honda 919 elec system power, battery

i bought a 2005 919 with 5400 mi on it a few weeks back, and i love it - what a great bike!

so i installed a Lanzar speaker and amp stereo system on the bike ( [url]https://www.amazon.com/Lanzar-OPTIMC90-Motorcycle-Snowmobile-Weatherproof/dp/B003HH96IU[/url] ) which sounds great, but when i parked the bike and tried to restart it after riding for a while that day, the battery was shot and wouldn't restart the bike.

I noticed while installing the system the battery itself is physically smaller than was on my 92 nighthawk 750, so am i just adding more power request for the stereo from a smaller less powerful battery?

anybody good with electronics, car/cycle mobile stereos, or know about the bike's elec system for running and charging the batter while in use?

Thanks!

Are you sure the amp is not being left on/powered? (Hence draining the battery?)

If it isn't being left powered, it means your charger (alternator) isn't big enough to handle the extra load.
In that case, a bigger battery will merely extend the reserve time until it recharges.

As to a bigger battery - that's merely a physical thing; not system changes are required.
(Smaller batteries may require current limits, and different battery types like AGM or Gels may require some mods - but they have little if any advantage in this situation.)   


IN summary - find out why your battery is flattening. Age/temperature? Underated alternator? Being drained whist "off"?

i installed the stereo/speakers/amp seperately from the bike electronics with a power cutoff switch, so it is not left on or draining the batter when the bike is not running.  that should eliminate the battery draining question.

though how would i find out about the underated alternator?  I assume I can check the batter age... can i somehow test the battery's viability?

Thanks!

A voltmeter across the battery.

Charging should be 13.8-14.4V.
Less indicates undercharging.
Although anything above the battery voltage is charging, it may not enough to recover cranking & used charge.

Voltage dips at low RPM (especially with headlights etc) is normal.
Overcharging is when above 14.4V longterm.

A battery will often be ~13.8V after charging but after resting (12-24 hours or after surface charge is removed) it should be 12.6-12.8V fully charged without no load.

A flattery (flat batt - as in totally discharged) will be 1-1.5V lower - ie, ~11.3V (rested and no load).
(Normal cranking batteries should not be discharged to under 70% capacity.)

I use a "0.1V = 10%" rule - ie, if the full battery is 12.7V, then at 12.4V it is 30% discharged (0.3V => 30%).

But don't confuse open circuit (non-loaded) battery voltages with batteries under load. EG - a fully charged 12.7V battery may drop to 11, 10, or 9 volts during cranking.   

And temperatures affect voltages.
The above is a rough guide....

oldspark wrote:

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A voltmeter across the battery.

Charging should be 13.8-14.4V.
Less indicates undercharging.
Although anything above the battery voltage is charging, it may not enough to recover cranking & used charge.

Voltage dips at low RPM (especially with headlights etc) is normal.
Overcharging is when above 14.4V longterm.

A battery will often be ~13.8V after charging but after resting (12-24 hours or after surface charge is removed) it should be 12.6-12.8V fully charged without no load.

A flattery (flat batt - as in totally discharged) will be 1-1.5V lower - ie, ~11.3V (rested and no load).
(Normal cranking batteries should not be discharged to under 70% capacity.)

I use a "0.1V = 10%" rule - ie, if the full battery is 12.7V, then at 12.4V it is 30% discharged (0.3V => 30%).

But don't confuse open circuit (non-loaded) battery voltages with batteries under load. EG - a fully charged 12.7V battery may drop to 11, 10, or 9 volts during cranking.   

And temperatures affect voltages.
The above is a rough guide....

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hmmmm, lots of info there... so what do i do when? should i put the volt meter over the battery while cold and not running? should i put voltmeter across battery after bike has been running with stereo pumping for a while to see where the battery is after extended use?

