Battery Monitors Y/N ?

[commocean]

How many of my Mac brother and sisters use battery monitors out there. If so, what kind and what can I expect to pay, roughly.

[Luke]

I installed a "Link 10 Single Battery Bank Monitor" by Xantrex.
It works as advertised. Approximately $200.00.

Luke
DreamChaser
1999 26X

[Catigale]

There is no substitute for a battery monitor for prolonged (>3 days)cruising except ....our approach

We have basically reduced our electronic needs to nil so that we only need the battery to start the engine - even then, we can pull start if needed (50 HP EFI)

On an 8 day trip with 2 good batteries to start we dont run out of electrons this way. We also carry a battery booster as a third backup, which doesnt count in the boat budget since it goes into the car in the winter.

Search on Xantrex and you will find some of the folks who have the real monitor solution implemented though.

[kmclemore]

I have the Link 20 and love it.

Here's a link to some previous postings on the subject:

http://macgregorsailors.com/phpBB/viewt ... 4331#74331

http://macgregorsailors.com/phpBB/viewt ... 5689#85689

[jthiltibran]

If you don't already have one, take a look at the Garmin GPSmap 178C Sounder. This model allows you to monitor the battery voltage level. You have the option of modify the displayed page to show a host of data, time, date, battery voltage ect...

[richandlori]

For anything else but 1/2 day sailing, I can't imagine not having some sort of battery monitor. The link 10 was one of the best electronic items I purchased....hands down.

[c130king]

jthiltibran's post made me look at my Garmin manual. I have a 478 and it has an "external voltage alarm". It can be set to go off when the external voltage hits a preset level. I presume that means I can have it alert me when the boat battery gets below some level.

My question is what should that level be. I have a single battery. The only electronics I am running off the battery while sailing is the GPS. My VHF is a handheld.

ON EDIT: The simple sounder is running as well...forgot about that.

Can anyone recommend a level that would leave me sufficient voltage to start my 40HP Merc?

I always have the portable jumper battery with me. But this will give me a bigger level of comfort for those long day sails when the GPS is running for a long time.

Thanks,
Jim

[Moe]

The answer to [the original poster's] question has to be qualified by how much power you use, how much battery capacity you have, and what and when are your charging sources.

With both our Mac 26X and the Capri 18, a single Group 24 house battery easily fulfilled/fufills OUR electrical requirement for 4 days/3 nights at anchor. This coincidentally roughly aligns with our cell phone, camera, and handheld VHF batteries (given limited use), 10 gallons of freshwater, and 2.8 gallon potty (with me using "the jug"). Our C-18's 10 amp on-board charger can recharge the battery overnight, while the other batteries are recharging off either 12VDC or 120VAC with their own chargers. As long as we get a marina slip with 120VAC power every fourth night, we don't need to monitor our house battery. Like Catigale, we prefer the K.I.S.S. concept of energy conservation.

If your electrical use for a trip will exceed your battery capacity, and you must rely on charging from the outboard alternator, solar panels, etc, then yes, a battery monitor is invaluable. It integrates charge and discharge currents over time.

Monitoring battery voltage or specific gravity (and then doing the required temperature compensation) is inconvenient if it's to be anywhere near meaningful. It really needs to be done several hours after charging so the surface charge can bleed off, and under no-load conditions. Many GPS or fishfinder units have a voltage read-out and it's typically no more accurate than a cheap multimeter, which I carry for troubleshooting (I had a 178C). You don't need to spend a lot of money to monitor voltage, especially if you aren't going to temperature compensate.

[edit] Sorry if it appeared my answer was to c130

[c130king]

( On Edit: Sorry Moe, I thought you were answering me. Either way...as always...thanks for the info. Its always good to hear from those with all the 411. )

I think I have the standard battery that came with the boat. I don't think the PO upgraded this in anyway. To be honest I do not know what it its specs are.

I don't cruise...yet. And don't really use the battery that much. I have never had an issue with battery power.

