I'm afraid that using a generator in series with the battery will not work, unless you connect the generator to a gasoline-powered motor.

It is not just a matter of boosting the voltage of the battery, you need an increase in total available power.

Your scooter/motor/battery/gross (loaded) weight is a problem. With lead-acid batteries, the amount of power they can deliver is related to the surface area of the plates. Automotive-type batteries are lighter in weight than SLA or marine batteries, but they will not last long at all in this type of application. Unfortunately, other battery technologies are far too expensive to be affordable in this situation.

You might consider a moderate battery upgrade; ie: increasing from 12AH to 20AH or 25AH batteries. You will still have a net weight gain, but it will be less than the 35AH batteries.

Note that both batteries should have the same AH rating; you wouldn't want to mix a 20AH with a 12AH.

 

the most efficient way that we can get 24v out of a 12v 35ah battery (it will become 24v 17.5ah, the law of the conservation of energy), is to find 2 12v 17.5ah batteries and connect them in series.

 

The bike generator is only 6W. You need hundreds of Watts. The little generator will fry but the scooter won't move.


Besides, something must use a lot of power to drive a generator. It gets hot so it actually uses more power than it provides. So it wastes power instead of increasing the power.

It would have also been a waste of time and some $$. Thanks for the info.

the most efficient way that we can get 24v out of a 12v 35ah battery (it will become 24v 17.5ah, the law of the conservation of energy), is to find 2 12v 17.5ah batteries and connect them in series.

My scooter uses two 12V 15AH batteries. Consequently, the increase of 2.5AH will probably be insignificant. However, thank you for presenting me with another option.

You might consider a moderate battery upgrade; ie: increasing from 12AH to 20AH or 25AH batteries. You will still have a net weight gain, but it will be less than the 35AH batteries.

Note that both batteries should have the same AH rating; you wouldn't want to mix a 20AH with a 12AH.

This is an idea that I’m ready to try. I can currently go about 5 miles on 24V 15AH. That averages to approximately 1/3 of a mile per AH (if I did my math correctly). The 20AH batteries (28 1bs total) will only get me a little over 6 ½ miles. The 26 AH batteries (38.5 1bs total) will get me to 8 ½ miles. I did not include the extra weight of the batteries. It seems that the 26AH batteries would be my best option with my current motor.

However, your original suggestion gives me the longest ride time for the $$$:

SLA batteries are designed for deep-cycle type loads. Here's one that's 12V 35ah, but weighs 25lbs:
http://www.batterywholesale.com/battery-store/proddetail.html?prodID=380

You do need to keep in mind the maximum safe load for the scooter, and of course the size of the batteries…. Well, how much do the original batteries weigh? If you replace them with the new batteries, you can deduct the weight of the originals from the new batteries!

Since I liked the above suggestions, I put 50-pounds of my weight set (that was collecting dust and cobwebs) on my scooter because using two of the suggested batteries will total the same weight. I didn’t feel comfortable with the extra weight. I also realized that the scooter would be unable to pull me up an incline—which it can barely do now.

When I added the extra 50 1bs to my scooter, I forgot to deduct the weight of the batteries that are on it as you had suggested (about 20 lbs). I should have only placed 30 lbs of extra weight on my scooter—a big difference when you’re near the maximum weight it can carry. Unfortunately, I know the motor will still be unable to pull me up the inclines that I encounter while riding and it will go slower (I can’t keep up with my son now). I know it would also struggle with the additional weight of the 26AH batteries. Consequently, I’m seriously considering upgrading to a stronger 24V motor. I found this one:

http://www.thesuperkids.com/600wabrcuels.html

It’s 600 watts, which gives me 100 watts more than I currently have. It also requires more amps (36). It comes with a 40 amp controller (my scooter motor is 500 watts and comes with a 25 amp controller). It states that this motor does not use more power. I don’t understand how I could travel the same distance with this motor and not use more power than my current motor. Can some explain this to me before I buy it? If this is true, I have to assume that the 35AH batteries are sufficient….

