# right scheme?



## Ziggythewiz (May 16, 2010)

The reverse swich goes wherever you want to switch it.

Voltmeter connects to each end of your battery pack. Mine is on a shunt on the controller side of the contactor, and on the negative battery terminal.

Assuming it's a shunt type ammeter, it goes on the shunt.

A DC-DC connects to the AUX batt, and may need a diode and inductor to protect itself. Several threads on the topic.

Your battery pack needs to have each end connected to the controller. As shown you're only using one battery.


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## PStechPaul (May 1, 2012)

The schematic looks pretty good, although there may be some mistakes. The negative lead for the controller needs to connect to the last battery to get 48 VDC. And I'm not sure about the on/off switch - where it's located it would need to switch 600A and 48V. If it's the emergency switch or main pack disconnect then it's OK. I don't see a shunt for the ammeter. It will probably go on the negative side of the battery pack to the controller. And it may need to be isolated, or at least have small properly rated fuses in both leads to the meter.










You need to check the wiring diagram for the controller to find out how to connect the reverse. It may just go to the controller common.

BTW, to show the image, you need to get the JPG. You can right-click on the image and select properties which shows the JPG and then copy/paste into the IMG tags.


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## poprock (Apr 29, 2010)

Any chance of a picture of the Daihatsu?


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## rico12410 (Nov 23, 2012)

Thank you guys..
You are most helpful..

I have revised the scheme
sorry PStechPaul, I could not paste the picture straight to the page.. have search many ways 








http://www.freeimagehosting.net/gzh4p

What is the amperage I should use for the meters?

Ziggy: "A DC-DC connects to the AUX batt, and may need a diode and inductor to protect itself."
OK, I will search for the post discussing this.

Paul, the ON/OFF switch is the main switch.. not only for the emergency situation.
Should there be another switch?

regarding the reverse switch, goldenmotor just show me this;








http://www.freeimagehosting.net/uq2sn

hope to hear from you guys again..
thank you..


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## rico12410 (Nov 23, 2012)

Poprock, you can see the trimobile here
http://www.facebook.com/photo.php?f...87867763.19844.120244814701697&type=1&theater

I made the fiberglass version of it.. hopefully will run on the electric motor
http://biobemo.tumblr.com/


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## PStechPaul (May 1, 2012)

You just need to use the following format:
http://www.freeimagehosting.net/newuploads/8o5we.jpg

And substitute the image identifiers:
http://www.freeimagehosting.net/newuploads/gzh4p.jpg











http://www.freeimagehosting.net/newuploads/uq2sn.jpg










The ammeter should connect to the shunt with two small fuses (like 1A 250V). The reverse switch (pin 9) should go to GND (pin 8). And I think your connection from B+ to the ON/OFF switch is wrong. Probably a switch closure to GND will turn the controller ON. There should be another heavy duty switch from the B+ to the controller as emergency disconnect. And the 600A fuse should be located as close as possible to the battery (+).


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## rico12410 (Nov 23, 2012)

Hello Paul and friends,

hereby my revised drawing.. I hope, I nailed it this time








http://www.freeimagehosting.net/hmk7i

please advise

Thank you very much guys


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## PStechPaul (May 1, 2012)

There are still some problems. I modified your JPG schematic to show what I think is best. The positive wire to the voltmeter may go anywhere on the battery (+) circuit, depending on what you want to measure. You might want it directly to the battery pack, where it will always show a reading even if the circuit is turned off, although it will present a slight drain on the battery pack. Or you may put it on the OUT side of the main contactor, where it will read only when energized. I added fuses on that circuit as well. 

The fuse to the ammeter was incorrectly placed. I moved it. And I also added a second 600A fuse to the battery pack (-). This might not be necessary. If the connection from the battery (-) is a straight shot to the controller, there is little chance of a short, and the fuse at the battery (+) terminal should provide the needed protection. If all the battery jumpers are also very short and direct, also no problem. 

