Topic: Battery location

[jamesbekman]

Hi Everyone,

When you see those pictures of people relocating the battery to above the rear wheel in a cafe type one piece seat and tail, doesnt that drastically increase the chance of the rear tire hitting the new pan that was put in place to mount the battery?  Seems there are clearance issues with the tire when going through full suspension travel.  Or am I mistaken?

[bjbuchanan]

A lot of those guys hide it in their seat bumps. They usually use a physically smaller battery, whether it have less amps and be kickstart only or be real expensive and have the same CCA as stock. Either way you can't use the cheaper lead acid because you turn it on its side and it will leak.

[jamesbekman]

Yea thats the other thing I dont get.  Wouldnt our bikes drain the smaller battery at idle?  Since the bike doesnt start charging the battery till 1500rpm?

-James

[bjbuchanan]

You don't quite get how charging systems work. You can put a monster truck battery or a baby battery, both still drain because the charging system doesn't put out enough for the draw until 2500 up.

The kick only bikes don't have a  battery that can handle the amp draw of the starter so you can't use the starter. A kick only drains at idle too

[jamesbekman]

Yes and what battery size is sufficient for around town driving without having to worry that your bike is going to die? 

[jamesbekman]

I am fully aware of lead, AGM, anti gravity style, lithium batteries, the charging system of our SOHC's and how they do in fact differ with a cars alternator and for that matter other bike charging systems... 

In regards to aftermarket batteries, Shorai's lithium batteries for example have to have a 13.1v charge on the battery at idle which our bikes do not achieve.  Same with the anti gravity battery...

So to rephrase my question, I am wondering if people are hitting the top of the back tire when they mount there AGM battery straight across the frame like this.... 
http://s4.photobucket.com/user/liverpol98/media/Picture3008.jpg.html
and this http://s133.photobucket.com/user/ProTeal55/media/450-36.jpg.html

and are people who have a different than stock battery experiencing any other adverse effects like charging issues, the battery draining too fast due to having a smaller battery fitted, a newer technology battery fitted, or a battery for a different use fitted as seen in the last photo I linked to.  Any new experiences with antigravity batteries or Shorai?

Thanks

James

[bjbuchanan]

Search the cafe hoops, the guys hit if they do that flat panel, that's why the second is kicked up just a little. If you get how it works then you already knew your answer. Yeah, they deplete. Yes, you can't do anything about it.

Straight across, flat panels like that are done by someone who clearly didn't think at all why the curved brace was there and probably doesn't consider function at all. Guys run shorai and ballistic, use the top left google search.

[jamesbekman]

Thanks for your input. 

Im looking to hear further from people who actually have experience running them. 

Ill look into that google thing.

Cheers.

[CapeCafe]

Hey James-  Take a look at the pics below.  I moved my electronics behind the seat on my 1976 CB550 and used an 11AH AGM battery. I wanted to get as close to the 12AH stock since I use all the stock electronic features of the bike and didn't want to worry.  As you can see from the pics, I installed a modern combined regulator/rectifier and placed it in front so it gets cooled by the air forced under the seat.  To keep from having the tire hit the bottom of the electronics tray I built, I used a rear shock that was 1.5" longer than stock and had it sprung correctly to my weight (230lbs).  I never bottom out.  Because I raised the rear up 1.5" from stock, I used a heavier fork oil in front and installed a steering damper to handle any possible head shake.  I can't really notice any new quickness in the steering with the altered geometry.  The bike tracks straight as an arrow and handles decent for a 70's era bike.  When building your tray, I'd suggest using cardboard to mock up any battery you are considering and then place the mockup in the spot your planning and see if everything else fits around it.  Good Luck

[calj737]

James - I use a Shorai as well as have flattened out my pan. But, my rear tire is down to 16" and shocks longer.

As for charging issues, the voltage is not the critical issue; after all it's a 12v battery for a 12v system. The Shorai I use is a 14Amp/Hour unit. This is higher than stock. Battery is very small, light weight, vibration and spill proof. I recommend it highly as it has been trouble free and very flexible with install location.