My other option is this 1000 watt 36V motor that can run on 24 volts at 666.6 watts, and it’s only $40 more in price.

http://www.thesuperkids.com/10wabrmofors.html

This motor will give me 66.6 watts more than the 24V 600 watt motor. Furthermore, I have the option to add another battery and get the maximum 1000 watts. It also sates that this motor does not use more battery power. How can a 1000 watt motor running at 666.6 watts on a 24V system not use more battery power than a 500 watt or 600 watt motor? There must be a theory that someone can enlighten me with before I spend my $$$ on these scooter upgrades? If the 1000 watt and 600 watt motors don’t use additional battery power, which motor should I buy for a 24V 35AH system?

Thank you.

 

I need some additional help. The info that I previously posted about the scooter is incorrect. I found out that the scooter actually has a 24v 30 amp controller (not 25 amps) when I removed the original batteries, which weighed 20 pounds. I called the manufacturer and also found out that I have a 750 watt motor instead of a 500 watt motor (the info that came with the scooter was for a previous model). From reading some electronics info, I’ve learned that power = volts x amperes. My scooter was using two 12 volt 15 AH batteries—24 X 15 = 360.

Does this mean that the motor was only running on 360 watts?

If I get two of the suggested 35 AH batteries, will the power increase to 720 watts since the controller is 30amps—24 x 30 = 720?

I need to know because I was about to order a stronger motor for my scooter. From what I understand, I was running on less than half the power of the motor. Therefore, I shouldn’t need a stronger motor if I was using less than half of the original motor’s power.

If I’m wrong, please correct me.

Thank you.

 

You lucky Devildog, you!

Forget about ordering the new motor or another controller. Sounds like the 35AH batteries will be a very good match for your existing controller & motor.

The 35AH rating won't increase the top speed your scooter has - but they will keep it going about twice as long as the 15AH batteries. Don't forget, the additional weight will decrease your range somewhat, particularly if you live in an area with hills. Try keeping your tires inflated close to their maximum ratings - but watch for potholes and debris on the roadways. Tires get damaged more easily if they're run at higher pressures with high loads.

You might have a look at the controller to see what kind of transistors (likely power MOSFETS or IGBTs) they used. It may be possible to upgrade them.

 

Thanks for the reply. Are my calculations correct?

My scooter was using two 12 volt 15 AH batteries—24 X 15 = 360.

Does this mean that the motor was only running on 360 watts?

If I get two of the suggested 35 AH batteries, will the power increase to 720 watts since the controller is 30amps—24 x 30 = 720?

I’m going to need the extra power to pull me up the inclines that I encounter on the trail my son and I ride. I also need the extra power for the additional 30 pounds of the 35 AH batteries.

You might have a look at the controller to see what kind of transistors (likely power MOSFETS or IGBTs) they used. It may be possible to upgrade them.

Here’s a link to the controller that I think is on the scooter:

http://www.thesuperkids.com/30coforscgtm.html

I’m assuming it’s a 30 amp controller because this is the model number—24 30 (24 volts 30 amps I'm assuming).

I could possible upgrade to this controller:

http://www.thesuperkids.com/cu40co.html

However, I’ll see how the scooter runs with the original controller.

I’m also having a problem coming up with a way to mount the 35 AH batteries. The only idea that I’ve thought of is using a plastic toolbox that’s big enough to hold both batteries.

 

Wait a minute - on the page you linked to, it says the 30 Amp model is specifically for all 250 & 350 Watt Motors - and yours is a 750 Watt motor? In other words, they're using a 30 Amp model for a 14.58 Ampere load. Wonder Watt (sic) the story is?

Well, does your controller get warm at all?

Going for the higher-rated controller would mean that less power would be dissipated/lost in it. It's probably a PWM controller that uses power MOSFETs. The better the MOSFET for your application, the lower it's internal resistance when it's ON. Some of those MOSFETS even in a TO-220 case can handle up to around 70 Amperes.

Mounting the batteries - well, you sure need to keep those suckers tied down to the scooter. I've seen nice plastic battery holders at boat supply places, but those might be a bit large for your application. You don't want them to be able to bounce around at all, as the battery plates will get damaged really quickly.

