Secondary battery setup??

[moosulkwanman]

Was noticing that police applications use a secondary battery and would ask my fellow ST owners this.....What is the best wiring method for a secondary battery in regards to charging while riding? Primary battery wired for starting and main headlights , secondary battery maybe connected to low drain GPS, audio equipment, etc, but should one connect the two batteries and the secondary battery charged in line with the primary battery, or connected direct to the alternator? Thinking of rigging in a secondary battery, like a LiFe Shorai......

 

[nhdiesel]

Re: Secondary batty setup??

You need a battery isolator. It allows charging the 2nd battery without the chance of killing it if the main battery goes dead.

Sent from my XT881 using Tapatalk 2

 

[moosulkwanman]

Re: Secondary batty setup??

Thanks for the tip

 

[Slasher]

I've seen a picture of an IBR bike set up with two batteries... IIRC he had his aux batt on the passenger seat. Where were you planning on mounting yours?

 

[nhdiesel]

When I do my aux. tank I might try mounting a 2nd battery. If I go over the pillion seat with the tank I could have my hydration system on one side of the tank and the battery on the other.

The battery would just be for an emergency situation. A 2nd battery will be of little help if you aren't charging good enough to handle your accessories. Dual batteries will only ensure you can start the bike if the main battery is dead. This alone could be quite handy on a dark night in a rural location.

 

[Jeff F]

I have 2 batteries on my fishing boat & in another life had a similar setup on a motorhome. In both applications there could be heavy draws from pumps, aerators, cabin lights etc.

What's the need on a bike?

 

[nhdiesel]

Only what I posted above...a backup in case the main battery dies. Other than that, not much use for a 2nd battery on a bike. Maybe if you want to be able to power a radio or other accessories around a campsite without fear of killing the main battery?

 

[Jeff F]

...a backup in case the main battery dies. Other than that, not much use for a 2nd battery on a bike.

mmmK, gotcha

 

[moosulkwanman]

I would just want a backup power source for starting that I could switch on if my main battery fails, you know, way out on a ride...I ride solo mostly... Lately, my fork lights draw down my battery when riding, so this is a concern. These fork lights seem to draw more power than normal, i checked all connections , the switch, why would that be? I keep my tender on the battery overnight, did the quick test, the bAttery did read 9.8 volts when starting after the three minute high beam load test, so my battery is fading...the LiFe batteries are looking interesting, nbut saw the yuasa s for $65!!!

 

[nhdiesel]

the three minute high beam load test

HUH? Three minute? Where did you get this from? Three minutes with high beams on will just about kill an ST1300 battery. Heck, 45 seconds with them on killed my brand new Scorpion last year. To do a load test, turn the lights on for a FEW SECONDS then watch battery voltage while cranking it.

 

[T_C]

I would just want a backup power source for starting that I could switch on if my main battery fails, you know, way out on a ride...I ride solo mostly...

Ideally.. use a lead acid and a LiFe. Draw off the LiFe for your auxiliaries when stopped, use the OEM flooded for normal running. Just one thought.
T

 

[st1300r]

Lately, my fork lights draw down my battery when riding, so this is a concern. These fork lights seem to draw more power than normal, i checked all connections , the switch, why would that be?

That needs to be fixed 1st. It may be the alternator isn't doing it's job.
Could also be an aging battery that can't except charging.

What voltage are you seeing with the bike
-at idle
-at idle with the fork lights on.
-at say 5000rpm.

Any other high load items on at the same time. Heated jacket liner etc.

Check the connections at both ends of the battery cables.
Clean and reconnect.

Corroded terminals for the fork lights switch etc aren't going to cause excessive draw unless you have a short and see smoke.
They'd heat up from the resistance at the connection but it shouldn't draw more current than normal.

 

[Mellow]

Was noticing that police applications use a secondary battery and would ask my fellow ST owners this.....What is the best wiring method for a secondary battery in regards to charging while riding? Primary battery wired for starting and main headlights , secondary battery maybe connected to low drain GPS, audio equipment, etc, but should one connect the two batteries and the secondary battery charged in line with the primary battery, or connected direct to the alternator? Thinking of rigging in a secondary battery, like a LiFe Shorai......

I have to ask why YOU....

Police needs dictate a 2nd battery due to the nature of their work but not all that many folks here have been stranded by a bad battery. .. Yes, it happens but having 2 batteries will just mean you're thinking you need 3.. LOL

I'd say get one of those light weight Shorai ones and just keep it in the bike without worrying about charging it... it will keep a charge and you can hook some cables to it if you need to jump your battery or you can switch it out... I just don't think a 2nd battery is necessary... of course, that means my bike won't start today.. LOL

 

[moosulkwanman]

I thought the same about that three minute test, but check out the quick battery test described in the battery forum......

was thinking of putting secondary battery either under the passengers seat, removing the tool kit....or more likely in my givi trunk if it will not fit under the seat......but not committed to this project yet......might as well just carry a charged shorei battery , as light as they are, in the trunk and just replace the main battery with it if I need to....instead of going to all the trouble of rewiring my st......nothing as annoying as taking an st apart to redo GPS,audio, light systems....but it would be nice to flip a switch connecting a spare battery .....hhhmmmm

 

[moosulkwanman]

Mellow, i tend to agree, I have only been stranded once, because I left my highway spot lights on and didn't know it.....was way out in the woods....but even then it wasn't long before I got jumped off.....I was just thinking the exact same thing, just keep a Shorai stashed for emergency. In the trunk....no need to redo all my wiring, install an isolator, change alternator connection, divide up systems between the batteries.....What a pain. I already have jumper wires running through my fairing pockets that I use to jump my battery so I don't have to take off the saddlebag and side cover...could just run some jumper wires back into the trunk, but leave them disconnected, if regular running battery fails, just clip the jumpers to the extra battery,......no worries !!

