Batteries, chargers and replacements

sijohnston said:
was away camping over the weekend and for the first time, ran my heated vest, aux lights, heated grips, GPS, autocom and HID's, and the alternator couldn't cope. Would a hawker battery help, or is the alternator simply not up to the task and I'd be better dumping the aux halogens?
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ba jesus how about trying to run your laptop, sky tv and electric kettle of the bike aswell! poor old alternators tongue is hangin out pant! pant!

get some ready brek down ya keep that warm glow around yerself :augie
 
As far as I am aware the HIDs just draw the same as the standard dip/main beams. As John Armstrong says the draw from the GPS and Autocomm is negligible. So that leaves heated grips/vest and auxilliary halogens.

On my trip before last to Morocco two 1200GS bikes had flat batteries running auxilliary lights in conjunction with frequent stops and starts.

I reckon your best bet would be to replace the halogens with LED 'presence only' lights.
 
John Armstrong said:
If you start of with the higher capacity battery fully charged then it will delay the inevitable, by a bit.
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that's true but the battery being bigger will draw a larger load to charge back up, so taking more out of the alternator,

the only solution to a deficit of supply power is to supply more power which an uprated alternator would do :nenau
 
LED's seem like they're the way forward, at the risk of looking like a chav. Am in the US on Thurs for 10 days, so if anyone knows the best stockists of such items out there, kindly point me in their direction. Thanks for the physics, the advice, and the concern! :thumb
 
Arrrgh ...

What are these Hawker Batteries? How are they different to the OE fitted unit? Generally speaking, a battery's capacity is determined by its size ... surface area of the plates acting with the electrolyte etc etc... There's only a limited volume where the battery fits and you'd need a rocket science battery to give you more than an amp/hour or two over standard...

What is the standard battery capacity anyway - 12Ah? I don't want to teach anyone how to suck their own eggs, but for those who don't know, a 12Ah battery will give a current of 12 amps for one hour, or 1 amp for 12 hours, you just need a little maths to work out the various permutations... The Mule's original post a couple of weeks ago generated a lot of valuable advice (some of it mine too lol..) but you just need to be able to work out how much stuff you can run before you start eating into the battery's reserve - before the water tank starts to empty if you prefer to look at it like that ... but whichever way you look at it, like a water tank or a bank account, if you take more out than is going in, it will eventually run out completely. Amps are amps, it makes no difference whatsoever whether you take 100 amps for lighting or 100 amps for heated clothing, it's still 100 amps and will deplete the battery or use alternator output in exactly the same way.

Agreed the alternator isn't huge, but it will cope with the 'normal' demand placed on it under 'normal' conditions... AFAIK the alternator isn't an external unit so can't be swapped for one with a higher output - I had plenty of experience of this with my old ST1100 and the perennial 28amp v. 40 amp alternator argument ... fortunately mine was an ex Police bike so had the higher output alternator, but plenty didn't and they were pretty quick to upgrade.

I think you just have to accept that there is a limit to what the alternator can do, and work within that ... Reduce current demand wherever you can, half power on grips, turn off the Aux lighting - or as Tim suggested, use LED lighting which uses next to no power at all... If there's a meter to fit, them make it an AMMETER because that's what will measure the current that's flowing in the circuit - it's current that recharges a battery, not voltage ...

Simples Sergei ...
 
aye, i got all that. someone else suggested a hawker battery but i did think at the time that eventually it will go down too, if my understanding of current supply and demand is right. anyway, i'll just to have manage it smart. cheers.
Greggers said:
Arrrgh ...

What are these Hawker Batteries? How are they different to the OE fitted unit? Generally speaking, a battery's capacity is determined by its size ... surface area of the plates acting with the electrolyte etc etc... There's only a limited volume where the battery fits and you'd need a rocket science battery to give you more than an amp/hour or two over standard...

What is the standard battery capacity anyway - 12Ah? I don't want to teach anyone how to suck their own eggs, but for those who don't know, a 12Ah battery will give a current of 12 amps for one hour, or 1 amp for 12 hours, you just need a little maths to work out the various permutations... The Mule's original post a couple of weeks ago generated a lot of valuable advice (some of it mine too lol..) but you just need to be able to work out how much stuff you can run before you start eating into the battery's reserve - before the water tank starts to empty if you prefer to look at it like that ... but whichever way you look at it, like a water tank or a bank account, if you take more out than is going in, it will eventually run out completely. Amps are amps, it makes no difference whatsoever whether you take 100 amps for lighting or 100 amps for heated clothing, it's still 100 amps and will deplete the battery or use alternator output in exactly the same way.

Agreed the alternator isn't huge, but it will cope with the 'normal' demand placed on it under 'normal' conditions... AFAIK the alternator isn't an external unit so can't be swapped for one with a higher output - I had plenty of experience of this with my old ST1100 and the perennial 28amp v. 40 amp alternator argument ... fortunately mine was an ex Police bike so had the higher output alternator, but plenty didn't and they were pretty quick to upgrade.

