phase charging 3 batteries

[MASTER Brian]

Is this possible? ...so that I can charge all 3 batteries off of the boat alternator.

I thought there was a thread talking about this with 2 batteries and bass pro shops lists this phase charger.
http://www.basspro.com/servlet/cata...varTarget=browse&cmid=PP_P2_1&cmCat=CROSSSELL

All 3 batteries are seperat. 1 battery is for starting the boat, the other 2 are for the troller and wired indepently to troller, where the troller is switched from 12v to 24v.

I can upload a diagram of my setup if need be.

 

[bruceb58]

Re: phase charging 3 batteries

Unfortunately, you can't do it like that since your trolling batteries are set up for 24V. You could charge one of the batteries that way but not the one battery whose negative lead goes to the positive of the other(your trolling motor may be doing this internally).

 

[MASTER Brian]

Re: phase charging 3 batteries

my batteries are independent of each other and the troller combines them to 24v.

Here is a pic of my setup....

 

[bruceb58]

Re: phase charging 3 batteries

You still can't use that combiner unless the trolling motor is converting the 12V to AC before it is using it...which I doubt.

In order to charge the two batteries using two of those combiners, you will have to tie the grounds of each battery to the ground of your start battery. Can you see now why you might have a problem?

Is there an online manual for your trolling motor available. Ican take a look at it to help you.

 

[MASTER Brian]

Re: phase charging 3 batteries

Why would tieing the grounds together pose a problem?

As for a manual, I don't know. I'll see what I can find.

 

[rickdb1boat]

Re: phase charging 3 batteries

I see no reason you can't do it as long as the batteries are separate. This would be the case the way it's wired to the troller right now. At no point should you read 24 volts the way it's set up. It's done internally in the troller...

 

[bruceb58]

Re: phase charging 3 batteries

You can't tie the grounds together because the trolling motor is connecting the positive of one battery to the ground of the other internally to form 24V.

Do this test...connect a meter between the two grounds of the trolling motor batterries. If it measure 12V when the trolling motor is in 24V mode, it is internally connecting the -/+ connection.

 

[MASTER Brian]

Re: phase charging 3 batteries

My boat is at the shop, but when it comes back, I'll look into that and post my findings!

 

[--GQ--]

Re: phase charging 3 batteries

Sure you can charge all three batteries from your alternator provided a 4 poles two position manual switch is placed between the batteries and the trolling motor controller unit. There maybe an automatic switch designed for such application. Might want to search your local marine stores.

I'll make a diagram upon request.

 

[MASTER Brian]

Re: phase charging 3 batteries

I'd love to see a diagram. I haven't gotten my boat back yet, so I haven't been able to find out exactly what troller I have. However, when the boat is underway the troller won't be being used, so at that point, each of those two batteries would be totally isolated anyways. Or at least that's how I'd see it.

A manual switch would be fine, but an automatic one would be cool as well.

 

[bruceb58]

Re: phase charging 3 batteries

When you make that diagram, make sure you include the grounding and the internal connection of the trolling motor and you will then see why it won't work.

Who makes your trolling motor?

 

[bruceb58]

Re: phase charging 3 batteries

Take a look at this drawing. On the top is your present hookup assuming the switch inside the trolling motor is as shown. At the bottom shows how you would reconnect the batteries with an isolator.

Note the problem when your trolling motor is switched to 24V mode. The positive of battery 3 is connected to the negative of battery 2. This would short out the charging circuit that is trying to drive battery 3.

 

[--GQ--]

Re: phase charging 3 batteries

Position the switch to the left for charging. To the right for trolling mode.

Make sure your alternator is big enough to handle three batteries. d

 

[--GQ--]

Re: phase charging 3 batteries

I can't believe you made me do it. Bruce you owe me 10 bucks. 8)

 

[bruceb58]

Re: phase charging 3 batteries

GQ,

OK...that will work.

Now find a 4 pole double throw switch!

 

[Gone]

Re: phase charging 3 batteries

Cutler-Hammer makes one that I use for a different purpose (speaker switching). It is only rated @15 amps, though. I haven't tried looking for a larger one. They get pricey fast.

CD.

 

[MASTER Brian]

Re: phase charging 3 batteries

I believe my XP150 has a 30 amp alternator, will that handle 3 batteries?

How big of a switch do I need to hunt for?

Thanks!!

Also, would 2) 2 pole double throw switch's work if they were both switched at the same time? I'm not that electrically inclined! :'(

How about this one on ebay.... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7501617666&category=26211

 

[MASTER Brian]

Re: phase charging 3 batteries

BTW...the troller is a min-kota. I'm not sure how old, but my guess it came on my boat new, which is an '86 Ranger.

 

[bruceb58]

Re: phase charging 3 batteries

I would think that a 15 Amp switch would be too small. I am betting that in 12V mode you are going to pulling 30 Amps. If both batterries were both fully charged that could equal out to 15 Amps per side(12V mode) but if one battery was low for some reason, more current would be pulled from the other. I would look for a 50 Amp switch at least so that you had some safety margin.

Regarding the 30 Amp alternator...it is just math...I am not sure how much you use your trolling motor and at what speed and how long you run it.

If you are running your trolling motor full blast for an hour it will take over an hour of running your engine to charge the batteries back up.

I am also going to assume that you are using wire in the range of 10 AWG to 6 AWG. You will need a switch that will allow that size wire to be connected to it.

Why don't you call Minn Kota and ask them what people use with your set up? Maybe there is an easier way than what we are thinking of.

 

[MASTER Brian]

Re: phase charging 3 batteries

Well, I found a 32 amp switch, but it's rated for 250V. Not sure if it would work or not. If I found a 50 amp one, would the volts matter if it were at least 12v?

Through the link I provided, the guy had a bunch listed. They ranged from 15-32 amp and from 120V to 250V with or without spade connectors. Then some were On/On maintained, some were on/off/on maintained. Or some variation of that.

Very good prices on all of them. Then there is still the option of the stealth charger I mentioned in another thread, which just monitors the primary battery, when it gets fully charged it charges the 2nd, then the 3rd battery. I can get one for around $100, I believe.

Am I correct that the diagram GQ displayed would always charge all 3 batteries, when the switch is "ON"? That might be better, especially when running from spot to spot. You'd at least be getting some recharge instead of waiting for one to get full, so the next in line could be charged.

I just don't know enough about electrical stuff.