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Discussion Starter · #1 ·
Hey guys,

Just wanted to record the progress of my Kohler R/R upgrade. Got the idea courtesy of a stickied thread here.

This is the R/R I purchased:

Voltage Regulator for Kohler 25 755 03S 41 403 05 s 4140310s 4140309 41 403 09 | eBay

I will be running an 8-cell Ballistic battery, so I'm trying to improve voltage regulation. I know a lot of people have had difficulties with LiFePo batteries and this set-up, but I'm willing to give it a try regardless.

What I have done so far:

1) Unplug rectifier from wiring harness

2) Cut wires to rectifier (green, pink, yellow, red/white)

3) Connected pink and yellow wires to AC on the Kohler R/R

4) Connected red/white wire to B+ on the Kohler R/R

5) Taped up green wire

6) Mounted R/R on the frame

7) Made the headlight charging connection modification (also courtesy of a stickied thread here)

I have not received the ballistic battery yet so I will be doing voltage tests with my current lead-acid battery.

With the old set-up (solid-state rectifier mod and stock regulator) I was getting no more than 13 V at high RPMS, and had a resting voltage of around 12.6 volts.

Will update soon when I do more/take pictures! Any feedback would be great.
 

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AS long as your R/R does its job, none. It will shut down the charging system when the voltage on the battery reads the cut off voltage. At least it should.
 

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I will be running an 8-cell Ballistic battery, so I'm trying to improve voltage regulation. I know a lot of people have had difficulties with LiFePo batteries and this set-up, but I'm willing to give it a try regardless.
Do we assume that is in a 4S2P configuration (4 cells in series, in parallel with another 4 cells in series)? I should think so, because 8 cells in series would make a 26.4V battery.
With the old set-up (solid-state rectifier mod and stock regulator) I was getting no more than 13 V at high RPMS, and had a resting voltage of around 12.6 volts.
Measured with an averaging DVM? One often gets lower-than-expected readings with such a meter, as the voltage arrives in pulses, and the regulator chops the voltage at the peak; as the battery nears full charge, this happens sooner in the pulse, giving an even lower average reading. An oscilloscope or peak voltmeter will give you a better idea of how the system is charging.
 

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Discussion Starter · #6 ·
Unfortunately all I have is a simple voltmeter. As you can tell I'm not much of an electrical guru...

But on the bright side I installed the ballistic battery and measured voltage across the terminals:

Resting voltage (warmed up) was about 12.6-12.7V
Voltage at 4000 rpms was about 12.9-13.0V

Are these numbers a bit too low? Will this just drain the battery rather than charge it?
 

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What was the battery voltage before you started? Lights on? Numbers look OK if the lights were on and the battery needed some charging. Those batteries like a little less juice than standard lead acid or AGM so you may be just fine.

Little graph I like to refer too when some of this comes up forget which battery site I got it off off.

battery-state-of-charge.jpg
 

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Unfortunately all I have is a simple voltmeter. As you can tell I'm not much of an electrical guru...

But on the bright side I installed the ballistic battery and measured voltage across the terminals:

Resting voltage (warmed up) was about 12.6-12.7V
Voltage at 4000 rpms was about 12.9-13.0V

Are these numbers a bit too low? Will this just drain the battery rather than charge it?
The rated voltage of a LiFe cell is 3.3V, which is about 50% charge, and is fully charged at 3.6V. I looked up that battery, and it is 4S2P configuration, or four cells in series, in parallel with another four in series. So, at 50% charge, it should be 13.2V. Is your 'resting voltage' with the key off? If so, that is a very low state of charge; if the engine is idling, then, like most 450s, it represents a slow discharge. At 4K rpm, you are showing a maximum of 3.25V per cell, which is not charging much, unless the peaks are much higher, and your regulator is creating a large ripple voltage at the battery; still, it means the battery is not taking much charge if the average voltage is that low. I would suggest using a separate charger to bring it to a full 14.4V, then start the bike and measure again.
 

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Also, your voltage output will remain lower then full if the battery/system is using more current then the alternator can put out. A low charged battery, and/or a higher capacity headlight (IE: 55W/60W) will draw more power than the alternator can put out, reducing the available voltage.

another possibility is your voltmeter is wrong. Seen plenty of that. I have a number of voltmeters, from really cheap, to over $1000. I often check voltage with different meters to make sure. My more expensive meters read RMS volts. Cheaper meters use averaging. For pure, smooth DC, averaging is ok. For anything with less than a smooth line, the RMS are more accurate.

I have a couple of free (Harbor Freight) meters. Some of them read right, some don't.

For the LiFE, you really need a reasonably accurate meter to check state of charge. Find a friend with a good meter and compare reading to get some confidence that your meter is right. A volt difference in accuracy can mean the difference between frying the battery (possible fire) and not charging it fully, reducing it's life.

Some of those Kohler clones are not very good. They are cheap Chinese made clones. I would not be surprised if yours has a problems. While they rectify and regulate, they often have more internal resistance. They prevent you from getting all the power you could. I replaced my Kohler Clone with Sonreir's unit. The R/R has less internal resistance, and better regulation. See Sparckmoto.com for info. With Sonreir's unit, my voltage is higher at lower RPM, yet max voltage is more tightly regulated.

You could have a number of small issues, adding up.

The regulator does not regulate any voltage until the voltage climbs above it's setpoint. For instance, my regulator regulates at 14.3 volts. The regulator is idle, doing nothing at 13.5 volts. Nothing is done until the output reached 14.3 volts. Permanent magnet alternators are a different animal than field excited alternators. FE Alternators regulate the output by adjusting how much current the alternators make. PM alternators regulate by shunting excess current to ground.
 

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Discussion Starter · #10 ·
Sorry for late response. Wrapping up finals this week and haven't had much time. I just ordered the r/r unit from Sparckmoto.

I think the high resistance in the Kohler clone was the issue, which led to poor charging. The ballistic battery read 13.7V after charging it with a ballistic specific charger (still measured with my cheap voltmeter), and when it was installed in the bike, the voltage at idle was around 12.7 and increased to barely 12.85 with the throttle halfway open.
 

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Discussion Starter · #11 ·
Got sparckmoto unit in mail. Came quickly and looks good. Will be installing shortly once i get my connectors from vintageconnections. Matthew at sparckmoto was great and super helpful! I'll have to move the r/r mount to the lower rear fender so it can reach the black wire from the main harness. Home for the holidays so should have time here and there to work on it. I'll keep updating as I go!
 

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Discussion Starter · #12 ·
Hi all,

Been a while but I finally got the r/runit from sparckmoto installed on the bike.

For some reason though I am still getting low voltage reading across the battery terminals. At idle I am reading no more than 12.7 V and at mid range throttle it only boosts to around 12.9-13 V. The 8 cell ballistic battery I am using is rated for minimum of 13 volts and will not charge at the output my motorcycle is giving.

What could be wrong?
 

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The charging system design is regulated by the regulator as a "not to exceed this voltage". A permanent magnet alternator cannot be regulated except for the not to exceed method.
It is likely that your alternator cannot put out enough current at idle to raise the voltage higher. This is actually normal.

You need a battery that actually meets the alternator specification. A 13.1 volt minimum battery is not a good choice for your bike.



Sent from planet Earth using mysterious electronic devices.
 

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Hi guys
I am just starting with this, I bought a 500T on which someone had reversed the battery terminals and fried the reg and wiring, so as I have to do a rewire from scratch this seems best option. Seen a lot of these on FleaBay for about $20 anyone here had good or bad experiences and can recommend a choice that works OK?
Cheers
 
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