36v to 48v conversion

[sms-shop]

Originally Posted by sunking

OK there is only one real way to do that. Just like a car you need a bigger gas tank. For an electric vehicle that means more battery capacity.

So do not let anyone fool you going from say 6 volt to 8 volt batteries is going to increase your mileage as the exact opposite is true.

Batteries have 2 key numbers you need to pay attention to:

• Voltage
• Amp Hours

Here is the deal. Battery capacity or electrical energy is expressed in Watt Hours. To get a rough idea of how much energy a battery contains, multiply the rated battery Voltage by the rated Amp Hours.
So let's look at 2 examples a Trojan T-105 (6 volt battery) and T-875 (8 volt battery.

A T-105 is rated 6 volts @ 225 Amp Hours. It takes 8 batteries to get 48 volts @ 225 Amp Hours. Use the formula of Volts x Amp Hours and you get 48 volts x 225 AH = 10,800 watt hours

OK now let's use T-875's in a 48 volt cart. It takes 6 8 volt batteries to get 48 volts. A T-875 is rated 8 volts @ 175 AH. So 48 volts x 175 AH = 8400 watt hours.

So which has more energy? 10,800 or 8400?

Simple huh?

Here we go again baffling with the bull sh!t again......

[scottyb]

Originally Posted by sms-shop

Here we go again baffling with the bull sh!t again......

NoShit ..... Now we just need to know how far a cart will go on a watt hour with 23" tires in muddy hill country

[e-z-go1988]

Originally Posted by sunking

OK there is only one real way to do that. Just like a car you need a bigger gas tank. For an electric vehicle that means more battery capacity.

So do not let anyone fool you going from say 6 volt to 8 volt batteries is going to increase your mileage as the exact opposite is true.

Batteries have 2 key numbers you need to pay attention to:

• Voltage
• Amp Hours

Here is the deal. Battery capacity or electrical energy is expressed in Watt Hours. To get a rough idea of how much energy a battery contains, multiply the rated battery Voltage by the rated Amp Hours.
So let's look at 2 examples a Trojan T-105 (6 volt battery) and T-875 (8 volt battery.

A T-105 is rated 6 volts @ 225 Amp Hours. It takes 8 batteries to get 48 volts @ 225 Amp Hours. Use the formula of Volts x Amp Hours and you get 48 volts x 225 AH = 10,800 watt hours

OK now let's use T-875's in a 48 volt cart. It takes 6 8 volt batteries to get 48 volts. A T-875 is rated 8 volts @ 175 AH. So 48 volts x 175 AH = 8400 watt hours.

So which has more energy? 10,800 or 8400?

Simple huh?

Ok!!
746W = 1HP
10800 WH /746W = 14.46
14.46 / 8.3HP motor (in my cart) = 1.74H (1 hour and 45 min)
So if I am using all my available HP then I should get approx 1 hour and 45 min of pedal time?
Simple huh?

[dereckbc]

Originally Posted by scottyb

NoShit ..... Now we just need to know how far a cart will go on a watt hour with 23" tires in muddy hill country

Well I see things have not changed here in the last year since I last posted. Same few people who have no knowledge of electical principles or simple math formulas and feel threatened by those who actually work in the industry and have the experience to answer intelligently with sound advise. Ow well boys will be boys. Mine is bigger than yours.

[dereckbc]

Originally Posted by e-z-go1988

Ok!!
746W = 1HP
10800 WH /746W = 14.46
14.46 / 8.3HP motor (in my cart) = 1.74H (1 hour and 45 min)
So if I am using all my available HP then I should get approx 1 hour and 45 min of pedal time?
Simple huh?

WH / W = H

10,800 WH / 746 W = 14.46 Hours to 100% DOD

But of course no one would run a battery down to 100% DOD, and you assume the motor is 100% effecient which it is only 75% so 1 HP = 746
W / .75 = 994 watts.

But any electrical engineer who works in the EV field knows you do not measure run time by the wattage alone. They use the Peukert Law and battery to wheel effeciency of the vehicle. So taking Peukert Law a 6 Trojan-T-105's have a capacity of 10.8 Kwh derated by .6 = 6.48 Kwh capactity at a C8 discharge rate. So that gives you about 3.2 Kwh if discharged to 50% DOD. So with a battery to wheel effeciency of 150 wh/mile gives you about 3.2 Kwh / 175 wh / mile is around 18 miles assuming a flat level hard surface.