I killed the battery again riding over the weekend with the stereo playing and had to jump it, then after riding for 20ish minutes on sunday and not riding since then, the battery had enough kick to start on its own today. so it seems like the battery can hold its charge but with the stereo on running for awhile, it its too much for the alternator/system (?) when engine is on and draws from the battery and drags it down...

can the system be goosed somehow or a bigger alternator (or whatever) added to provide the extra juice when running to power the stereo without eating into the battery?

anything else i'm missing? my mechanical degree only took my to EE101, so i basically get it, but electricity is still more magic than reality for me

Thanks! Garrett

Normally running & charging should be 13.8-14.4V.

If you think the stereo is the reason, measure battery voltage with stereo on and off and see what the difference is for the same test conditions.

For example warm the bike up measure battery voltage with stereo off and then turn the stereo on and see what your battery voltage is. If the stereo is consuming more power then the alternator is capable of outputting this should be reflected in a decrease in battery voltage.

As oldspark mentioned lower voltage at low RPMs is normal so maybe test this at 2 different engine speeds.

so i checked voltage on the battery while idling after bike sat for 3hrs today, giving 13.45V

with stereo on at 8 out of 10 volume the voltage dropped to 12.91V, then when upped volume to 9/10 the volume dropped further to 12.75V, and seemed to vary based on music/song density up and down a little, possible to drop a bit further...

so it appears alternator cannot handle power required by stereo when turned up for driving speeds - so is the answer to purchase a higher output alternator? is such a thing possible?

Unless you have bad voltage drops from the alternator & grounds (see the "Big 3"), then yes, your alternator is undersized. Else maybe worn brushes (if it has them).

I don't know if higher output alts are available for yours - you'll have to search - but except perhaps for permanent magnet types, it should be possible to rewire your alternator, and - if needed, - maybe beef up the regulator. Again - search.

Maybe a 919 club?
(Is that a Duc? I modified my old Duc 750 "permanent magnet" 2-phase 120W alternator so that it would charge when under 3,000 RPM (over 100kph/60mph in top gear), and so that I could start with a flat battery (the standard regulator needed power to start passing power - most annoying when the alternator does NOT need electrical power to generate!).

oldspark wrote:

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Unless you have bad voltage drops from the alternator & grounds (see the "Big 3"), then yes, your alternator is undersized. Else maybe worn brushes (if it has them).

I don't know if higher output alts are available for yours - you'll have to search - but except perhaps for permanent magnet types, it should be possible to rewire your alternator, and - if needed, - maybe beef up the regulator. Again - search.

Maybe a 919 club?
(Is that a Duc? I modified my old Duc 750 "permanent magnet" 2-phase 120W alternator so that it would charge when under 3,000 RPM (over 100kph/60mph in top gear), and so that I could start with a flat battery (the standard regulator needed power to start passing power - most annoying when the alternator does NOT need electrical power to generate!).

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I have searched some and found nothing off the shelf for my bike.  What is a regulator vs. an alternator?  It sounds like I am going to be S.O.L. for an affordable solution, winding coils myself I would not recommend...

any other last thoughts?

Yep - get smaller audio.

The alternator is the generator that produces power.
It's a spinning magnet that generates electricity in surrounding stator wires.
They go through power diodes to convert generated AC into DC for the battery etc.

The regulator regulates the alternator output - ie, tries to keep it with (say) 13.8V and no more than 14.4V.


For cars & bikes alternators almost always a spinning electromagnet and the regulator varies the the spinning rotor's current to vary the stator output. Brushes are used go connect the regulator's electricity to the rotor. (When these are too worn, alternator output drops.)

Boats and some bikes (like my old Ducati) use a permanent magnet rotor.
Their output varies with engine speed. Since the rotor can not be regulated, their regulators usually dump excess voltage (eg, a big Zenor diode) though some only pass what is required.

oldspark wrote:

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Yep - get smaller audio. 

The alternator is the generator that produces power. 
It's a spinning magnet that generates electricity in surrounding stator wires.  
They go through power diodes to convert generated AC into DC for the battery etc.