[Muckinfuss]

You can use the stock 550 shocks with a straight hoop (no upkick required) and a flat bottom tray in a ½ inch hoop without any issues whether welded on the hoop or under the hoop.  That is, as long as you are using a stock swing arm. 

Stock 550 shocks have 2.2 inches of travel in them.  Pull one, take off the spring and measure fully extended and fully compressed.  Subtract.  See....2.2 inches.

The rear tire, if stock 18” rim, has 3.25” gap from the top of the tire to the bottom of the tray using a 1/2” tube hoop welded to the frame level top edge of hoop to top edge of stamped shock mount and the tray welded to the underside of the hoop.  Put the bike up so the rear wheel is off the ground and both shocks installed...ie.: full drop.  Lay a flat bar like a ruler into horizontal position on or under the hoop, where your tray will be, and put a square on the tire so it's perpendicular (plumb) and where it intersects the flat bar...that's the max distance the tire can travel before hitting something.  This is important, because I won't guarantee that every manufacturer of tires makes their rear tires the exact same diameter, even tho they are supposed to when using the metric or P system.  All 130/90/18 rear tires should be within a couple of millimeters of identical circumference....in theory.

The shock isn't mounted 90 degrees perpendicular, it's canted 74 degrees.  That means that the 2.2 inches in the shock are reduced to just a hair over 2 inches max wheel travel....so far.  Call that vertical measurement side b of a right triangle.  We already know the length of the hypotenuse...2.2 inches and two of the angles...90 degrees and 74 degrees.

To find side b, we have to use some trigonometry:
sin(angle)=opposite leg/hypotenuse

sin(β)=b/c

After substituting β=74o and c=2.2 we have:    sin(74o)=b/2.2
b=2.2*sin(74o)
b=2.2*0.9613
b=2.1148

The next step for a CB 550, because the rear wheel axle is a nominal 2 inches from the shock connection to the swing arm...is to figure that into the wheel travel.  The radian for the arc has been increased. More trigonometry.  (many street motorcycles put the shock mount right above the axle so no additional calculations are required at this point.  Motocross are a whole other story since the shocks are so far from the axle to increase wheel travel!)  I'll jump right to the answer....it's still less than three inches when all said and done. 

If you're still apprehensive....form your tray over some 6” schedule 40 pipe and gain almost ¾ inches more gap when you weld it into place.  Or you can spend a few hundred bucks on longer shocks.

[DaveBarbier]

The Shorai I use is a 14Amp/Hour unit. This is higher than stock. Battery is very small, light weight, vibration and spill proof. I recommend it highly as it has been trouble free and very flexible with install location.

Hey Cal, I have the exact same battery. I'm planning to install after I get my carb situation rectified. What did you do to the charging system in order to keep the battery working well? What do you do if you're in traffic and idling longer than you should?

I bought a reg/rec in anticipation and a little digital volt display to keep an eye on the possibility of over or under charging. Necessary?

Was this a pretty straight forward install for you or were there hassles getting the charging system working well?


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1978 Honda CB550K

[calj737]

Sorry for the thread jack, James-

My electrical is all new. I've used MotoGadget m-unit, LEDs everywhere, and a new Reg/Rec. For proper charging, I've just made sure to use quality wiring, perfect bare metal grounds, and all my electronics are crisp, new, and working perfectly.

As for idling in traffic, I don't have that issue for my rides. But, my MotoGadget gauge does have a built-in volt meter, and thus far, even stop and go riding, never seems to wear the battery down. It's a strong battery, recovers very quickly and holds a charge for weeks. (I literally just started the bike today for first time since my son scuffed it up, and it cracked before the starter turned the crank a full revolution ((seemingly)). So I'm pretty happy with Shorais. Have them on 3 other bikes too.

Hi-jack over-

[DaveBarbier]

Sorry for the thread jack...

Words
Words
Words, etc.

...Hi-jack over-

Thanks!


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1978 Honda CB550K

[jamesbekman]

Not hi-jacked at all!  Thanks for all the info !

Cheers,

James

[lucky]

I would make sure that rec/reg gets plenty of cool air.