Does this setup allow for 7A of headroom for my DIY heated vest?

[Darkstar]

I'm building a heated motorcycle vest using high temp 30 AWG, 600V rated wire. The power source is my battery, the 12V 14.5 amp MotoBatt AGM, which has two set of leads. One set is connected to a wiring harness (with 20 amp-fuse) that drives a nautilus horn (18 amps@12volts ) and my sweet GS500. I have 100' of the wire which I plan to cut into two 40' lengths of wire, and then run them parallel through a vest, with plans of connecting it to the second set of battery leads. The Wikipedia wire gauge table reflects a total resistance of ~2 Ohms (draw 6-7A) for this setup, providing ~72-100W of heating power. The question is, does this setup provide 7A of headroom?

[philward]

Someone might chime in with the exact numbers but from my experience - not great.

I ran a twin headlight on my GS and that was pretty marginal when it came to putting charge back into the battery.  I suffered a few flat batteries and got quite good at roll-starting.  And that was only the addition of 60W - you're looking at 85.

[Darkstar]

Not what I wanted to hear, but I appreciate you saving me from problems. Know of a workaround?

[mr72]

I agree with philward. That's >50% more current than the headlight draws, and the headlight is far and away the largest current draw on the bike. You might have better luck if you replaced the headlight with an LED headlight that draws only 2A or so (high beam) which would give back ~3A of headroom compared with the halogen OEM light but that only gets you less than half of what you want.

IMHO to do it right will require you to run a battery tender most of the time and I would carry a Li-Ion jump pack just in case. Or for that matter, power the vest from it's own power source, like a couple of ~4AH Li-Ion battery packs like I use for mountain bike lights.

[Darkstar]

The specs say the two rear light bulbs are 5w each and the headlight is 55w. So if I swap those bulbs out with LED (+5w) and disconnect the headlight altogether (I never ride at night), I get an 60w going to my 85w vest. Will it still work if I'm 25w shy? If I only switch the vest on while cruising?

[mr72]

Replacing the tail light with LEDs is a good idea and certainly will help but you will need an LED light controller to handle the brake/tail and then add a license plate light/LED of some kind. On my bike, there's a stick on LED light strip for the license plate light. That will give you some additional margin to charge your battery while running your vest.

If you're only riding during the day then you can always also disconnect the gauge lights and maybe get an amp of extra capacity.

I don't know where you are located but running a motorcycle without the headlight on during the day is most likely illegal, and IMHO unsafe as well. I'd work hard to find a different solution.

[The Buddha]

In the day time you could set the headlights on very low current, or switch them off. Also you're not honking that 18 amp horn all the time. Just remember to turn off all the electrics including the vest 5-10 mins before you stop. That will pump the battery up just fine for that next start session, unless your carbs wont let it fire up first try. Besides, the bike makes more than enough via the alternator, much of it is dumped as heat in the R/R. You just need to get all that wasted heat into your vest - needs to be vested heat. LOL.
Cool.
Buddha.

[Darkstar]

voila!

[ShowBizWolf]

I agree with mr72 that LED's in the brake light is a good idea!

I bought some bulbs from superbrightleds.com this summer and I love them. Didn't need a controller of any kind though... or a different light for the license plate... the bulbs I bought are white and I installed 'em inside a GSF style red lens. They shine down white onto the plate and the brake light is bright eye-catching red.

This thread is really interesting, I hope you update your progress and show us some pics of what ya make!!

[mr72]

I agree with mr72 that LED's in the brake light is a good idea!

I bought some bulbs from superbrightleds.com this summer and I love them. Didn't need a controller of any kind though...

Yeah it depends on what bulbs you get. In my case, the PO did it and then I made an additional mod but it uses a trailer-type LED light controller and the bulbs are just essentially "single filament" type bulbs (there's no filament...).

[Darkstar]

superbrightleds.com

I just read this thread and it looks like they're not  strong enough unless you wire up a controller.
http://gstwins.com/gsboard/index.php?topic=35515.0

If this is the case, I think I'll keep it simple and go with Buddha. All I need to do is wire the vest in and then install an on/off switch to the headlight. Since the vest will only be used >60mph, and drivers don't look in rear view mirrors, I can turn the headlight off and the vest on when I get on the highway. Safe for daytime use anyway.

