Charging vs. Discharging at Idle - Is this a Solution ??

So, My Seca 550, like all XJ's and most bikes, does not seem to charge at idle (by design, if you look at the attached voltage curve from the manual), in fact, if charging output is less than battery output at idle, it is actually DIS-charging at idle.

At idle, or any revs below 1500 RPM, I have low voltage issues like signals won't flash when brake light is on, dim running lights and headlights, weak idle spark, etc. I'm in stop and go traffic and idling a lot, and this situation leads to shorter battery life.

Notwithstading the fact that the usual issues have all been addressed (i.e. all connection points super clean and corrosion free), I really want to fix this "factory issue". I may have a solution and want the experts on here to chine in on what they think about this:

Our Vmax group swears by using the Yahaha Venture Regulator Rectifiers on their Vmaxes due to the fact that is is one of the only R/R units that actually monitors voltage DRAW and ups the DC output when the voltage drops below a certain amount. The result with using a Venture R/R on the Vmax vs. the stock R/R is dramatic - at idle, lights, horn, etc. are all as bright as when at "revs" and the battery stays fresh, regardless of how much idling you do.

I want to acheive this result - shown by the RED curve I've drawn on the attached voltage graph - for my Seca, and I've got a couple of used Venture R/R's coming my way. I'm hoping installing one on the Seca will improve things quite a bit, but was wondering about Stator compatibility of Seca 550 vs. Venture. The details I can find are:

Venture Stator coil resistance 0.3 to 0.4 ohms vs. 0.5 for Seca
Venture stator 20-25 VAC @ idle vs ??? for Seca (Hitachi LD117-03)
Venture Stator 100 VAC @ 4000 rpm vs. ??? for Seca
Venture Stator rated at 300W vs. ??? for Seca

So, anyone think this is worth trying, and can anyone quote values for the Seca ??? above? If the stators are similar enough, I'm hoping swapping in a Venture R/R will really help idle charging. Comments from all experts are encouraged and appreciated!!

 

I've never had any issues with either of my 550 Secas as long as the battery was in good shape; and I spend a lot of time in stop-n-go traffic.

 

Before you go to far, have you measured/replaced the alternator brushes?
How old is your battery?

I know it's not an answer, but making sure you didn't forget those charging issues.

 

Yep, brushes are good and armature mating surfaces were cleaned when I rebuilt the engine 2 or 3 years ago. And yes, a fresh new battery helps the situation quite a bit, but after 2 seasons now matter how well I stay on top of battery maintenance, the battery is no longer robust enough to prevent low idling voltage.

My issue is that batteries in general do not like cycles of charging and discharging, which is what the factory setup encourages even in normal use. I'm convinced it helps lead to premature battery failure - even the manual says batteries need replacement every 2-3 years. I say F**K that - I'm sick of forking out $80 every two years simply because the idle charging voltage is squat and killing my battery early. I'm not expecting 6-8 years like a car battery, but 4 years or so should be achievable with good maintenance. This is the other benefit that has been noted using Venture regulators on the Vmaxes - its been claimed even non-AGM batteries last a lot longer since they charge, not discharge, during idle.

 

You cannot use a Venture voltage regulator. The Venture (and Vmax) use a permanent magnet rotor and the XJ uses a field coil rotor. The regulators are entirely different animals.

On the Venture the magnetic field in the rotor is fixed. The alternator output is simply a function of engine RPM. When there is too much output the regulator shunts the extra power to ground to keep the system voltage down.

On the XJs the regulator changes the magnetic field in the rotor. When the alternator is producing too much power the regulator weakens the magnetic field to manage the output.

On my 1989 Venture the alternator won't charge at idle either. The modern Venture has the same engine but the rotor may have stronger magnets or more windings in the stator. Even so, like the XJ, accessories can be an issue for all years of the Venture.

At idle your XJ regulator will energize the field coil for peak alternator output. It isn't enough because the thing isn't spinning fast enough - just like my Venture

One nice thing about the Venture - the ignition system will work at very low voltage. I had a failure and the radio and clock died before the ignition did.

I call BS on the Vmax guys. Neither the Vmax or Venture regulator senses load. They both sense voltage and increase the load if the voltage is too high. This is why it's potentially damaging to jump start this type of system from a running car or truck. If the voltage regulator reads high voltage it will increase the load trying to reduce it. It eventually burns up because it's made to deal with a 30 amp alternator, not the 63+ amp alternator in a car or truck.

 

It is, even with a conventional lead-acid battery. I regularly get 4~5 years from bike batteries; and recently "accidentally" got SEVEN years from a DEKA manufactured, private label (defunct auto parts chain) battery. I say accidentally because the PO mis-represented the age of the battery; when I decoded its date code when it finally did fail (confirmed via an email from the mfgr) it was well into its seventh year.

The key is staying on top of maintenance; not only the battery itself but the BIKE as well, so that the charging and regulating systems are working as well as they can be.

You can still find a new, high quality battery for your XJ for under $40 if you're smart about your shopping.

 

MiCarl thanks for your excellent insight - you are correct the stators are different designs and therefore the venture R/R will not work javascript:emoticon('post',%20'message',%20':x')

You are also correct in stating that the venture R/R's do not sense load (i.e amperage draw) but instead sense voltage drop. On the Vmax/Venture, quite often during idle battery voltage will drop below 12 volts, especially when running auxiliary items like extra running lights, heated vests, etc. The regulator senses the drop and kicks out more charging voltage. This is the purpose of the second set of + and - leads on these R/R units - they send the voltage "information" to the R/R to dynamically adjust the R/R output voltage up.

The Vmax guys swear the change from the stock Vmax regulator to the Venture regulator allows a dynamic charging voltage that more closely follows the red line I drew on the voltage vs. RPM graph I posted. It is this type of charging voltage "profile" that I'm trying to achieve, and they say it helps with battery life by preventing small cycles of charging and discharging, not to mention better idling. I have seen it myself - no difference in headlight brightness between idle and any revs.

And yes BigFitz, some batteries do last longer than others but I've been ANAL about keeping every stinkin battery I buy for either bike topped up with distilled water as required and even fully (trickle) charged during downtime and indoors over winter. Doesn't matter in the least, they are all dead within in two years, sometimes less (warranty is one year only), and here in Ontario Canada where everything is ripoff priced plus 13% tax, the cheapest YUASA equivalent lead acid battery you can find will set you back at least $80 if not more.javascript:emoticon('post',%20'message',%20':evil:'). I wish I could by a battery for $40 !!! Not even remotely possible here.

So, any thoughts on how to achieve that red line in the graph?

 

So, I guess no easy solutions can be found to get decent idle charging voltage. I'm a little ticked off right now because I had to push start my bike again, because my battery is nearly shot just entering its 3rd season despite anal regular maintenance. Before I kill another $80 battery within the next 2 years, does any one have any ideas about how to improve IDLING charging voltage? Charging oltage at 2,000 RMP+ is not an issue. I'd like to get the best charging voltage possible in the hopes my next battery lasts the 4-5 years Bigfitz' does.

Bike has 45,000 miles now but brushes were not down to the wear bar at 35,000.

 

sometimes the little braided brush leads are corroded internally even though the brushes aren't worn out all the way. The leads are little braided "tubes" that can be corroded internally and the only way to see it is to flex them and carefully inspect.

 

Thanks for that tip, Bigfitz. Likely no way to fix that, I guess replacement is needed if that's the case.