 

[Garry in AZ]

I understand being prepared, but carrying around a second battery "just in case" seems a little bit like solving a problem you don't have. Just make sure your charging system is working properly, your existing battery is in good condition, and maintain your connections. You don't need a second battery.

Here is a bit of electrical information. When your motorcycle (or car) is running, the alternator is the current source for all of the electrical devices. It continues to be the source, right up until you reach the point where you are consuming 100% of it's output. After that, any additional current demand must be drawn from your battery, which is at that point in a discharge condition. This happens because electrical devices will always draw from the point of highest potential, otherwise known as the path of least resistance. When your bike is running, the alternator is roughly 1.5 to 2 volts higher than the battery, which automatically makes it the source.
If you are measuring higher than normal voltage drop when you turn an accessory on, the reading you see may not be "real" depending on where you have your voltmeters leads connected. For example, if you are measuring the voltage at the light connector, the voltage drop will be higher there than it would if you were measuring it across the battery terminals. This is because the wires that feed your lights have resistance, and they will cause a voltage drop, especially if the wire gauge is marginal, or if the connections are not clean and tight. Even switches can build up resistance that will cause voltage drops when measured at the load.

Also, here is something that many people don't realize when they run a pair of batteries... they have actually INCREASED the demand on the charging system, because the second battery will draw some current to keep it maintained.
Of course it's your bike, your money, and your decision, I just wanted to provide a bit of fact about how things work. :capwin:

Garry

 

[nhdiesel]

I understand being prepared, but carrying around a second battery "just in case" seems a little bit like solving a problem you don't have. Just make sure your charging system is working properly, your existing battery is in good condition, and maintain your connections. You don't need a second battery.

Here is a bit of electrical information. When your motorcycle (or car) is running, the alternator is the current source for all of the electrical devices. It continues to be the source, right up until you reach the point where you are consuming 100% of it's output. After that, any additional current demand must be drawn from your battery, which is at that point in a discharge condition. This happens because electrical devices will always draw from the point of highest potential, otherwise known as the path of least resistance. When your bike is running, the alternator is roughly 1.5 to 2 volts higher than the battery, which automatically makes it the source.
If you are measuring higher than normal voltage drop when you turn an accessory on, the reading you see may not be "real" depending on where you have your voltmeters leads connected. For example, if you are measuring the voltage at the light connector, the voltage drop will be higher there than it would if you were measuring it across the battery terminals. This is because the wires that feed your lights have resistance, and they will cause a voltage drop, especially if the wire gauge is marginal, or if the connections are not clean and tight. Even switches can build up resistance that will cause voltage drops when measured at the load.

Also, here is something that many people don't realize when they run a pair of batteries... they have actually INCREASED the demand on the charging system, because the second battery will draw some current to keep it maintained.
Of course it's your bike, your money, and your decision, I just wanted to provide a bit of fact about how things work. :capwin:

Garry

I have considered a second battery myself simply because of how quickly the battery is drained if the key is left on or there is any kind of a problem. I found myself pushing my bike in Kansas last year because I turned on the key long enough to write down the odometer mileage on my gas receipt during my SS1K. Now I only do that when its running- essentially, the only time the key is on is if the bike is running. Its still easy to drain a battery though, such as last Saturday when I stopped the bike and didn't get off right away...forgetting that my heated jacket was on. Less than 1 minute, and the battery wouldn't start the bike. If you rarely find yourself in rural locations, especially late at night, then there would be little use for a 2nd battery. I only see them as beneficial in a "save your butt" scenario if you do something dumb and kill the battery in the middle of nowhere. Especially during an IBA ride or in the middle of a rally.

 

[mnxs54]

I found myself pushing my bike in Kansas last year because I turned on the key long enough to write down the odometer mileage on my gas receipt during my SS1K.

I must say if this happened on my bike I'd replace the battery. I do it all the time without problems. But also, on my bike I put a relay in the headlight circuit so that they don't come on until I turn them on.
I agree with those who say that a second battery is WAY overkill. I'd carry extra tires before I'd carry an extra battery.

 

[T_C]

could just run some jumper wires back into the trunk, but leave them disconnected

I guess you mean disconnected on both ends? Generally jump wires are unfused and I wouldn't want to be running large unfused wiring any further then necessary.

If you already have a jump start connection point with the wires in the fairing pocket, just make a cord to connect between battery and these wires, keep the cord stashed away. And/or put some large alligator clips on the end so you could use the spare batteyr to jump another bike.

 

[nhdiesel]

If you were going to carry a spare battery in the trunk you'll still want to secure it. Stuff bounces around a lot in our trunks and it would be BAD for a battery to get damaged and spill all over everything else you have in there. So it will need to be secured. Since you would be coming up with a way to secure it anyway...you might as well mount it somewhere out of the way, like under the rear of the seat if there is room. To connect it the simplest way would be a large relay with a switch. An older Ford starter relay would work perfectly, and is WAY over-rated for the needs. Use it with a momentary switch. If you find your battery dead just push the switch, then hit the starter switch. Charge the battery at home occasionally. In order to charge automatically while riding, a battery isolator will be needed. Its like a relay but with one circuit set up like a one way check valve. Power will flow from the charging system to the battery when the bike is running, but neither battery can run the other one down when the bike is off.

I must say if this happened on my bike I'd replace the battery.

The battery was a 2 week old Scorpion. Yes, it was a defective battery but it shows how easily something can happen. Even with a brand new OEM battery the battery is way too small for our bikes, and even worse if we have additional electronics added.