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Discussion Starter · #1 ·
If I have 3 battery boxes, #1 48v(4 cells), #2 120v (10 cells) and #3
144v (12 cells)
Should I wire them so each box is a big battery and string them up
with a return cable? Or should I have each box split with the to and
from, so that there isn't a long return cable?
If I fuse each box can I use all fuses rated for 312v (should I use
400v fuse?) or do the fuses have to be different sizes depending on
where they are in the string?
would it be a good idea to have breakers instead so I can break up the
pack while performing maintenance?
With less than 300amp current draw what size cable should I use? Is
gauge 4 the same as AWG 4?

Thanks,
--
Tehben
'90 Toyota 4x4 Pickup
'hElix EV'
Website: www.helixev.com
evalbum: http://www.austinev.org/evalbum/1225

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Discussion Starter · #2 ·
Hello Tehben,

The ampere is going to be the same anywhere in the circuit when you cannot
these batteries up all in series.

Using fuses or circuit breakers, the ampere should at least be 125 percent
over the maximum amount you may use. The voltage of the fuse is at the
rated voltage that is use. If you have a 250 volt circuit, than a 250 volt
rating fuse will work.

Make sure you use DC fuses on a DC circuit. It does not matter if you use a
higher voltage fuse, unless the fuse size in the higher voltage may get too
large for installation.

In my EV, I use a 500 v Limitron rated fuses that is the size as a 12 volt
fuse. The fuse holders are all 600 v rated that accepts the same size fuse
down to 0.1 amp.

At one time, I had a battery box in the front and in the back. I used the
400 amp Anderson Connectors to connected these battery boxes in series and
have only one 400 amp semi-conductor fuse in the circuit.

Roland




----- Original Message -----
From: "Tehben Dean" <[email protected]>
To: "EV mail list" <[email protected]>
Sent: Friday, August 17, 2007 10:58 PM
Subject: [EVDL] wiring and fusing battery box?


> If I have 3 battery boxes, #1 48v(4 cells), #2 120v (10 cells) and #3
> 144v (12 cells)
> Should I wire them so each box is a big battery and string them up
> with a return cable? Or should I have each box split with the to and
> from, so that there isn't a long return cable?
> If I fuse each box can I use all fuses rated for 312v (should I use
> 400v fuse?) or do the fuses have to be different sizes depending on
> where they are in the string?
> would it be a good idea to have breakers instead so I can break up the
> pack while performing maintenance?
> With less than 300amp current draw what size cable should I use? Is
> gauge 4 the same as AWG 4?
>
> Thanks,
> --
> Tehben
> '90 Toyota 4x4 Pickup
> 'hElix EV'
> Website: www.helixev.com
> evalbum: http://www.austinev.org/evalbum/1225
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Discussion Starter · #3 ·
Hi Tehben,

A few comments inserted.......


--- Tehben Dean <[email protected]> wrote:

> If I have 3 battery boxes, #1 48v(4 cells), #2 120v
> (10 cells) and #3
> 144v (12 cells)

I think you mean "batteries" where you use "cells".

> Should I wire them so each box is a big battery and
> string them up
> with a return cable? Or should I have each box split
> with the to and
> from, so that there isn't a long return cable?

I'm not clear what you mean. But I would advise to
figure out cable runs to minimize total cable length
and maximize safety.

> If I fuse each box can I use all fuses rated for
> 312v (should I use
> 400v fuse?) or do the fuses have to be different
> sizes depending on
> where they are in the string?

I recommend a fuse in each battery compartment. That
way each is protected in case of an incident. And
each fuse must be rated for the total battery system
voltage and current.

> would it be a good idea to have breakers instead so
> I can break up the
> pack while performing maintenance?

Up to you. Breakers can be hard to come by or
expensive. I think Roland mentioned an Anderson
connector. Using a few of these in the right places
might be a good way to isolate battery boxes for
service.

> With less than 300amp current draw what size cable
> should I use?

Figure your average current and size it a for little
higher than that. Less than 300? Would that be 299?
Could be looking at 2/0 AWG. And remember, especially
if you have long cable runs, the larger gauge will
have less voltage drop. If you can afford it and it
fits in, bigger is better.

> Is
> gauge 4 the same as AWG 4?

Yeah, I think so. AWG stands for American Wire Gauge.
Most times you see "4 gauge" or "4 AWG". Which means
the same thing to me.

Hope this helps.

Don't see a lot of action on the old EVDL. EVerybody
must be at the races.

Jeff M

>
> Thanks,
> --
> Tehben
> '90 Toyota 4x4 Pickup
> 'hElix EV'
> Website: www.helixev.com
> evalbum: http://www.austinev.org/evalbum/1225
>




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Discussion Starter · #4 ·
> > If I have 3 battery boxes, #1 48v(4 cells), #2 120v
> > (10 cells) and #3
> > 144v (12 cells)
>
> I think you mean "batteries" where you use "cells".

Yep, sorry :)

>
> > Should I wire them so each box is a big battery and
> > string them up
> > with a return cable? Or should I have each box split
> > with the to and
> > from, so that there isn't a long return cable?
>
> I'm not clear what you mean. But I would advise to
> figure out cable runs to minimize total cable length
> and maximize safety.

