How to: Fix your Vmax's low voltage or charging problems

[Erikvb]

Worked through this post and its been fun. I've had several incidents where I couldnt re-start the bike after a ride.

Summary of what I have done:

- Finned r/r (was on the bike already, mine is a '93)
- deleted the connector between stator and r/r
- ran a direct wire from r/r to battery (both + and -)

Result: good charging from >1000 rpm. I'm finally getting up to 14,2V:clapping:

Remaining problem: at idle I get about 12,6-12,8v. It picks up quickly if i give it a little more revs, but this is not how it should be, I should be getting high 13's at low revs as well.

It might be enough in most cases but city traffic it just don't cut it. Battery gets drained and if i'm unlucky I walk..


What am I missing?
- I measured the stator outputs and its giving me 14,7-15VAC at idle. Lower than RaWarriors 20VAC but should be high enough (Q: what is a normal value?)
- Could it be that my r/r is only rectifying but not regulating? And if so, how to test that? Checking diodes seems a waste of time since the output is good enough when revving.
Is the regulator only meant to LIMIT the output at 14,4V maximum only?


What am I overlooking?


My last read-outs:
On cold start, Idle (700-800rpm): 12,3V
1000 rpm: 13,2V
2000 rpm: 14,2V
Back to idle --> 12,9-13,0

 

[thor_eyerdhal]

Set the idle at 1000...

Mine is set at 1000-1100 with 13.7V
Unde 1000 => <13V too low for me...

 

[Miles Long]

As per the Electrosport chart-
Before doing any fault-finding, make sure you are dealing with a good battery.
How old is it, what type, did you have it load-tested?
As per stator AC output, you should get 50+ volts on all three legs,, when the bike is spooled up(5000+ rpm)
Cheers!

 

[Erikvb]

As per the Electrosport chart-
Before doing any fault-finding, make sure you are dealing with a good battery.
How old is it, what type, did you have it load-tested?
As per stator AC output, you should get 50+ volts on all three legs,, when the bike is spooled up(5000+ rpm)
Cheers!

The battery is the stock item. I have no idea how old it is because it came with the bike when I bought it in October '14.
But... It's well-maintained. Filled to the brim. Tested 12,6V with ignition off and during start it stays above 10V (load test).

I'm getting good Volts >2000 rpm. But idle-1000 rpm it sucks. 13V at best. People here are boasting about 14V or more at idle. Is that true or are they sticking their multi-meters in the wrong place??

13V and then switching on lights + fan for cooling means you are draining the battery (<12,5V)


What is your Volt reading at idle, Miles? and what is idle on your bike?

 

[Traumahawk]

A good number of the people here that are getting 14+ volts at idle have wire the R/R directly to the battery (with inline fuse of course) and that completely BYPASSES the factory crimp in the wiring harness.

That is the quickest way to increase your volts that I know of. That is assuming everything else is in perfect working order.

 

[CaptainKyle]

A good number of the people here that are getting 14+ volts at idle have wire the R/R directly to the battery (with inline fuse of course) and that completely BYPASSES the factory crimp in the wiring harness.

That is the quickest way to increase your volts that I know of. That is assuming everything else is in perfect working order.

Yep ! I just wire all mine direct with a 30 amp fuse now & say the heck with that crimp.

 

[Erikvb]

A good number of the people here that are getting 14+ volts at idle have wire the R/R directly to the battery (with inline fuse of course) and that completely BYPASSES the factory crimp in the wiring harness.

That is the quickest way to increase your volts that I know of. That is assuming everything else is in perfect working order.

Well, got that but no 14v at idle. What do you have?

 

[Traumahawk]

This is off of memory....but wanting to say 13.6.....maybe 13.8 at idle tested at the battery.

Its funny.....the ignitech unit I have.....reads 12.6 to 12.8 at at idle.....so there is some voltage loss in the harness itself.

I was always taught that even 12.5 at idle is good. Your not draining the battery until below 12 volts...because it is considered a 12 volt system.

 

[Miles Long]

The battery is the stock item. I have no idea how old it is because it came with the bike when I bought it in October '14.
But... It's well-maintained. Filled to the brim. Tested 12,6V with ignition off and during start it stays above 10V (load test).

