Author Topic: How many 250 watt solar panels can I hook up to a MNKIDD-M-W controller?  (Read 629 times)

Lake of the Woods

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This is my first post and I am not very knowledgeable about this subject so please bare with me.

I have a MNKIDD-M-W marine controller on my boat hooked up to 2 x 250 watt solar panels (500 watts total) used to charge my 2 - Rolls 12 volt (S12-290 AGM) batteries.  260AH@20HR, 280AH@72HR, 290AH@100HR.  The batteries recommended charge current is 52A and the max charge current is 91A.

I'm not sure what all this means but my question is will my charge controller handle a third 250 watt panel? Would a third 250 watt panel (for a total of 750 total charging watts) be overkill for my current charging setup?  I also have a 40 amp battery charges for when I am on shore power and a 9kw generator that can power the battery charger when I am off shore power.

My 2 Rolls batteries start my 2 gas engines and also work as house batteries for the boat.  I also have a 2000 watt pure sine inverter hooked up to the batteries to run my LCD TV.  I never let my batteries go below 50% charge.

Mark
Lake of the Woods

Vic

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Hi Mark,   Welcome to the Forum.

It appears that the two 12 volt batteries are connected in parallel  --   a 12 V system  -- is this correct?

If that is correct,   then 750 Watts of PV is a bit excessive.

Here is the PV String Sizing Tool,  where you can enter the data on your system"
http://midnitesolar.com/sizingTool_kid/index.php

Let us know the Sizers results.   Thanks,    Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

Lake of the Woods

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Hi Vic,

Thanks for the response.  I'm not at my boat so I can't check the specs on my controller for a few days.  I don't know what PV means? and the sizing tool lexicon is Klingon to me.  My batteries are set up to be independent (but there is a switch to charge battery 1, or battery 2, or battery 1 & 2).  The boat is also set up with a switch to allow the batteries to be parallel briefly in the event that one battery fails.  The set up is one battery starts the starboard engine (gas) and also serves as the house battery (lights, toile x 2 pump, water pump, car radios, refrigerator / freezer (norcold), bilge pumps x 5, bridge electronics.  The other battery is set up to start the Port engine and 9 kw generator.

I'm not sure if that helps.  The fridge is the battery pig and uses about 6 amps of power.  The rest of the 12 VDC electrical is minor (lights LED) pumps do not go on very often.  I have no issues during the daylight hours but I do get nervous sometimes in the night as the fridge likes to burn battery power.  I suspect I will eventually look at Lipol batteries for the house, but then I'm into different battery charger / inverter setup and much more money.  I'm just out of my league with this stuff.

Mark
Lake of the Woods

Vic

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Hi Mark,

Ran the Kid Sizer,  with some made-up numbers for the PVs (ie Photovoltaic Solar Modules (panels)),  and assumed that the PVs would be in parallel.

The result is attached.     Later, Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!