Anyone added a second battery?

[ehaze]

http://www.cabelas.com/spodw-1/0000971.shtml

http://www.go2marine.com/product.do?no=16887F

 

[glocklt4]

http://www.cabelas.com/spodw-1/0000971.shtml

http://www.go2marine.com/product.do?no=16887F

Great, thanks. And how did you attach it to your boat? I am getting my boat out Friday, so I don't have any pictures right now to go off of to know how my stock one is attached.

 

[HavingFun]

Great, thanks. And how did you attach it to your boat? I am getting my boat out Friday, so I don't have any pictures right now to go off of to know how my stock one is attached.

Some short stainless steel screws. It feels like you are drilling through the bottom of your boat but your not. I doubled checked mine before drilling the first hole. Remember to chamfer the hole to prevent gel coat spider cracks.

 

[glocklt4]

Some short stainless steel screws. It feels like you are drilling through the bottom of your boat but your not. I doubled checked mine before drilling the first hole. Remember to chamfer the hole to prevent gel coat spider cracks.

Excellent, thanks. Any particular technique on boats for chamfering? Just run a drill bit a tad, or do I need an actual chamfering tool?

 

[HavingFun]

Excellent, thanks. Any particular technique on boats for chamfering? Just run a drill bit a tad, or do I need an actual chamfering tool?

You can use an oversized bit and run the drill slow or buy a chamfering bit. A 3/8" drill bit would work. You just want to round out the top of the hole. If you go too deep then the screw won't work. I know its hard to drill into the boat. To feel better you can remove one of the screws from the current tray to see the length.

This is an easy mod. Put the new tray in the new location. Mark the holes with a marker. Remove the tray and drill with the small bit then run the large bit. Screw the tray in. When I did this I got a battery plus store to make the cables. Its cheaper then buying them pre-made. A auto stereo store can also make the cables.

 

[glocklt4]

You can use an oversized bit and run the drill slow or buy a chamfering bit. A 3/8" drill bit would work. You just want to round out the top of the hole. If you go too deep then the screw won't work. I know its hard to drill into the boat. To feel better you can remove one of the screws from the current tray to see the length.

This is an easy mod. Put the new tray in the new location. Mark the holes with a marker. Remove the tray and drill with the small bit then run the large bit. Screw the tray in. When I did this I got a battery plus store to make the cables. Its cheaper then buying them pre-made. A auto stereo store can also make the cables.

Cool, that's exactly what I was thinking with the 3/8's drill bit. I will tackle this Frida and let you guys know how it goes, thanks!

 

[glocklt4]

Went to west marine tonight to get the battery, case, and cables since I plan on starting the install tomorrow night.

I picked up a dual purpose 27 series SeaVolt 80Ah, 810 cranking amp, 150min reserve from them for $119, two 2' positive cables @ $20 each and one 1.5' neg cable @ $17. Then I went to Academy to see what their prices were since they carry some marine stuff. Got a dual purpose 27 series Exide 730 cranking amp battery from there for only $44. The Exide website says that this is good on a 20amp troller motor for 10 hours, so that tells me it's rated at 200Ah, which is much better.

Considering that this battery will be mainly for backup in case I drain the primary with stereo, I have a hard time seeing that i should spend 3x's the amount for SeaVolt (which I don't even know is a good battery really). I do not plan to sit in party cove all day long with stereo going, so I don't think that I would run it down very often. Also, I'll find out tomorrow night when i pull the boat out if the primary battery is really deep cycle or not. Thoughts?

I think those cables are a bit expensive. $57+tax for 3. As i've read from other posts, I'll probably just stop by a car stereo place and get them to make me some tomorrow instead. The ones from West Marine were not tin plated. Academy had tin platted for $25 each.

I am curious how this should be wired up though. The diagram for the Blue Sea switch just shows that positive from each battery goes into the switch and into the combiner. It does not show if you hook the neg of the second battery directly to the neg of the primary battery, which is then connected to the engine block and power bus:

 

[HavingFun]

Went to west marine tonight to get the battery, case, and cables since I plan on starting the install tomorrow night.


