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What batteries do I need?

 

I¡¯m not very clear on how amps and amp hours work.
Ultimately I looking for a clear answer.
I have an all original Comutacars.
I would love to go the 38mph and 40 mile range.


But don¡¯t want to spend $200 or 300. Per. Battery.

Feel free to explain what I¡¯m looking for or provide a link of what I need.

Thanks in advance.
 

I can explain Amps and Amp-hours, to get you started.

TL;DR: Amps is basically how much torque the car is producing. The more amps it can draw, the more tourque it can produce. Amp Hours is range--the more AH, the further you go.

Now for a more detailed explanation.

Power is measured in Watts (W). When you get large numbers of watts, (like over 1 horsepower's worth), it's measured in Kilowatts (KW). For example, the motor in the 6HP ComutaCar is rated for 6000W, or 6KW. That's actually 8HP, but it probably isn't 100% efficient--thus the 6HP rating.

Watts is volts times amps. The ComutaCar uses a 48V battery system, but the number of amps it draws varies a lot depending on if you're accelerating, coasting, or going up a hill.

To understand voltage and amperage a little better, let's imagine power (in watts) as a river. The speed of the water in the river is like the voltage--how fast it's going. The amperage is how wide the river is, or how much volume of water there is flowing.

Thus, a large, slow river is like a low-voltage, high amperage. A small waterfall would be more high-voltage, low amperage.

This explanation is in no way scientific, but it seems to help.

Another way to look at volts and amps, specifically relating to motors:

Volts is how fast the motor can go: The more volts, the faster it goes.
Amps is how strong the motor is (how much torque it has): The more amps it can draw, the stronger it is.

One thing to know: The motor can only draw as many volts as the batteries supply--but the number of amps is usually completely variable. If the car is rolling down a hill, expect very few amps drawn. If you're going up the next hill, expect hundreds of amps drawn. The motor will (try to) draw as many amps as it needs to keep up to speed.

Now that that's all out of the way, we can look at Amp Hours (AH).

AH is a rating for batteries, and it means how many amps the battery can supply for an hour.
For example, let's say I have a 10AH battery.

If I connect it to a motor that draws exactly 10A, it will run for an hour before needing recharged. If my motor only draws 5A, it will run for two hours--and so on.

Note that the AH rating is not how many amps the battery can output--so, despite my battery being rated for 10AH, I could probably pull 30A from it--it would just last only 1/3 of an hour.

Hopefully that helps clear up the mystery around Watts, Volts, Amps, and Amp-Hours!


- Jacob Field
1980 Gold ComutaCar
 

Price is what you can find... But I have interstate gc2-ecl-utl. 115 min @75a 225ah@20 hrs. On my 6hp dana I can get 38mph max. Depending bon tire pressure. 40 miles is my ablsoute max. That can vary depending on many things, wind, temp, braking, tire pressure,passenger, phase of moon, mood I'm in.

It's the farthest my batteries take me safely, but it is dangerous close and no big hill at the end.??

On Sat, Apr 20, 2019, 3:57 PM justinbreal87@... [C-Car] <C-Car@...> wrote:
?

I¡¯m not very clear on how amps and amp hours work.
Ultimately I looking for a clear answer.
I have an all original Comutacars.
I would love to go the 38mph and 40 mile range.

But don¡¯t want to spend $200 or 300. Per. Battery.

Feel free to explain what I¡¯m looking for or provide a link of what I need.

Thanks in advance.

 

¿ªÔÆÌåÓý

Dave,?
? ?Great to see this form blow up with conversations! I have read most of these posts, you mentioned you installed and altrax 48600 controller. I'm about to do the same, I still have the original three phase contact system in my 1980 Comuta-car. I'm a bit confused about wiring the new system with a new? pb 6 throttle, new main contactor, f/r contactor (new or keep original) , and last but not least, where to put the charging leads. I'll dig more into it when the parts come in but if you had some pointers or drawings, that would be great.
? ? ?Thanks a bunch!?
Cheers?
Tony



Tony Perreault?


-------- Original message --------
From: "Dave Brice dbrice3721@... [C-Car]"
Date: 4/20/19 1:49 PM (GMT-08:00)
To: C-Car@...
Subject: Re: [C-Car] What batteries do I need?

?

Price is what you can find... But I have interstate gc2-ecl-utl. 115 min @75a 225ah@20 hrs. On my 6hp dana I can get 38mph max. Depending bon tire pressure. 40 miles is my ablsoute max. That can vary depending on many things, wind, temp, braking, tire pressure,passenger, phase of moon, mood I'm in.

It's the farthest my batteries take me safely, but it is dangerous close and no big hill at the end.??

