Hi all. I could use some advice on boat battery charging. I'm getting a boat with one cranking battery and two deep cycle trolling motor batteries in a few weeks. I bought a Minn Kota Precision 10 amp 2 bank battery charger to charge the two trolling motor batteries. Did I make a mistake? Should I get a 3 bank charger instead to charge the cranking battery and trolling motor batteries simultaneously or can I do that with the 2 bank charger?

In a word yes.

Your cranking battery also powers any & all accessories, live well pump(s) as well as any & all electronics.

Ever hear any one complain because their batteries were always charged and ready to go ?

Me neither.

I'm running 36 volt plus the cranker and use a 4 bank Quad Pro to keep me in the juice.

#pieceofmind

A-Jay

 

Thanks for the quick reply. Very nice boat. I went with the 1875 Renegade. I will have to return the 2 bank charger for a 3 bank. Can I ask you what kind of batteries your running (make and model)?

Just throwing this out as another option....I don't know if the boat you have has battery compartment size issues like mine does. I couldn't find a way to fit a 3 bank charger in my boat, but had just enough room for a 2 bank. So I bought and mounted the 2 bank for the TM batteries, and use a small portable, inexpensive single bank charger for the cranking battery. 

11 hours ago, Jibber82 said:

Thanks for the quick reply. Very nice boat. I went with the 1875 Renegade. I will have to return the 2 bank charger for a 3 bank. Can I ask you what kind of batteries your running (make and model)?

 @Jibber82Thanks and that Renegade looks like a sweet rig ~ 

I'm running 4 Optima BLUETOP D31M's.  (Light Grey Case) 

Only two years into them but very happy so far.

 

https://www.optimabatteries.com/en-us/bluetop-dual-purpose-deep-cycle-and-starting

 

From Optima: 

BLUETOP Marine Battery: The BLUETOP starting battery (dark gray case) is to be used when a dedicated starting battery is required; it should never be used for cycling duty. The dual-purpose BLUETOP (light gray case) can be used for both starting and deep cycling; it is a true deep-cycle battery with extremely high cranking power.

Also use for:

Trolling motors, marine applications with heavy electrical accessories and RVs should use a dual-purpose BLUETOP (which is both a starting and deep-cycle battery)

Marine applications and RVs when the battery’s only function is engine starting

Note: The difference between BLUETOP and YELLOWTOP deep-cycle batteries is that BLUETOP batteries have both automotive (SAE) posts and threaded studs, while YELLOWTOPS (other than D31T) only have SAE terminals.

If you ever get confused about the colored tops, just remember: If it has a dark gray case, then it’s a starting battery; if it has a light gray case, then it’s a deep-cycle (dual-purpose) battery.

A-Jay

Awesome A-Jay. That is the exact information I was looking for. Now I just need to figure out if there's a way to fit a 3-bank charger and 3 Optima D31M's in an 1875 Renegade. If not I'll have to go the route ww2 is describing.

Norco Genius Gen3 waterproof marine deep cycle battery charger:.11 1/2"X 8 1/2" x3"

VMax MR 137-120 gr 31 AGM trolling motor marine deep cycle, gr 27 cranking.

Over 10 years on this set up with no issues to date.

Tom

7 hours ago, ww2farmer said:

Just throwing this out as another option....I don't know if the boat you have has battery compartment size issues like mine does. I couldn't find a way to fit a 3 bank charger in my boat, but had just enough room for a 2 bank. So I bought and mounted the 2 bank for the TM batteries, and use a small portable, inexpensive single bank charger for the cranking battery. 

^^^that's what I've always done in all my boats. Onboard charger for tm batteries, and seperate portable charger for crank battery/batteries

The three bank will be less hassle if you can get it to fit.  Like A Jay I am running 4 optima batteries and a 4 bank.

As stated a 3 bank would be ideal. If u can't return the 2 bank of just buy another 1 bank charger for the cranking.  I'm currently running a 3 bank for my trolling and a 2 bank for my cranking and extra battery.