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Batteries/Charging

  1. Siren has 5 batteries.
    1. 1 Engine battery
    2. 2 House Bank 1 batteries wired in parallel
    3. 2 House Bank 2 batteries wired in parallel
    4. See the electrical diagram for details
      1. While discharging the batteries, each bank is isolated so a bad battery will not completely drain the other two banks.
      2. While charging, the BlueSea Charging Relay and the Newmar Battery Integrator automatically connect all banks. The boater just has to plug in the shore power to charge, no flipping battery switches.
      3. If charging by solar, the boater does nothing. When the sun is out, the batteries connect for charging. When there is no sun and the voltage drops below a set-point, the batteries automatically isolate themselves.
    5. New Batteries installed 07/13/2020
      1. $380 each from Battery Bill’s in Honolulu, HI
      2. Northstar NSB-AGM31
      3. 12 V
      4. AGM (Absorbed Glass Matt)
      5. Group 31 size
      6. 103 aH capacity
      7. 1150 CCA (Cold Cranking Amps)
      8. 1370 MCA (Marine Cranking Amps)
      9. Bluetooth capable, beaming out battery health, charge percentage and Volts to your app. I LOVE this!
    6. New batteries installed 06/30/2014
      1. $306 each from West Marine
      2. West Marine 15020258
      3. 12 V
      4. AGM
      5. Group 31
      6. 105 aH Capacity
      7. 1000 MCA
    7. Batteries installed from previous owner
      1. East Penn Deka 8A3DTM
      2. 12 V
      3. AGM
      4. Group 31
      5. 105 Ah
      6. 800 CCA
  2. Charging method
    1. Shore power
      1. A shore plug connects to the boat providing power to the Freedom F20 Inverter/Charger. This is a smart charger that can be configured for a wide variety of uses. It bulk charges until the voltage hits a set point, then starts the acceptance stage until the amps flowing into the batteries drop to another set point, and finally float charges to keep the batteries happy for a long lifespan.
      2. The batteries are monitored by the Heart Interface Link 2000. The user can read the Volts, Amps, Amp-hours used and time left to discharge on this interface. The user can also program the Freedom Charger settings through this panel. The panel however, does not control the actual charging of the batteries. The Freedom Charger itself is self-contained and will accurately charge the batteries even if the interface panel becomes disconnected or displays inaccurate information.
      3. When disconnected from shore power, the Freedom F20 Charger is no longer used for charging. Solar, wind and engine power each have their own smart chargers, so the Freedom’s only function at sea is to invert 12 VDC power to 110 VAC.
    2. Solar power
      1. 200 W of solar energy from two panels mounted on the bimini provide power to an MPPT Smart Charge Controller. Bulk, acceptance and float phases provide the correct voltage to the same power terminal used by all charging sources, including shore power. (Again, see the wiring diagram.)
      2. One issue while using solar power for charging at sea is when there is cloud cover, dropping the voltage below 13.2 V. In this case, the Charging Relay and Battery Integrator will not connect and only House 1 is charged. The solution to this cloudy weather problem is to connect the batteries together manually. Turn all battery switches on, including House 1 and House 2 to charge the house batteries and Engine and Combined to charge the engine battery. Note that if the solar voltage drops below the lowest battery voltage, that battery will then start charging from a fuller battery! Close monitoring is required.
    3. Engine power
      1. The engine alternator can provide power, converting diesel into electricity.
      2. The alternator sends up to 130 A to the Balmar Alternator Regulator, also a three phase smart charger. (2 green lights is Bulk, 3 green lights is Accept and 4 green lights is Float.) The regulator requires a special magnetic tool to configure it’s setting, but once set it doesn’t need to be touched. If I decide to change over to Lead Acid rather than AGM, however, I’d have to change that setting on all of the smart chargers.
      3. The Alternator Regulator sends the correct voltage to the shared power terminal where it is then distributed to the batteries.
    4. Wind power
      1. Siren had wind power when I bought her, but I removed it since it was old, noisy and then threw a blade into a crew-member’s leg halfway to Molokai (5 stitches and a good story behind the scar.
      2. The wind power can feed into the same solar controller which will regulate the power into Bulk, Accept and Float stages on to the shared power terminal and on to the batteries.
Battery compartment diagram
Simplified charging diagram
5 new batteries!
Strapped in and ready for anything
The old batteries lasted 6 years.
Bulged, cracked and too hot to touch.
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