phase charging 3 batteries

[bruceb58]

Re: phase charging 3 batteries

You need to add and isolator or a combiner to his circuit otherwise the trolling motors would pull down your start battery. Problem with the isolator is that you won't be able to fully charge the batteries. I have a feeling, your alternator does not have a remote sense line.

If your trolling motor had a different type of configuration where you supplied it strictly 24V, this would work:

http://www.yandina.com/trollinfo.htm

I remember that Stealth charger that you mentioned before. You need to find out if the grounds are not common with eachother which you need for your application.

 

[MASTER Brian]

Re: phase charging 3 batteries

Bruce, I don't know if the alt ahs the remote sense line or not, so I probably would need the isolator. How is that wired? Is it wired between the start battery and the alt?

As for the stealth I found an online manual for the stealth charger ( http://stealth1charging.com/download/Manual243622004.pdf ). It says it has 1 ground. :% I emailed them to see what they had to say.

What if, I went that route and wired a switch between the grounds to kill the common ground, prior to supplying the power to the troller motor? I have 2 breakers in the engine compartment I have to switch on prior to useing the troller, wouldn't be much more to just flip a switch prior to reseting the breakers.

Of course this does add complexity to the system and I don't want to forget and fry $600 worth of electrics....:^

 

[MASTER Brian]

Re: phase charging 3 batteries

Well, I called them and they said the stealth would work, but I'd have to leave the breaker "open" and the troller set at 24v, while running the boat to charge the trolling motor batteries.

The other nice thing about this setup is that I could just buy a single bank onboard charger to charge all 3 batteries. Then they also sell a cable that goes to the tow vehicle to charge all the batteries while towing.

With all that said, I'm still interested in what we have been discussing as well, but it sounds like the isolater keeps me from a full charge, which might be harder on the batteries life span.

 

[bruceb58]

Re: phase charging 3 batteries

I looked up the manual and you will still have the same problem with having to switch out the grounds. Is there a way to wire up you trolling batteries in series and supplying your motor straight 24V? That seems to be the most straight forward way.

If you are to leave as is and add the switch, I would definitely put some 20 Amp breakers in line with the charging feeds.

The isolater would be wired so that the output of the alernator goes to the input of the isolator and the 3 outputs would go to the 3 batteries. The problem is that you will have a diode voltage drop across it and the batteries will never get fully charged. I would probably wire it up so that the starter battery is on the input side of the alternater to make sure it was fully charged and anything that went to the trolling batterries is at least better than what you have now.

There is another option and I have been hesitant to mention it. Use an inverter to drive a 2 bank battery charger. I believe the grounds would be isolated but you would definitely want to check that first with the charger manufacturer. You would lose some efficiency but you would also have a charger for when the boat is being stored. This method would need significant investigation.

 

[MASTER Brian]

Re: phase charging 3 batteries

Bruce, did you read my post directly above yours? It sounds like that stealth is the best method of attacking this, if I can get a good buy on it still.

When I get the boat back, I'll run some tests and see what I get when the troller is plugged in and switched between 12v and 24v.

The only way I know to leave the motor at 24v is to leave the switch in that position. Otherwise I'd have to run all new wires, etc. If the cable comes unplugged or the troller gets inadvertantly set at 12v, doesn't sound like it would cause much issue, other than not charging those batteries.

 

[bruceb58]

Re: phase charging 3 batteries

Yes...you are correct. If you leave the trolling motor switch at 24V and the batteries are hooked up in series even if the motor is not "on", that stealth charger would work. However, if you put the switch in 12V mode, you would be putting 24V across the two batteries in parallel.

Nothing is easy!

 

[MASTER Brian]

Re: phase charging 3 batteries

See that's what worries me and that wouldn't be good! I will have to ask about that again. I thought she said it wouldn't hurt, maybe I mis-understood. If it was just me and one or two other people, no biggy. Problem is I have a 14 month old daughter and other children/adults that get in and out of the boat.

It would be too easy for that to get moved to 12v.

 

[--GQ--]

Re: phase charging 3 batteries

Hmmm, too many posts to read. Fast forward....As a follow up, your local electrical supply house has many makes/models of the switch ur looking for. They are rated no less than 120v; more what you need for your application. And yes two double pole switch will work also. It's rather clumsy if you ask me.

But why bother with a manual switch? All your switching can be done automatically with the use of relays. When the engine is running, the batteries are in charging mode. Trolling mode when engine is OFF. If you want to get fancy, add a green and a red LED to indicate the Batts mode. All you need is a 12v relay with 12 contacts: 4 common, 4 normally open and 4 normally close. Wiring is the same as diagram above with exception of the coil and two LEDs. Piece of cake 8)

By the way, your staring batt. is completely isolated from the trolling batts.

 

[bruceb58]

Re: phase charging 3 batteries

GQ,

I believe he is going to have a tough time finding that relay for a reasonable cost.

You have a source? 12V coils for a relay of that type and current capacity are going to be very pricey.

I think you can get away with a single pole double throw to the battery #2 ground on my drawing(second from the top on your drawing) and just simple battery combiners to the positives of the two batteries. The trolling motor would always be connected to the positive terminal of the batteries and to the negative of the lower battery(no need to switch that one) and the combiners(SPST) would only close when the engine was running.

