Determining capacity of new charging system

[MAC10]

I have replaced my 78 GS 1000 charging system with a Rick's stator and a a new SH 775 RR. It is charging at a solid 14.3 volts. Test trips show it to be very reliable and steady now. Headlight is bright with no dimming as used to happen. A big improvement and peace of mind. The information here made it possible.I am very grateful to the generosity of the members of gsr.

How do I determine how many watts I have to play with? I will definitely need to run an electric vest which needs 50 watts. Driving lights for spotting deer are a very good idea where I live. I am not knowledgeable about electric stuff other than what I have learned from working on my bike.

Can the gurus here point me to this info on the site, or give me some guidance?

 

[posplayr]

Ironically the total power capacity your charging system can deliver has nothing to do with the things you changed. The maximum power has to to with the magnetic strength of the rotor. So the point is that it is essentially constant assuming you are above say 3k rpm. People have reported being able to safely add up to 5 amps of additional load. If you swap out incandescent for led signal/brake lights you can probably pick up close to another 5 amps. Figure a maximum of perhaps 120 watts at rpm of you swap to led.
you can use a volt meter as you ride around to see how much your loads are pulling down the charging voltage at the battery. Stay above 14.0v

 

[MAC10]

Thanks posrplayer. I took your advice and went for a half hour highway run last night with my heated vest (50watts) connected. Charging remained at 14.3, except when climbing the steepest grade when it dropped to 13.9. No dimming of lights, and the vest stayed hot. All the bulbs are stock at the moment.

I will experiment some more and post the results here for reference.

 

[posplayr]

Good info, do you loose a lot of rpm on hills? Or more specifically how low was the rpm to drop to 13.9v? I understand it might not be real consistent.

50 watts is closer to 3.5 amps so 5 amp might be an over statement. The LEDs will save quite a bit. Will vary but figure over 4 amps minimum if all signal lights are swapped. On my gs1100ed there are a lot of dash light ; if they were all on it is close to 50 watts.

 

[bwringer]

For driving lights, look into the wide range of LED lights available nowadays. They can be spendy for the good stuff -- the cheap LEDs can still make very good marker/visibility lights for being seen, but the optics of the expensive lights are far better for helping you see. There are a few great threads going on over at ADVrider.com . There's even a pretty darn good H4 halogen substitute LED bulb on the market for $40 or so, but I don't know if it would fit into a GS headlight housing.

I definitely wouldn't try hooking up a pair of 55W halogens to a GS... actually, I do remember seeing a thread a while back where someone tried this. It didn't end well. :nonchalance:

 

[MAC10]

Thanks bwringer. I had planned to try a single 55 watt light , mounted on the right side, to light up the ditch for deer. I would not want to push it on this old bike until I know what I have to work with. I will also replace the light wiring with heavier brand new stuff, and install a relay. That will happen when I install a fuse block.

Right now I am using a 55 watt Osram Night Breaker, which is an excellent h4 bulb with good optics. I can recommend it.

 

[Steve]

I have not tested a bike with a really good stator and a series regulator yet, but the one bike I did use for testing would barely handle an extra 55 watt headlight bulb. It would only keep the voltage above 13.5 if the engine speed was over 4000.

I know everyone insists that you need over 14 volts for proper charging, but the key word is "proper". Since static battery voltage is about 12.8, anything over that will, technically, charge the battery. The question is how well and how quickly.

If you don't mind riding with an eye on the voltmeter, you could certainly add the brighter lights, but be ready to turn them off when you slow down and the voltage starts dropping.

.

 

[jona]

Am I wrong? The Acc. outlet in my fuse block [stock] is 10 amp. I ASSUME 10 amp, is max draw?

 

[posplayr]

I have not tested a bike with a really good stator and a series regulator yet, but the one bike I did use for testing would barely handle an extra 55 watt headlight bulb. It would only keep the voltage above 13.5 if the engine speed was over 4000.

I know everyone insists that you need over 14 volts for proper charging, but the key word is "proper". Since static battery voltage is about 12.8, anything over that will, technically, charge the battery. The question is how well and how quickly.

If you don't mind riding with an eye on the voltmeter, you could certainly add the brighter lights, but be ready to turn them off when you slow down and the voltage starts dropping.

.

Steve what bike are you describing? It is a bike with 12 pole stator?
With regard to battery charging, if all you have is 12.9 volts then you will not be able to counteract whatever it is that drained your battery. In other words you need the higher voltage to recharge quickly from the large drains.

