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egarant's avatar
egarant
Explorer III
Apr 14, 2014

Solar Charge Cotroller

Hi All,

I recently purchased a Trace 20 am MPPT Solar Charge Controller from Amazon.

I have two Sears Group 31 Platinum (same as Odyssey) AGM 12v batteries fora total of 200 amp hours.

A few items have raised my eyebrows since I opened the manual.

One, it has only settings for GEL, FLOODED and SEALED....no setting for AGM.

The charge rate on the Trace controller is:

Boost (Absorption): 14.4 for Sealed, 14.6 for Flooded, 14.2 for Gel
Float: 13.8 for everything
Equalization: 14.6 for Sealed, 14.8 for Flooded, none for Gel

From what I have read, both the Bulk and Float (especially) rates seem high.

Too high?
  • HMS_Beagle's avatar
    HMS_Beagle
    Explorer
    Apr 14, 2014
    For AGMs, put in on the flooded settings. 14.6 bulk should be OK for AGMs, 13.8 float again good, maybe a little high. The 13.8 would be way high for flooded batteries in my opinion, unless you like putting water in them every week. For AGMs, you really should have temperature compensation if you are leaving them on float. Odyssey for example says 13.7 at 20deg C, 14.4 at 0deg C, 13.4 at 40 deg C. That's a pretty big range.

    The number one killer of AGM batteries seems to be failure to charge completely every couple of weeks, number two is float voltage inaccurate for conditions (temp). Flooded batteries are tolerate of both.

    Odyessy information is available here.
  • 2oldman's avatar
    2oldman
    Explorer II
    Apr 14, 2014
    I would consult the battery specs for that information.

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