Anyone converted a stock alternator (1100 or 1300) to High Capacity ?

[aSTerix]

I guess I should have used a visual at the outset !!!

Here is a different way of explaining that hopefully is a bit clearer:

I think we are all agreed on the following :

1) Changing Star (Wye) to Delta does NOT increase alternator output power
2) Changing Star to Delta simultaneously INCREASES ac Current output by SQR(3) and DECREASES ac Voltage output by same SQR(3)

What I previously didn't make clear is this :

A) I have an 12v device (air con) that benefits from higher current output and can handle the lower voltage (in fact it is more efficient at the lower voltage )
B) my question was specifically related to the cut in speed as nicely shown by this sample graph :



Cut in speed is tricky to calculate without having the original alternator graphs so was wondering if anyone had done it and could let me know what they found

The typical solution is to change the gearing on the high output alternator and spin it faster, not an easy option on the ST1100

(the reason I want high current at low speeds is because its when I'm sitting in traffic that I want the air con to be effective, it doesn't have to be so effective at crusing speed)

(and the reason why I am experimenting with air con is a long story involving several personal experiences that involve baking in 50C (122F) heat )

Hopefully that clears up a lot of the discussion points and lesson learned on my part, next time its something technical use a visual !!

 

[Larry Fine]

Now that we understand your goal, I suggest an alternative, at least to experiment: A second battery, wired near the load.

Over time, an alternator replaces energy used; one should keep more than one battery charged, as long as you move regularly.

From what you've said, with a second battery's extra current capacity in reserve, the voltage sag at idle shouldn't be an issue.


Just to mention, and as mentioned above, a charger's voltage must exceed the battery voltage for current flow to be induced.

A lowered-voltage alternator may not put out enough voltage to assure being able to start the engine after being highly loaded.

 

[aSTerix]

Now that we understand your goal, I suggest an alternative, at least to experiment: A second battery, wired near the load.

Over time, an alternator replaces energy used; one should keep more than one battery charged, as long as you move regularly.

From what you've said, with a second battery's extra current capacity in reserve, the voltage sag at idle shouldn't be an issue.


Just to mention, and as mentioned above, a charger's voltage must exceed the battery voltage for current flow to be induced.

A lowered-voltage alternator may not put out enough voltage to assure being able to start the engine after being highly loaded.

Thats an interesting idea, also if I make the second battery a Lithium then I can also use a different charger . Thanks for this, has got my mind working

 

[T_C]

Thats an interesting idea, also if I make the second battery a Lithium then I can also use a different charger . Thanks for this, has got my mind working

If you make 2nd battery lithium, 1st is lead be sure to isolate. Well anytime you have 2 you should isolate, but with 2 different chemistries, especially!

I did mix on my bike when I first started pulling a trailer. Lead on bike and lithium in saddlebag that would go in the p'up camping trailer. Put in a time delay relay (30 seconds) that would connect the LiFePO4 to the charging system after the engine was started.

 

[W0QNX]

OK there is a real easy answer. To have more RPM when you are not rolling down the highway....that is what the idle screw is for.

 

[aSTerix]

This just got a tadge more complicated , as I was dismantling the alternator I found 8 diodes so had a look in the HSM and sure enough its tapping the neutral/centre point for that extra 10% power. End result if I rewind it will be a 10% power output reduction at mid rpm upwards (which I can live with ) but also circulating currents around the Delta which may cause overheating.

 

[T_C]

On the ST13 the max alternator ouput is normally list as 5k (or 5.5k) rpm. Most folks never get the engine up that fast on a consistent basis anyway. If you are looking for max ouput while crawling in traffic, you are already in the lowest part of your operating RPM range. I think the cut-in and climb to curve, if the sample graph given is anywhere close, is going to be way too low to be useable for when you need it most.

 

[Larry Fine]

Thats an interesting idea, also if I make the second battery a Lithium then I can also use a different charger .

My suggestion is aimed at leaving the alternator alone. Save the time, money, and reliability you would otherwise lose.

A single diode between the bike and the second battery should be all the isolation you need and will add a 0.6v drop.

Effectively, the second battery will run the AC unit, and the bike will keep it charged whenever it's capable of doing so.

 

[Larry Fine]

This just got a tadge more complicated , as I was dismantling the alternator I found 8 diodes so had a look in the HSM and sure enough its tapping the neutral/centre point for that extra 10% power. End result if I rewind it will be a 10% power output reduction at mid rpm upwards (which I can live with ) but also circulating currents around the Delta which may cause overheating.

Yes, there are four pairs of diodes, not three. Again, I believe you should leave the bike's electrical system alone.

 

[Al st1100]

 

[Shawn K]

Yes, there are four pairs of diodes, not three. Again, I believe you should leave the bike's electrical system alone.

Trying to reinvent the wheel, when he could address his heat issues with an evaporative cooling vest.

 

[T_C]

Trying to reinvent the wheel, when he could address his heat issues with an evaporative cooling vest.

Dubai has considerable humidity. Evaporative vest is not so good. Thermal pack vest (phase change) maybe, but then you have to recharge and only good for so long.

 

[aSTerix]

Trying to reinvent the wheel, when he could address his heat issues with an evaporative cooling vest.

I have tried these and unfortuately they don't work , during the day they evaporate too quickly and at night they don't evaporate.

I am open to lots of cooling suggestions though so please keep the coming, there is bound to be somethin I haven't tried yet. (Basically i don't ride June-September)

 

[aSTerix]

My suggestion is aimed at leaving the alternator alone. Save the time, money, and reliability you would otherwise lose.

A single diode between the bike and the second battery should be all the isolation you need and will add a 0.6v drop.

Effectively, the second battery will run the AC unit, and the bike will keep it charged whenever it's capable of doing so.

I was coming to the same conclusion, I will rebuild the alternator for reliability and a bit more electrical efficiency and work on alternative methods of running an a/c

 

[jrp]

I was coming to the same conclusion, I will rebuild the alternator for reliability and a bit more electrical efficiency and work on alternative methods of running an a/c

If you can shoehorn two (identical) small lithium ion batteries, wire them in parallel and last longer in the traffic jams.

 

[TipSTer]

Dubai has considerable humidity. Evaporative vest is not so good. Thermal pack vest (phase change) maybe, but then you have to recharge and only good for so long.

I understand now Steve living in Dubai. most of the summer temps is over 100F Air condition make sense ah. Adding on unit will needed more power or adding a generator unit.

 

[Ron]

I'm a little late on the subject. Where did this end up?

@[U]aSTerix[/U] and others. Did you consider circulated cool water as an option? Consist usually a vest with tubing sewn on it and cool/cold water from a tank circulated. In somewhere like Dubai, I would have a 12vdc refrigerated unit as opposed to an ice water reservoir supplying the water. I found a couple links in a quick search.

Circulating Cool Water Vest Systems and Accessories - Cooling Vests | Polar Products

www.polarproducts.com

COMPCOOLER Micro Refrigeration Cooling Unit

COMPCOOLER Micro Refrigeration Cooling System, Mini chiller delivers 100W cool capacity, precise liquid temperature control from 5℃ to 30℃ (41℉to 86℉) accuracy +/-1℃(2℉), once circulation liquid reaches to set point temperature, system intellectually control the cooling capacity to that temperature.

www.compcooler.shop