Battery and GPS question. - Maxum Boat Owners Club

Smithbrother · 07-19-2011, 02:00 PM

Hi Folks,
Was out on the water last Saturday and had the switch to Battery #1. Fell asleep with the water pump for faucets on and the cd player playing. Woke a few hours later to silence and found the battery to be drained. I switched to Battery #2 and started the boat for the short trip home. I placed the switch onto "Both" to keep the boat running and possibly recharge somewhat the #1 battery. QUESTION: Other than trickle charging #1 back to life what are my other options? How do you listen to the radio all day at anchor without draining the battery? Will starting the engine for a few minutes every now and then be enough to buy me more time?

Also my fiance bought me a new Garmin GPS Chart plotter sounder. Can I follow the red / black wires from the VHF radio to the block and add the gps wires on to them? I'm not sure if I have any open space and have no wiring diagram. I have a thru hull depth sounder that came with the boat.. is there such thing as an adapter that will convert a Garmin wire to mate with the exsisting Faria sounder? I know a lot of questions but I am mechanically challenged.

Thanks
Dave

seapuppy · 07-19-2011, 02:08 PM

well..sorry bout draining the batt. Dave...but yes..you can fire the engine up and it will charge your batt. ...you may have to run it at a fast idle for awhile...but a larger batt. would probably be a better idea....if your running a gp 24...a gp 27 might be the plan..

to hook up your gps...look on your dash...there should be a switch there called ACC....connect it there....as for your xdcr...no..don't use the faria xdcr....just take your new garmin unit and glue it right next to the existing one...or I'm sure the it came with a transom mounted xdcr....mount it on the transom..it will give water temps along with depth....

SP

shrew · 07-19-2011, 05:03 PM

Think of it this way, would you run the stereo in your car with the key on Accessory at a BBQ for 6 hours and expect the car to start? Probably not.

It's all going to depend on the amp hour draw of the devices which are running and the amp hour capacity and discharge of the battery. Keep in mind that if you have a fridge, that will take a good amount of power. The stereo will also take a large amount of amp hours. You may want to consider a Group 27 as Seapuppy said, or even a Group 31. AGM batteries would be better than flooded for a variety of reasons. You could also look into wiring some 6V golf cart batteries in a series to make 12V. Technically 2 6v batteries in Series would be 12 volt. 4 6V batteries would need to be wired in series/parallel to also equal 12V with more amp hour capacity. (4 x 6V in series would be 24V and would not be compatible with your boat system).

Consider turning down the fridge to 2.5 -3 if there is one running. Consider using AM/FM rather than CD or Aux devices. Turn off all unessential devices, like electronics while at anchor. We bought a couple of rechargable speakers and use the rechargable speakers and an iPod to listen to music all day. This uses 0 amp hours from the house batteries.

Just a couple of thoughts.

tackleshep · 07-19-2011, 06:02 PM

and if your boat doesn't have an on board charger I would recommend putting her on a trickle if your not going to use her for a week or more. Just a good idea to keep them fresh and save some life.

Or just buy 3 or 4 new batteries and never worry again

Smithbrother · 07-20-2011, 04:03 AM

Thanks to everyone. I have run the stereo for a few hours in the past with no problem so I thought it was ok. I have a 2100sc3 so no fridge. Both batteries are brand new and had a full trickle charge at the beginning of the season and due to a busier than usual summer have only taken it out twice. I don't know what a group 27 or group 31 are. I will take the suggestion to try an Ipod or am/fm instead of CD's and start the engine at a higher rev once an hour maybe 1500rpm? The admiral thinks the boat hates us because when we purchased the boat the two batteries that came with it crapped out last season and had to be replaced because they were old and as the guy at auto zone said "they were toast".

After we got back to the Marina I opened the back ski locker and it would not latch closed. I don't know why but something was not lining up and after an hour in total darkness, sweat rolling into my eyes, pissed off and getting eaten alive by mosquitos and biting flies I just left leaving the locker wide open. It was a stress filled upseting end to an otherwise nice day. I'm headed out Friday in daylight to try and figure out why the locker is not latching. And will go to home depot and get a portable battery jumper. Worst case scenerio is I have Sea Tow. Thanks for the suggestions and letting me vent.
Dave

ss3964spd · 07-20-2011, 02:30 PM

Dave,

Just for additional reference, was out on our 2400 SC3 this past Saturday. Dropped the hook in a popular spot, shut everything down, switched to Battery 2, and stayed there for about 4 hours listening to the radio and also had the VHF on. When it was time to go I left the switch on #2 and the engine fired right up.

"Group" generally refers to the physical size of the battery and thus it's capacity. Generally, larger batteries will last longer than small ones. Batteries will have a specification called NNN Amp Hours - where NNN is a number. Say, 600 for example. A battery with a 600 amp hour rating means it will power a 1 amp load for 600 hours (roughly), assuming it is fully charged. If you draw 2 amps the rating decreases to 300 hours. etc-etc.

