Battery Saver

[tlombard]

Does anybody have any experience or suggestions regarding battery savers? The reason I'm asking is that I'm considering purchasing one to make sure my main battery doesn't get run down and leave me stranded.

Background: My boat has two batteries but the switch isn't wired up 'properly' as most would say it should be. I didn't install it myself and wouldn't have done it this way but the way it is set up is with the positive of both batteries being wired to the switch and then nothing hooked to the third terminal. The main battery is wired directly to the rest of the boat as it was from the factory and then there are two amplifiers wired directly to the second battery.

My first thought was to scrap that setup and completely rewire the entire thing so I could truly use the main, second or both. After some thinking I'm not sure if I want to go through that trouble as I would have to completely replace the battery cable to the main battery to cover the extra distance to the switch. The other part is that with the way it is now, if I turn the switch to one, then the amps will still run off of only the second battery which still solves the issue of them draining my main battery the same as it would otherwise. Of course the head unit will still be running off of the main battery but the head unit would be the only thing while anchored other than the auto bilge pump which has only come on once in five days on the water and that was because we literally dumped water into the boat to make sure it worked. The second battery running amps will drain way before the main with only the head unit.

Before I head down again, I'm going to pick up a jumper box in case of dead batteries for whatever reason but I was thinking that a battery saver on the first battery might just give me extra insurance as well. Properly understanding the way things are set up versus just taking the previous owners advice on how the switch worked helps. The guy I bought it from didn't realize how it was actually set up apparently and I never took the time to think it through after looking it over.

Last Saturday I learned my lesson the hard way as to how everything is wired. I hadn't done my due diligence to trace the wiring and thought that leaving the selector on 2 would only pull from the second battery and leave the main battery untouched. That was wrong as I learned when I ran both batteries dead. Of course I didn't have a jumper box or jumper cables. Thankfully my dad was tied up with us on the pontoon. After he swam over to visit some friends on another boat, I hopped onto the pontoon and stole the battery from there and hooked it up in place of my second battery (thankfully there is plenty of room to drop it in next to it). The boat fired right up and I let it idle for awhile charging the main battery as well as the pontoon one and then was able to switch the cables back up to the second battery while the motor was still running to charge that. I then hopped back over to the pontoon, hooked that battery back up, made sure it started and was good to go. Didn't play the stereo anymore after that!

I almost got away with it without my dad ever knowing how I managed to get the boat started but he came back a little earlier than I thought and showed up before I put the pontoon battery back. When he left he was assuming that he'd have to tow me back. When he got back he saw my motor running and was surprised. He asked me how I managed that. I just chuckled and looked to my left. He followed my eyes and noticed the seat on the pontoon was up and figured out what I did. He just laughed and wondered why he didn't think of that since he's the mechanic and master of coming up something to get home when things go south.

 

[bruceb58]

Wire it up properly. Worth it in the long run.

 

[tlombard]

I still may, but any advice/experience regarding battery savers? My decision on the battery saver is completely independent on the wiring of the battery switch.

 

[H20Rat]

Battery savers are meant for a single battery solution, and although it technically would work, it is not the right approach. You are trying to duct tape something together instead of fixing the problem, no one is going to tell you to do that. You are also adding additional cost and stuff to fail, and if the battery saver fails, your engine doesn't start.

Get a marine battery isolator and a couple of decent battery cables and be done with it, you don't have to rewire the entire boat, just a couple feet of cable. You still keep the switch so you can completely disconnect the batteries, the isolator just connects your house battery to the alternator when the engine is running, and isolates when the engine is off.

Realistically all you do is splice the isolator into the line that runs to the secondary battery, and move your amp power feeds to that one. Done.

In the end, you will have spent less on a system that performs far better! (battery savers are around $100, a 120 amp isolator is $60.)

 

[tlombard]

Smokingcrater, I get exactly what you are saying and I am able to isolate my second battery from the rest so that the amps only pull from that battery as it is set up currently. I am able to use the switch as it is to isolate the second battery from the rest of the boat entirely and the amps are hooked directly up to the second battery now.

An isolator is a good idea though since that would help protect me from my own stupidity and cheaper. In the end, it still does the same thing as simply remembering to put the stupid switch in the first place.

The 'problem' is myself and stupidity with not taking the time to understand how the system was set up initially and taking the word of the person I bought the boat from who wired it up but clearly didn't understand exactly what he did. Instead of selecting 1 on the switch (which will cut the second battery out completely other than to the amps), I was putting the switch on 2 which was allowing the amps to drain the second battery and the first at the same time. That much was obvious after I ran them both dead and examined exactly how things were wired. I have also now tested this to confirm that when the switch is on 1, the second battery is completely cut out of the electrical system other than the amps that are directly wired to it.

