Marine? Battery

Posts regarding the electrical systems and electronics on a Telstar.
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Cathyalan
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Location: Stoughton, Wisconsin
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Marine? Battery

Post by Cathyalan »

I must say this forum/web site is quite helpful.

My "new to me" 2005 Telstar 28 come with an Interstate SRM-24 battery. Was this original equipment for Telstar? The dates were not punched on it so I do not know it's age.

I am looking to replace it and add another in parallel with a Blue Sea Systems switch. I have a 20HP Honda and will sail 4-5 weeks (not in a row) this season on the Great Lakes. Some anchoring, more slipping. I'm sure I don't need Cadillac batteries but need a couple of batteries that are more than adequate. No refrigeration (but thinking about it), no CD player, no TV, may need to charge my laptop with an inverter on occasion, basic instrumentation, auto-pilot, added a couple LEDs at nav station and galley light.

Any recommendations? I have been looking a Interstate...180AH for $103.00 Some various brands at Batteries Plus and I saw a recommendation for Sears.

Thanks,

Alan
Cathyalan
Cathy & Alan #313
Ron
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Marine? Battery

Post by Ron »

I think most of the boats came thru with two AGM deep cycle Interstate "Mobility" batteries - normally used for scooters, wheel chairs, etc. They are on the small side - around 35 amp hours each. Both are stored in the nav station, along with the switch.
Ron Marcuse
Telstar 28 #359 "Tri-Power"
Dan

Marine? Battery

Post by Dan »

I'd recommend going with two golf cart type GC2 batteries. The Exide brand is quite good and comparable to the Trojan T105s but available for quite a bit less money—often selling for $75 or so at places like BJs and Battery World. This will give you 225 amp-hours or 112 usable hours of battery life at a reasonable load. However, if you don't have some sort of passive recharging capability, you'll be hard pressed to keep them topped off while cruising unless you're stopping at marinas every other night, since the alternator on the 20 HP really isn't up to the task IMHO.
Cathyalan
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Marine? Battery

Post by Cathyalan »

Well, two quite different responses. I was going to get two Interstate SRM-27B, 180amp each at 55lbs each for $103.00 each. To Ron that sounds like over-kill, to Dan maybe that's not enough. We may very well go 3-4 nights without a slip. No instrumentation at night, anchor light is rated at 1 amp, a 100ma LED in cabin, and a fluorescent, a couple of portable, battery LED lanterns. During the day, instrumentation, auto-tiller much of the time (being 5-7 hours on long days. Any comments about solar chargers? I was not aware the Honda 20 was inadequate, it says in the manual it has a 7amp alternator???

Lots to learn.

Thanks for the responses.

Alan
Cathyalan
Cathy & Alan #313
Ron
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Marine? Battery

Post by Ron »

Alan -

You asked what came standard with the boat. Answer was these smallish scooter batteries. Never said that 35 amp hours apiece was enough for long distance cruising. It's OK for the way I normally use the boat - maybe 10 hours max as a day sailor. More than enough power to keep the autopilot and stereo working and the beer cold. I'd upgrade to something in size (and weight) between the golf carts and these if I ever did anything longer than a weekend. Last boat had 6 golf carts and a seperate #24 starter, but I was not using it like this. The boat also weighed around 24,000 pounds and the extra battery weight was negligible. Two golf carts are OK, but I wouldn't want to permanently store this kind of weight back in the transom, so I'd look for somewhere else to hide them (this probably can't be done). Also - two 6V golf carts make one 12 volt battery and I'd like to see a backup if I'm anchored out somewhere off the beaten path. To me, something like two #24 deep cycles might be a decent compromise. I'd rather hide them somewhere in the middle, but that's probably not do-able either.

The Honda 20hp (with electric start) alternator is rated at 12 amps. That's not enough to quickly charge a pair of 6V golf carts, or anything else with a decent amp-hour capacity. The manual start 20hp came with a 6 amp alternator. Not sure where you got the 7 amp number. Maybe the older ones came with that?
Ron Marcuse
Telstar 28 #359 "Tri-Power"
Dan

Marine? Battery

Post by Dan »

It really depends on how you're going to be using the boat. If you're just daysailing, then the small scooter batteries are probably all you need.

However, if you're going to be going on longer cruises, especially longer ones without marina stays, then the 12-amp alternator is really not sufficient, and a larger house battery bank will be needed.

I use two 130 watt solar panels on my boat. These are enough to keep the batteries topped off while the boat is on a mooring, even with the refrigerator running 24x7. I have written a basic primer on Solar Power on Boats on my blog, which you can read here.

If you have any questions, you can contact me through my blog.
Cathyalan wrote:Well, two quite different responses. I was going to get two Interstate SRM-27B, 180amp each at 55lbs each for $103.00 each. To Ron that sounds like over-kill, to Dan maybe that's not enough. We may very well go 3-4 nights without a slip. No instrumentation at night, anchor light is rated at 1 amp, a 100ma LED in cabin, and a fluorescent, a couple of portable, battery LED lanterns. During the day, instrumentation, auto-tiller much of the time (being 5-7 hours on long days. Any comments about solar chargers? I was not aware the Honda 20 was inadequate, it says in the manual it has a 7amp alternator???

Lots to learn.

Thanks for the responses.

Alan
Cathyalan
drsm
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Marine? Battery

Post by drsm »

Just to muddy the waters a little more, I'll relate our experiences from a 10 day cruise last Fall in Lake Michigan. We have the standard issue batteries, and they were new last year. We use the batteries rather lightly, with no refrigeration, no stereo and minimal lighting (we went to bed when it got dark). Anchor light and interior lights have been converted to LEDs. We have a 40W solar charger hooked to battery #2, which is generally reserved for anchor light and interior lights. We charge #1 with the 20HP Honda. Instruments were run off #1 and motor was started with #1. We were forced to do some motoring every day due to light winds, so probably charged with the alternator more than we usually would. Never used shore power during the trip. Never had any battery issues. Note that we did not use the autopilot, so that might have changed the equation.

This year, I've gone to running the instruments from #2 when under sail, just to save #1 for starting purposes. The boat sits on a mooring with the solar charger rigged, so for weekend sailing and occasional overnights, I don't worry about #2 getting drawn down too much.

Steve
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