A sailing boat question.

Hi.
I am trying to design a simple and efficient solar system for a sailing boat that is very similar to the one in the photograph (a Dick Newick trimaran). The boat has two 12v 105 amp gel batteries wired in parallel. It has two Lorentz 130 watt 24v PV modules placed in the same position as the one(s) in the photo, the rationale being that the further apart the modules, the less the chance that they will both be in shade (and shade happens !). My intention is to have each module wired to a separate SS-MPPT-15L solar controller. The rationale for the two controllers is that the modules are going to be at different angles to the sun and experiencing different shade patterns so I can't see how one charge controller would be able to run both modules at their MPPs. What I am wondering is , will the two controllers, wired to what is effectively a single battery , confuse each other ?

Cheers.
Graham.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,980 admin
    Re: A sailing boat question.

    No--you can parallel controllers on one battery bank. Unless the controllers have digital communications between each other (some higher end models do). They will not exactly track each other in charging modes as one controller things the battery is fully charged when the otherone does not (which is not a problem for the batteries--all averages out together in the end).

    Remember to add a Remote Battery Temperature Sensor to your system--If these are MorningStar MPPT controllers--the really need the RBTS.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: A sailing boat question.

    you can use separate controllers for the same battery bank as was said, but do not share the pvs by paralleling them.
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: A sailing boat question.

    Also, partial shading of one panel greatly affects PVs which are wired in series, but not so much PVs which are wired in parallel.
  • System2System2 Posts: 6,290 admin
    Re: A sailing boat question.

    Thanks for the answers, the controllers (MorningStar) won't share the pvs and I will get the RBTS(s).

    Cheers
    Graham.
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: A sailing boat question.
    dwh wrote: »
    Also, partial shading of one panel greatly affects PVs which are wired in series, but not so much PVs which are wired in parallel.

    Sorry, I was in a hurry when I wrote that.

    For panels in series, if one panel is in partial shade, it reduces the output of the whole string. In parallel, only the output of the panel actually in the shade is reduced - the others continue to put out full power.

    BTW - Nice Boat!
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