Forum Discussion

JKFlipFlop's avatar
JKFlipFlop
Explorer
Sep 15, 2014

Battery Isolators damaging your deep cycles?

Guys,

In order to get a full life span out of your deep cycle auxiliary batterys they are SUPPOSED to be charged using a 3 stage cycle.

Bulk charge, absorption charge, then float charge.

Any 3 stage battery charger will accomplish this and solar panel
charge controllers do this automatically.

If you are using a battery isolator, all it does is connect your alternator to your aux battery bank once your starter battery has reached full charge.

In other words, you are charging your battery bank without any 3 stage method. Does this mean a large majority of RV owns are damaging their deep cycle batteries?

1 Reply

  • RoyB's avatar
    RoyB
    Explorer II
    When you are saying BATTERY ISOLATOR I am assuming you are referring to a SMART RELAY type battery isolator and not a high current diode type.

    The SMART RELAY type monitors the battery voltages and will switch into the alternator system when needed charged but only when the ALTERNATOR is in CHARGE MODE. The ALTERNATOR system also produces the various different stage voltages. I see DC voltages across my truck start battery in the different charge stage modes all the time ranging from 13.2VDC to 14.4VDC.

    The real important about the smart relays is they will switch away from your truck start battery/alternator setup when the extra battery is below 50% charge state so to not run down the truck start battery.

    Here is a good description on how the BLUE SEA SI-ACR SMART RELAY works.


    BLUE SEA SI-ACR SMART RELAY

    SI-ACR RELAY functions explained

    MORE SI-ACR RELAY INFO