Trolling Motor Battery Set Up

[Ant_man]

G'day Folks,

I am a fly fishing guide from Australia and am not having any luck finding out some information; so as an occasional lurker here, I thought I would break my silence and post. I hope that someone can help me.

I have a Riptide 55 on the front of my boat. It is a brilliant motor. I recently decided to upgrade the battery system that runs this motor; not just for extra amp hours but also as a back up for my outboard as I have been having problems with an electrical fault that drains the main cranking battery. It's a real bummer.

Anyway, I got some feedback from a couple of the better tournament fishers here in OZ and I purchased 2x Trojan 12V 145Ah Flooded Lead Acid Battery and a CTEK 12Volt 25Amp 8 States Battery Charger - Multi XS25000. I dropped the boat off for the install and when I picked it up the guys said that they didn't have the batteries I had ordered and paid for weeks earlier so they upgraded me at their expense to a better Trojan battery. Even better!

A month later I am in the middle of a big lake; 350 miles of shoreline and a long way from the ramp. I go to start the boat and the cranking battery has died again. No Sweat as I have two massive 12 volters up front. I connect the jumper cables to the Trojans and nothing. Cannot start it. I try every configuration possible. Eventually it strikes me that they are wired in series not parallel!!

So not believing what I am seeing I disconnect one of the batteries and take a good look. They have given me 2x Trojan 6V 250Ah Flooded Lead Acid Batteries wired in series!!

My question is this.does anyone else out there use 2 x 6V batteries in series as opposed to 2 x 12V batteries in parallel?

I thought that I had a 12V system as originally designed and purchased. I have just checked the final receipt they gave me and it has been amended from the first receipt to say 6V batteries. Lucky I have the original one to argue my point as I requested a 12V system from the very start.

With 2 x 6V, the way I see it, I am just introducing more chances of failure into the system. With 2 x 12V batteries I can use either battery independently to start the outboard if the cranking battery

fails, its almost like having three chances. With 2 x 6V making up my 12V system both become useless if either of them has a problem. Same thing with the trolling motor; it becomes redundant if either of the 6V batteries dies; but with 2x 12V you could pull out the offending battery and keep fishing.

Can anyone please tell me what the advantages of 2 x 6V batteries rigged in this fashion for this purpose, actually are? I have emailed the company tonight (Sunday night) to try and sort it out. Not sure what their attitude is going to be but either way would appreciate any feedback into this problem that I am having.

Thanks and tight lines.

Antony

[George Welcome]

6 volt batteries have a larger capacity than the 12. In theory the configuration they gave you provides the same amp hour usage as the 2 12 volt in parallel.

In either configuration you have a problem if there is a battery failure.

When batteries are parallel a failing battery will drain the good one. In series this is not the case, however being left with one good 6 volt is no good either.

Two suggestions: First and most importantly find the drain before something burns up. Second, separate your trolling system from your starting system.

[Ant_man]

G'day George,

Thanks mate. First off the boat is brand new. It has had a drain down of cranking battery on each outing. Running a Mercury 60 EFI 4 stroke. There is no obvious current draw that I can find - (i.e. by slowly removing the negative terminal from the negative battery post and listening for static/crackles) and there is no way a sounder can drain down a battery in a matter of an hour or two. I don't have a schematic diagram of the motor but there is a large, fuse (25AMP) located on the port side of the engine. It blows as soon as the engine is started. I only just found this out. I purchased the boat on Dec 6 and booked it in for warranty repairs on Dec 12 but the wait was over a month. The boat actually goes into the shop in about 12 hours time. Hopefully they can correct this.

FYI the trolling set up is completely independent of the other electrics/outboard system. All it runs is the Minn Kota and a tiny 20 Litre refrigerator. I guess I didn't explain this well enough in the inital post!;-( The outboard, bilge, livewell, nav lights, sounders etc all run off the cranking battery.

I wasn't aware that a faulty 12V in parallel would drain the other. All things being equal though, would you want two 12v in your system or two 6v? What I am thinking is that  with 2 x 12V at least both the batteries in the trolling set up could be capable of independently starting the outboard if needed.

Any thoughts? What would you do?

Thanks

Antony