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Need a battery and wiring Diagram

Old 11-21-2016, 08:37 PM
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Default Need a battery and wiring Diagram

Hi guys.
I have been rebuilding a 1989 28ft Randell with a 165hp volvo penta. Just about finished but would like to rewire the batteries but not sure how to wire up. She has 2x12v starting batteries, 2x12v house or accessories batteries. 2x cohertsy switches. Im adding a 240w solar panel and a 1500w inverter. Could anyone help me out with a diagram and what else i would need IE brakers and size. Charging isolators etc.
Any help would be much appreciated.
Old 11-23-2016, 02:30 PM
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Breaker size will be determined by wire size.

You size your wires to ensure acceptable voltage drop for your load and distance using a calculator like the one available on the BlueSeas website. Your chosen wire will have a maximum rating in amps.

Then you choose a breaker with a trip rating that is: -
- More than your expected load
- Less than your wires capacity

You might also want to consider replacing your switches with a battery management panel from Marinco or BlueSeas. This will greatly simplify layout and automate battery charging.

I know nothing about solar or inverters sorry.
Old 11-23-2016, 05:00 PM
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Thanks for the tips Mike!
Old 11-23-2016, 07:22 PM
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As for solar, you won't get 240 Watts. Panels are sized on there maximum loaded voltage approx 18 volts not 12. Which equates to 13 amps not 20 amps. The output on a bright sunny over a 10 hour period and various angles will generate on average 6 amphours = 60 amps / day.
The output of the panel goes to a voltage regulator to provide 14.7 bulk and drops to 13.8 for trickle but there are 2 types. One is MPPT for maximum power point tracking and PWM types for Pulse Width Modulation. The former allows panels to be wired in series to create 48 volts and take advantage of using smaller cable over long runs because voltage drop to the regulator, which should be at the batteries, is not of concern. The PWM type can't accept a higher voltage. The point of all this is that your inverter which I take to mean inverting the 12 volts DC from the batteries, to 120 vac will not receive enough charge from the solar. At 1500 Watts max output you will have 12 amps @ 120, but the inverter will need 150 amps from 12 volts to provide it.
Hope this helps in your calculations. Solar is only good for a backup unless you have lots of panels. The last point, depending on the solar regulators voltage output, the solar may stop the charging from any constant voltage charging source such as your engine alternator if the solar regulator voltage is greater than the alternator. You need to provide isolation via a relay, wired to the ignition so that the solar regulator is disconnected when engine is running to maintain isolation.

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