Of course, smaller boats like ours have less space for large batteries. Mine came with a single lead acid group 24. I could have maybe squeezed in a 27 or 31 but, given the factory location of the battery, I doubt it. I decided to install a switch and a 2nd Gp 24, but this one is a AGM type (no liquid acid in it).

Dan

shrew · 07-20-2011, 02:34 PM

OK, so you have a starting and house battery. Only use the starting battery to start and the house battery for everything else. When you start the boat, change to the starting battery. When you're sitting on the anchor, run off the house battery. This way, if the house battery dies, you can still start the boat.

If you were to start the boat on one battery and run the electric on the other, then the alternator would only ever charge the starting battery and not the hosue battery. You would technically need to start the boat on the starting battery, then switch to the house battery in order for the alternator to charge the house battery. Yo my knowledge, you don't want to run the motor with the battery switch set to BOTH to get the alternator to charge both batt's simultaneously.

Flooded batteries will loose charge over time simply by sitting with no draw on them. They will need to be regularly maintained with a trickle or smart charger. If the boat doesn't have one, strongly consider installing a 2 bank battery charger in the boat. Make sure it is a marine charger and is 'smart' so the batteries don't get overcharged. Make sure the charger is plugged in whenever you leave the boat.

My guess is, if the boat is not sitting regularly on a charger and was only charged at the beginning of the season, this could account for your battery issues.

Smithbrother · 07-20-2011, 03:04 PM

Thank you ss3964 for the battery explanation, I don't know the size but they are deep cycle and look about the same size as my car battery. Shrew was right when he said smaller boat...it is next to impossible to get them in and out. They are as far back as you can get to the right of the engine and the guy that put them in skipped lunch fearing he would not be able to twist in far enough to reach them... really poor design. Shrew Thanks as always for the advice. I did plan on starting the engine with #2 then switch back to #1 to charge it on the way home but did not know if it would have enough juice to keep the engine running smooth. I will try it Friday when I go out. About how high of an rpm do I have to run at for it to charge properly? Thanks again.

tackleshep · 07-20-2011, 03:49 PM

I would have never thought of the battery charger until buying our bigger boat and that being a necessity. I personally think the 100+ bucks you would spend on a installed 2 bank battery charger might give you some good piece of mind and make those new batteries last a lot longer. Plug it in at the end of the day and not worry about it anymore.

We have two jetski's on our dock and we've installed chargers in both of those as I'm tired of buying $100 batteries to start each year.

ss3964spd · 07-20-2011, 07:42 PM

The single battery in my 2400 SC3 was installed in the same place; deep recesses of the right rear. seriously difficult to get to, and nearly impossible to get the battery out. Is why I relocated mine when I added the 2nd battery.

Note that if the battery/ies is/are significantly discharged then running the engine - even at a fast idle, for 5 or 10 minutes probably isn't going to help much. Indeed, since the engine starter draws so much current, you might actually use even more power to start the engine than you will generate but ruinning it for 5 or 10 minutes.

Dave, if the boat is not stored on the water, and if you are turning the battery switch to Off after putting the boat away, the battery/ies should be fine for at least a couple of weeks - if not more. My honey-do truck sits for weeks at a time and always starts.

Dan

Smithbrother · 07-21-2011, 03:53 AM

Relocating my batteries may need to be considered. I have valet service for the boat because the bottom is not painted. The Marina keeps it on a rack till I call ahead and they splash it. When I'm done I shut the switch to off and they pull the boat, spray it and put it back on the rack. It is docked when I arrive and all I have access to is water. They don't have any lights in this area or electric so I really can't put a trickle charge on it while its 30 feet in the air on a rack. I will have to work something out with the yard operator. Maybe he can put it on a ground rack near electric power for me to recharge them. I only get out on the boat about 1 a month due to job ect. The admiral is getting fed up, wants to purchase a bigger boat to comfortably sleep on and just leave it at our own dock with electric and water then store it there for the winter. Sigghhh

ss3964spd · 07-21-2011, 02:30 PM

Ah, rack storage - I understand the challenge. If the batteries are fully charged and in good shape they should last for a month. Sounds as though part of the problem might be that when you do use the boat you simply don't run it long enough to fully recharge the batteries. Depending on the state of discharge it could easily take an hour of engine run time at 2000 + RPM to get a battery fully charged, more if you are trying to charge both. Ditto for a battery charger - 15 minutes isn't going to cut it.

Given how you use the boat consider replacing the batteries with AGM (Absorbed Glass Mat). A lead acid battery, deep cycle or not, does not hold a charge for nearly as long as an equivalent AGM. Will still need to run the boat enough to charge them though.

And oh:

Quote:

Originally Posted by Smithbrother

The admiral is getting fed up, wants to purchase a bigger boat to comfortably sleep on and just leave it at our own dock with electric and water then store it there for the winter. Sigghhh

Why are you posting here and not out shopping? I'd kill to hear those words. LOL

Dan