Battery configurations... will this work?

Battery configuration, will this work?

Current configuration: one motor with 38 amp alternator output, one starting battery, one deep cycle marine battery, a/b switch to switch. Two trolling motor batteries (24v) stand alone with onboard AC charger.

Option A proposed configuration: one motor (new to the configuration) with 7 amp alternator connected to starting battery, one motor with 38 amp alternator output connected to the same starting battery. remove the A/B switch. Install a Minn Kota 3 bank DC charger connected to the starting battery with the iginition circut connected to the larger motor/alternator. The the three deep cell batteries would be connected to the output side the the MK DC charger.

Option B proposed configuration: one motor (new to the configuration) with 7 amp alternator connected to starting battery, one motor with 38 amp alternator output connected to the same starting battery. Leave the A/B swith. Install a DC to AC inverter and connect the onboard AC charger. Manually control the charging of the accessory deep cell with the A/B switch and have a diconnect/connect for the AC inverter.

Will either of these options work or what needs to be tweeked?

Can I have two motors connected to one starting battery and possible at times have both motors running?

The goal is to be able to use the big motor to charge the trolling motor batteries. The boat is moving to a dock with no AC power available so really I am using the big motor as a generator when needed.

Thanks in advance for your thoughts, this community is the best when it comes to seeking honest, helpful opinions :-)

Tracy

I would look at a solar option. I use a single large panel from Harbor Freight with regulator to charge 2 trolling motor batteries. They are in a 24v configuration. I currently only charge one at a time and disconnect the joining cable (that connects the batteries in series to form the 24v). I do have another output from the regulator but haven't been able to determine the output current of that to try to charge the other battery. It has a LIGHT symbol on it as if it is for powering an external light.

It wouldn't do a quick charge but outputs 2+ amps so can recharge in a day. Charges even if cloudy.

good luck.

tadams,

I run my main motor and a kicker which has two batteries connected with a a/b switch. house battery has all the electronics stuff on it along with the kicker motor charge line.I did this so while trolling I am charging. Main motor is connect to battery also. I leave the starting battery isolated in case of battery failure or drain. I put the switch in both on initial run and charge it thru along with on board 110v charger. 24v trolling motor is isolated only for the trolling motor. I added a Yandina Trollbridge from defender.com and pulled the auxiliary charge line to it.(trollbridge parallels my batteries when running main motor and puts them in series for trolling motor so i can add charge while moving). Due to the gps of i-pilot I have to disconnect my trolling motor to do this (no big deal pull the plug out). Look this product up they give you some great wiring diagrams and helped me out when I called. They may have a better set-up for you. Also, you can add a charge line off you truck if you want to charge while driving. Yandina is the name of their boat where they use there own products. Goodluck, hope this helps.

-tight lines-

I hold no vested interest in these companies, I just like this product and it saved me alot of money verses buying a new on board charger that would do this.

You can use your 38 amp alternator to charge all three but not at the same time. You will need a three position switch. Seeing that your trolling motor will use two 12 volt batteries in series you can charge each of them individually with a 12 volt AC generator (Technical name for alternator) . The best method is the slow charge rate from an ac charger that you plug in, but using an inverter would require that the engine runs a long time to replace the charge and it is much less efficient so it would take even longer and require fuel. I am assuming that the 7 amp charging system is from the stator system on a kicker motor? This would be adequate to keep that battery charged and possibly your main battery, but it will work its tail off.

You need to be aware that connecting many systems together can bring about problem that result from electrolysis.( the transformation of metallic compounds resulting from current flow) All of the systems and batteries need to have separate conductors paths and never use the hull, stringers, or chassis as a ground path. It can literally eat away your boat, and outboards/units

My 2 cents

Kent

Attachment 4288
Here is a quickly drawn wiring diagram that will work. Circuit protection will need to be included. Just make a shout out and we can figure this if you need.

That small if alt. More than likely won't be enough to charge all 3 batteries. You don't want your charging system running at max all the tine. I would think you would want at least a 100 amp alt to do what your planning.

I don't know if that wiring would work that way, I think if you left the trolling motors in series to get 24v, then pulled that switch the charge by the 12V system, the 24v volts would back feed through the same wire, would you not need a break switch going in the series line between the 2 batteries used for the 24v motor?

Yes, you would have to put a switch in the ground side of the second batteries ground path. Otherwise there would be a short for the first battery in the 24 volt system. As long as you are only charging the batteries the 37amp Alternator will produce enough current. It would not though produce enough if you tried to use the trolling motor while running the engine. This would be unusual though. I have wired many series-parallel systems on different units over the years which only had low current generators. If you have many other consumers the current requirements will be greater. It would help to know if the charging system on the big engine is on an inboard or an outboard. Increasing the charging system capacity is very easy on an inboard, but no so easy on an outboard.

I threw this drawing together a little to quickly. There will need to be a switch on the negative side between the battery and the ground cable returning to the charging unit/alternator. Also, each of the positive path switches need to be only used one at a time. A 4 positon rotary battery switch would make this much easier and safer. You cannot charge both batteries on the 24 volt system at the same time.

You might be interested in using a "Stay-N-Charge" unit. It will charge your trolling batteries while the main motor is running, once your house batteries are fully charged. I've used one on my boat for 7 years. I don't use it any longer though since I troll with the big motor now for walleyes.
Rickerd

Quote:

---

Originally Posted by rickerd

You might be interested in using a "Stay-N-Charge" unit. It will charge your trolling batteries while the main motor is running, once your house batteries are fully charged. I've used one on my boat for 7 years. I don't use it any longer though since I troll with the big motor now for walleyes.
Rickerd

---

To me, that sounds like the easiest fix for the situation. I use my electric motor for GPS anchor mode because I fish a lot of structure. It is the cats patoot!! So after a good day of use my batteries need a good full up. Nothing like a good AC hook up....

Minn kota also makes a charger that charges the trolling batteries while running. Had one on my last boat. Works great. My buddy had a lot of issues with the stay in charge system. Good luck. Aaron

Thanks all for the good information, I believe I will do both a trollbridge (to keep me going for long weekends) in combination of a solar dock panel (to make sure I am charged to start the weekend).