The regulator regulates the alternator output - ie, tries to keep it with (say) 13.8V and no more than 14.4V.  


For cars & bikes alternators almost always a spinning electromagnet and the regulator varies the the spinning rotor's current to vary the stator output.  Brushes are used go connect the regulator's electricity to the rotor. (When these are too worn, alternator output drops.) 

Boats and some bikes (like my old Ducati) use a permanent magnet rotor.  
Their output varies with engine speed.  Since the rotor can not be regulated, their regulators usually dump excess voltage (eg, a big Zenor diode) though some only pass what is required.

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First - thanks for all your guys help.  I mean that...

Second - so if I after I'm done riding, if I shut off the stereo and rev the bike and hold the rpms for  some period of time (30s-1 or 2min) that will accelerate the battery chargiing, correct?  If yes this might be good to give the battery a little charge/energy bump before parking (hopefully)...

Lastly - can the regulator be modified to not "dump" energy so it goes all to charging the battery?  Or am I misunderstanding this, or assuming Honda  would have already done this very efficiently?  Or is winding the alternator less of a monster scary project than it sounds?  What about adding a 2nd smaller battery into the system somehow?  Going smaller audio isn't as fun as going bigger, so trying to find a reasonable countermeasure to the power drain issue is my goal...

Thx!

Yes & No.

Running without that radio means spare power for the charging (it's not "acceleratinge the battery charging" - it IS charging).
Whether is is enough, you'll just have to find out.
Most cranking batteries probably replace most of their (lost) cranking power within a minute or 2, but complete charging takes longer (it's a of a 90/10 rule - the last 10% takes 90% of the time).
You may not need 100% recharge for sustainable starting, but the battery won't last as long (the further fro 100% charged, the more/faster a battery sulphates).


Jigging the regulator - not really. You lack TOTAL power. You could disconnect the battery all together. Or the audio. That's your choice. That the alternator "charges" both makes no difference.


You can give rewinding a go, but it may require a rotor boost.
And if it's a perm-magnet motor, you may get no gain.
My Ducati perm-Mag rewind (or rather reconfig from "center-tapped" 2 phase stator to single-phase end-tapped stator was merely for charging at ~1,000-1500 RPM instead of 3,000 RPM - but that was at half the current.... (ie, a voltage boost, but no power boost).

Sadly your SOL, bikes like yours just weren't meant to have additional electrical loads added to them. The bike doesn't even put out enough power to charge the battery at idle and at cruising speeds has just enough to charge the battery and run the bike.

If you must have tunes I'd look into battery powered setups that aren't connected to the bike. Alot of rocket riders that ride with tunes have a earbud or helmet speaker and ipod setup; not legal in alot of places but that's how they have it.

catback wrote:

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Sadly your SOL, bikes like yours just weren't meant to have additional electrical loads added to them. The bike doesn't even put out enough power to charge the battery at idle and at cruising speeds has just enough to charge the battery and run the bike.

If you must have tunes I'd look into battery powered setups that aren't connected to the bike. Alot of rocket riders that ride with tunes have a earbud or helmet speaker and ipod setup; not legal in alot of places but that's how they have it.

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That's how it seems to keep turning out - battery keeps dying and I have to jump it...

So two questions:

1. Is there any kind of battery meter component i can put on the bike instrument panel to indicate battery level/power so i can see when low? That will let me know to rev engine after riding to charge it before shutting off bike.

2. Are there ANY creative alternatives to add some extra cells or battery(s) and some minor circuitry to charge it/them once the main battery has been fully charged by the alternator? Something has to be possible, and I'm committed to having tunes on the bike (non-headphones based) as long as the cost is not outrageous.

???

oldspark in his 2nd Reply wrote:

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A voltmeter across the battery.
.....
The above is a rough guide....

---

That's your battery & system level meter.


Maybe attach alternators off the crank, else gearbox.
Or maybe wheels.
Else solar power or wind generators.