[mr72]

I can turn the headlight off and the vest on when I get on the highway. Safe for daytime use anyway.

Whatever you say!

Most reports I have read say "visibility" is the main cause of most motorcycle accidents... that is, the other driver fails to see the motorcycle. Less headlight sounds like a certified bad idea in that case. In my MSF class they told us we should run the high beam during the day for this very reason.

It's your life and your risk tolerance, maybe your ticket or insurance claims, so I'm sure you will do whatever you want. Personally I think there are way better ways to solve this than to run without your headlight.

[Darkstar]

Thanks for your concern, but I'm OK with slightly more risk. I generally ride in the long gaps between cars when I'm on the highway. I wouldn't be riding motorcycles at all if I was trying to avoid risk altogether. Aaaand if I wire the the vest to equal the 59w headlamp, I can reroute the high/low beam switch as a controller, where [high beam] = high beam on, and [low beam] = headlight off/vest on.

[philward]

The flat battery was only a very occasional thing, it must be said (but still an outcome you need to be aware can easily result with even moderate additions to the GS electrical load).  And in winter time I would do exactly as Buddha suggested which is turn off my heated grips for a good 10 min or so before arriving to get more charge in.

With all the filament lamps throughout the bike you can certainly claw back a whole host of watts.  But after listing it all out on a spreadsheet (which I no longer have) I ended up not bothering to take this route, mainly because LED alternatives weren't as easily available as they certainly are now.  And the bike happily served its purpose with just a little careful management for a couple of years in this double-headlight-plus-grips configuration before I eventually sold it.

(the grips I think were 4A but I never ran them on full, ever.  I estimate that they were probably accounting for, 15-30W.  But remember they only got occasional and seasonal use unlike the second headlight which was on from go to whoa).

[ShowBizWolf]

Dunno if this will help anybody but I went back and found the bulbs I bought for the tail light:
https://www.superbrightleds.com/moreinfo/tail-brake-turn/1157-led-bulb-dual-function-24-led-forward-firing-cluster-bay15d-retrofit-car/157/694/

They only have two left atm but I figured I would share anyway. I am really happy with them and maybe someone else would like them too.

[Darkstar]

Thanks, these will free up some watts. My initial calculations were wrong because I used 12.8v battery instead of our 12v. Here they are corrected if you're interested, using our 12v battery and the hook up wire I bought (rated for 0.105 ohms/ft.). Option A is for one 30' strand of wire running through the vest. Option B is for two 50' strands running parallel, and better to use that one for a full jacket as opposed to a vest. 54.7>52 assigned to the headlight, so if I run 4 feet of 18 gauge SAE extension, it brings it down to 2.99 ohm = 48watts = 4.0amps.

(A) 30' x 0.105 (2)= 3.00 ohm = 48.00 watts/4.00 amps
(B) (2) parallel 50' x 0.105 = 2.63 ohm = 54.70 watts/4.56 amps

[78530i]

When I was a winter rider, I had more difficulty keeping hands warm.

[Darkstar]

Certainly, but I recently read an article suggesting that I should think of my core first. Saying that one reason hands and feet get cold is because the blood has moved towards the core when its cold, to prevent damage to the organs. So if you keep the core extra warm the hands and feet will follow. I tried bundling up my core on my last ride and it helped a lot, but I know there are limits.

[Endopotential]

 drivers don't look in rear view mirrors, I can turn the headlight off and the vest on when I get on the highway. [/quote]

The driver right in front of me wouldn't be my biggest concern, unless they stomp on the brakes suddenly.

It's the cars in opposing traffic, or the ones on intersecting streets, that I worry about.  Those are the ones who hopefully see your headlights, or the lack thereof.

[mr72]

Thanks, these will free up some watts. My initial calculations were wrong because I used 12.8v battery instead of our 12v.

Your battery is probably over 12v when the bike is not running and the system will float at about 14v or so when the engine is running above idle.

That makes option a 62 watts and 4.4a and option b is 74.7w at 5.3a.

One of these in your pocket would run your vest for an hour and not require you to sacrifice your headlight or overload the GS charging system or melt plugs.