Simple answer

[GILow]

Originally Posted by jp.beauchemin71

My roof is nearly flat and I dont think shade will be a huge problem.

Does this boat have a mast?


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[jp.beauchemin71]

No mast its a 28' power trimaran.

[four winds]

Originally Posted by jp.beauchemin71

No mast its a 28' power trimaran.

Nice, sounds like a good candidate for an all electric boat and an enthusiastic sailor. I might be profiling a bit, but it seems tri owners fall in the can/do sail camp.

Edit,...... Oh snap, you said power tri.!.

Enjoy the challenge. Don't plan long routes. A long distance electric powered tri has no simple solution.

[GILow]

Originally Posted by jp.beauchemin71

No mast its a 28' power trimaran.

Well that will help but I would still be worried about relying on series panel voltages. I guess you can but try and see how it works out. I feel it will be disappointing in overall performance. It's not going to start charging until later in the morning than you'd like and it will stop charging earlier in the afternoon too. Crossing my fingers for you.


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[smac999]

Originally Posted by jp.beauchemin71

yes its mainly for running my 48volt outboard. My house current is tiny a few LED lights and charger for cell and table. So would this work: I wire the Panels so they put out 72V. Use this MPPT (It's the cheapest 40A I could find that will handle 72in - 48 out).Then use a completely separate small system for house power.

if this is the only means of making the boat run (charging the engine batteries) you probably want to buy the best, not the cheapest....

for house you could probably find a 48-12v dc to dc charger and add a small 12v battery. or a 48-12v dc power supply with no battery. but battery adds more safty if the unit ever failed.

[jp.beauchemin71]

Well truth is I wish it was a sailing Tri. Used to have a Searunner 31 but alas my physical condition doesnt allow me to do to much sailing anymore so I found a design for a low-power Tri with more interior space. The Electric outboard I use for short trips and where I live (Ottawa, ON) there are locks everywhere so Electric is easy. I do have a 9.9 but just use it on long runs. And truth is the best is just out of my price range.

[four winds]

Well it sounds like you got a handle on it, in your type of boat choice.

An interesting alternative to the sailboat-to-trawler plan.

[a64pilot]

I would use four MPPT chargers, one of each battery, then when I wanted to go anywhere throw the knife switches I would have one per battery to closed, ganging them into one 48 V bank, knife switch one way connects to MPPT, the other to series connect the bank.
Downside is you can't use the bank for propulsion, while charging, not connected this way you couldn't anyway.


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[Fiveslide]

Originally Posted by jp.beauchemin71

No mast its a 28' power trimaran.

I don't have anything to add to your discussion, but I would like to see some pictures of the boat. Sounds like an interesting little powerboat.

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[GILow]

Originally Posted by a64pilot

I would use four MPPT chargers, one of each battery, then when I wanted to go anywhere throw the knife switches I would have one per battery to closed, ganging them into one 48 V bank, knife switch one way connects to MPPT, the other to series connect the bank.
Downside is you can't use the bank for propulsion, while charging, not connected this way you couldn't anyway.


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I was thinking along similar lines. But have the knife switch toggle the bank between four 12v batteries in parallel vs series. That way a single mppt controller could be used (not as efficient but probably more cost effective). I tried sketching the schematic to see if I could post it here but each attempt looked moe like spaghetti than the last.


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[dlymn]

Wire batteries in parallel and feed the panels into a suitable charge controller. Then get a 12v DC to 48v DC converter for the outboard motor. There are plenty on the internet. The battery bank services the 12v equipment on the boat as well as the converter. Now the problem becomes whether you are charging the outboard or using it directly for propulsion. If for propulsion, you might pay a lot for a converter that will carry the wattage.