The other reason (other than extra loads) to be concerned about lower than full 14.5v charging is that dirty connections are usually the reason assuming all else is good. The dirty connections can either just get worse, or as has been seen in many fuse boxes , the corrosion causes heated connections with melted and shorting fuse boxes.

So the point of a high voltage (i.e. getting the last few tenths of a volt out of your charging system) is it indicates a clean set of connections. Setting asside the issue of dirty connections, being over 14.0v is adequate in most most cases of battery recharging.

 

[posplayr]

Jona
You can pull 10 amps without blowing a fuse, but that does not mean you will not drain the battery. So the answer to your question is yes you are wrong assuming you can draw 10 amps continuously for extended periods of time.

 

[jona]

Thanks posplayr

 

[Steve]

Steve what bike are you describing? It is a bike with 12 pole stator?

No, I have been fortunate enough to not have a bike with a 12-pole stator.

I think it was one of the previous 850s that I had, but can't say for sure. I was just using jumper wires to connect different loads to the bike while a voltmeter was attached, just to see what I might be able to get away with.

I fully agree that higher voltage is necessary to properly charge the battery, but you have to admit that with a constant voltage of 13.0 at the battery, you could go forever. You won't have any reserve for anything else (brakes, turn signals, horn, etc.), but you will not be draining the battery.

.

 

[bwringer]

Thanks bwringer. I had planned to try a single 55 watt light , mounted on the right side, to light up the ditch for deer. I would not want to push it on this old bike until I know what I have to work with. I will also replace the light wiring with heavier brand new stuff, and install a relay. That will happen when I install a fuse block.

Right now I am using a 55 watt Osram Night Breaker, which is an excellent h4 bulb with good optics. I can recommend it.

In case it's not already clear, that added 55 watt light will be pushing it, especially since you mentioned above that a heated vest was also a requirement.

You're gonna have to spend a few bucks to reach your stated goals.

First off, invest in a volt meter. Here's the one I have on my V-Strom (modern Suzukis also suffer from the exact same crappy electrics... it's tradition now)
Wire it DIRECTLY to the battery to get a true reading:
http://stores.advmonster.com/waterproof-digital-voltmeter/

Next, junk that old-tech 55 watt accessory Bambi fryer. Old-fashioned incandescents produce more heat than light with your precious electrons. Pony up a few bucks for something like this:
http://stores.advmonster.com/model-30-led-off-road-spot-light/
It's a high-quality LED unit that draws around 10 watts. $50. There are lots of other options out there -- go nuts.

You might also take a good long look at this bulb -- it's an LED substitute for an H4 halogen. If you can find just a skosh more room behind your stock bulb, it should fit.
http://stores.advmonster.com/h4-led-headlight/
$45, and the light output is excellent. Best of all for your needs, it draws a measly 20 watts.


Last, but not least (actually, you should do this first), you'll want to invest in a HIGH-QUALITY sealed battery. Ditch the old-skool wet battery pronto if you haven't already. One of the very best AGM batteries on the planet is the MotoBatt. I've got two (on two different bikes, derr), and they're amazing. If you already have a good AGM, great.

Do NOT waste your money yet on a Lithium Iron battery. They're fine in some applications, but they do NOT respond well to abuse. You're going to be pushing the limits, so it's best to go with an AGM battery that can handle being discharged and/or marginal charging conditions.

 

[Grimly]

I see the usual BS is being spouted by the seller of that 10W triple LED light - 1500lumens my backside - more like 800.
Honestly, when I see an honest seller (or one who simply has a clue) I'm more inclined to reward them with business.
As things stand, dishonest and clueless sellers just ring alarm bells with me and I take it as some kind of warning sign that if they're so ignorant and/or careless of the truth, their after-sales service is likely to be rubbish, too.

 

[posplayr]

No, I have been fortunate enough to not have a bike with a 12-pole stator.

I think it was one of the previous 850s that I had, but can't say for sure. I was just using jumper wires to connect different loads to the bike while a voltmeter was attached, just to see what I might be able to get away with.

I fully agree that higher voltage is necessary to properly charge the battery, but you have to admit that with a constant voltage of 13.0 at the battery, you could go forever. You won't have any reserve for anything else (brakes, turn signals, horn, etc.), but you will not be draining the battery.

.

Well it would be a good benchmark to know what kind of load can be put on a bike and still maintain 14v battery voltage at say 3k rpm. Right now it looks like about 50 watts or 3.5 amps.