how many amp consumption in the form of extralights, GPS, heated grips, chargers etc can you have on the Tenere...?

The generators output is rated as 14v & 20.8amp at 5000 rpm (291.2W).

Good question - it also concerns me.

I have heated grips and GPS, then recently added 2x 55W spotlights.

Not wanting to suffer from the battery failing to charge, I swopped the bulbs in the spotlights for LED's as they only draw 2W, but I am not that impressed.

The LED's are bright and help make me more visible but the quality and focus of the beam is pathetic and they do nothing to light up the road ahead.

Must be something to do with the position of the light source not being at the focal pont of the parabolic lens in the lamp - but I am no expert :-(

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That's pretty much it.

I once calculated that with everything (standard bike - no accessories) switched on (and I mean absolutely everything) the total power consumption on the Z would be about 288W, leaves only a couple of Watts spare! This isn't likely to happen though unless you're prone to riding around with your finger on the headlight flash, the hazards on, sounding the horn, braking at the same time in hot weather with the radiator fan running!!

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Sorry, I’ll be a bit more practical! Might seem a bit boring, but hey ho!

I did a lot of calculations when I got the bike and this is what I found…

The connected load (everything within the electrical system) for the Z is for argument’s sake about 300W or 21A, which pretty much matches the peak alternator output. However, this does not include the starter motor circuit, but we’ll ignore this for a minute as it is effectively a direct load on the battery rather than the alternator because it is drawing current only when the engine/alternator is not running.

The demand load is what the bike’s system uses at any given time (dipped headlight, side lights, fuel pump, ECU, ignition, instruments etc), which is unlikely ever to be as high as the connected load. The demand load on the Z is about 105W (7.5A) when the bike is running in standard trim at 5000rpm (slightly less if you’ve got LED side/number plate lamps fitted). This equates to a maximum of 195W (14A) of spare capacity in the alternator, but only assuming the demand load does not increase, which it of course will when random and cyclical loads such as the brake lights, indicators, radiator fan, horn, headlamp flash are used. This extra demand can be up to 195W (14A), using all of the spare capacity, but it is unlikely. It is important to consider the effects of starting now; the battery 20-30 minutes after starting will have a fairly high current draw itself to bring it back to a stable voltage, increasing normal demand load above 105W (7.5A) .

There is no exact formula to work out what you can actually safely use of the 195W (14A) spare capacity, you can assume that third will be need to be called on at any one time (more after starting). This leaves approximately 130W (9A), but you still need to add a further margin of safety for battery recovery.

A pair of 55W spots (8A) will use up all the spare capacity and allow no margin for extra demand load. I run Vision X Solstice LEDS, which are 20W (1.5A) the pair, so leave a good 110W (7A) spare. Add grips 30W (2A), GPS 15W (1A) and there’ll still be 4A (56W) spare for other accessories and the recovery time of the battery.

What’s the current draw of your vest Keith?

At the end of the day this may help, but it still involves a lot of assumptions and variables.

Note: Calculations based on 14V assuming charging voltages between 13.6 and 14.4V)

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Excellent detailed reply

Looks like it was a reasonable precaution to swap my spotlamp bulbs to LED's.

If anyone is interested, this is a rough comparison on brightness (conventional H3 55W bulbs on my GS vs LED's on my Tenere).

Attached Images

spotlamps.jpg (79.5 KB, 79 views)

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Keith, I run a very similar set up but reverted to Halogen bulbs in the spots after the LEDs began to disintegrate internally (vibration??). I also have a heated vest.

I find if I connect the vest along with everything else that it is just too much for the alternator, turn off the spots and there is more than enough capacity for the vest. I have a 35w HID dipped beam fitted so tend not to use the spots so much as there is plenty of light coming off the front of the bike already.

One thing I have noticed is that if battery voltage begins to drop the orange EMS light begins to flicker on before it drops too much - time to turn something off. There is usually still enough juice to start the engine again providing the engine is warm.

I love my heated vest this time of year, good investment.

Cheers.

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If you're worried about the power consumption of your accessories and need something to monitor what's going on I can recommend fitting a �10 Gammatronix LED battery/charge monitor from ebay. It is a single LED that changes colour according to charge state/battery voltage.

I posted something here http://www.xt660.com/showthread.php?t=14737 a while back.

One of the best/cheapest mods I've done. Particularly considering the problems the Z has with reg/rect and charging issues.

Note: They're on offer at the moment too - http://www.ebay.co.uk/itm/GAMMATRONI...#ht_3324wt_905

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