I think you just have to accept that there is a limit to what the alternator can do, and work within that ... Reduce current demand wherever you can, half power on grips, turn off the Aux lighting - or as Tim suggested, use LED lighting which uses next to no power at all... If there's a meter to fit, them make it an AMMETER because that's what will measure the current that's flowing in the circuit - it's current that recharges a battery, not voltage ...

Simples Sergei ...
Click to expand...
 
davidgibson999 said:
In any case get it sorted cos I don't fancy running down a boreen in Donegal again sweating like a badger trying to get you started again :D
Click to expand...

My battery was flat after I had to run down that boreen. Do you realise how much wattage is required to move my girth :D


sijohnston said:
LED's seem like they're the way forward, at the risk of looking like a chav. Am in the US on Thurs for 10 days, so if anyone knows the best stockists of such items out there, kindly point me in their direction. Thanks for the physics, the advice, and the concern! :thumb
Click to expand...

You know it makes sense. :thumb The choice of champions :clap

3790802230_9095e518d8_b.jpg
 
TexasMule said:
8d.GIF


8e.GIF


Stupid me, that explains everything....:eek:
Click to expand...

The most important formula in this thread is simply... watts / volts = amps.

So 55W divided by 12v = 4.5 amps.

Which means, if you have a 4.5 a/h battery, a 55W bulb will drain it in 1 hour (if not charged). So the question is, how many amps can the alternator generate? With this figure and simple maths, we can work out how many watts you can draw before the battery starts to drain.

Power meters measuring volts doesn't really come into it (i mean is does, but a good measurment). Example, you can have a battery which is so flat that it cannot start a bike, yet it can still measure 12v on the meter.
 
roddy said:
that's true but the battery being bigger will draw a larger load to charge back up, so taking more out of the alternator,
Click to expand...

How can I put this politely? 'No'.

The alternator output increases as the battery voltage decreases but it is regulated so that it will not generate more than it is capable of reliably generating ie so that you don't burn out the windings etc).

A bigger battery will simply take longer to fully charge if the alternator is working to its maximum.

Greg
 
Greg Masters said:
The alternator output increases as the battery voltage decreases but it is regulated so that it will not generate more than it is capable of reliably generating ie so that you don't burn out the windings etc).
Click to expand...

True! but the bigger battery as it drains will get to a point where it will draw more of the alternator "reserve" wattage than a OEM battery so taking you up to the capacity of the system quicker ?
 
roddy said:
True! but the bigger battery as it drains will get to a point where it will draw more of the alternator "reserve" wattage than a OEM battery so taking you up to the capacity of the system quicker ?
Click to expand...


Roddy .. Another plumbing analogy ..

The alternator supply is like mains water ... a bigger tank just takes longer to fill as the mains pressure (i.e. alternator output) is constant...

The rate at which the battery receives charge is pretty much linear until you get close to max charge which is when the regulator /rectifier kicks in and starts to dissipate excess current (like a water tank overflow pipe) in the form of heat.

I love plumbing me ...

G
 
No - That's too simplistic if you look at the variables we're considering. The alternator doesn't have a 'reserve wattage' - once it is spinning over a certain speed it will be producing its maximum output which is controlled by the regulator. The charge going into the battery will obviously be dependent on the demand for current in the circuit, with any surplus going to charge the battery. If you run into a current deficit, in other words you're using more current than the alternator can supply, then voltage in the circuit will tend to drop (Ohm's Law again here) as demand increases. However, if you're in this position then there's not going to be a surplus of current left to charge the battery, so you're back to square one.

It goes back to the simple fact that the more power you use the less current is available to charge the battery.


G
 
If its slow commuting that drains the battery will these LED indicators help,
E bay iten No 180422779307 BMW LED INDICATOR BOARDS F800 F650 at £30 per pair. I dont know how much power they use but the std bulbs consume 42W and are used quite a bit round town.
 
Greggers said:
It goes back to the simple fact that the more power you use the less current is available to charge the battery.

G
Click to expand...

This I know hence the statement,
roddy said:
but the bigger battery as it drains will get to a point where it will draw more of the alternator "reserve" wattage than a OEM battery so taking you up to the capacity of the system quicker ?
Click to expand...
change "reserve" (meaning the spare capacity within the system that lets the battery charge before you start adding all sorts of electrical goodies to the bike and it starts to give out power instead of taking it) to "surplus" and viola



roddy said:
the only solution to a deficit of supply power is to supply more power which an uprated alternator would do :nenau
Click to expand...
 
Ahhh ... ok ..

So - the alternator has an output of 400 watts, assume that the ignition circuit consumes about 50w, the always on headlight is 50 watts, LED tail-light negligible but assume around 10w... Just for a giggle, assume the 'constant' consumption is 150 watts, which leaves you with 250 watts to play with. What's left for charging depends on how YOU use your accessories... aux lights at 110w, heated jacket at 90w, grips at 30w...

Like I said in the Mules original post, you just have to be aware of the consumption of each accessory you're using..

YMMV of course ...

G

ps - I know it's not Ohm's law d'oh :blast
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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