I thought maybe there were some thoughts on what voltage will turn over the motor.

I do not know what the capability of my alternator is. I don't have a shorepower hook up.

I will look into these sort of mods/upgrades in the future...when I am living on the same continent as my boat.

If somehow I have really great winds and I am sailing for several straight hours using the GPS and Depth Sounder and somehow drain my battery to a point I cannot turn over the motor...I will pull out the portable battery pack and hope it works...otherwise I will hope the winds are good for me to sail back to the boat ramp.

Thanks,
Jim

[James V]

My Merc 50 starts at 11.8 volts. I just use 2 batteries and the Merc Smart System guage by turning the swtich on and checking the vlotage. If the motor does not start then I switch to the other battery and charge everything up for 2+ hrs. That is when the sun is not shining enough for my 2 20W sloar pannels or I play the radio to much.

[Moe]

c130,
Our Garmin 178C GPS/Sounder on the Mac drew about 600 milliamps with the screen on bright, or about 5 amp-hours for every 8 hours use. We didn't use it much, nor do I use the sounder on the C-18 unless in unfamiliar shallow water or outside a marked channel (risky even with charts, especially in hurricane-modified waters).

If your battery is a typical Group 24 deep-cycle or dual-purpose battery (not just a starting battery), it should have 70-80 amp-hours capacity when fully charged.

Not sure about your alternator, but I will say it's a good idea to put your battery on a charger or charge maintainer (Battery Tender or Battery Minder) when you aren't on the boat. The longer a battery sits at less than full charge and the further it is below full charge, the more it sulfates (and the shorter its life). That's compounded by the fact that flooded cell batteries self-discharge considerably. A charge maintainer compensates for that and will even make up for the 5 AH use in 48 hours or so.

I have no idea what voltage your modern ignition needs to fire or your starter motor needs to crank, but I can say we had a two-stroke pull-start only 40HP Merc on a fishing boat, with no battery at all, when I was a kid and it was no problem to get going. I recommend you learn how to pull-start yours when you get back to the CONUS. Hope this helps.

[c130king]

Thanks Moe.

I've tried the pull start on two different occassions. I could not get it to work.

As to using a charger or charge maintainer...boat sits in a dry storage lot when not in use. No access to power.

Probably taken the boat out 70 times. Never had a problem...yet. I use the multi-meter occassionally to check voltage...never seen less than 12. Normally a tick or two over 12.

Probably my next mod...someday...will be to add a second battery, monitor, shore power, etc...

But thanks again to you and the others...I have a lot to learn about the electrical system.

Jim

[Moe]

Because our state park docks don't have electrical power, and because we use a considerable percentage of the battery charge, our C-18's battery goes home with us each weekend.

For dry storage, I'd think about a 5 watt solar panel (per battery) if you can place it where it won't be shadowed by anything during the majority of the day.

[edit] For what's it's worth, an almost-empty 5 gallon water jug and the used potty bottom go home each week also. So does the ice chest and partially melted milk jugs of water, a canvas bag with muddy, nasty anchor rode and chain to be washed and not generate mildew in the cabin, as well as a canvas bag with the most valuable stuff (inflatable PFDs, electronics, and binoculars). Before we leave for home, I put a filled 5 gallon water jug and a clean, spare potty bottom in the boat so those are ready to go next weekend.

[c130king]

A solar charger. That is another thing to look into. Based on my useage that might be a good idea.

Thanks,
Jim

[Catigale]

Jim - scanning the Mercury website the 40 50 60 HP Engines seem all to have the same alternator rating of 193W for non-Bigfoot and 223W for Bigfoot engines. Backing off the engine draw (a number Ive always wondered about) Ill guess you can charge 2 80 Amp hour batteries from 1/2 to full charge in about 5 hours running time.

If your usage is always taking your batteries down to the 'wont start' regime I would get the Xantrex and get serious about monitioring your usage.

Yamahas are rated at 17 Amps (204 watts roughly) too at WOT...so roughly same numbers