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Lithium Iron Phosphate - off grid power

Q1: Welcome to Off Grid living.

Li Fe PO4 Battery technology

Custom Lithium from Brisbane is perhaps the best technology on the market. With a Smart Battery Monitor built into the 24 Volt cells, the battery is protected from over charge, under charge and balance issues.

Here is the new technology running on Nickel Iron Phosphate technology.

However the old batteries could not push out the required 45 amps for very long.

So I purchased a 24Volt LiFePO4 cell at 310Amp/hr, and running this to a low cut out voltage of 25.1 Volts, this leaves around 80% of the State of Charge left, about 250 Amp hr to run the Inverter all night.

The inverter needs 25 to 45 Amps to run, assuming 20 Amps continously.

So running 15 hours each day without sunshine, drains 300 Amp/hr every day.

So the battery cell is ran flat to 25.1V every day.

Initially the Inverter was switching off too often ( low battery Voltage warning ? ) and reading up on Victron Forums, I discovered poor connections might be the problem?

So throwing away re-settable fuse breakers and buying a fixed fuse that blows up when overloaded, I installed a fixed fuse holder with a 70 Amp fuse.

Upgraded the wire lug to a 10mm fixing hole and 25mm cable.

Now things seem running nicely.

The Inverter is draining 45 Amps and the Voltage is 26.3V

( I use cheaper Hall Effect Ammeters, rather than fancy Victron products)

The solar panels are still pushing 11 Amps into the batteries, despite it nearly being dark.

A picture of the Inverter Custom Li Fe PO4 battery and the three Solar Controllers

The red arrow shows the solid fuse I replaced the other faulty fuse system.

The view from the other side, showing Air Conditioner and Inverter.

Between is a switch for turning on Hall Effect Sensors to read current coming into battery and current leaving battery.

I like to keep things simple.

On it's first virgin run, the Air Conditioner gets the room to 9 degrees.

Now lets see how this goes into the night, and how long the room needs to be switched on to cool and how long the Air Conditioner is switched off for.

Will the 300 Amp/hr make it through the night ?

Its 7:30 pm on the first night, draining still at 43 Amps.

The room is at 8 degrees, but not its mass. So I suspect it will take many hours of cooling before the Inverter switches off and the desired temperature is reached. Let's hope so and let's hope the battery get through the night.

Li-Fe PO4 battery technology

Created by Rob Thompson. Hosted since 10/01/2012.

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