On Sat, Apr 20, 2019, 3:57 PM justinbreal87@... [C-Car] <C-Car@...> wrote:
?

I¡¯m not very clear on how amps and amp hours work.
Ultimately I looking for a clear answer.
I have an all original Comutacars.
I would love to go the 38mph and 40 mile range.

But don¡¯t want to spend $200 or 300. Per. Battery.

Feel free to explain what I¡¯m looking for or provide a link of what I need.

Thanks in advance.

 

I don't have any drawings, I just used alltrax directions... But, the f/r contactor needs some rewiring on the control side. I have it set up so the keyswitch runs a solenoid ( I used my old solenoid from the resistor circuits) basically it has a 12v coil. So keyswitch turns it "on". The secondary circuit I have it switching 48v for the alltrax to turn on, and for the footswitch on the pb-6. That runs back to the alltrax. 2nd thing to do is to change the wiring so that fnr contactor actually switches with the switch, rather than the switch then the gas pedal. The goal is to have key on, and when fnr is selected the contacts move.? The new main solenoid does the footswitch now, not the fnr solenoid. Confused?? Let me know and I'll try and clear up any questions. I attached a couple pics of how it looks.?

On Sun, Apr 21, 2019, 1:17 PM Tony Perreault tony_399@... [C-Car] <C-Car@...> wrote:
?

Dave,?
? ?Great to see this form blow up with conversations! I have read most of these posts, you mentioned you installed and altrax 48600 controller. I'm about to do the same, I still have the original three phase contact system in my 1980 Comuta-car. I'm a bit confused about wiring the new system with a new? pb 6 throttle, new main contactor, f/r contactor (new or keep original) , and last but not least, where to put the charging leads. I'll dig more into it when the parts come in but if you had some pointers or drawings, that would be great.
? ? ?Thanks a bunch!?
Cheers?
Tony



Tony Perreault?


-------- Original message --------
From: "Dave Brice dbrice3721@... [C-Car]" <C-Car@...>
Date: 4/20/19 1:49 PM (GMT-08:00)
Subject: Re: [C-Car] What batteries do I need?

?

Price is what you can find... But I have interstate gc2-ecl-utl. 115 min @75a 225ah@20 hrs. On my 6hp dana I can get 38mph max. Depending bon tire pressure. 40 miles is my ablsoute max. That can vary depending on many things, wind, temp, braking, tire pressure,passenger, phase of moon, mood I'm in.

It's the farthest my batteries take me safely, but it is dangerous close and no big hill at the end.??

On Sat, Apr 20, 2019, 3:57 PM justinbreal87@... [C-Car] <C-Car@...> wrote:
?

I¡¯m not very clear on how amps and amp hours work.
Ultimately I looking for a clear answer.
I have an all original Comutacars.
I would love to go the 38mph and 40 mile range.

But don¡¯t want to spend $200 or 300. Per. Battery.

Feel free to explain what I¡¯m looking for or provide a link of what I need.

Thanks in advance.


On Sun, Apr 21, 2019, 1:17 PM Tony Perreault tony_399@... [C-Car] <C-Car@...> wrote:
?

Dave,?
? ?Great to see this form blow up with conversations! I have read most of these posts, you mentioned you installed and altrax 48600 controller. I'm about to do the same, I still have the original three phase contact system in my 1980 Comuta-car. I'm a bit confused about wiring the new system with a new? pb 6 throttle, new main contactor, f/r contactor (new or keep original) , and last but not least, where to put the charging leads. I'll dig more into it when the parts come in but if you had some pointers or drawings, that would be great.
? ? ?Thanks a bunch!?
Cheers?
Tony



Tony Perreault?


-------- Original message --------
From: "Dave Brice dbrice3721@... [C-Car]" <C-Car@...>
Date: 4/20/19 1:49 PM (GMT-08:00)
Subject: Re: [C-Car] What batteries do I need?

?

Price is what you can find... But I have interstate gc2-ecl-utl. 115 min @75a 225ah@20 hrs. On my 6hp dana I can get 38mph max. Depending bon tire pressure. 40 miles is my ablsoute max. That can vary depending on many things, wind, temp, braking, tire pressure,passenger, phase of moon, mood I'm in.

It's the farthest my batteries take me safely, but it is dangerous close and no big hill at the end.??

On Sat, Apr 20, 2019, 3:57 PM justinbreal87@... [C-Car] <C-Car@...> wrote:
?

I¡¯m not very clear on how amps and amp hours work.
Ultimately I looking for a clear answer.
I have an all original Comutacars.
I would love to go the 38mph and 40 mile range.

But don¡¯t want to spend $200 or 300. Per. Battery.

Feel free to explain what I¡¯m looking for or provide a link of what I need.

Thanks in advance.

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