Simple electrical advice needed.

C

capt. meares

New member
While recently overnighting on the bay at anchor, I realized there was a potential of possibly wearing down my battery, losing power leaving me stranded in the bay. I currently have just one (1) battery. I will list all the items that this battery was running to paint the picture clearly for my question....

1) two house lights (all bulbs throughout boat are LED) used for3 hours.
2) Navigation lights (LED) left on all night.
3) Lowrance GPS Elite 5 (left on all night for anchor alarm)
4) Anchor light (LED) left on all night.

While not using the boat, my single battery is ALWAYS plugged into a battery tender.

Question #1. Can I continue to get by with just one battery with this being a typical night of usage? I am a big fan of keeping everything simple as a C-dory is meant to be.

Question #2. If the answer is NO to question #1, would it be acceptable to always bring a fully charged jump pack as an alternative to adding a second battery?

I never plan on needing a microwave, hair dryer, satellite TV etc. Again, I like to keep it simple.

Thanks
 
What size/type is your one battery?

If you know the rated amp hours, great. If not, even the group size would help (24, 27, 31, etc.).

It's a simple matter of math, but certain numbers are needed to plug into the equation. Battery size/type would help.
 
I suggest you get a digital voltage meter (free from harbor freight with coupon) and check the battery voltage every couple of hours. You might be doing just fine. If it's 12v or better it will easily start a good normal starting engine. If it gets low, start the engine for a while and recharge it enough to get by. Having a jump starting box would make a great back up. The new lithium ion models are very small and powerful and hold a charge for a long time. Good luck, Bob
 
The driveway test is a good idea. You could try starting the motor at 10 volts. Some Chart plotters and GPS have low voltage alarms that may help monitor what is going on. I can appreciate your feelings about keeping it simple but I suffer from battery discharge anxiety. The only solution for me was to install a two battery system with a A/B switch. I always have a fully charged start battery. I can sleep now.
Skeeter
 
Skeeter":3qt98um1 said:
The driveway test is a good idea. You could try starting the motor at 10 volts. Some Chart plotters and GPS have low voltage alarms that may help monitor what is going on. I can appreciate your feelings about keeping it simple but I suffer from battery discharge anxiety. The only solution for me was to install a two battery system with a A/B switch. I always have a fully charged start battery. I can sleep now.
Skeeter
Click to expand...

I agree with Skeeter, I couldn't sleep with any draw on one battery. I would even get fidgety anchoring for lunch :| . Toooo many things can go wrong. A good booster pack would be OK.

I would caution against making a habit of trying to start your boat with a low(or undersized) battery though. It will draw more amps than normal - leading to an overheated starter and eventually burning it out.

Regards, Rob
 
There is a major problem with the "Driveway test". What is your end point? I make it a rule to avoid discharging a 12 volt battery to less than 12.2 volts, resting voltage. At 10 volts you will have damaged the battery, and decreased its life span.

I would prefer a good 3 stage battery charger over a "battery tender", especially if the battery was deep discharged.

Why do you leave the navigation lights on a night? No reason, unless you are under way.

Same for the depth sounder? There have been very few times when I left a depth sounder on--and during those times, I was standing an anchor watch, or at least checking ever hour or so--or more often.

I bought my first ocean going boat (29 foot Columbia sail boat) in 1962. It had a single battery. After the first night on the hook (long before LED's) and my battery was down--I vowed to never have that issue again.

I would not have a boat where I could not start the engine by hand, with a single battery. Pull start, then single battery--for example a RIB I owned. I sort of break the rule with my 18 foot Caracal Cat. Some times, i have the bank of trolling motor batteries which would give me a back up, or I take a jump pack. But this is only a day fishing boat.
 
Another thought just came to my old brain. Many GPS units both read system voltage and have a low voltage alarm somewhere in the menu. If you have one, set it when you set the anchor alarm.
 
I would add a house battery, either a group 27 or 31. That with a bit of cable and a two battery switch isn't that expensive. I moved mine to the port side. Pics in the album.

Like Dr. Bob mentioned, why are you leaving your navy lights on? The 360° white anchor is all that's needed.

Going across the Tillamook bar would make me nervous without having an easy second way to start the main engine.
 
Why are your nav lights on all night? You only need the white anchor light on while anchored. Not much of a savings, but also not required.

We nearly drained a group 31 deep cell after three days in Desolation, but we have a fridge and watched movies on our laptop. It was a good learning experience and I was not concerned as we have a group 27 starter too.
 
All good suggestions. I have "twin" engines on my boat. I only have one Group 24 battery for each engine. I have no other battery for a "house" battery. I have a 1-2-Both switch that selects which I'll use for the house battery for that trip, or may switch to the other battery if we drain the first one down close to what we can safely start the engine. I also have a Link 10 battery monitor on each battery to really see what the condition of discharge is, VERY good piece of mind. There is a less expensive monitor now available, I forgot the name. I recommend a monitor though that does more than just voltage.

