Northwest Fishing Reports

Does anyone have an electric trolling motor that runs on a 24 volt system? I just bought a motorguide brute series off craigslist and it runs off 24 volts, a system that I am not familiar with at all. I'd like to be able to charge these batteries with my outboard, but then that's a total of 3 batteries that I'd need to charge including the battery for the outboard itself. I know it has to be possible to charge the batteries with outboard, but I would assume I would need some sort of battery selector or something (but maybe not?). I just don't know where I'm starting here, so any suggestions/options/ideas would be appreciated. Thanks! :bounce: :bounce:

Hey Drewp,

I have a 24v setup on my Fish n Ski.

My cranking battery is charged by the alternator, no big deal. Sounds like what you want. My two batteries for the 24v system are charged by a Guest 2 bank charger that I plug in when the boat is sitting in my driveway or at camp. I have used the batteries for 8 hours straight in one day (I have a 70# MinnKota, pushing around a 3500lb boat) with no problems. I wouldnt be too worried about running out of juice on the water.

The problem with using a battery switch is that sooner or later you will forget to put the switch back on your cranking motor or not charge one of the 12v on your 24v setup.

Getting a 2 bank charger specifically for your trolling batteries means never having to worry about it.

http://tinyurl.com/3xyw68


I realize this doesnt answer your question, only introduces more questions and opinons.. but hey.. thats what I'm here for.

The problem with using a battery switch is that sooner or later you will forget to put the switch back on your cranking motor or not charge one of the 12v on your 24v setup.

Getting a 2 bank charger specifically for your trolling batteries means never having to worry about it.

I agree. I worked at a Marina, and now handle boat insurance claims. Battery Switches are a nightmare waiting to happen. Either you forget to charge the cranking battery or the whole dang thing shorts while charing and causes a fire

Well, thought I should follow up on how it turned out. I ended up installing a Voltage Sensitive Relay (VSR). It's actually a pretty cool little deal. It's a small box that you run the power from cranking battery through, and the relay inside opens and sends charge to your other batteries only once your start battery reaches ful charge. Since it's automatic, I don't have to worry about forgetting to flip a switch, and it will not allow me to draw power from my start battery when using the trolling motor. Here's a link with a description of the VSR if anyone's intersted. Easy to install and not that expensive.

http://www.iboats.com/Voltage_Sensitive ... _id.341868

On the commercial fish boats I've run some were 24 volt except for the starting system and the same for the 36 volters. An outboard won't have the push but with a 200amp alternator we would run an inverter off the start batteries, normally three 8d's with a voltage regulator in between them and the inverter. It would shut the inverter off at 11 volts. Off of that we ran a stepdown a transformer to get the desired voltage and a huge fullwave bridge rectifier to flatten the wave.
Looks like you got and easy solution. Cool!

So are you thinking of using 2 of those little guy's? It looks like they'll only charge one battery at a time.

Drewp wrote:Well, thought I should follow up on how it turned out. I ended up installing a Voltage Sensitive Relay (VSR). It's actually a pretty cool little deal. It's a small box that you run the power from cranking battery through, and the relay inside opens and sends charge to your other batteries only once your start battery reaches ful charge. Since it's automatic, I don't have to worry about forgetting to flip a switch, and it will not allow me to draw power from my start battery when using the trolling motor. Here's a link with a description of the VSR if anyone's intersted. Easy to install and not that expensive.

http://www.iboats.com/Voltage_Sensitive ... _id.341868

That's an interesting alternative. The only concern I have is that if this unit fails, then the circuit for your cranking battery is broken -- hence no start.

It does look like a cool deal, and if it fits your needs then all the better.

Bodofish wrote:So are you thinking of using 2 of those little guy's? It looks like they'll only charge one battery at a time.

Well, the guy that helped me out when I went to Boater's World said that it will charge both batteries in the 24 volt bank. I hope he's right

TCB, the VSR actually interupts the power going from the cranking battery to the 24 volt bank, so I think if the unit fails, then the only thing that will happen is the batteries won't recieve a charge in the 24 volt bank. Again, I hope

We'll see how it goes...I'm going camping for the weekend in Entiat on the Columbia. Reports to follow on Monday.

I hope you're right. The specs on that unit show it charging a single 12V battery. I thought you were going to run two batts to get the 24v. Just personal preference for me, I would never use your starting batt to run a trolling motor period. If you do run two batts for the troller then if you charge them one at a time the pack would have to be split or you're trying to charge 24v with a 12v charger. If both batteries are not charged equaly when they are connected they will equalize each other in other words if one is 24v and the other is 16v they will both be 20v in short order.If you are using the starting batt as one of your batteries for the troller, I realy suggest you take along one of the jump starter type emergency starter batteries. Cheap insurance all around for any boat you can't start by hand.
On board charger and plug it in at night. They're even available that run off your Auto system while driving. OB's just don't have the strongest alternators. A couple big deep cycle batts are going to take more charging than just your run to the fishing grounds. A tip on any lead acid batteries weather they be liquid or gel. They like to be charged completely all the time. If you take them out and use them on the bottom half of the charge all the time you will substantialy reduce their life.

Sorry if I'm rambling but most salesmen don't even have the slightest comprehension of basic electrical theory.

Well, now you got me worried! But it seems to me that the VSR does not allow the start battery to drop below 13.7 volts. And it only sends charge to the two bank batteries if the start battery is full. Hopefully I don't get stuck up **whoops**creek without a paddle!

So you have one battery for the starter and two for the troller three batts total? I'm assuming. The vsr can only charge one of the batteries in your 24v bank at a time. If that's the case your starter should be fine.
24v bank, can only be charged one batt at a time as the vsr will only charge 12v. If you charge the bank the best you can hope for is a 12v charge on the bank. You could have ten batteries in the bank and it will only charge the bank the max output of the charging system on the OB, 12v unless the batteries are split up for charging or you have a way of stepping up the voltage. Is that more clear? I'd hate to see you get stuck or worse burn up the troller or your charging / starting systems. If your starter batt is in series with the troller batt you have 24v and that will burn up your starter in a hurry not to mention any other 12v devices on your boat.
I'm rambling again, sorry. need more info about the setup.

Drewp wrote:
TCB, the VSR actually interupts the power going from the cranking battery to the 24 volt bank, so I think if the unit fails, then the only thing that will happen is the batteries won't recieve a charge in the 24 volt bank. Again, I hope

Ah, I must have misread the implementation. Good luck! I'll be at banks, hopefully the weather ends up nicer than predicted.

I'm curious how everything turned out on this charging issue. I have a 36 Volt Trolling Motor and I put 3 separate solar panels on them to keep them charged as I use them and they also keep them topped while sitting. If I sit for more than a week I disconnect them. They work great and only cost $30 a piece as opposed to over $300 for the 36v charger the boat shop wanted to charge me.

Drewp
The otboard will need to run for quit a long time if you want it to charge the two other batteries at least an 1hr or more becuse the first 15 to 20 min. of run time the motor will be putting back the the juice it took to start the motor. Also you must have an alternator not all outboards do. I whould go with a 3 bank charger also for those days when you only run the outboard for 5 min. at a time 4 or 5 times in a day.