three batteries, one for cranking, two wired in series for trolling m'tr

[JohnKee]

I am going to install three identical group 27, dual purpose batteries in a new 17 1/2 foot Sportfish, powered by a 90hp Yamaha or Honda o/b.

 

[ob]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

Did you have a question?

 

[JohnKee]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

I am going to install three identical group 27, dual purpose batteries in a new 17 1/2 foot Sportfish, powered by a 90hp Yamaha or Honda o/b. <br />My trolling motor is 24 volts, and the group 27 is recomended for it.<br /><br />My question: 1. Can the 12 volt alternator on the o/b charge the 24 volt troling system? (The dealer says "No", but can't give me a good reason --or at least one I can understand)) <br /><br />2. Do I need two on-board chargers to charge the three batteries or can one charge both systems? <br /><br />Thanks,<br />JohnK

 

[rickdb1boat]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

I would let the Motors charging system charge your starting battery and get an onboard charger for the trolling Motor Batteries, as the charging system of the engine is not designed to charge 3 batteries. I don't know off-hand how many AMP's your system puts out, but I'm sure it's not enough to charge all 3. You could get a battery isolator switch to change batteries when running so the others could charge up some, but you would have to run quite a ways to bring them all the way up.

 

[JohnKee]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

Rick, thans for the response.<br /><br /> The alternator on the o/b is, I think, 20 amps.<br /><br /> My first question could be rephrases to ask "Is it POSSIBLE ( i.e. without damage to the o/b's alternator) to charge a 24 volt system?" I guessed that if it was possible at a all, it might take a rather long time.<br /><br />What I was intending to do was to first charge the cranking battery, while running; and after it is fully charged switching to the 24 volt, batteries, while running, and also charging them. The boat will be used in Puget Sound, and there may be an hour or two between uses of the trolling motor. I will only use the trolling motor to set up drifts for fly fishing, but it's conceivable that I will be without shore-power for a few days at a time. So It's important to be able to charge the trolling motors while out of port. This means charging them on the o/b's alternator, IF POSSIBLE. Is it possibly without damage?<br /><br />The second question asks whether I need two on-board chargers to charge these batteries when I do have shore-power; or are there chargers I can install that will charge both the 12 volt cranking , and the 24 volt trolling batteries.<br /><br />Best,<br />Johnk

 

[rickdb1boat]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

To the first question, No, But with a battery isolator you can charge each individual 12 Volt battery as needed. As for number 2, I would go with something like this one at West Marine. Model # 2099042. Just go to the West Marine site and enter the Model # above. Sounds just like what you need, although a little pricey.

 

[rickdb1boat]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

To clarify a bit, you cannot hook 24 Volts to a 12 Volt system without something burning up. That's why I suggest an isolator...

 

[SlowlySinking]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

JohnKee, sorry, but your dealer is right, the 12 volt alternator cannot charge a 24 volt battery. To charge any battery you must use a charging voltage higher than the voltage of the battery being charged, in effect, you have to pump in the current. To see this in inoperation check your cars battery voltage with and without the engine running, you will see the difference. The engine off voltage will be 12 to 12.6 volts, with the engine running you will see up to about 14 or so volts depending on battery charge and air temperature. You could wire a switch to parallel the pair of 12 volt trolling batteries for charging and then in series for 24 volts for the trolling motor, but you can't have both at the same time.

 

[JohnKee]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

Rick,<br /><br />So if I install an isolator and the one charger from West Marine that you suggest, then I just plug this hummer in and all three will be toped off--i.e. I'll be "pickin' in tall cotton"? <G><br /><br />(Since I have begun this project I have become acustomed to sticker-shock!)<br /><br />Thanks very much, <br /><br />JohnK

 

[rickdb1boat]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

That's correct John. You will be good to go and that charger will make it simple to charge all your batteries at once from shore power. Good Luck,

 

