Revised Headlight Relay

[Kiwi_Roy]

A while back I identified the problem with powering the headlight relays direct from the battery with a Ducati Energia regulator, It effects the charging slightly.

Without the headlight current passing through the loom the Voltage drop between battery and regulator is lost and the battery gets charged to a lesser Voltage

 

This may not be an issue for you but if you are having trouble starting in cold weather it could be one cause.

If you don't already have headlight relays its a simple method of brightening up your life with a single relay and a couple of feet of wire.

 

Headlight Relay - Ducati Energia.pdf

 

I first became aware of this when I added a pair of headlight relays, I didn't know why my battery was undercharging at the time so I just cranked up the regulator setpoint. Helping another owner it suddenly clicked and so we added a diode in series with the reference to boost his Voltage by ~0.6.

[luhbo]

... but if you are having trouble starting in cold weather it could be one cause....

 

Could you give an estimation what percentage of total battery capacity this loss would mean? I mean, if starting the bike might need 1,5 Ah, how much of that would be regained after 20 minutes of average commuting at 4000 rpm under standard winter conditions?

 

Hubert

[The Monkey]

Thank you Roy, what are your views on regulators that bypass the loom (with its inherent issues)and hook directly to the battery. I see Electrosport offers this option in addition to the stock wire hook up. Cheers, thanks again for keeping the lights on.

[Kiwi_Roy]

Thank you Roy, what are your views on regulators that bypass the loom (with its inherent issues)and hook directly to the battery. I see Electrosport offers this option in addition to the stock wire hook up. Cheers, thanks again for keeping the lights on.

I really have no experience of the modern ones, after 2004 they changed as you say.

My gut feeling is they will be a lot more reliable not relying on the relay bases to make good contact, they also ground to the battery negative thus eliminating the steel to aluminium contact where the reg bolts to the frame.. If I had to purchase a new one that's the way I would go for sure.

I didn't mention adding additional driving lights etc, they should be wired thru a different relay direct to the battery otherwise the voltage drop will cause over-charging.

I also think loose connection in the reference probably contributes to regulator failure.

 

It would be interesting to know what the Electrosports are set for.

[Kiwi_Roy]

... but if you are having trouble starting in cold weather it could be one cause....

 

Could you give an estimation what percentage of total battery capacity this loss would mean? I mean, if starting the bike might need 1,5 Ah, how much of that would be regained after 20 minutes of average commuting at 4000 rpm under standard winter conditions?

 

Hubert

What I'm trying to get across is without the headlight current passing through the original wiring the regulator doesn't get the benefit of the Voltage drop. Two bikes that I know drop ~0.6 Volts

The regulator setting I see is 13.8

With normal wiring 13.8 + 0.6 = 14.4 (thats what the battery charges too)

With headlight relays it will only charge to 13.8 a loss of 0.6 Volts

 

If you figure 12V is flat and 14.4 fully charged 13.8 is 1.8/2.4 or 75%

 

I may not have my facts straight but it's 25% lower than normal.

 

This would be a lot more significant if the battery normally only charges to 50%, it would end up 25% charged.

You will never regain the 25% because the regulator stops charging once it sees the battery at 13.8 (It thinks the battery is 14.4)

 

I hope this is clearer than mud

[emry]

http://www.yuasabatteries.com/pdfs/TechManual_2009.pdf READ

 

Yuasa knows something. 12.8 is fully charged (lead acid). Anything over that charges the battery. (assuming its plates are not sulfated) Higher equals faster charging (more ampere, but possible battery overheating) Most regulators set voltage ~2 volts above current battery voltage. A classic indicator of a bad battery is low charging voltage and high charging amps.

 

What is needed in battery capacity is based on battery condition, tempurature, and engine condition. In that order. Percents are based on intial battery capacity and current condition. Engineers have formulas for that.

 

Roy is on the right track. A good well servied battery is still the key to easy starting.

 

... but if you are having trouble starting in cold weather it could be one cause....

 

Could you give an estimation what percentage of total battery capacity this loss would mean? I mean, if starting the bike might need 1,5 Ah, how much of that would be regained after 20 minutes of average commuting at 4000 rpm under standard winter conditions?

 

Hubert

What I'm trying to get across is without the headlight current passing through the original wiring the regulator doesn't get the benefit of the Voltage drop. Two bikes that I know drop ~0.6 Volts

The regulator setting I see is 13.8

With normal wiring 13.8 + 0.6 = 14.4 (thats what the battery charges too)

With headlight relays it will only charge to 13.8 a loss of 0.6 Volts

 

If you figure 12V is flat and 14.4 fully charged 13.8 is 1.8/2.4 or 75%

 

I may not have my facts straight but it's 25% lower than normal.

 

This would be a lot more significant if the battery normally only charges to 50%, it would end up 25% charged.

You will never regain the 25% because the regulator stops charging once it sees the battery at 13.8 (It thinks the battery is 14.4)

 

I hope this is clearer than mud