My batteries, when new, had about 105 Amp-Hour capacity each. I generally won't discharge them past 70% (~70 AH remaining). So you have about 30 AH to use. We have a 2-light rule on the boat, hard to enforce at times with lots of kids, but it means to not have lights on all over the boat at one time. Each light (incandescent) draws 1 amp, including the anchor light or each running light (which aren't needed at anchor as others have pointed out). The stereo is about 0.3 amps. TV w/DVD playing, about 4 amps (so a 2 hour movie discharges 2hr x 4amps = 8 AmpHours). My GPS draws about 0.2 amps (I think). You'd be surprised how little energy most of the solid-state electronics use, but you need a monitor to make an accurate list. I don't have a refrig, nor microwave, no need for a weekend or even a week of boating like I do. I like the KISS principle like many of us.

I do have a non-KISS item on board (plus the TV and DVD player), a Wallas 1300 heater. So for those chilly nights we sometimes get here in SoCal, I make sure at least one of the batteries is up to snuff to start it with it's 5 amp startup current for 3 minutes, thereafter it's about 0.3 amps to run the pump and fan, very efficient.

I also have a 30 Watt, flexible solar panel that I'll throw on the roof if I'm going to stay in one spot without running the motors every couple of days. It usually brings the battery back to nearly 100% in one day. And like others have said, you can always start the motor and charge for a half hour. I also bring a emergency jump start battery on most trips, but remember, I have 2 engines. So as long as I can start one on the good battery, I can then switch to BOTH and charge both from that one engine, then later (and this is important to the health of your regulators on the engines -- don't ask me how I know) I switch it back to separate before starting the second engine.

One caveat on battery monitors like the Link 10's. They do not account for the degradation of the capacity of the battery as they age. My batteries are about 5 yrs old (which is phenomenal BTW). By taking a few voltage readings (after 12 hrs of rest) with known discharges, I have calculated that the capacities are way reduced over what they were when new, like maybe 70 amp-hours now, so I plugged in the new numbers to the Link 10's as a temporary solution until I replace them, probably this winter.

Hope this helps and didn't confuse you too much. Sorry if it did.
 
Thank you all for the input. After reading everyone's responses I have decided the simplest solution is to add a second battery. While I have gotten by with just one battery for the last year without any issues, I must say its better to be safe than sorry.

I will also discontinue the practice of leaving nav lights on all night. Just trying to make myself more visible ( helps me sleep better :? )

Now I will be looking into albums and find the easiest wiring diagram for adding a second battery.

Thanks again.
 
Your issue of being highly visible was my concern too. I ended up going on Ebay and buying a 16' led strip with a peel and stick backing on it. I built a box with 2 on off switches and mounted it at the roofline on the port side over the dinette. I drilled 1 hole thru the cabinside high enough to be under the eve of the pilothouse roof and ran the wires out to connect to the light strips. I stuck the light strips to the inside of the eve of the roof and ran 1 strip around the front and the other around the rear of the inside of the eves. The result is a fully illuminated boat but the lights don't shine directly inside. The lights illuminate the house sides and decks very well and still use almost no juice. I can use the rear one as cockpit lighting as well. It's one of my favorite mods. Next time I'm near the boat at night I'll take some pics and put them in our album.
 
capt. meares":3e0aq162 said:
Thank you all for the input. After reading everyone's responses I have decided the simplest solution is to add a second battery. While I have gotten by with just one battery for the last year without any issues, I must say its better to be safe than sorry.

I will also discontinue the practice of leaving nav lights on all night. Just trying to make myself more visible ( helps me sleep better :? )

Now I will be looking into albums and find the easiest wiring diagram for adding a second battery.

Thanks again.
Click to expand...

Here's a simple diagram from the internet... Be certain you get marine grade wire, do proper crimping of terminals, have appropriate security for the terminals and battery tie down...

Battery.png
 
One item to remember is that you want to use cable the same size as the engine battery starting cable for the new battery, and connecting to the switch. Be sure that the switch is "Make before break"--to protect the diodes on the engine charging system.

Get a 2 bank 3 stage battery charger and hook it directly to each of the batteries.

As for "making the boat more visible"--it actually causes confusion and is illegal to leave the running lights on when you are not actually running the boat.

The "LED" strip lighten is OK--and probably a good safety feature, assuming that the lights are low intensity, indirect and white. Direct Blue, red or green would be illegal, and cause confusion.

On some of my large boats, where the "anchor light" was 60 to 70 feet in the air on top of a mast, I would put secondary riding lights at the extreme bow and stern at about 10 feet off the water, or leave "spreader" lights to illuminate the deck, since many boaters are not looking up 70 feet to see an anchor light.

Generally the 2 mile visibility anchor light is more than adequate for visibility.
 
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