Also the on/off switch for the controller should not be in series with the main battery circuit. It will be a small switch (probably a key switch) wired only to the controller approximately as shown.

It may be advisable to add fuses in the wires to the individual batteries from the charger, especially if they go through a wiring harness where a short may occur. You should consider every possibility of failure and protect against each, or understand the consequences and accept them.


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## rico12410 (Nov 23, 2012)

wow, thank you very much Paul!
I will study your schematic and update you (i hope) soon 
thank you very much.

ps: how big the fuse I should use between individual batteries and the chargers?
thx again


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## PStechPaul (May 1, 2012)

The fuse size should be about the same as your maximum charging current, and no larger than the current rating of the wire you use. For four batteries as shown, you can use just five wires with a fuse on each, and then branch off from the terminal block to the chargers with individual pairs, which would not need to be fused. Hopefully the chargers have their own protection.


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## rico12410 (Nov 23, 2012)

Hello Paul,
Thank you again 
I have revised the drawing (again) 








http://www.freeimagehosting.net/dab8v

I've changed the big fuses to 400 A, since I am going to use only 4 batteries @ 100aH. (so 4 x 100A = 400 A?)

Do I did it right for the terminal block? I am only using two chargers, and I put a switcher for them so I can choose one active charger or both. This is due to capacity of one charger is 500+Watts.

I have put the DC-to-DC converter also in there.. I am right connecting it?

Thanks a lot


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## PStechPaul (May 1, 2012)

It seems to be mostly correct, but I'm not sure about the 1A fuse from battery pack (-) to the DC-DC converter. That would be OK for up to 48W. Also, I think the fuse should go on the (+) side.

I don't know about the charger switching. You need to switch both leads so that they connect either to one battery or the other. A DPDT switch is what is needed.


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## iruraz (Sep 4, 2012)

@rico12410 , why did you use two chargers? Is it about capacity or necessity? And I wonder that why didn't use a bms?

Regards.


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## rico12410 (Nov 23, 2012)

Thank you very much Paul
I will revised it again soon.

..also I will search regarding DPDT switch

thank youuu



PStechPaul said:


> It seems to be mostly correct, but I'm not sure about the 1A fuse from battery pack (-) to the DC-DC converter. That would be OK for up to 48W. Also, I think the fuse should go on the (+) side.
> 
> I don't know about the charger switching. You need to switch both leads so that they connect either to one battery or the other. A DPDT switch is what is needed.


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## rico12410 (Nov 23, 2012)

Hi Iruraz,

I think it is about capacity and necesity..
I will drive the ev from my house which just has 800watt to the office which has 13.000Watt capacity.
the 20A charger I have needs 503 watt each.
so if I am charging in my house, and when it is almost full (in trickle charging mode), I can switch the second charger on.. so both chargers are active.

is this make sense? or I got it wrong?
I think, BMS would cost too much for me..

Thank you



iruraz said:


> @rico12410 , why did you use two chargers? Is it about capacity or necessity? And I wonder that why didn't use a bms?
> 
> Regards.


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## iruraz (Sep 4, 2012)

rico12410 said:


> so if I am charging in my house, and when it is almost full (in trickle charging mode), I can switch the second charger on.. so both chargers are active.
> 
> is this make sense? or I got it wrong?
> I think, BMS would cost too much for me..
> Thank you


I think it is make sense. I think it is depend your drive.

I have no idea about your charger usage because I have no much experience about chargers.

And I wonder your scheme editor. Which tools did you use to draw scheme?

Regards.


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## rico12410 (Nov 23, 2012)

Iruraz, I am using adobe illustrator to draw the scheme..


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## Ziggythewiz (May 16, 2010)

rico12410 said:


> I've changed the big fuses to 400 A, since I am going to use only 4 batteries @ 100aH. (so 4 x 100A = 400 A?)


4 batteries in series, providing 100A each, is only 100A total (but 4x the voltage).

