R&R Size

[Guest]

I just received a r&r i bought off ebay today and its alot bigger than I expected. Its off a Honda Rancher, SH753AA. It is going on a 81 450e, which will be hidden under the seat. So my question is, what is the smallest sized R&R I can use, closer to the stock size. The one I got is twice as big. Thanks.

[tom203]

I just received a r&r i bought off ebay today and its alot bigger than I expected. Its off a Honda Rancher, SH753AA. It is going on a 81 450e, which will be hidden under the seat. So my question is, what is the smallest sized R&R I can use, closer to the stock size. The one I got is twice as big. Thanks.

Bigger is better- if it fits! Can you post pic next to your stock one? or offer measurements of this monster? Basscliff has list of R/R's, but if you want a slightly smaller than Honda size look for one off a kawasaki ninja- a Shindengen but slightly smaller, but still able to handle the stator output.

[wahoo]

Well stock one is 2.5 by 2 and the honda one is 4.5 by 4, just going to be harder to hide. However, my GS750 needs a r&r, so I can use this one there. I just need one closer to the stock size. What size ninja should I look for?

[Steve]

Bigger is better- if it fits! ...

Very true.

Because of the design, the R/R generates a bit of heat.
The bulk of the housing and its fins will dissipate that heat.
The more heat it can dissipate, the better it will be.

.

[tom203]

Well stock one is 2.5 by 2 and the honda one is 4.5 by 4, just going to be harder to hide. However, my GS750 needs a r&r, so I can use this one there. I just need one closer to the stock size. What size ninja should I look for?

My, that is big- that ATV must have A/C and a decent stereo. The Honda R/R's I have measure 3 by 3. The ninja 250 R/R measures 3.1 by 2.1 and I think it was a common unit for many years and likely used on ninja 500's also.

[Steve]

My, that is big- that ATV must have A/C and a decent stereo.

Those would actually require a smaller R/R.

The R/R has to dump heat from all the power that it WASTES, not what the bike uses.

.

[wahoo]

Thanks, thats sounds more like what Im looking for.

[Adler]

Those would actually require a smaller R/R.

The R/R has to dump heat from all the power that it WASTES, not what the bike uses.

.

Wouldn't all that equipment mean the stator would have to be pretty hefty? so when all the equipment is OFF, the R/R is dissipating more wasted energy.

[tom203]

Wouldn't all that equipment mean the stator would have to be pretty hefty? so when all the equipment is OFF, the R/R is dissipating more wasted energy.

Maybe Steve was testing the forum members to make sure they've been paying attention to R/R issues- you win the attention prize! All the stator output goes thru R/R-what happens after that depends on actual load demands.The R/R doesn't mean to waste power, it just has to dump excess juice ; unfortunately (unless you got a Compufire R/R ) the stator keeps delivering its full output not knowing that R/R has all it needs already.

[Steve]

The question was about the R/R and the load, no mention was made of stator.

My point was that if you add more load, you will reduce the amount of waste.

Yeah, you will reach a point where supply is not enough, and that's where a larger stator would be necessary.

And, ... what's the point of the A/C and stereo if you're not going to use them?

.

[Normk]

There are two main types of voltage regulators used on permanent magnet alternators which is something not usually appreciated when discussing this subject.

Several members have posted circuit diagrams for various systems which may be of interest to review but in brief the two types in lay language are:

1) Load or Zenor diode type

2) Clipper circuit or threshold type

Voltage regulation as applied to vehicle charging systems is terminology misleading to some because the voltage is not regulated but rather the maximum charging voltage is limited to a set point. This means that the only control is for the voltage regulator to prevent the voltage from exceeding the set point. Voltage can be below that set point for some or all of the vehicle's operation depending on engine speed, alternator characteristics, etc.

The subject of regulating alternator output must be divided between the discussion of permanent magnet rotor equipped alternators which are typical of smaller/less sophisticated motorycycle and power equipment; and controlled field alternators which are typical of automobiles and motorcycles having more sophisticated charging systems. The second type of alternator is controlled by varying the rotor field current in order to control output.

