Deep Cycle vs. Cranking

[fishwish]

Question for you all...

When I purchased my "new to me" boat last summer, it came with two cranking batteries running through a battery switch. I had no problems with this set up for the rest of the season, and it worked just fine.

Now, on my old boat, I always had two deep cycles through a switch that also worked great, but seemed to make a little more sense considering the draw of downriggers, electronics, lights etc. and it never had a problem cranking over the engine.

I am now thinking that I want to switch one of my batteries to a deep cycle, so that when I am back at the dock in the evening, I can just run off the deep cycle for the lights etc, and have the one cranking battery left alone.

What are your thoughts? What set up do you all run?

A little info on my boat: Main: Volvo Penta 5.0 GI, Kicker for trolling: Yamaha 8 hp High Thrust (obviously with charging)

Thanks for any advice,

FishWish

 

[bigbruce]

I have a VP 5.0 GXi and a Honda 9.9 kicker. The boat came with two deep cycle batteries connected through a Guest 1, 2, both, off switch. I have recently replaced this switch with a Blue Seas on/off switch and a Voltage Control Relay. I haven't had any issues starting the engine with the deep cycle. When the time comes to replace the batteries, I will put a marine cranking battery for the engine and a deep cycle for the "house" loads.

 

[Whole in the Water]

I have Interstate cranking and deep cycle batteries in my boat. The cranking for starting and deep cycle when trolling and using downriggers. The key is to keep them both charged up (i.e ~13+ volts). Cranking batteries are designed to provide a lot of power over a short time frame whereas deep cycle provides a bit less power over a longer period.

It is very important to never run/charge the batteries on the "both" battery selector switch as this will shorten the life of both batteries overtime. The reason being is the weakest battery will in essence steal power from the stronger battery. You can either monitor this yourself or install an ACR switch to avoid this from happening. If you have a motor over 150hp or a hard to start kicker I would go with one of each battery type. My 2 bits.

 

[Sr SQ]

My starting batteries are crankers and my house battery is a deep cycle.

 

[Skipjack]

I have two start batteries on the 1 position and one deep cycle one the two position. Once i started the engine last weekend on the 1 position, i ran the boat for a couple hours on the both position thinking i was charging all three. Is what Whole in the water true, this is a bad idea? Should i be switching back and forth between the two positions when running to properly charge both banks? Opinions please..

 

[tubber]

You'll get 3 pieces of feedback.
- some guys run on both a lot and have no problems, but they are considered to be running the risk of not being able to re-start the main because a weaker battery could suck power from the good one, so even the both position may not provide enough juice to start the big motor.
- start and run 10-15 minutes on pos 1. then switch to pos. 2 for the rest of the run and to fish, then switch to pos. 1 for the run back in. Only you would know if your deep cycle is maintaining its level just by trolling, so it may need to be charged up eventually.
- Get an ACR

 

[Geno]

This is what I do F250 and F9.9. Not sure if its right or not but it works and have not been stuck yet (knock on wood). I have a interstate cranking battery for my start and a trojan deep cycle for house. I make sure both my batteries are charged before I leave the house and run out on my start battery. Before I start fishing I switch to my house (runs stereo, mfd, radar and riggers). If I'm overnighting I leave my batt switch on the house. Usually I just keep it on house for the run out the fishing grounds the next morning. I keep my start battery seperate at all times so I will always be able to start my main engine. I have never killed my house battery even on 4 day trip, at least not yet. I never use the both setting on my battery switch. Not sure if this is the best way but works for me.

 

[Sr SQ]

- Get an ACR

Agreed, then you never have to think about it or switch anything.