I'm getting good Volts >2000 rpm. But idle-1000 rpm it sucks. 13V at best. People here are boasting about 14V or more at idle. Is that true or are they sticking their multi-meters in the wrong place??

13V and then switching on lights + fan for cooling means you are draining the battery (<12,5V)


What is your Volt reading at idle, Miles? and what is idle on your bike?

I keep my Max in an unheated garage during the winter, battery in( Odessey 680, no trickle charging required!), non-ethanol gasoline with Seafoam added, and I start the bike about once every two weeks, letting it warm up till the fan comes on.
I just fired it up, after sitting idle for 10 or 12 days, after reading your inquiry.
With about 3/4 choke, the old girl started instantly (in warmer weather, it starts quicker than that!)
Idling volts at startup (no headlight) were 14.2. After warming up, - I set the idle at 1100 rpm - volts dropped to 13.6, with the headlight on, to 13.2 . Energizing the fan( I have an override switch) dropped the volts to 12.6. Revving the motor > 3k rpm, and the voltage goes close to 14, fan and headlight on.
As for electrical mods, I did the "crimp" fix years ago. Four years ago, I pigtailed the + RR wire, running the extra one(with a 30 amp fuse) directly to the battery. So the battery is now getting juice from two wires, kind of a redundant system. I also ran the ground wire directly to the battery. As I recall, these mods gave me almost an extra idling volt at the battery.
As for your particular situation, the stator seems to be working fine. Beg, borrow, or steal a known good battery to try, or take yours into a shop to have a proper load test performed. If it proves to be wonky, invest in an AGM.
Cheers!

 

[Erikvb]

Did another test tonight...just a quick one; it is FREEZING here!

@Miles; done the complete crimp delete straight to battery thing before my posts. Thick gauge wires, soldering, crimped it all in snuggly.

Before turning ignition: 12,7V (-> Healthy!)
Cold start, choke on, 1000 rpm: 14,0V (?? better than yesterday with no changes)
2000 rpm 14,2V (as before)

Dropped the choke off (800 rpm) 13,3V.


Conclusion; below 1000 rpm this set up will only charge a little. I will raise my idle revs because they seem too low at 800.

New trick: my US-model doesn't allow me to run without headlight on. So...since this is a 50-60Watt parasite I popped the breaker out.

At 800 rpm 13,3V went up to 14,2V......:boxing00::boxing00:
14,2 Volts and it stayed there through the whole rev range.

So, 2 fixes more; increase idling and make a switch for the headlight
And top of that; install a Volt meter on my dash. I need to know what the bike is doing or I won't enjoy riding.


Without these two I risk an empty battery when in slow traffic.

 

[Traumahawk]

Did another test tonight...just a quick one; it is FREEZING here!

@Miles; done the complete crimp delete straight to battery thing before my posts. Thick gauge wires, soldering, crimped it all in snuggly.

Before turning ignition: 12,7V (-> Healthy!)
Cold start, choke on, 1000 rpm: 14,0V (?? better than yesterday with no changes)
2000 rpm 14,2V (as before)

Dropped the choke off (800 rpm) 13,3V.


Conclusion; below 1000 rpm this set up will only charge a little. I will raise my idle revs because they seem too low at 800.

New trick: my US-model doesn't allow me to run without headlight on. So...since this is a 50-60Watt parasite I popped the breaker out.

At 800 rpm 13,3V went up to 14,2V......:boxing00::boxing00:
14,2 Volts and it stayed there through the whole rev range.

So, 2 fixes more; increase idling and make a switch for the headlight
And top of that; install a Volt meter on my dash. I need to know what the bike is doing or I won't enjoy riding.


Without these two I risk an empty battery when in slow traffic.

I believe that under your faux tank.....there should be a sticker saying what RPM to set the idle at. For the early Vmax's......it was 1000 rpm....and for my 07....its 1100 rpm. I think you will be much happier when you set the idle where it needs to be.

so....set it for 1100 rpm....and see how that turns out?

 

[Erikvb]

I believe that under your faux tank.....there should be a sticker saying what RPM to set the idle at. For the early Vmax's......it was 1000 rpm....and for my 07....its 1100 rpm. I think you will be much happier when you set the idle where it needs to be.

so....set it for 1100 rpm....and see how that turns out?