A while back, I bought some grey closed-cell foam runner semi-gloss mat material from my local Home Depot - they cut it off a roll. It's designed to be fairly non-skid and feels cushy when you're standing on it. That would be a good material to use to cushion your batteries inside a container to keep them from banging around. It was around a couple bucks per foot.

Then you could strap the container down using bungee cords. Or get a couple of ammo cans, bolt them to the scooter chassis (try to keep the center of gravity low and aft of amidships for better handling/braking), line the cans with foam, and drill holes/install grommets for the wires to pass through. Army/Navy stores generally have ammo cans as well as webbing material - you can get mighty creative with that stuff.

Then again, just pick up a few rolls of ordie tape, and go to town

 

Does this mean that the motor was only running on 360 watts?

I don't think that's the case.
Remember its 15 AH. That is the measure of the energy stored in the battery.
More appropriately its the measure of charge in battery.
It can run for 15 A for some time or at 30 A for half of that time.

The watts(power..which is the rate at which energy is used) a source provides depends on the load on it..If the load demands more power, larger current flows from the battery, whether or not the battery can handle it or not is another story.
meaning a 700 watts motor if, running at that wattage(which depends on the amount of load you are making it handle i;e more speed, more weight,work against gravity,etc.) will require that much power from battery.In short larger power motor if running at its designed wattage will drain you battery faster.

35 AH battery will also provide same current(If the voltage is same) that the 15 AH was providing. Just that it will last +1.33 times longer.You can check this with an ammeter.

Good thing you found out the motor's actual rating else you might have replaced it with 600 watts(this will have increase the time battery wud have lasted though) and then wonder, why is it going slower?

A more powerful motor IS 'more powerful' meaning it requires more power..Unless the motor is so efficient that it demands the same power that a less powerful one previously required( and believe me, no level of designing/technology can make a 1000 watt require as much power as the 500 W motor required) (also that is the case if the rating of motor is the 'shaft power' ..i'll have to confirm whether a motor is rated for I/p--which should be electrical in KVA or o/p ---max power available at shaft..for which KW rating is correct)

 

35 AH battery will also provide same current(If the voltage is same) that the 15 AH was providing. Just that it will last +1.33 times longer.You can check this with an ammeter.
correct)

I don’t understand…. I can get 35 amps from a 15 AH battery, but I can’t get 24 Volts from a 12 Volt battery. I need to do some more studying.

Thanks for the explanation.

Wait a minute - on the page you linked to, it says the 30 Amp model is specifically for all 250 & 350 Watt Motors - and yours is a 750 Watt motor? In other words, they're using a 30 Amp model for a 14.58 Ampere load. Wonder Watt (sic) the story is?

I called the manufacturer again, and it was confirmed that my 24 Volt 30 Amp controller is from another model. Now here’s another twist to this scooter story—I discovered that the 750 watt motor on my scooter is also used on a 36 Volt 25 Amp model of the same scooter (it’s also called the s750). I was told that my scooter could be upgraded to the 36 Volt 25 Amp version if I install this controller:

http://www.monsterscooterparts.com/cu36v25a5co6.html

However, I would need three batteries. Three 12 Volt 26 AH batteries would weigh about 58 pounds (2 pounds below the max weight of the batteries that I can put on the scooter. Three 20 AH batteries would weigh 42 pounds.

My other option is to install this 24 Volt 35 Amp controller:

http://www.monsterscooterparts.com/cu24v35a5col.html


I don’t know if the extra 5 Amps is worth the extra money.

Consequently, which system would provide the most power for my 750 watt motor? Furthermore, which system will provide me with the longest ride?

A. 24 Volt 30 Amp controller with two 35 AH batteries

B. 24 Volt 35 Amp controller with two 35 AH batteries

C. 36 Volt 25 Amp controller with three 26 AH batteries

D. 36 Volt 25 Amp controller with three 20 AH batteries

These are the only options that I could come up with. Please comment on which option is the best or provide another option that I can consider.

Thank you.

 

I don’t understand…. I can get 35 amps from a 15 AH battery, but I can’t get 24 Volts from a 12 Volt battery. I need to do some more studying.