Sizing your fuse depends on exactly what type you are using. For many of them you don't want to size it to the max amps, but somewhat above your average amps. A 400A fuse may take an hour to blow at 400A, and minutes at 60-800A. You have to look at the spec sheet and size appropriately for reasonable protection.


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## rico12410 (Nov 23, 2012)

Hi Ziggythewiz,

the specification said:
The peak input current: 300A
The peak output current (1 min): 600 A
Voltage of battery pack: 48 V

so how many amp should I use for the fuse?

thank you


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## Ziggythewiz (May 16, 2010)

rico12410 said:


> the specification said:


What specification? The controller?

What kind of fuse(s) are you looking at?


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## rico12410 (Nov 23, 2012)

yes, that is the spec for the controller..

what kind of fuse(s)?
please recomend.. i am in the dark for the many kind of fuses..
i thought, I just need to 'see' how big or small (the spec) of the fuse i need?




Ziggythewiz said:


> What specification? The controller?
> 
> What kind of fuse(s) are you looking at?


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## Ziggythewiz (May 16, 2010)

One style is the a50qs or a30qs

Here's the datasheet for the 30: http://www.discountfuse.com/v/vspfiles/downloadables/Ferraz/PDF/a30qs.pdf

For this one, you'd probably want somewhere around a 125A to 150A fuse, depending on what you think typical usage will be, and how you want the fuse to behave.

For example: I have a 400A controller. I usually pull up to 220A. Flooring it I would see > 300A for < 2 seconds. I could use a 125A fuse that would allow 350A for 2 seconds, so in the unlikely event my controller failed full on, I would just need to hold the brakes for a few seconds for the fuse to cut power (In case my manual cutoff didn't work/I panic etc).

Currently I have a 400A fuse that likely would never burn without a full pack short. I need to get a couple smaller ones for better protection.


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## rico12410 (Nov 23, 2012)

thank you for the datasheet..

wow.. but you I am sorry you lost me..
don't understand: "how I want the fuse behave"
i will drive mild

so for the controller in my last drawing, with;
--
The peak input current: 300A
The peak output current (1 min): 600 A
--
which fuse do you recommend?

thx




Ziggythewiz said:


> One style is the a50qs or a30qs
> 
> Here's the datasheet for the 30: http://www.discountfuse.com/v/vspfiles/downloadables/Ferraz/PDF/a30qs.pdf
> 
> ...


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## Ziggythewiz (May 16, 2010)

High current DC fuses are very different from the fast-acting fuses most people are accustomed to.

Your fuse is not going to protect your electronics, just your batteries and cabling.

How you size the fuse will determine if it acts as a slow-blow or really slow blow fuse in something less than a full short circuit. Even in a full short, it's possible the fuse wouldn't blow if the batteries can't put out enough current for the fuse to trip quickly.

For your system, to start with I'd recommend using a 150A fuse if using the style mentioned above, or one with a similar burn curve if you use a different brand. 

Then once your system's running you can get measurements for actual usage, and add an additional fuse with a lower rating if appropriate. That's what I need to do with mine.


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## rico12410 (Nov 23, 2012)

*finale?*

hello..

hereby is my last drawing for the daihatsu trimobile..

I just put one 20A charger for it to make the scheme simple 
hope anyone care to send input, before I blow anything.. 

thank you


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## rico12410 (Nov 23, 2012)

thank you ziggythewiz for your insight..
I will search and try your approach, start with 150A fuse

thank you


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## PStechPaul (May 1, 2012)

Hooray! 

I think your final schematic is OK. Good luck!


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## Ziggythewiz (May 16, 2010)

Is that charger specifically designed to charge 4 batts in parallel that are also connected in series? If not they're all shorted.


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## PStechPaul (May 1, 2012)

Ziggythewiz said:


> Is that charger specifically designed to charge 4 batts in parallel that are also connected in series? If not they're all shorted.


I assumed that it was one 12V charger that could be switched to each battery sequentially. That would require a 2P4T selector switch of appropriate rating. That would work, but is very inconvenient. Four separate chargers with isolated outputs would be a more practical solution, and a single 5 position connector could be used.


