OK, I left the power on last time out and my cranking battery was dead as a door nail. I have an old charger that I converted with a trolling motor plug so I can plug into the bow receptacle and charge my two in parallel batteries. I don't usually have to charge my cranker. So I cut the plug off and charged the cranker so I could go fishing last weekend. Now I need to buy an on-board charger. My old one will get alligator clips again and be for other uses.

SO ... which one do you recommend? I have two trolling motor batteries in parallel @ 12 volts and one cranking motor for the big motor and electronics. Do I need a 3 or 2 bank?

I have a MK 12volt 55# copilot, MK 12volt vector 55# and the other assorted electronics Lowrance X91, Garmin GPS.

I appreciate the help, thanks!

karpbuster

P.S. I may be wrong on the parallel it may be in series, but if it would make it 24 volt, it is not - it is a 12 volt system.

I'd think about a 15amp unit like this for the (2) 12V TM batteries, since you essentially are charging 1 big 12V battery http://www.dualpro.com/store/items/9/20/

and a smaller 5amp unit for the starting battery out back http://www.dualpro.com/store/items/9/28/

HRG

I like Minn Kota's stuff. If you still want to be portable, they make a 3 stage electronic,
http://www.minnkotamotors.com/products/chargers/detail.asp?pg=mk110p
I have one and use it as backup since I gott my MK220, which is two banks at ten amps. You can still use it to charge your two paralled batteries.
http://www.minnkotamotors.com/products/chargers/detail.asp?pg=mk220

I would be tempted to go the 3 bank route. Never know when you might go the 24v route, and you're already set up. Not sure how you'd set up the parallel with 1 bank. Would it work if one of your batteries failed.(one of your parallel units I mean) I believe DualPro has extentions for starting batteries if you mount up front, and then you're dealing with only 1 mounting and 1 plug in. Not an expert by any means, but just a couple of things to think about. Mike R.

I would be tempted to go the 3 bank route. Never know when you might go the 24v route, and you're already set up.



2nd that.....go 3banks.

I recommend a 3-bank. Run one pair of wires to your cranking battery and two pairs to your two trolling motor batteries. That way, your TM batteries get twice as much charging current as your cranking battery. As said earlier, if you ever convert from 12 volt to 24 volt, you won't need to change chargers.

Do a little reading before buying your on-board charger. Some (maybe all) brands allow you to hook up multiple charger wire pairs to the same battery to increase the available charging current (my 2-bank Guest charger, for example, is hooked up with both pairs of charger leads connected to the same battery). If you do the hook-up described above, you want to be sure the charger design allows that. You'll also find some chargers that will direct their entire charging capacity to a single battery if that's the only one needing a charge, while others do not (my Guest does not).

Check out the Stealth 1 AC/DC dual unit

http://www.stealth1charging.com/

Just put the Stealth 1 DC unit in.

Boat already had a three & Dual Minn Kota for the Three 36 volt trolling batteries & the Cranking And House (Electronics's Battery).

Wired it to have a Backup using the House to help the Cranking Battery and also #1 Trolling to back up the House Battery.

TR1 Auto Pilot uses a lot and so do these 2008 Electronics's

I am on it, I will buy a 3 bank. So the best method is to run additional wires to each battery from the charger and they are each on their own bank. And the charger will charge each one independently and as needed to keep them up but not over-charged?

Dual Pro, Minnkota, Guest and Stealth ... ??? Which one works the best in that config? The Dual Pro has the most votes thus far. The info I see is all say the same thing, micro processor controlled, etc. If you would be so good as to put down the model# of the unit you like as well.

Thanks again.

karpbuster

I'm sure that people are tired of my "rant" on this subject, but I fail to see or understand how a dual battery, parallel-wired 12V set-up can charge each battery independently, as long as both jumpers are in place. The use of the 3-bank is good, and certainly gives you future flexibility if/when you go to a 24V TM. My 2 cents worth is to install a disconnect, like this one: http://www.gamainc.com/batdis.shtml (the side-post model) in the positive-side jumper, and when charging the TM batteries, open the disconnect. This way, each bank of the charger only see's the battery it's hooked up to, and not the jumpered combo.
HRG

Hi HRG,

So they are not independent, thus the two chargers. Well that is the same amount of money based on your URL's, just have to charge from two outlets. Hey I am clueless on this and apparently so is Sportsman's Warehouse, where I just went during lunch. They have the MK and have no clue how they work, just read the box. Which I did, didn't help, except bank = battery.

