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Discussion Starter #1
question . I have two Vulcan 750 a 1995 and a 1989. I would like to know would it be safe to install a second battery wired in parallel so I would double my ability to provide a stronger power to my starter or is it an issue to put to much additional strain on our bikes stators by doing this . With recent manufacture of iron phosphate batteries that are small and can easily be placed in saddle bags. Is this a doable solution for the poor electrical problem our bikes have or is it a bad move.

My bikes both start well but its the hot restart that gives me issues . When the bike is hot its hard to restart some times . Would appreciate some thoughts on my idea
 

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FREEBIRDS MC CENTRAL NY
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do you have wet cell or AGM?

Sent from my LGL34C using Tapatalk
 

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One bike is agm the other bike is a shorai lithium iron phosphate, I just want to try and increase my power to start
 

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To answer your question.... You can run two batteries in your bike, but I'd advise against it. The other battery would put a strain on your charging system. They do make "battery isolators" that would prevent this, but unless you are running A LOT of other electrical accessories, I see no need.
 

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1986 VN750
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Bad move.

If you are having trouble starting, address the issue, don't just band-aid it with trying to parallel up some batteries.

I third the pickup coil mod. Direct power to the coils did a ton of good.
 
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NewB to Vulcans
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Not a good idea to parallel batteries as each one will charge and discharge differently. Whichever is the most easily charged will be constantly overcharged and vice versa.
 

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Not a good idea to parallel batteries as each one will charge and discharge differently. Whichever is the most easily charged will be constantly overcharged and vice versa.
That's why I said you'd need a battery isolator....to prevent this exact thing.
I'm not sure even then if this would help. You'd need to rewire the bike so one. Battery only is used to start the bike, and the other powers all the lights and accessories. A lot of work for something you really don't need on a bike like the Vulcan. A Goldwing with a big stereo, heated seats, etc...be a good candidate... but you'd also have to make sure the charging system could handle the extra load. I think Harley Police bikes had two batteries.....
 

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Discussion Starter #10
I see all of your points. Well taken I guess I will try the coil mod. Thanks to all
 

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I see all of your points. Well taken I guess I will try the coil mod. Thanks to all
You might also look into the Two Wire mod. It removes the start circuit and the ignition start circuit from the junction box.

http://www.vn750.com/forum/19-electrical/77946-two-wire-mod-17.html

http://www.vn750.com/forum/19-electrical/94698-short-video-blue-wire-two-wire-mods.html

The junction box is a black hole of voltage loss, anything to remove circuits from there will help.

I only have the Two Wire and the Blue Wire mods, even though the headlight comes on when the key is on, my hot starts are better. So in the JB, I've bypassed the start relay and the headlight relay. Next mod is a separate fan relay and I'll have no active relays in the JB.

There is also the pickup coil mod, which is said to improve starts.
 

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1986 VN750
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You might also look into the Two Wire mod. It removes the start circuit and part of the ignition circuit from the junction box.

The junction box is a black hole of voltage loss, anything to remove circuits from there will help.

I only have the Two Wire and the Blue Wire mods, even though the headlight comes on when the key is on, my hot starts are better. So in the JB, I've bypassed the start relay and the headlight relay. Next mod is a separate fan relay and I'll have no active relays in the JB.

There is also the pickup coil mod, which is said to improve starts.
I've done two wire, blue wire, and coil mods; she loves to start now. Hot, cold, no problem.

Two wire/blue wire mod helps. Really reduced voltage loss in the system. Starting was fine, but power @ the coils was still lower than battery voltage. Did the coil mod, and now I read battery voltage @ the coils.
 

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A battery isolator will alternate charging between the two batteries, while allowing both batteries to supply cranking amps.

But as stated, it's a band-aid fix with no promises. Would be best to eliminate some factory wiring faults.
 

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Yup Tanner, that junction box is great for the turn signals, horn, and brake light. :)
 
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