Extra batteries extend up time (reserve time) but need charging some time...

I did not read this entire topic, but I do have something to say about Honda charging systems.  I ride a Honda Silverwing.  It is a 600cc twin.  It is outfitted with a stator type charging system.  The only Honda that I know of that has an alternator is the GL models.  At 75K miles my Stator failed.  I ride with my High beams on in the daytime.  Probably about an extra 4 amps of current there.  I have an alpine head unit under the seat.  The way I listen to it, no more than 3 or 4 amp surges.  I do not know if the stator was just going to fail or if the extra amperage all the time may have caused the failure.  I now ride with the low beams on and only pulse the high beams when deemed necessary. 

I know it is illegal to ride without a headlight.  On my bike while I was awaiting the arrival of the new stator, I could press and hold the start button to turn the headlight off.  My bike requires the left brake lever to be depressed really hard for the starter to engage.  I am sure your bike will not spin the starter unless in neutral or the clutch is depressed.  You may be able to do that to charge the battery a bit.

oldspark wrote:

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oldspark in his 2nd Reply wrote:

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A voltmeter across the battery.
.....
The above is a rough guide....

---

That's your battery & system level meter.


Maybe attach alternators off the crank, else gearbox.
Or maybe wheels.
Else solar power or wind generators.

Extra batteries extend up time (reserve time) but need charging some time...

---

anybody have any ideas here on how i can add some extra batteries to the system? perhaps something for extra reserve power that i can take inside and charge nightly after rides... could i just hook up some 12v cells in parallel to the main battery? other ideas?

Well yes - you said it.
Connect another 12V battery in parallel and recharge at home.
Common ground and fused +12V feed at each battery end (unless you are sure you have good connection security - no chance of shorts).

I can't say much about motorcycle batteries, but just had to post about how ironic your bikes are: I had brand new 2007 919 AND I had a 91 Nighthawk 750. What a coincidence! I'd probably faint if you said you used to have an 82 GS-750 and a 76 KZ-650!

My 1972 Yamahahaha RD350 & later RD400 had an alternator.
My 1972/3 Ducati twin has a permanent magnet rotor - but what would you expect for Italian electrics - it even had those old ceramic fuses - for a V-twin motorbike!

And I'm certain my 1984 kumandsuckme GPz900s have alternators, though all I recall was their "complex and flawed" cooling fan relay system, and great headlights....

I had no idea that stator system were so common (except for marine and recreational etc). But for large or road bikes...??!!

hmmmm... i'm not coming up with a solution here, much less an elegant one, to solve my power woes for my stereo.

can anyone assist with maybe finding alternator and battery specs for my bike and circuit schematic design to solve this bugger? extra battery: are any specific battery types unacceptable? can the alternator/regulator be tweaked to charge better or more efficiently? can i install a 2nd power system to run the stereo only? other ideas or outside the box thinking?

riding sans tunes is not as cool as with... =(

I though most of that had already been answered.

As to battery, I'd suggest sealed - not a wet cell.

oldspark wrote:

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I though most of that had already been answered.

As to battery, I'd suggest sealed - not a wet cell.

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most had been answered, but not all...

on a motorcycle forum someone suggested the following for a 2nd battery setup:

"Get a diode from your local electronic shop, must be at least 15 amp reverse rated. Then connect your second battery via the diode in the positive rail to the bikes battery +. ( Connect with the white stripe pointing towrads the positive of the secondary battery). The secondary battery will also need an earth lead run to a good metal part of the frame. This will power the amplifier, but not allow the amplifier to drain the main battery. It will charge up via the bikes alternator when off load."

would this 10Ah battery work: https://www.amazon.com/Replacement-Battery-VOLT-250-FASTON/dp/B000RP5HHY

how can i calculate/estimate how long the 2nd battery will last? where can i get a diode?

That has been answered.

You are not getting any extra power from your alternator.
Forget the diode etc - there is no point...

Just get a second independent battery to power your sound.