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Thread: Charging issues

  1. #1
    Join Date
    Oct 2012
    Location
    Southminster, essex
    Posts
    9,222

    Default Charging issues

    I have a 15 amp dolphin triple stage charger powered from shore power.This is connected to starter as principle battery & domestic bank as secondary bank
    I have a red flash starter battery (new)
    I have 2/ 90 amp agm domestic batteries
    I have a victron VCR fitted this year
    My alternator was serviced at the start of the season
    Alternator charges at 14.4 volts as shown on NASA BM1( fitted to domestics only so cannot tell what goes to starter)
    Shore charger floats at 13.7 to domestics as shown on BM1but recently started to boost at 14.7 V
    Do not know what charges are to starter as not shown on BM1
    I do not have fridges etc only basic instruments & autopilot which are turned off in port.
    Engine is Volvo MD2020D with standard alternator

    What concerns me is that even after as much as up to 10 hours motoring, if I immediately connect the shore power, the fan on the shore power charger comes on (does that when main charging as opposed to trickle charging) indicating that it still has to top up the batteries. This can run for as much as 30 minutes & the BM1 shows that the amperage to the domestics starts as high as 7 amps & up to 14.7V, gradually dropping off before going to float mode. Is it possible that the charge is going to the starter & trickling back to the domestics?

    I find that on checking voltages they balance out after 48 hours. The starter is never noticeably higher than the domestics

    Could this be a fault in the VCR stopping alternator charge going to the starter battery meaning that the starter has not been charged by the alternator & has been drained somehow?
    I have checked it is wired correctly.
    How do i check it is working correctly ?
    Is the shore charger then actually charging the starter which is then somehow sending power to the domestics which is why the BM1 shows high charge rate? How do i check?

    I ask because I have just had to fork out £150-00 for a new Red Flash after 18 months as the last one died after less than 18 months inspite of regular charging over the winter. I do not want a repeat
    It is all down to the fact that my wife does not understand me !!

  2. #2
    Join Date
    Apr 2002
    Location
    Cornwall
    Posts
    8,811

    Default Re: Charging issues

    The alternator should be connected direct to the engine battery, charge to engine battery does not go through VSR. It only parallels the service bank with the engine battery, it is more complicated but do not worry.

    When the mains charger is on, the VSR will link banks as one, so mains charger is only charging one bank of three batteries,

    If alternator is running at 14.4 volt it will not fully charge batteries, connecting mains charger @ 14.7 volt will put further charge into the battery as you are seeing.

    You need a multimeter and check engine battery matches service battery on charge, if so all is working.

    Brian
    Kddpowercentre VASR charge

  3. #3
    Join Date
    May 2007
    Posts
    37,270

    Default Re: Charging issues

    Sounds like your Red Flash has died of overcharging.
    Due to the VCR, it's connected to the house bank whenever the engine is running or the shorepower is connected.

    The battery charger is putting out high voltages which may be OK for the house batteries.
    It is starting with a boost cycle which will be unnecessary when the engine has just been run for a long time.
    The BM1's shunt adds impedance so the engine battery takes more current than it should.

    My suggestion would be to switch off the VSR when on shore power. Connect the shore power cherger to the house batts only.
    If the boat is going to be unused for a longish period connect a maintenance charger to the engine battery, like a little Ctek or perhaps a small solar panel and float controller. Or just manually connect it to the charger once a month for some hours in the winter.

    You could also look at the settings of the charger, I'm not familiar with that brand.

  4. #4
    Join Date
    Apr 2002
    Location
    Cornwall
    Posts
    8,811

    Default Re: Charging issues

    Quote Originally Posted by lw395 View Post
    Sounds like your Red Flash has died of overcharging.
    Due to the VCR, it's connected to the house bank whenever the engine is running or the shorepower is connected.
    .
    The engine battery will stop taking charge if a fixed voltage is present, i.e. 14.4 volt, current will slowly fall to a few milliamp, theory behind the VSR

    Problems can arise from different charge voltages with different types of battery, that needs looking into manufactures spec's, but a switch in the VSR neg will isolate VSR during mains charging.

    Brian
    Kddpowercentre VASR charge

  5. #5
    Join Date
    Mar 2006
    Location
    Manchester
    Posts
    16,916

    Default Re: Charging issues

    I think my chargers, (240V connected to shoreline), both run at absorption voltage for a minimum of an hour, whatever the state of charge of the batteries, then they revert to float. There is an algorithm used when they are started to assess whether they need to run for longer than 1 hour, so the hour is a minimum.

    So I would not be surprised to see 14.4v, (or whatever you have absorption voltage set at), for an hour after turning on the shore power.

    Whether that is the cause of your batterys demise - I dont know.
    Narrowboating From Stretford!!

  6. #6
    Join Date
    May 2007
    Posts
    37,270

    Default Re: Charging issues

    Quote Originally Posted by Richard10002 View Post
    I think my chargers, (240V connected to shoreline), both run at absorption voltage for a minimum of an hour, whatever the state of charge of the batteries, then they revert to float. There is an algorithm used when they are started to assess whether they need to run for longer than 1 hour, so the hour is a minimum.

    So I would not be surprised to see 14.4v, (or whatever you have absorption voltage set at), for an hour after turning on the shore power.

    Whether that is the cause of your batterys demise - I dont know.
    Most chargers start off with a minimum period of absorption.
    The issue is probably how does this charger decide when to go to float?
    The house batteries are possibly causing it to delay going into float long after the Red Flash is fully charged.

    OTOH, I think Red Flash batteries are only warranted for a year, so maybe 18months is what you should expect?
    A few Land Rover abusers I know have decided that RF batteries are overhyped. YMMV.
    I suggest RTFM and make sure the charger is giving it what it wants. Or buy something you can top up perhaps.

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