Think of "Amperes" as a rate - akin to miles per hour. (Amps are actually "Coulombs per second, but don't think too hard about that just yet.) Think of "Amp-hours" as being sort of like miles. Sort of.

Voltage, on the other hand, is more like weight. It is a steady force.

 

Ahh, wait a sec
Let's try this from an analogy standpoint.
Current = volume
Voltage = pressure
An analogy to a high-voltage low-current circuit would be a sweeper nozzle attached to a garden hose. The high pressure causes a stream of water to travel quite a ways. A firehose is a more extreme example.

An analogy to a low-voltage high-current circuit would be the Mississippi River. Lots of water flowing at a (generally) slow pace (unless it's flood season - even then, the flow rate is relatively slow. I'm sure a number of residents along it's banks may disagree with me.)

If you used three 12v 26ah batteries in series, you would have a higher top speed than you would with two 12v 35ah batteries; exactly how much higher depends upon a number of factors like rolling resistance, wind resistance, and inclines (hills). The faster you go, the more wind resistance comes into play. It takes considerably more horsepower to move a given weight up an incline quickly than it does to move it up the same incline slowly. 1 horsepower = 745.7 watts, or 33,000 foot-pounds per minute.

The higher top speed comes at a sacrifice; a decrease in range due to increased power demand. If you keep your speed down (particularly going uphill or against the wind), you'll get a good bit more distance.

With two 12V 36ah batteries, you won't get the top speed you would with the three batteries.

If you manage your power usage, you should be able to get more miles with the three 26ah batteries than you would with the two 35ah batteries. That is, unless you try to keep up with your speed-demon kid.

 

I don’t understand…. I can get 35 amps from a 15 AH battery, but I can’t get 24 Volts from a 12 Volt battery. I need to do some more studying.

Again remember its 15 Ah...In a way that is the energy available...It is not the current rating...

An Ideal voltage source where the voltage is constant will provide current based only on the load (which depends on the system resistance.) So theoretically a 1 volt battery will still provide 150000 A if a load of 150000KW(resistance in circuit =6.67x10^-6) was connected to it...OHM's Law : V/R = I...
Whether the source can handle that much is another story dealing with metallurgical considerations....
How long wud this battery last?
If its a small battery with only a small energy capacity say 0.1 Ah, then..
0.1 Ah = 3600 coulombs,
1 A = 1 coulomb/ sec...150000A= 150000 coulombs/sec..
hence,time which it will last
= Ah/A = 3600/150000= .024 sec


Electric potential(voltage) is the potential in the source to move a charge...
Consider it as potential in a body at hight 100m...and current as the speed at which it falls. If the air resistance(resistance in circuit) to it while falling was quite large the speed(current) would be less. But if the air resistance was less the speed will be quite large. But certainly the air resistance won't raise the hight(potential) of the body, will it?

 

Recca02,
While your math does have merit, you're leaving out something very important; that is the battery's internal resistance.

Hate to confuse things.... but batteries are more than just a source of power; they also have an internal resistance.

This is what causes batteries to heat up as power is drawn from them; the current flow across the internal resistance. At low levels of current flow, it's not very significant. As current flow increases, the resistance becomes more of a factor. In an extreme case, such as the battery terminals being shorted together, ALL of the power of the battery will be dropped across the internal resistance of the battery, very likely resulting in an explosion.

 

Recca02,
While your math does have merit, you're leaving out something very important; that is the battery's internal resistance.

Hate to confuse things.... but batteries are more than just a source of power; they also have an internal resistance.

This is what causes batteries to heat up as power is drawn from them; the current flow across the internal resistance. At low levels of current flow, it's not very significant. As current flow increases, the resistance becomes more of a factor. In an extreme case, such as the battery terminals being shorted together, ALL of the power of the battery will be dropped across the internal resistance of the battery, very likely resulting in an explosion.

I agree, that is why I made it a point to describe the voltage source as an ideal one. Nothing is free of resistance..not even a good political move

Referring to a practical battery source would have become a problem for discussion as even the battery voltages don't remain constant..This is exactly why I think first things start out with assumptions of ideal cases.

 

Check out 4 or 5 window's,lot's of info.