because, again the Prius' battery is about half the size of regular car battery what the charges expect.

    As Tom said, in ready mode the traction battery supplies the current via a DC/DC converter (in a somewhat complex way depending on many circumstances: like, load, 12V battery temp, 12V battery status (voltage). And this is the ONLY way safely use any accessories (perhaps beside your radio even headlights will quickly deplete the small batter)


    Cheers
     
    #3 szgabor, May 31, 2012
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