The idea of the battery saver was basically just a thought as a fail safe to save me from myself if I were to do something stupid and forget to put the switch in the correct position to make sure the amps are only pulling from the second battery, not to fix an existing problem that actually needs a solution. Well, a solution other than 'don't be stupid' which can never be completely overcome when you're talking about me. Unlike a lot of people, I don't claim to be perfect. I have made dumb mistakes and will in the future. Anybody who hasn't is either lying or they never leave their house regardless of what they claim on the Internet! I take my time and try to do everything correctly but distractions happen.

 

[bruceb58]

You should be able to easily wire this up correctly by just moving existing cables around. It isn't rocket science.

 

[roscoe]

" and then was able to switch the cables back up to the second battery while the motor was still running to charge that."

This may have caused some damage.
Not knowing what motor you are running, hard to tell.
Could have damaged your voltage regulator.
Check out your charging system to make sure it is running properly.


As far as a maintainer goes, it is a simple low amp output battery charger.
just plug it in when the boat is not in use, and it will keep the battery topped of.

 

[tlombard]

" and then was able to switch the cables back up to the second battery while the motor was still running to charge that."

This may have caused some damage.
Not knowing what motor you are running, hard to tell.
Could have damaged your voltage regulator.
Check out your charging system to make sure it is running properly.


As far as a maintainer goes, it is a simple low amp output battery charger.
just plug it in when the boat is not in use, and it will keep the battery topped of.

I did actually switch back to the first battery before making the swap so that the second battery was effectively disconnected before making the change and then went back to the all setting to charge that second one back up. Everything is working properly with the charging system.

And I would love to keep a maintainer on the batteries but I don't have that option other than maybe a crappy solar powered one that probably wouldn't do a thing. The boat is stored in a storage lot at the lake with no power available. So much easier to keep it there and tow it a couple of blocks to the ramp compared to towing an hour each way! Plus the storage is insanely cheap at $30/month (and is secured with cameras and code at the gate).

 

[gddavid]

I think your idea to carry a jumper box is a great idea that negates the need for the battery saver, is a cheap solution and could be helpful to others. As others have said, you are best served to change wiring configuration at the switch, it sounds like you only need to move a couple of cables to different posts.

Do a little research about your existing switch and determine if it is a "break before break" or "make before break" as it can impact the way the way your alternator is connected and protected from damaging the voltage regulator.

A diode type battery isolator does simplify operation however they reduce the efficiency of your charging set up because there is a voltage drop as current passes through it, reducing the effectiveness of your alternator, you can adjust for this by moving the sensing wire directly to one of your batteries but then you may risk overcharging the other battery. There are more sophisticated isolators on the market that can overcome these issues. I suggest you research up on this stuff as running a big stereo system requires a lot of charging which your outings may not always provide. There are a variety of battery combiner options that may make the most sense for the way you use your boat and won't require you to remembering to switch the battery selector every time you start up or turn off the boat to relax to your tunes.

 

[stingray3]

Is it ok to charge my Battery while still hooked up in the boat ? Crestliner I/O MerCruiser 140 Thanks

 

[bruceb58]

I think your idea to carry a jumper box is a great idea that negates the need for the battery saver,

He already has 2 batteries! If he had them wired up properly, there is no need for a battery saver or a jump box. No need for multiple band aids for the original problem.

Basically, wire the switch up properly and add an ACR(automatic charge relay) and there will never be a problem having a dead battery unless you are foolish enough to leave the battery selector in the BOTH position.

With the time spent looking at this thread, I could look at the wiring of the battery and see what needs to be changed. It's not rocket science.

 

[gddavid]

unless you are foolish enough to leave the battery selector in the BOTH position.

Which really isn’t that far fetched. As cheap and compact as jumper boxes are these days it is simple and cheap insurance. By all means the switch should be set up correctly but another backup can't hurt. I loaned mine to a guy struggling to start at the ramp last weekend, I don't know if he got it going but I felt like I did what I could to help.

 

[bruceb58]

If you want to carry a jump box to help others that is one thing. To think that you need it on a boat that already has 2 batteries is another. That's the reason you have 2 batteries...so you never need something like a jump box.

I have never needed to have my switch in the BOTH position so it never goes there.