Hello from southern Chesapeake Bay

phillard · **Joined:** 10 Jul 2007 14:32 **Posts:** 10

We bought SENARA in August '06. She was in great shape with many upgrades, but we went a little farther by entirely upgrading the electrical system. Now everything stays cold in the fridge while we are on the hook for a few days. We just returned from a 2 week cruise around the Chesapeake Bay - we love her! Glad to be part of the T37 forum.

T37Chef · **Posted:** 10 Jul 2007 18:22

Welcome,

Would you share what your using for refrigeration and what electrical upgrades you did. We too just got from a 5 day trip on the bay, we have a cold plate but in this heat it needed about and hour of the engine running to refreeze her? (Didn?t matter much as we ended up motoring allot on Saturday and Sunday
Embarassed

)

phillard · **Joined:** 10 Jul 2007 14:32 **Posts:** 10

Sure! I moved the hot water heater further aft, and used the space for one of the two new 8-D AGM house batteries. So now we have a standard AGM starting battery, plus the two 8-D batteries for house. We set up an "auto parallel" switch to protect the starting battery. So when drawing down current, if the starting battery drops to 12.6 volts, the system switches over to the house set. When charging, the system charges the starting battery up to 13.6 then the system switches over to charge the house set. Additionally, we upgraded the alternator to a 100 amp to handle this. We added breakers for new circuits and installed a Xantrex battery monitoring system to be able to see all of the loads and statuses. Sounds like overkill - but when you do a load calculation including our Adler Barbor fridge unit, new instruments, stereo, lights, VHF, etc. it really adds up to a lot of load. We also had to consider the fact that we like to stay out on the hook for a few days at a time. Then you have to consider the manufacturer's recommendation of not drawing down any battery below 50% - so now you need double the load calcs. Therefore the size 8-D batteries. Things stay cold, the boat always starts, and any rafters come aboard in the evening because we can turn on the lights. I hope that helps explain. I do have a set of electrical drawings if you are interested.

Jay · **Joined:** 22 Oct 2006 19:25 **Posts:** 61

We had two 8Ds for house batteries and a Group 27 flooded battery for the engine. When it came time to replace the 8Ds we opted for four 6 volt Trojan T-105s, a battery box, and a profill watering system. The 8D's prematurely failed due to a PO charging them with a 2 stage charger/inverter designed for flooded batteries. Rather than replace the charger/inverter with a 3 stage designed for AGM, the flooded battery alternative at $350 for 460 amp-hours made much more sense. Jay.

phillard · **Joined:** 10 Jul 2007 14:32 **Posts:** 10

Good point - when you switch to AGMs, you have to upgrade/change the charger. I also took another recommendation and upgraded the voltage regulator while upgrading the alternator.

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