I am curious how this should be wired up though. The diagram for the Blue Sea switch just shows that positive from each battery goes into the switch and into the combiner. It does not show if you hook the neg of the second battery directly to the neg of the primary battery, which is then connected to the engine block and power bus:

I'm not an expert but I think you can hook up the negatives together and they would share the ground to the engine. You will have a few wires that should be connected directly to your starting battery. They power the bilge pump and the memory for your radio. They are easy to spot when you take the positive off the battery. I suggest the starting battery since that is the least likely to be fully drained.

 

[glocklt4]

I'm not an expert but I think you can hook up the negatives together and they would share the ground to the engine. You will have a few wires that should be connected directly to your starting battery. They power the bilge pump and the memory for your radio. They are easy to spot when you take the positive off the battery. I suggest the starting battery since that is the least likely to be fully drained.

Yeah, agree with hooking negatives together, as long as the negative from the main battery to engine ground is large enough to handle power from both batteries. I may have to check the size of that cable out.

As for hooking up the stereo, do you think it would be best to tie it into the 2nd battery, or the primary (leaving the 2nd to be purely a backup).

 

[billandamy]

glock, I may be wrong, but is that switch just to have both batteries ON or OFF in tandem, and not isolated from each other?:huh:

The switch they are putting in for me is a battery 1, battery 2, both off, or both on. This way, when I raft up, I switch to battery 2 for the radio, leaving my battery 1 off line for starting. Then switch to battery 1 when I want to go home or run the boat.

The way you have it, Im not getting how it saves the battery...it looks as if whatever you do you are draining both batteries?

 

[glocklt4]

glock, I may be wrong, but is that switch just to have both batteries ON or OFF in tandem, and not isolated from each other?:huh:

The switch they are putting in for me is a battery 1, battery 2, both off, or both on. This way, when I raft up, I switch to battery 2 for the radio, leaving my battery 1 off line for starting. Then switch to battery 1 when I want to go home or run the boat.

The way you have it, Im not getting how it saves the battery...it looks as if whatever you do you are draining both batteries?

The switch does All off, 1 on, both on. The idea is that you use BOTH on when the primary is dead.

So yeah, i'm trying to figure out if I hook the stereo into primary as well so that everything pulls from primary, until it is dead... then I would switch to combine both and be able to start the engine still. I have no idea what it will take to drain the primary though. Stereo i'm looking at getting is probably 50-60amps (based on fuses). Realistically that should only use 40amps or so consistently, and would give probably 3-4 hours of use. I don't see us sitting there for more than that time with the stereo going... I like to cruise around which would power it back up.

 

[billandamy]

The switch does All off, 1 on, both on. The idea is that you use BOTH on when the primary is dead.

So yeah, i'm trying to figure out if I hook the stereo into primary as well so that everything pulls from primary, until it is dead... then I would switch to combine both and be able to start the engine still. I have no idea what it will take to drain the primary though. Stereo i'm looking at getting is probably 50-60amps (based on fuses). Realistically that should only use 40amps or so consistently, and would give probably 3-4 hours of use. I don't see us sitting there for more than that time with the stereo going... I like to cruise around which would power it back up.

Hmmm...hopefully an expert chimes in, but I had thought if one battery is dead, and you switch to a good and bad on the same line, something electrical which I do not understand prevents the new battery from having enough power to start the boat.

Thus why the switch I am getting installed and I see most people get.

i could be wrong, just that sticks in my mind for some reason.

 

[glocklt4]

Hmmm...hopefully an expert chimes in, but I had thought if one battery is dead, and you switch to a good and bad on the same line, something electrical which I do not understand prevents the new battery from having enough power to start the boat.

Thus why the switch I am getting installed and I see most people get.

i could be wrong, just that sticks in my mind for some reason.

Hmm, good point. I think I have heard something of this as well, but not sure.

 

[glocklt4]

Received the kit today. Here is a scan of the schematic.

Most everything makes sense except that I don't have a neg power block. As i mentioned above, is it ok to tie the neg on battery 2 as well as the ground from the combiner directly to neg of battery 1?

Also, I am not sure exactly how the starter wiring works. It has main power on a big cable always attached but normally in open loop, and then a low power wire carries power from the starter switch to a relay inside the starter to close the loop on that main big line for starting, right? The situation in the schematic doesn't seem to give me the ability to run the starter from either battery, only the primary. The only thing I see happening here is that the power to run the relay and turn on the big line from the primary battery is switchable. What am I missing here? The switch is rated at 700amps, but my battery is rated at 800, and I'm not sure if that's too much to pass through it if I were to connect it directly to the switch rather than the battery.