You could use a couple of these:
http://www.yandina.com/c100Info.htm

and find a 50 Amp or higher SPDT switch for the one ground or just use a switch. Battery #3 will always get a charge regardless of switch position which is nice

 

[--GQ--]

Re: phase charging 3 batteries

Bruce, the electrical supply house has many make/models. Several brands come to mind but I rather not say. Don't want to be anyone cheap commercial. Check local supply house website or better yet give them a call.

Total cost is roughly $100

 

[bruceb58]

Re: phase charging 3 batteries

I am an electrical engineer and I checked a few of our suppliers and turned up nothing.

 

[MASTER Brian]

Re: phase charging 3 batteries

Hmmm, too many posts to read. Fast forward....As a follow up, your local electrical supply house has many makes/models of the switch ur looking for. They are rated no less than 120v; more what you need for your application. And yes two double pole switch will work also. It's rather clumsy if you ask me.

But why bother with a manual switch? All your switching can be done automatically with the use of relays. When the engine is running, the batteries are in charging mode. Trolling mode when engine is OFF. If you want to get fancy, add a green and a red LED to indicate the Batts mode. All you need is a 12v relay with 12 contacts: 4 common, 4 normally open and 4 normally close. Wiring is the same as diagram above with exception of the coil and two LEDs. Piece of cake 8)

By the way, your staring batt. is completely isolated from the trolling batts.

I will say I am intreged by this, but I guess I don't know enough about electrical stuff to know what to ask for. I have tried some online searches, but have so far come up with nothing. Do you mind elaborating for me a bit? Especially on the coil and a bit on the relay. I understand 12v with 12 contacts, but is there an amp range? I'm worried if I make some calls I won't know what to tell them.

Also, how would the LED's work? I'm guessing one would show when charging the other when not charging. Kind of a piece of mind sort of thing. Here again, I wouldn't know exactly how to wire that, but could probably figure it out. What causes the relay to provide a chargeing current? Does the running of the motor, just cause the relay to open up?

I was almost sold on the Stealth charger, but this might sound like a better option for about the same amount of $$. Would this method allow the batteries to become fully charged? .....I'm also guessing it wouldn't matter if the troller was in 12v or 24v mode (obvioulsy off), or if the circuit breaker for the troller was open or closed.

I would love some manufactures of this stuff to aid in my searching if you don't mind emailing me @ blg@cox.net. I understand you don't want to be a billboard!!

Sorry for all the questions, but I'd like to do something soon, so I can get a charger for the winter. Which does beg another question...would your method allow for a single bank charger to automatically charge all 3 batteries, if I tied into the + and - lead that cones from the alt?

 

[Gone]

Re: phase charging 3 batteries

I have reservations about the Stealth Charger. It's a DC to DC convertor (for all practical purposes an inverter with a DC output) that conveniently omits the charge current capabilities in the manual. It only talks about voltage which, in a charger, is least important. As Bruce says, these are inefficient devices (60%). If it only puts out 3 amps max, that's like a trickle and throws away 2 more just to power it.
Use GQ's circuit. If you are as inexperienced as you say, keep it simple. Use the manual switch(es). The relay will be costly.
(I assume that you are doing all of the work yourself)

 

[MASTER Brian]

Re: phase charging 3 batteries

Thanks for the info crusty. I think I will try GQ's circuit. If I have a complete diagram as well as what parts, I have no doubt I could make it work, but that's putting a lot back on someone else to draw up. I realize GQ gave me the basic diagram, maybe I can find a local electrical supply that could tell me how to wire in the relay with the LED's and the Coil.

Yes, I'd be doing it all myself... I'm actually a bit shocked this isn't a more popular idea. Of course, maybe people don't realize it is possible.

 

[--GQ--]

Re: phase charging 3 batteries

Brian, I've been busy. Give me some time. I'll get the Line Ladder Diagram up.

 

[MASTER Brian]

Re: phase charging 3 batteries

GQ, thank I'll wait for that. I still don't have the boat back anyways.

Bruce, I also, wanted to say thanks for your email as well. I have just been swamped lately as well!

 

[bruceb58]

Re: phase charging 3 batteries

Which model Minkota do you have? I was looking at a few Minkota wiring diagrams the other day. I think there may be a much easier way to do this.

 

[MASTER Brian]

Re: phase charging 3 batteries

That I can't tell you. I actually finally found a manual in with all my boat stuff that says Motor-guide. Is that even Minkota? It's been a Monday and I can't think!!

I'm going to try to pick the boat up tonight and I'll look at the troller to see what it says. One manual I have says Brute. The other just says1985/1986 Owner's manual. It does appear to have some wire diagrams, but they depend on model. That's also assuming this is the original troller!

With all that said, if I had to guess I'd say the 750 Brute, it fits what I know about the motor.

 

[bruceb58]

Re: phase charging 3 batteries

Motorguide Brute 750 is what you probably have then...not a Minkota. I believe they were made by OMC.

 

[MASTER Brian]

Re: phase charging 3 batteries

Bruce, I'm going to go pick my boat up in about 30 minutes. I'll look tonight and let you know. I may have been thinking of the troller for my crawdad. Sorry about that!