I guess there is no "simple solution" plug-in and charge up all 3 batteries?

karpbuster

Just to clarify, the Dual Pro chargers ARE (3) independent units in 1 case, but my point is, if the jumpers are in place between the batteries, the charger really doesnt know which battery it is charging. The 3-bank is the way to go (or a 2-bank up front, and a single out back), but I'd like to see the disconnect. Think of it this way, if one of your (2) battery combo goes dead, how would you know? You still get 12V out of the strong one, but the weak or dead battery will hasten the decline of the good one.
HRG

Hot Runr:

You're right- parallel wired batteries cannot be charged independently. If you use a 2-bank charger to charge two parallel-wired batteries, it makes no difference whether both pairs of charger wires go to the same battery or each pair goes to a different battery. What you do get from running two pairs of wires from a 3-bank charger is double the charging current if the charger isn't smart enough to direct the charge where it is most needed (some are, some aren't). I expect Karpbuster's parallel TM batteries are more discharged than the cranking battery at the end of the day, so more charging current available to the TM batteries is what I'd want. Your disconnect idea is a very good suggestion, just one extra step in the process.

Karpbuster- there are several simple solutions to plug in and charge your 3 batteries. Some of them are...
1. Use a 2-bank charger that can re-direct charging current to the most discharged battery- one bank for TM batteries, other for cranking battery. Example- Cabela's Pro Sport II 12 which will deliver up to 12 amps to any battery in the system. $80.
2. Use a 2-bank charger that doesn't redirect current, wired as above, but know that your 2 TM batteries are going to share the same charging capacity as your single cranking battery. Example- Guest Model 2611 will pump 5 amps to your TM batteries. $100.
3. use a 3-bank charger that doesn't redirect current and wire 2 of the banks to the TM batteries to charge them more quickly. Example- Guest Model 2613 will pump 10 amps to your TM batteries. $170. It takes a 3-bank charger to support a 24 volt TM system and still charge the cranking battery, should you ever want to do that.
4. Use a 3-bank that can redirect current- Example Cabela's Pro Sport II 20 Plus- $130. This, coupled with HRG's TM battery disconnect might be the best choice. Nice thing is you can't hurt anything if you forget to open or close the disconnect.

By the way, my examples are based on my historic good experience with Guest chargers, but nothing more than reading about Cabela's chargers

I have a 3 bank pro mariner that I really like, had it about 4 years now and it still works flawlessly

KB - you were on the right track, before HRG distracted you with a technical correction.

Batteries in parallel generally act like one battery that is twice as big. So, if a 10 amp charger will charge a normal battery in a reasonable amount of time, you would need a 20 amp for a battery twice as big for the same amount of time. If you try to use just the 10 amp charger, it will take twice as long as just one battery would take. Getting a charger that big, and wires that heavy, can get to be an issue......
So, hooking two "banks" up, one to each battery, can give you the same effect.

Because the batteries are wired together, they are not being charged independantly. And, if you have one battery that is stronger (higher voltage) than the other, it will actually try to charge the other one, at least to the point to where both are equal. So, you can put the wires from two banks of your charger on to just one of the batteries, and as long as the other battery is connected, they will still both charge in a reasonable amount of time. Hooking one or both up to two banks is your choice -whatever is easier to do in your boat. Just don't run two banks to one battery without the other one connected - that runs a risk of overcharging.

The down side? If one of the batteries goes bad and won't accept a charge, you may end up ruining the second also, as it constantly is trying to charge the bad one, and running itself down to nothing in the process. This will happen whether you have a charger connected or not - so is not an issue with having a charger, per se, but may result in you fooling with things longer trying to figure out the problem.

So yes, go for the 3 bank. Hook one bank up to each battery, and enjoy having one less thing to fool with when you want to go fishing......

I have been down this road many times.
Take it from a touring pro. go with the 3 bank minnkota charger.
It has the fastest recovery charge and it is bullet proof.
I am on my third dual pro charger, in my current 620 Ranger.
In the past, I ran minnekota chargers, And That will be the case from now on.
Back when everybody was running 24 volt,
some riggers would skimp by with a 2 bank charger, and use a loop to parallel the main with one of the 2 trolling batteries.
I had that setup in my older boat.
It did work, but it took the bank charging the two batteries twice as long to reach full charge.
After some time, the batteries would develop a load imbalance memory.
Use a 3 bank and run the leads to each battery.
You may need to install a disconnect on the parellel batteries.
Ask your boat dealer or call minnekota techical support.