Charging my AGM batteries

basewindow
basewindow Solar Expert Posts: 63 ✭✭
in Off Grid Solar & Battery Systems #1
Hi all again from OZ

I know there has been some discussion in relation to this and I have read a number of posts etc, but I just want to confirm a few things.

I purchased a Solar Regulator that had settings for AGM batteries. This was the default setting, which I connected it all up and everything seemed okay, however...

Having checked the Batteries (Vision 6FM100 12v) themselves they state:
Constant Voltage Charge
Cycle Use: 14.4-14.7V
Standby: 13.6-13.8V

I have checked my Regulator settings for the AGM settings and they are:
Bulk Charge/Absorption: 14.3V
Float: 13.5V

Am I right in assuming the terminology used, Cycle Use=Bulk/Absorption and Standby=Float???

If so Have I been under charging my batteries for the last year, and should I adjust my Regulator settings to something more like:

Bulk=14.5v or 14.6v and Float=13.6v or 13.7v

Any advise would be welcome.

Cheers, Cam.
Off Grid shack - Victoria Australia. 480W array, 500Ah AGM at 12V. 30A PWM Manison CC. Trimetric 2030. 300W Pure Sine Inverter. 120lt Dometic Gas Fridge. Composting Toilet. 5000lt water tank with 12v 35psi pump. Bosch Hydropower 16 for nice hot water. 4kw Fuji Micro Generator (dead after 7 years) 5kva Subaru Generator.
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Comments

  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #2
    Re: Charging my AGM batteries

    Cam, from here http://www.mce-ups.com/images/product_level5/download/6fm100-x.pdf ,
    it calls for a Constant Voltage charge at 14.4 to 14.7 V and a max current of 30 amps
    also calls for temperature compensation if you have it on your charge controller

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • basewindow
    basewindow Solar Expert Posts: 63 ✭✭
    #3
    Re: Charging my AGM batteries

    Okay. Well the Reg has a set point of 14.3v for the Bulk Charge. It would appear the panel puts in about 6-7amps during this stage and obviously tapers off with the Absorption phase.
    What I was asking is I suppose, is the variance of 0.1v or 0.2v of the Reg set point of 14.3 compared to the recommended of the battery (14.4-14.7v) going to make any difference to the % charged of the battery or the battery life?
    And should I adjust the Reg Bulk set point to something higher?
    Thanks
    Cam
    Off Grid shack - Victoria Australia. 480W array, 500Ah AGM at 12V. 30A PWM Manison CC. Trimetric 2030. 300W Pure Sine Inverter. 120lt Dometic Gas Fridge. Composting Toilet. 5000lt water tank with 12v 35psi pump. Bosch Hydropower 16 for nice hot water. 4kw Fuji Micro Generator (dead after 7 years) 5kva Subaru Generator.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
    Re: Charging my AGM batteries

    yes, i would raise it to maybe 14.55v at least, but minimally to 14.4v. the 14.4v to 14.5v range may be good to do if battery temps are above 25 degrees c and you haven't any temperature sensor. similar with the float voltage being centered in the range and lower to maybe 13.5v with high temps. if you experience cool battery temps (say 10 degree c range) and no temp sensor you may need to raise those voltages to the upper end of that charge range specs.
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  • basewindow
    basewindow Solar Expert Posts: 63 ✭✭
    #5
    Re: Charging my AGM batteries

    Thanks.
    I've just bought a battery temp sensor but haven't installed it yet. Which battery of my two to I stick it to or doesn't it matter. Temps range from 10(night)-30C(day) in summer and 0-18 in winter. Will the sensor automatically adjust the voltage when I install it? (Spoze I should just read the manual)

    Cam.
    Off Grid shack - Victoria Australia. 480W array, 500Ah AGM at 12V. 30A PWM Manison CC. Trimetric 2030. 300W Pure Sine Inverter. 120lt Dometic Gas Fridge. Composting Toilet. 5000lt water tank with 12v 35psi pump. Bosch Hydropower 16 for nice hot water. 4kw Fuji Micro Generator (dead after 7 years) 5kva Subaru Generator.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #6
    Re: Charging my AGM batteries

    a sensor should allow for the controller to automatically shift the voltages to suit the battery temps. it shouldn't matter which one you put it on, but if they give instructions on where they prefer the sensor to be placed on a battery then follow those directions. you should also check the amount of offset the batteries require and if the controller will meet that spec. common is 5mv per degree c difference per cell. my agms call for 4mv/degree c/cell and many controllers do not adjust, but mine does.

    with a sensor in place then center the voltages for absorb and float in their respective range without the sensor in place first and then connect the sensor.
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