Done. It is 1000 for a 1993. And it will stay there

My next project; LED DRL lights and a switch so I can choose whether I run 10Watt LED or the Original 55W headlight.
LEDs will normally not beam very Well in the distance. But they DO make you visible during the day.

 

[Miles Long]

Done. It is 1000 for a 1993. And it will stay there

My next project; LED DRL lights and a switch so I can choose whether I run 10Watt LED or the Original 55W headlight.
LEDs will normally not beam very Well in the distance. But they DO make you visible during the day.

Another option - a headlight equipped with a low-wattage running light, together with a two-postion handlebar switch - running light or low beam (high beam still on stock switch).
These headlights are available from aftermarket bike and car shops - but I thought they were quite common on European motorcycles already???
On my bike, I always use driving lights, either a pair of MR 16 30 watt, or a pair of H3 55 watt. During daytime use, I think just a running light in the headlight would be sufficient to provide enought forward visibility. So eventually I will purchase a running-light equipped headlight, or make one myself.
Cheers!

 

[Creekwalker]

Last week I bought my 2nd Vmax in 6 months. A short ride revealed some electrical issues. The numbers for the charging system were good but the connection between the alternator and R/R was melting. Followed Ra's experiences and hardwired the connection. Just wanted to say thanks for a great article and much appreciate the other suggestions.

 

[Redbone]

Very Nice, Welcome to the forum!















unk:

 

[hellyear]

yusing your advice as a gide i cleand all the erths and unwond the harnes back to the crimp cut the + for the rr at the crimp and atached it to the batery 14.3 volts hellyea :clapping: :clapping: :clapping: waas onley geting 12.3 befor and would drop to 10-11 when it was reved above 3000 rpm :ummm:

 

[oz1961]

This has been a great thread for me as well as the help from another Vmax owner.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
<o> </o>
Three years ago when I bought my 85 Vmax the owner said he was having trouble with the battery charging.<o></o>
I put a new battery in and it seemed to fix the problem to a point<o></o>
<o> </o>
But I have had to always charge the battery before a ride and it has never been great<o></o>
A month ago I had had enough and decided to fix it once and for all<o></o>
I changed the regulator<o></o>
Soldered the wires<o></o>
Put two new earths<o></o>
<o> </o>
But still the maximum Volts I was getting was 12.4 at 2000 RPM<o></o>
<o> </o>
I needed a new stator<o></o>
I received the new stator but when I was removing the old stator a stud broke in the casing<o></o>
<o> </o>
It couldn’t be removed properly so I bought a used one<o></o>
Put it back together and fixed!!<o></o>
<o> </o>
Now I am running 14.53 volts at 2,000 RPM even on high beam and the thermo fan on.<o></o>
<o> </o>
The lights are brighter<o></o>
And the performance is cleaner and crisper<o></o>
<o> </o>
And the biggest shock is no more hot or cold starting problems<o></o>
I should have fixed it three years ago<o></o>
<o> </o>
It only cost be abou$220 to do everything<o></o>
<o> </o>
I am grateful for this thread and the help of others to be able to fix the problems with confidence.<o></o>

 

[19vmax97]

Thank you very much. Labored engine crank start when hot, fine in a few hours... New battery in last week, now to diagnose following the steps above. Thank you!!

 

[Zeus36]

1997 VMAX
I have 12.99 volts DC static and 13.25 VDC @ 1500 RPM from a fully charged battery. I will be looking into eliminating the R/R connector and going straight to the battery with the positive side. The age of the battery is unknown and will be upgraded to an AGM. Normally I solder everything (former Navy Electronics tech), but have discovered Posi-Locks, and Posi-Taps. Great for testing... They also have an inline Posi-Fuse that will take 12 gauge wire and a 30-amp blade fuse.



http://www.posi-products.com/index.html

 

[Threebeards]

Hi, just in case anybody else is as clueless with electrics as I am, just a precautionary note, (and please correct me if I've got this ass backwards) I followed this to the letter, and when testing the stator, I believe I've misdiagnosed it as failed because I didn't realize that by:
following step 3.1 and eliminating the connector.
I've now a ground connection through the R/R .
Am I right in assuming the stator test should be performed either before losing the connector, or with the crimped connection BUT with the R/R NOT in contact with the frame or other ground?
Apologies if this is obvious to everyone else.
Thanks Adrian.