 

[Kurt]

Maybe I am missing you're question but. The "Perko" brand if similar uses a primay (+) out of the switch to the starter. The switch selector routes power in the switch from which ever battery you choose, 1 or 2 or both. This is done internally in the switch. IMO, I would run the stereo amp power to one of the batteries only independently.

 

[HavingFun]

Hmm, good point. I think I have heard something of this as well, but not sure.

The switch decides which battery starts the boat and which battery gets the charge from the motor. Since you have a battery combiner you only need to worry which battery starts the motor. The combiner will charge both batteries without letting a failed battery drain the good battery. You should never use the both position. See the attached drawing. It’s a different brand but it’s the same idea. The red from the motor goes to the common on the switch. The red from one battery goes to number 1 and the other goes to number 2 on the switch. The ground from the motor connects to one battery (I would use the starter battery) and the other ground goes to the other ground terminal on the 2nd battery. The combiner can be attached either at the switch or the positive terminal like in your original Blue Sea picture.

I would keep your starter battery separate from all other power uses and let the second batter handle everything else. The exceptions are the wires that need constant power like I mentioned earlier. You will see these wires when you disconnect the red for the first time.

Now you can keep the switch on number 1. Both batteries will charge. Have fun for the day and if the 2nd battery runs down then you can always start the motor with the 1st battery and that will charge the 2nd.

Nothing is absolute but generally you will know when you can't trust the first battery and then you either don't go out or you are careful not to drain the 2nd battery. When I did this mod I spent hours thinking about it but then I started the job and realized its a lot simpler then I thought.

 

[glocklt4]

Maybe I am missing you're question but. The "Perko" brand if similar uses a primay (+) out of the switch to the starter. The switch selector routes power in the switch from which ever battery you choose, 1 or 2 or both. This is done internally in the switch. IMO, I would run the stereo amp power to one of the batteries only independently.

Well if you look at the schematic i scanned in, you can see a solid wire that goes from pos of one battery directly to starter.

 

[glocklt4]

The switch decides which battery starts the boat and which battery gets the charge from the motor. Since you have a battery combiner you only need to worry which battery starts the motor. The combiner will charge both batteries without letting a failed battery drain the good battery. You should never use the both position. See the attached drawing. It’s a different brand but it’s the same idea. The red from the motor goes to the common on the switch. The red from one battery goes to number 1 and the other goes to number 2 on the switch. The ground from the motor connects to one battery (I would use the starter battery) and the other ground goes to the other ground terminal on the 2nd battery. The combiner can be attached either at the switch or the positive terminal like in your original Blue Sea picture.

I would keep your starter battery separate from all other power uses and let the second batter handle everything else. The exceptions are the wires that need constant power like I mentioned earlier. You will see these wires when you disconnect the red for the first time.

Now you can keep the switch on number 1. Both batteries will charge. Have fun for the day and if the 2nd battery runs down then you can always start the motor with the 1st battery and that will charge the 2nd.

Nothing is absolute but generally you will know when you can't trust the first battery and then you either don't go out or you are careful not to drain the 2nd battery. When I did this mod I spent hours thinking about it but then I started the job and realized its a lot simpler then I thought.

Your diagram and switch setup makes a lot more sense.

So is the switch I have really made for two house batteries or something? Are you not supposed to use "combine" mode to start the engine if the starter battery is dead on mine?

 

[glocklt4]

Your diagram and switch setup makes a lot more sense.

So is the switch I have really made for two house batteries or something? Are you not supposed to use "combine" mode to start the engine if the starter battery is dead on mine?

Haha... i just called Blue Sea to discuss with them. I had no idea that the "starter" pictured in the bottom right of this schematic was supposed to be the whole ENGINE. The power cable I was talking about going directly to the starter is the ALTERNATOR wire coming back to charge the batteries, ha.

So yeah, i feel like an idiot. Makes complete sense now. He said that combine mode is designed specifically to run both batteries in parallel for emergency starting.

Wow.... sorry guys, ha. With all the work i've done to my cars, rebuilding an engine on my vette... you'd think I would have noticed that. They need to make that descriptive!

 

[Nehalennia]