[93evinrude]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

JohnKee<br />There are two companies out there that make onboard chargers to do what you want.<br />They are Charging Systems International and Stealth.You may have to wait an hour or so as the Stealth site isn't coming up at the present time.I added a link to some feedback re Stealth you can look at for now.They both have products that allow you to charge your trolling batteries while running.<br /><br /> http://pub5.ezboard.com/fbbcboardfrm20.showMessage?topicID=34.topic <br /><br />www.stealthcharging.com<br /><br /> http://www.dualpro.com/

 

[JohnKee]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

Thanks Long Island Guy,<br /><br />Your explaination fills to void left by my dealer. <G><br /><br />JohnK

 

[JohnKee]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

Ottawa Poster,<br /><br />I've down loaded the info on both of the companies you mention. It looks like either product would do just what I want.<br /><br />Thanks,<br />JohnK

 

[crazybear-uk]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

hi <br />just to put the record straight and providing i have read this post correct you can charge a 24v system from a 12v charging system provided the 24v is made up from two 12v batterys by tapping into one of the 2 x 12v batterys = 24v. this will charge both batterys. <br /> In the system decribed this would be unadvisable because if either bank of batterys was to go low enough it would start dicharging via the lead linked between the two banks and if that wire was not large enough would burn it out due to the high amps that could be passed between the two banks. You will find this method used in many electricaly operated machines ie cherry pickers i have a machine in my yard that has 8 x 6v batterys wired up to run 48 volt motors that are charged by a 12v charger(tapped onto 2x6v batterys =12v)<br />regards<br />mark

 

[SlowlySinking]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

JohnKee, you're quite welcome, glad to help. <br />I checked the StealthCharger web site and it certainly appears to do what you need, that is, allow you to use 3 12v batteries, one for starting, 2 to provide 24v for the trolling motor, and the charging of all three simultaneously, a neat trick. There is one point of interest, the amount of charging current available for all 3 batteries and your drive engine's ignition, radio, lighting, and boat accessories is only what your drive engine's alternator can provide, otherwise you drain current from the starting battery, so for example, a 10 to 15 amp outboard alternator may or may not handle your operating boat system current draw much less charge the 3 batteries, there's no free lunch here. So, unless you run your boat engine long enough to recharge all 3 batteries you will need to supplement the charge with a shore based AC charger as noted on the StealthCharger web site. However, since it does what you want and automatically it looks like the cats meow.

 

[JohnKee]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

Thanks to all of you for the great posts. Thisboard is truely a find.<br /><br />SlowSink, I will check the demands of my electronics against the output of the 20amp alternator before I make the purchase.<br /><br />Crazy Bear, I think the unit isolates the two 12 volt batteries that are hooked in paralel for the 24 volt bank, and charges each one seperatly. To be sure I will check.<br /><br />JohnK

 

[NathanY]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

Have you ever thought about solar chargers? My dad uses them on his ranger 24v system, I dont think that he has put a chager on them since.

 

[SlowlySinking]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

Hi JohnKee, I rechecked the stealth site, the unit is apparently a programmable DC to DC convertor, with 12 volts in you select the output based on your trolling system's requirements by using supplied setup boards, in the setup you need the pair of 12 volt trolling batteries are always connected in series for <br />24 volts and charged in series by the 24 volt output of the stealth. The only info I didn't find is the price. Any idea of the price??

 

[JohnKee]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

NathanY asks: "Have you ever thought about solar chargers?"<br /><br />It's a perfectly reasonable question, Nathan, but I fish Puget Sound where the rainfall is about 150 inches a year --that's one hundred and fifty inches a year. There is a saying up here when there occurs a clear day: " Look, the mountains are out!"<G><br /><br />Slowsink,<br /><br />The price of the Stealth, without a gauge that shows the condition of the batteries, is $400.00. One can add another $90.00 for the gauge.<br /><br />Best,<br />JohnK

 

[JohnKee]

Re: three batteries, one for cranking, two wired in series for trolling m'tr

Slowsink,<br /><br />I didn't catch the fact that the Stealth actually feeds 24 volts to the two batteries hooked in paralell, instead of isolating each of the 12 volt batteries that go to make up the bank and then charging each one individually. Thanks for the close read.<br /><br />JohnK