Starting / House Battery Charging Question

[Saxacussionist]

My older '90 Honda 8 hp outboard died the last week of the season so I need to replace it before the beginning of the 2015 season. Since my wife hates to pull start the motor we are going to spring for electric start. I like the Mercury 9.9 with everything from starting, to shifting, and throttle on the tiller. The questions I have are - is it better to have a starting battery AND a deep cycle house battery, a 'marine' battery which is a hybrid so you lose some deep cycle storage, or since it is such a small engine, just one deep cycle battery? Second question, where would you locate the battery(s) on a 26S? Third question, if you have two batteries, can they somehow both be charged by the motor and single Ctech charger?

Thanks for your help!

Brad

[Sumner]

First since Tohatsu makes the Merc you might want to check pricing on the Tohatsu with the same options...

http://www.onlineoutboards.com/Tohatsu- ... oards.html

On the battery thing the motor doesn't need a start battery. A marine deep cycle will also work fine (they aren't true deep cycles but a cross between a start and a deep cycle such as used in golf carts). Right now the Mac has two 12 volt marine deep cycle batteries that were always run in parallel so both charged and discharge together which makes them last longer and charge quicker vs. charging one battery and then the other.

Since they are old I'm taking them out and I'm putting in two true deep cycle (Trojan T105) 6 volt batteries in series for 12 volts. They have a higher amp/hr rating than the 12 volt batteries you are going to find and will charge more efficiently also. They will start the outboard no problem. Walt on here has this combination. This is what I'd recommend you also do. It simplifies the wiring in you just need an on/off master switch.

Right now I have one battery under the sink (which was where it was when we bought the boat) and the other just behind it...



...under the extended V-berth and by 2 of the water containers. I think Walt has his just ahead of that on the other side of the bulkhead under the V-berth.

To wire the tow 6 volt batteries in series you would go from your main ground bus or post to the negative on the first battery and from the positive on it to the negative on the second and right after the positive terminal or on it (see my other post on this ( http://www.macgregorsailors.com/forum/v ... 10#p290810 )) have a main fuse and from it to your main positive bus or post and then to distribution breaker/fuse panel and onto your circuits.



You need large gauge wire between the battery where it connects to the main positive bus or post and the outboard since that is a long run to the stern and the outboard will be drawing some major amps when it is starting. If you need help ask or maybe my page on wiring will help here...

http://purplesagetradingpost.com/sumner ... de-30.html

I would also wire the outboard in such a way that it is always connected to a battery and can't be disconnected by a switch unless you are very careful not to do that when it is running. The manual will tell you to do this to protect the charging circuit on the outboard,

Sumner

============================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

[Saxacussionist]

Thanks Sumner, that is a TON of good information. I think I will go with my existing single deep cycle and just run some heavy wire back to the lazarette. If starting the motor takes too much of my current batteries power and leaves me short on power for the rest of the cruise, I will definitely consider the two 6 volt in series configuration. Just one last question, how did you get that heavy of wire back to your motor? The Honda has some very lightweight wire that runs to the current battery (under the sink) that is rated at 5 amps and the PO just strung it across the hull to deck bolts with a few zip ties. I'm guessing I should do a bit better job for the heavier wire?

Thanks!!

Brad

[Sumner]

... Just one last question, how did you get that heavy of wire back to your motor?...

I took pictures and will post them tonight. Nice day and it is suppose to change to cold so need to work outside on the Mac while I can,

Sumner

============================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

[Sumner]

See if these pictures help some and I'll post them in 3 posts if that is ok with the moderators....







Sumner

============================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

[Sumner]

Next set....







Sumner

============================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

[Sumner]

I've also run wiring fore-aft under the top liner sides but didn't do that with the other wiring as I wanted it to end up under the starboard settee in the cabin and didn't want it running down the side to get there but what follows can work for other applications, just depends what you are trying to do.





Ask questions if you have them,

Sumner

============================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

[Saxacussionist]

I like the idea of running it along the top liner. Thanks for all the effort you have gone to for this.

I think I have just one last question. What did you use to determine the wire gauge? #4 seems a bit large, even if it is a 15' run but I'm no expert by a long shot. I tried looking up the amperage draw to start a 9.9 but couldn't find it online.

Thanks again!



Brad

[Sumner]

....I think I have just one last question. What did you use to determine the wire gauge? #4 seems a bit large, even if it is a 15' run but I'm no expert by a long shot..

Don't forget the run is figured round trip so 15 feet is 30. With my forward battery and all the twists and turns it is probably 20 feet one way (40 round trip). Also I have the ...



http://purplesagetradingpost.com/sumner ... de-13.html

.... gen-set back there feeding elect. the other way. It has a 63 amp theoretical output but the most I've seen is about 25 amps but never let the batteries get really low.

I think Walt once figured the outboard could draw 40-50 amps for a very short period on starting, but I might be wrong on that. If you were ok with a 10% drop according to this site at 45 amps and 20 feet ...

https://www.colemanair.us/vp_asp/Script ... reSize.htm

... #6 would be good. For a 5% drop they recommend #4. If you just don't want the wire to burn up and aren't too concerned about the voltage drop during starting #8 would probably work.

For my wires from the solar panels I want maximum efficiency so use the 2%-3% drop on that calculator but my panels aren't on the wires we are talking about. Different ones going to the MPPT solar charge controller.

I got the wiring here...

http://www.genuinedealz.com/?tabid=2

... and they have good pricing and I only wanted to do this once and I have a tendency to get anal about some things ,

Sumner

============================
Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links
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