So how is that for baffling BS?

[dereckbc]

Originally Posted by e-z-go1988

Ok!!
746W = 1HP
10800 WH /746W = 14.46
14.46 / 8.3HP motor (in my cart) = 1.74H (1 hour and 45 min)
So if I am using all my available HP then I should get approx 1 hour and 45 min of pedal time?
Simple huh?

WH / W = H

10,800 WH / 746 W = 14.46 Hours to 100% DOD

But of course no one would run a battery down to 100% DOD, and you assume the motor is 100% effecient which it is only 75% so 1 HP = 746
W / .75 = 994 watts.

But any electrical engineer who works in the EV field knows you do not measure run time by maximum wattage. They use the Peukert Law and battery to wheel effeciency of the vehicle. So taking Peukert Law 8 Trojan-T-105's have a capacity of 10.8 Kwh derated by .6 = 6.48 Kwh capactity at a C8 discharge rate. So that gives you about 3.2 Kwh if discharged to 50% DOD. So with a battery to wheel effeciency of 150 wh/mile gives you about 3.2 Kwh / 175 wh / mile is around 18 miles assuming a flat level hard surface. So if your buggy goes 14 MPH, than about 1.5 to 2 hours.

So how is that for baffling BS?

[gornoman]

Originally Posted by dereckbc

Well I see things have not changed here in the last year since I last posted. Same few people who have no knowledge of electical principles or simple math formulas and feel threatened by those who actually work in the industry and have the experience to answer intelligently with sound advise. Ow well boys will be boys. Mine is bigger than yours.

It's one thing to work with electricity, and quite another to make these carts do what we want them to do. Your principals and formulas don't always apply to what happens when the pedal goes down. The guys you so easily dismiss have actually built carts that can do some amazing things. These same guys have been there and done that, with actual carts. They have learned from DOING, not simply going to school or working in a related industry. They win awards and set records, all by their own hands and efforts. Then guys like you come along, swing their dicks over their shoulders and quote Ohm's law. Please, until you have built and can display and PROVE your efforts, don't come here and trash the experts who give freely of their time and energy. Until then, it's simply hot air..........and there is a stiff breeze blowing today.

[kdeerman]

CamoCart,

LOOK WHAT YOU STARTED!!

[dereckbc]

Originally Posted by gornoman

It's one thing to work with electricity, and quite another to make these carts do what we want them to do. Your principals and formulas don't always apply to what happens when the pedal goes down. The guys you so easily dismiss have actually built carts that can do some amazing things.

I understand that, but you fail to realize I design, build, and test EV's for a living for the last 2 year, and 30 years experience in industrial motors and controls as an engineer. So I might know something.

It is a shame you as a moderator support such bashing of newbs who could bring a lot to this forum. You guys seem more intent on running off folks than building a memebership. It is a Good Ole Boy Network where only a few are allowed to answer without ridicule huh? Your egos get in the way. If you relly want to get good sound info on the EV filed I suggest you look at this forum. It is made up from professionals in the EV industry. You might be surprized and learn something from folks who are designing the EV's of today and tommorow.

[cdb770]

Originally Posted by dereckbc

I understand that, but you fail to realize I design, build, and test EV's for a living for the last 2 year, and 30 years experience in industrial motors and controls as an engineer. So I might know something.

It is a shame you as a moderator support such bashing of newbs who could bring a lot to this forum. You guys seem more intent on running off folks than building a memebership. It is a Good Ole Boy Network where only a few are allowed to answer without ridicule huh? Your egos get in the way. If you relly want to get good sound info on the EV filed I suggest you look at this forum. It is made up from professionals in the EV industry. You might be surprized and learn something from folks who are designing the EV's of today and tommorow.

Oh no, another Engineering God! I have been in the aviation industry for 16 years now, I don't know it all and ask questions quite frequently. My opinion of engineers is that they design most applications like they will never break, not sure if it is the God complex most of them have in thinking what "they create" will never be worked on, or broken ever in the history of time. But, I think that if you have helpful infomation you should always share it, but never make people feel like they are stupid for not knowing something! Why must you point to another site like this one is for the handicaped individuals? If you didn't like the board you wouldn't be on here to begin with, or are you just visiting with the little people?