Can I Run a 25watt 25 watt headlight bulb?

G

Grouper

Member
My local honda dealer only stocks a 25/25 bulb. My 71 ct 70 came with a 15/15. can anybody tell me if its ok to run the 25/25 on my bike? I dont want to wreak a stator or melt wires exc!
 
Adam-NLV

Adam-NLV

Well-Known Member
Yep, you won't damage anything but the battery may not charge that well running the 25 watt HL and as mentioned won't be as bright at idle speed. In theory you could try changing the tail light wattage to a lower value as that would "balance" the bikes electrical system but it's best to try and source the 15W bulb.
 
G

Grouper

Member
Adam-NLV said:
Yep, you won't damage anything but the battery may not charge that well running the 25 watt HL and as mentioned won't be as bright at idle speed. In theory you could try changing the tail light wattage to a lower value as that would "balance" the bikes electrical system but it's best to try and source the 15W bulb.
Click to expand...

ok, Thanks guys!
 
JPardue

JPardue

Active Member
If you just have to run the 25 Watt headlamp bulb, then for sure install a LED tail/stop lamp bulb. It draws less Watts than the 5 Watt tail lamp filament consumes, and especially less than the OEM stop lamp Wattage.

Superbright LED's offers an LED 6 Volt stop/tail lamp in white or red.

Jon
 
6

69ST

Well-Known Member
X2 on JP's LED suggestion. You might also install a newer-type sealed AGM battery which, at 4.6ah, more than doubles your stock leaker's 1.9ah charge capacity.

This is where a lot of gray area, including "it depends", enters the equation. If you don't use the headlight as a DTRL, then the battery will charge with modest mileage during the day. In this scenario, you could rewire the headlight so that it draws DC power from the tail light circuit. Keep in mind that when the headlight is powered, you will be running a partial-loss electrical system...meaning that the battery will discharge. However, 25w @ 6v equates to ~4.2a current draw, a 4.6ah battery should take roughly an hour to completely discharge, running at total loss, i.e. no charging at all, like with the engine not running. With the engine spinning a more or less steady 5000rpm+, there should be at least 10-15w of DC power going to the battery. I'd guesstimate closer to two hours worth of usable headlight power, with the higher capacity battery & LED tail light.

This is what I consider a half-assed, but potentially workable, solution. The reason being that, IMO, the headlight should remain powered as long as you care to ride...even if that's 12 hours at a shot, without discharging the battery. That said, I've been succesfully running a 12v/35w headlight, as described above, but with a 12v/5.0ah battery since 2006 and have never so much as connected a trickle charger during the winter. Longest ride with the headlight powered has been 45 minutes. Battery voltage was still 12.4 volts at the end of that ride, same reading I've gotten from this battery since day one. I don't use the headlight during daylight hours and rarely ride at night; also, this bike is powered by a Honda Nice 110, which has a more robust, 6 coil, 12v, alternator. Aside from using 6v parts and scaling-back the wattages to better match an old-gen, 6v, alternator, I cannot think of any reason why this wouldn't work the same on an early vintage CT70.

Just FYI, the reason for tapping battery power for the headlight (and leaving the yellow AC lead unused) is twofold. First off, you will get full brightness until battery voltage, under load, drops below about 11 volts. Second, I dislike a headlight that dies when the engine stops.
 
OLD CT

OLD CT

Well-Known Member
JPardue said:
If you just have to run the 25 Watt headlamp bulb, then for sure install a LED tail/stop lamp bulb. It draws less Watts than the 5 Watt tail lamp filament consumes, and especially less than the OEM stop lamp Wattage.

Superbright LED's offers an LED 6 Volt stop/tail lamp in white or red.

Jon
Click to expand...

Jon,for the life of me i cannot find a LED bulb on superbrights site that matches a 1154 6v dual filament taillight bulb.
 
JPardue

JPardue

Active Member
I know how you feel, the Superbrights site is not tuned to 6 Volt thinking.

They use a 12 Volt bulb 1157 dual contact bulb base, then sell it in 6, 12 and 24 Volt versions.

You want their part number 1157-W19-6V to replace an 1154 Stop/Tail bulb. Also offered in Red as a 1157-R19-6V

http://www.superbrightleds.com/cgi-...DispPage&Page2Disp=/specs/1156_57-x12-24V.htm

Click the See Prices and Buy button... there you select Voltage, color, and if white color you can choose 15 or 100 degree viewing angle.

Jon
 
Last edited:
6

69ST

Well-Known Member
For the 12v guys out there, this is the brightest 1157 LED array I've found, on Superbright's site, so far:
1157-x45-T: 45HP-LED BAY15D Tower Bulb

For those running 6v systems, not so good... :22:
 
G

Grouper

Member
racerx said:
X2 on JP's LED suggestion. You might also install a newer-type sealed AGM battery which, at 4.6ah, more than doubles your stock leaker's 1.9ah charge capacity.

This is where a lot of gray area, including "it depends", enters the equation. If you don't use the headlight as a DTRL, then the battery will charge with modest mileage during the day. In this scenario, you could rewire the headlight so that it draws DC power from the tail light circuit. Keep in mind that when the headlight is powered, you will be running a partial-loss electrical system...meaning that the battery will discharge. However, 25w @ 6v equates to ~4.2a current draw, a 4.6ah battery should take roughly an hour to completely discharge, running at total loss, i.e. no charging at all, like with the engine not running. With the engine spinning a more or less steady 5000rpm+, there should be at least 10-15w of DC power going to the battery. I'd guesstimate closer to two hours worth of usable headlight power, with the higher capacity battery & LED tail light.

This is what I consider a half-assed, but potentially workable, solution. The reason being that, IMO, the headlight should remain powered as long as you care to ride...even if that's 12 hours at a shot, without discharging the battery. That said, I've been succesfully running a 12v/35w headlight, as described above, but with a 12v/5.0ah battery since 2006 and have never so much as connected a trickle charger during the winter. Longest ride with the headlight powered has been 45 minutes. Battery voltage was still 12.4 volts at the end of that ride, same reading I've gotten from this battery since day one. I don't use the headlight during daylight hours and rarely ride at night; also, this bike is powered by a Honda Nice 110, which has a more robust, 6 coil, 12v, alternator. Aside from using 6v parts and scaling-back the wattages to better match an old-gen, 6v, alternator, I cannot think of any reason why this wouldn't work the same on an early vintage CT70.

Just FYI, the reason for tapping battery power for the headlight (and leaving the yellow AC lead unused) is twofold. First off, you will get full brightness until battery voltage, under load, drops below about 11 volts. Second, I dislike a headlight that dies when the engine stops.
Click to expand...

Wow! Thanks for your help.
 
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