Load or Zenor diode type regulators as used in GS applications are of the basic type used from early alternator days and best recognized by the Zenor diode under the forks of old Brit bikes. These old Britt bikes used a device called a Zenor diode which begins to conduct current only when the voltage applied rises above a specific voltage (set point). If an alternator is capable of producing more output current than the system requires, the voltage will rise to an undesired level.

In order to provent this effect, a Zenor diode of the appropriate voltage was connected between the alternator load circuit and ground (from + to negative) so that the Zenor would begin to conduct current when the voltage rose above the Zenor's voltage. The Zenor would thus act as a load in the same way as would switching on more lights or other loads to accept the load required to prevent the voltage from exceeding the set point.

Large capacity Zenor diodes are quite expensive compared to the combination of a small Zenor (or other voltage sensor device) so the Japanese and other more modern manufacturers began to use a Zenor in combination with a fast acting transistor, MOSFET, etc. to load the system to the set point voltage in the same manner as does a Zenor.

In this type of voltage regulator, the alternator delivers nearly full output (depending on RPM) and the voltage regulator "loads" the system to limit the voltage by "spilling" current to ground. It acts much as does a relief valve on an oil pump or compressor.

Measure the current flow in the ground circuit of this type of regulator and compare to the regulated output current which will show that both current values are the same.

The second type of voltage regulator used to manage permanent magnet alternator output, called a "clipper circuit" or "threshold" (maybe someone has a better term?) is more common in my experience. In this type of regulator, measure ground circuit current which will be found to be less than the maximum alternator output unless the system load corresponds.

Here's an example: measure VRR ground circuit current on many modern bikes or my old GS850G, engine rev'd up and headlight on, 8 amps. ground circuit current. Add additional load by connecting more lights or adjustable load and the VRR ground circuit current will rise to 14 amps. Adding additional loads after the VRR ground circuit current reached 14 amps. will not increase that current because the alternator has reached maximum output.

This type of regulator acts by interrupting or otherwise controlling rectified output from the VRR in order to prevent system voltage from exceeding set point.

Analogies for regulation might be made of controlling the water pressure to a lawn sprinker so that the water does not fly too far and soak the lawn furniture.

We could place a "Y" connector into the hose so that one leg of the "Y" leads to the sprinkler while the other leg to a valve which can be adjusted open to closed. If the water discharging from the sprinkler flies too far (to high water pressure), we can open the valve in the other leg to dump water which will reduce water pressure to the sprinkler. We can do this without leaving our chair which is better than walking over to the water spigot every time someone turns off the dishwasher or flushes a toilet.

This is the Zenor diode, adding flow/load approach.

An alternative would be to place the adjustable valve in the hose leading to the sprinkler and to place this valve near our chair. We can then adjust the flow rate in the hose in order to manage the sprinkler, again without leaving our chair.

Of course, it would be better to place an automatice device for the purpose but such a device would use one of the above methods to manage, either dumping or clipping.


Analogies always have flaws but this is an attempt to illustrate the difference.

Charging systems which use the Zenor/load methodology should not be affected by the number of lights or other accessoried up to the limit of the alternator however one could form a scenario in which the "clipper" type system could experience harder useage from higher loading.

There are problems with either approach but will leave the explanation of those to someone else as have taken too much bandwidth.

Maybe Steve was testing the forum members to make sure they've been paying attention to R/R issues- you win the attention prize! All the stator output goes thru R/R-what happens after that depends on actual load demands.The R/R doesn't mean to waste power, it just has to dump excess juice ; unfortunately (unless you got a Compufire R/R ) the stator keeps delivering its full output not knowing that R/R has all it needs already.

[Hacked850]

Since I'm running a sidecar on my 850 I have alot of room.Can I mount the RR anywhere??,if I buy a bigger than stock one can I just make all the wires longer and mount the RR maybe between the sidecar and the bike ( out in the wind to keep it cooler??).

[Steve]

Yes, in fact, mounting it in the breeze is the best-possible place.

.