Dedicated fridge battery ?

[grafozz]

I have bought a new battery of 90 A/H to run the fridge on ,
it will be charged by a dedicated solar panel of 80W charging for 8 hours (Greece ) = 24 amps - average 3 amps input - peak 5.5 amps as tested ,
I estimate the fridge will consume 2.5 amps for 12 hours running ( 50% running time ) = 30 amps drain

this would give a net battery drain of around 6 a/h which at 90 amps is a very small demand and give plenty of spare capacity .

I want to fit a switch in to the fridge wiring circuit so that the fridge can be switched back to the ships batteries at any time

can anyone show me how to wire a switch so that the fridge can be switched between the solar panel/ regulator and back to the ships batteries ,please ?

thanks ,
grafozz

 

[nimbusgb]

Once again mixed units of measurement.

What fridge unit? My very efficient Danfoss compressor runs at about 4 to 5 amps.

I agree you should get 20 - 25 Amp Hours out of the panel in summer.

If the fridge is running 50% of the time 24 hours a day ( 5 amps for 12 hours ) = 60 amp hours.

You are losing 30 Amp hours plus a day.

A simple single pole double throw switch would do what you want. Common connector to the Fridge power circuit, each of the poles to a separate battery.

View attachment 30073

You would do better to add the 90 a/h battery to the house bank in parallel. The added capacity is more beneficial this way because the total discharge over the bank is spread over more cells and results in a lower depth of discharge and an increase in battery life!

 

[macd]

+1 on all in nimbusgb's post, with the rider that it's possible the fridge could draw fewer than his Danfoss: the one on my last boat peaked at 3A drain. A dedicated fridge battery is just added complication with, if anything, a negative working effect.

 

[grafozz]

thanks , guys , good switch diagram .

I have a BM1 on each bank and when all is off then the fridge is switched on it shows a draw of 2.3 amps during on cycle .

it is a Shoreline 100 ltr fridge

 

[nimbusgb]

Pretty good current draw for a fridge, so your 30 Ahr is closer to reality provided it can maintain that duty cycle.