SunCat battery

[DanM]

My SunCat (2011 model) came with a factory-installed electrical package- monster 12 V marine battery, switch/fuse panel, charging outlet in transom (can be used with OB motor, but the boat also came with a solar charger). The system has worked fine for the past two seasons that I've had the boat, but it has now crapped out. I believe it is probably a dead battery. I took the battery out (ugh) and I'm going to get it checked this week. I hope it is a battery problem because anything else is more complicated. We only use the system for a cabin light, running lights, anchor light, and a tiny electric fan...... and all that is only sporadically. It seems to me that the Marine Deep-Cycle battery this boat came with is way overkill to run a few lights. I've seen, on this forum, references to using a portable jump-start battery to power lights. If that would serve our occasional needs and could be carried off the boat and recharged with house current, that would suit me fine. Does anyone have any current (no pun) experience with these? Any recommendations for what product would work and also physically fit in the forward locker? thanks, Dan

[captronr]

I am far from an expert, but I'll toss out my opinion.

First, getting 6+ years out of an original battery is very good.  Even if it still has a little life left and something else is wrong, it's time to replace it in my view.

In my last boat, I had two batteries, one for motor and one for house lights.  These were regular car batteries.  When the house battery got a little low, the lights ceased functioning.  My understanding is deep cycle batteries will provide power longer than auto batteries.  If that is true, I'd opt for the deep cycle ones.

Using a small jump start battery would work.  But to me the answer is in cranking amps and size matters (probably).  A jump start battery won't power as long as a full size battery. 

I just replaced the deep cycle battery in my  2012 boat.  I don't want to mess with it, other than an occassional charge. 

Best wishes,
Ron

[Tom L.]

Dan, I can only tell you what we did with our Sun Cat. As you have stated the electrical requirement is minimal and the time you use it also minimal. We had one additional current draw on our boat over what you described and that was a digital depth sounder. Also low draw.
We got rid of the monster battery in the fore peak and changed it for a Jump started. It only needed charging every few months and it was so simple and easy to carry off the boat, like a briefcase size, and charge at home. If we were over night in a dock it could be charged with a shore cord. Didn't really find that needed. The unit was from Harbor Freight. It was reliable and we used it for two years and it went with the boat to the new owner. I have a new one for my newest boat. So I am sold. It's very simple, reliable and easy to use.
Good Luck

Tom L.

[DanM]

Thanks for the responses so far. Tom, your experience is encouraging. I wonder if the newer, pocket-size jump starters with lithium batteries would keep the lights lit as long as the older, briefcase-size ones. They get good reviews, and one of those sure would be convenient and would eliminate the issue of how it would fit in the awkward space up forward.
  On related question, is it possible to switch out the bulbs in the cabin light, running lights, and masthead lights to LED's that would use less juice and make the jump start battery an even better option?

[Tom L.]

I am not familiar with the lithium batteries. So long as they can take the heat of storage on board I would think they would be OK.

It is possible to change out to LED but they may not be CG approved as navigation lights the cabin lights no issue. To be certain you may have to change the fixtures. But Unless you are going for an extended cruise of more than a few days without a 110 power source to recharge your battery it would seem to be overkill.

I stopped using the ships anchor light long ago and have a AA battery powered LED light I hang in the cockpit, very bright.

Another trick for me is I have a Garmin GPS, a hand held radio, several lash lights and small cabin fans all powered by AA batteries. I carry about 20 extra batteries. Over a two or three day trip I seldom have to even use the spare batteries. The Jump starter also has a usb port and cigarette lighter receptacle as well.

Tom L.

Tom L.

[Mike K]

I use one of those harbor Freight lead acid (small AGM ) battery inside. Works great for overnight phone charging (via USB charge ports right on the jump starter), and for plugging in my LED anchor light ( sailorsolutions.com) I hang from the topping lift at night ( plugs right into the cigarette lighter socket on the jump start battery)

I avoid powering the old incandescent (tungsten filament or Halogen) bulbs for a long time with it as they are power hungry compared to LED's. I do NOT use my incandescent mast head anchor light at night as that would probably kill the little battery after 4-5 hours. I also avoid having to sail or motor at night as the old navigation bulbs would also consume a lot of power.   

I have found it a very viable alternative as long as you are very careful minimizing power draw. I carry mine home after every overnight trip and charge it from home. That's the key with ANY lead acid battery- fully charge after use, and don't ever go below about 50% charge. In other words, NEVER let it get totally flat as it severely limits lifetime. So if the little jump start battery has a rating of 10 amp-hours (guess) then never use more than 5 amp hours for your power budget. A typical single incandescent bulb roughly burns 1 amp- hour, so you could leave it on about 5 hours max before needing a charge before damaging the battery.  That's why I use an LED anchor light with a power draw of about 0.1 amps per hour, you get about 10 times longer lighting than incandescent (tungsten filament or Halogen) bulbs.

One huge exception to using this would be if you HAVE to start an outboard engine with this every time. Not enough capacity for multiple starts AND general power needs.

[hoddinr]

I agree with CaptRon that your deep cycle 6+ year old battery is probably dead.  It's hard to kill a true deep cycle battery as they're made to discharge and recharge numerous times, but 6 years is still probably it. 

I still have a Deep Cycle in the bow alongside a dedicated marine battery charger wired to the battery. 

I also recently started using a solar charger (small) with clips to the terminals for the times when I can't get the boat home to charge it, or when it will be in storage for a long time (like this summer).  You are correct - it is very tough to get the battery out of the opening in bulkhead!  It barely makes it.  No room for a group 27, as the group 24 barely fits.

Ron

[Garyandjoanlee]

Hey Capt' Dan
Never did read if you have tried charging it?  Is it possible something was left on after the last use to drain the battery? The other cent of the two I offer is about the solar charger. I might be taking a leap but if the solar charger is the primary source of your battery juice, have you checked the volts coming from the panel (inexpensive volt/ Ohm meter)?  If so, is there a solar charge controller between the battery and the panel? Should be- and they go out often.  You might check the volts coming from the charge controller. I just added a second group 24 marine battery to my CP16 - both of which charge nicely from a 30 watt solar panel. (Electric motor+++). Hope this helps.