Pearson Boats - Common Systems > Electrical Systems & Electronics

Modernizing a 40+ Year Old 12v System. GROUP DISCUSSION

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selene:
Between Ed and Michael I am totally outclassed...so back to a few basics from me!

- Selene still has the two 110ah batteries, I don't have a fridge (yet) and my cruises are normally short, 3-5 days, so with solar and a bit of motoring that suffices. But I do plan on adding a starter battery when I find the right place for it.

- BIG fan of battery monitors - very useful. I have a spreadsheet with power consumption for each circuit, useful for monitoring, planning and more. Installed by the PO, Selene has Xantrex link monitor (coupled with Xantrex Truecharge charge controller).

As an aside, have you discovered https://marinehowto.com/? Great site (IMHO), he recommends a Balmar battery monitor.

- I went for the Morningstar Sunsaver Duo PWM controller (works well with two batteries). I only have a small 45w panel.

- I quickly ran out of switches, and added a secondary 8-switch 12v panel at the chart table seat back. Bluesea 8370 Circuit Mini Switch Panel. If I were to do it all again, I would go for something like this: https://www.bluesea.com/products/8380/DC_Main_%2B_22_Positions_White_Toggle - I think it will  fit the space where the current panel is. Incidentally, 22 switches seems like a lot, but I am now at 18 circuits, and ideally could add one more.

Valor:
Selene, Thanks for jumping on. I don't have a battery monitor as of yet.

How do you calibrate the monitor to the batteries? Do you subtract annually for loss of  battery capacity? If so, do you just  subtract something like 3% per year or is there a mechanical means to figure that out?

Does that Blue Seas panel you listed actually fit on our boat where the existing panel is? It looks really nice.

selene:
I'll be honest, I don't worry about recalibrating for capacity loss. In theory a modern battery monitor will deal with this automatically, continuously monitor battery usage, providing feedback as to the state of charge, battery health (available capacity), an indication of remaining capacity (based on your typical usage) - as well as other stuff, such as the obvious (such as volts and amps!).

But Ed is the electrical oracle!

As for the panel, I measured (twice) and it **should** fit (I think). Obviously check yourself! The real gotcha is that there is not a lot of real estate on the aft of the bulkhead, and the panel will eat up a lot of available space. This will require planning not only for the live circuits (connecting to the switches) but also the return/ground circuits. When I installed the secondary panel, some of the wires were the wrong length, so I put in a connection block between the existing wiring and the new panel. I bet you will also need some intermediate connection blocks.

Many other learnings from adding the secondary panel; I could go on, but key ones were:
- Connectors are expensive, there are a surprising number needed, and $ add up fast! Look for bulk deals, not many little boxes of 5. Ditto wiring. A spool length of Ancor (marine-grade) wire may be worthwhile.
- It's a good opportunity to label wiring! And a good opportunity to clean things up generally, and make the wiring runs and grouping clearer and more logical.
- There are a lot of ground circuits involved! I set up a row of grounding busses, mirroring the live circuits.

Oh, yeah, a good crimper and wire stripper is essential!! :-)

Alma:
An additional advantage of the DC-DC charger is allowing a high voltage input from solar panels wired in series. Two 40 volt panels in series (@660 watts!) is only 10 amps and 10 gauge wire can handle the load. VICTRON has a suite of modules that work well together.

Agreed the 323s have issues with trim under power and my 323 has a 12 gallon water heater (and the head and nav station) on the starboard side that contributes to a very slight list that would be exaggerated with batteries mounted on the starboard side close to the stern.

When I cut open the port side settee for a new water bladder I found a very nice space forward of the tankage that I think would be a good spot for an additional battery.

Cabling from the bow for batteries would be costly but its benefit would be worth it. Standard lead acid batteries would be subject to the exaggerated motion of the bow so good practice with VENTILATED battery boxes is recommended.

We primarily day sail out of a marina so our simple bone-stock two battery setup with a Balmar and old-school Balmar smart regulator suits us fine. So much so that I have jumped the battery temperature input to force the Balmar to be limited to only 30 amps charging. Nothing stirs the blood like having an alternator come off cold start and ramp up charging to a point the engine stalls. This so-called ‘small engine’ jumper is simple enough to disconnect for full output but we have never needed the Balmar’s full output. I’m guessing this configuration will increase the lifespan of all the components in the DC system.

I would love to see an elegant solar arch for a 323. Has anyone seen one?

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