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## rico12410 (Nov 23, 2012)

thank you friends!
You guys rock and save my day 
To simplify I am not using switches and charge the four batteries with only one charger.







[http://www.freeimagehosting.net/qo7uc]

I hope this can be a final scheme?

thanks again guys


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## Ziggythewiz (May 16, 2010)

Looks good. One charger at the right voltage is the way to go.


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## rico12410 (Nov 23, 2012)

thank youu


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## rico12410 (Nov 23, 2012)

*update*

Hi friends,

Just want to update on my projects..
please visit biobemo.tumblr.com to see the progress..

Yesterday was the first day for the bemo see the outside world.
The controller reach 71 degress celcius not long after i failed to drive the vehicle on to a steep road.

I am searching for a solution to cool the controller.. or to find the mistake I did, which causing it.


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## Ziggythewiz (May 16, 2010)

*Re: update*

How much does your whole build weigh, and what is the controller rated for?


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## rico12410 (Nov 23, 2012)

Hi Ziggy,

I haven't find a DIY way to weight the vehicle.
I am guessing, is about 750 kg?

the controler is 48V rated for 600A

thx


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## Ziggythewiz (May 16, 2010)

How much power does it take to go up that hill? What speed? Gear? How many amps can the batts put out?

My bug's less than twice the weight of your bemo but has nearly triple the power and doesn't do great on a hill.


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## rico12410 (Nov 23, 2012)

Hello Ziggy,

The batteries put out 100Ah..

oo.. perhaps my bemo need bigger power (motor + controller)?


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## Ziggythewiz (May 16, 2010)

A battery can have a capacity of 100AH, but it's max current will be in Amps. Do you have an ammeter in the car?

Does your bemo have a transmission? If so, what kind of gearing options do you have?


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## rico12410 (Nov 23, 2012)

No It doesn't have amp meter yet..
i use a note book connected to the controller.
i will check..

The bemo apply direct-drive system.
I thought that will save some weight..
Because I got the bemo in used condition, I think I must take the axle apart and ask somebody who can tell me the size of the gear (final gear?).


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## Ziggythewiz (May 16, 2010)

That's the problem with direct drive. It's tough to get good acceleration (especially up a hill) and a good top speed. The guys who make it work usually have pretty high voltage systems.


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## rico12410 (Nov 23, 2012)

thx Ziggy for commenting..

Do you think, I should install the gearbox, although it add to the weight?

my intention is that the bemo could be an alternative mean of public transportation in the city. Hope fully, it could carry 7-8 passengers (adding 490-600Kgs)

thx


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## Ziggythewiz (May 16, 2010)

Yes, a transmission would be a good addition, but you will likely need more power as well. A transmission would weigh nothing compared to that many people.

If you're serious about getting a people mover safely up a hill, take the time to calculate the amount of power required to do so and see how your current system stacks up.


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## PStechPaul (May 1, 2012)

I have calculated that, for direct drive, you need an electric motor about three times the size of that which will work OK with a transmission. That was for an AC motor that has a peak torque of 2-3x, so a series DC motor might be able to put out much more, but at a severe cost to efficiency and service life, and for short durations only. You really want to keep the motor within its continuous specifications for most of the time, and use the peak power and torque for occasional acceleration and hill climbing. 

You can use http://enginuitysystems.com/EVCalculator.htm to help with calculations.

I just looked through your website http://biobemo.tumblr.com/ and the progress you have made is quite impressive! I had not realized that it is a small three-wheel utility truck. You might want to check out the details of some similar vehicles made by http://www.taylor-dunn.com/ as someone else plans to use for an electric tram retrofit. They may be direct drive, which is OK for such low speed (15 MPH), where the differential may be geared to a ratio that allows full motor RPM (~3000) for the top speed needed. But if you want to operate on the highway, you need at least 50 MPH capability. (Actually, I'd be a bit scared to drive that fast in a three-wheeler!)


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