Re: New LiFePO4 Batteries for Aquarius


Jose Venegas
 

Ken,
Very nice video, thank you.  I love the way you cleaned up the spaghetti of cables behind the two large DC switches.   At the end of the video, you mention that you were going to install switches to control the source of the 220 V input to the boat ac systems. 
If you have not done it yet, or others are planning on doing it, my experience with this may be helpful. 
After installing my LiFePO4 batteries (8 Battle Born 100 AH) I installed a 5000 W inverter,  I connected its output to an outlet that I added to the white box on the engine compartment.  In my boat, that white box had originally two outlets: one from the shore power direct 220V and the second one from shore power at 110V that was passed through a transformer to give 220V.  There is also a large plug that can be connected to either outlet providing power to all the ac outlets and 220V devices of the boat including the water maker.  The cables coming from this plug go through the AMEL installed solenoid that automatically disconnects shore power and connects the output of the generator to the 220V boat circuits including all outlets, all appliances, air conditioning units, and battery chargers. Adding a 3rd outlet and connecting it to the output of the 5kW inverter allowed me to easily provide power from the inverter to the 220V boat circuits with minimal circuit changes. In fact, it also allows running the watermaker of the batteries !!!  The only issue came from the possibility of leaving one or two of the battery chargers ON while running from the inverter; a situation that you can imagine was highly undesirable.  In fact, the first day after the installation of the inverter,  I was charging the batteries with the generator and forgot to disconnect the battery chargers before turning OFF the generator.  The result was that all kinds of alarms and blinking LEDs came out of the inverter but there was no damage.  Obviously charging the batteries with energy coming from the batteries has a VERY  negative efficiency!!.  To solve this problem I installed two small ac activated NC relays on the cables feeding the battery chargers so that they would be open if the inverter is ON and the generator is not running.  As soon as the generator is turned on, the relays close, and the battery chargers can do their work.  This solution worked like a charm and I can leave the switches for the battery chargers ON when the inverter is ON, since the battery chargers are automatically turned OFF.  However, they will be activated as soon as the generator is started.  The relays are small enough to fit inside the AC box behind the switches.
Hope this is not too confusing but I will be happy to include a circuit drawing illustration for those interested.   

Jose Venegas
Ipanema
SM2K278.
Currently in Cartagena de Indias Colombia

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