Ok, ummm let me try to phrase that better.
If I have 3 boxes and treat them like 3 batteries and string them up
in series I will have the negative cable left over at the back of the
truck. WHich means a long run back to the controller.
But If I spit the two front boxes into 2 groups of batteries and
string one group in each box on the way to the rear box and then
string the other group on the way back to the controller I won't have
the long run.
>
> > If I fuse each box can I use all fuses rated for
> > 312v (should I use
> > 400v fuse?) or do the fuses have to be different
> > sizes depending on
> > where they are in the string?
>
> I recommend a fuse in each battery compartment. That
> way each is protected in case of an incident. And
> each fuse must be rated for the total battery system
> voltage and current.

So if I have a 48v battery and a 120v battery connected in series I
would use the same fuse for each box?

>
> > would it be a good idea to have breakers instead so
> > I can break up the
> > pack while performing maintenance?
>
> Up to you. Breakers can be hard to come by or
> expensive. I think Roland mentioned an Anderson
> connector. Using a few of these in the right places
> might be a good way to isolate battery boxes for
> service.

Do you have to worry about arcing when you plug and unplug anderson connectors?

>
> > With less than 300amp current draw what size cable
> > should I use?
>
> Figure your average current and size it a for little
> higher than that. Less than 300? Would that be 299?
> Could be looking at 2/0 AWG. And remember, especially
> if you have long cable runs, the larger gauge will
> have less voltage drop. If you can afford it and it
> fits in, bigger is better.

Well my controller says it has 282 max amp in. But with a heater and stuff...

> > Is
> > gauge 4 the same as AWG 4?
>
> Yeah, I think so. AWG stands for American Wire Gauge.
> Most times you see "4 gauge" or "4 AWG". Which means
> the same thing to me.



--
Tehben
'90 Toyota 4x4 Pickup
'hElix EV'
Website: www.helixev.com
evalbum: http://www.austinev.org/evalbum/1225

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
 

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70 Posts
Discussion Starter · #5 ·
Just so you know, the fuse's voltage rating is the voltage where it can
jump across the opening. So a 600V fuse could jump across the open
terminals at any voltage above 600 volts.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Roland Wiench
Sent: Saturday, August 18, 2007 9:22
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] wiring and fusing battery box?

Hello Tehben,

The ampere is going to be the same anywhere in the circuit when you
cannot these batteries up all in series.

Using fuses or circuit breakers, the ampere should at least be 125
percent over the maximum amount you may use. The voltage of the fuse is
at the rated voltage that is use. If you have a 250 volt circuit, than
a 250 volt rating fuse will work.

Make sure you use DC fuses on a DC circuit. It does not matter if you
use a higher voltage fuse, unless the fuse size in the higher voltage
may get too large for installation.

In my EV, I use a 500 v Limitron rated fuses that is the size as a 12
volt fuse. The fuse holders are all 600 v rated that accepts the same
size fuse down to 0.1 amp.

At one time, I had a battery box in the front and in the back. I used
the 400 amp Anderson Connectors to connected these battery boxes in
series and have only one 400 amp semi-conductor fuse in the circuit.

Roland




----- Original Message -----
From: "Tehben Dean" <[email protected]>
To: "EV mail list" <[email protected]>
Sent: Friday, August 17, 2007 10:58 PM
Subject: [EVDL] wiring and fusing battery box?


> If I have 3 battery boxes, #1 48v(4 cells), #2 120v (10 cells) and #3
> 144v (12 cells)
> Should I wire them so each box is a big battery and string them up
> with a return cable? Or should I have each box split with the to and
> from, so that there isn't a long return cable?
> If I fuse each box can I use all fuses rated for 312v (should I use
> 400v fuse?) or do the fuses have to be different sizes depending on
> where they are in the string?
> would it be a good idea to have breakers instead so I can break up the
> pack while performing maintenance?
> With less than 300amp current draw what size cable should I use? Is
> gauge 4 the same as AWG 4?
>
> Thanks,
> --
> Tehben
> '90 Toyota 4x4 Pickup
> 'hElix EV'
> Website: www.helixev.com
> evalbum: http://www.austinev.org/evalbum/1225
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

_______________________________________________
For subscription options, see
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Joined
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70 Posts
Discussion Starter · #6 ·
Jody - when you say "open terminals" do you mean with the fuse removed?
Because, often fuses of different voltage ratings will come in the same size
and shape, and fit in the same fuseholders.

I believe that a fuse's rating means that, if it blows at that voltage ( and
at its rated current, or less), it will succeed in opening the circuit. (
and, not arc within the fuse body)

Phil Marino

>From: "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[email protected]>
>Reply-To: Electric Vehicle Discussion List <[email protected]>
>To: "Electric Vehicle Discussion List" <[email protected]>
>Subject: Re: [EVDL] wiring and fusing battery box?
>Date: Mon, 20 Aug 2007 07:51:59 -0400
>
>Just so you know, the fuse's voltage rating is the voltage where it can
>jump across the opening. So a 600V fuse could jump across the open
>terminals at any voltage above 600 volts.
>
>-----Original Message-----
>From: [email protected] [mailto:[email protected]] On
>Behalf Of Roland Wiench
>Sent: Saturday, August 18, 2007 9:22
>To: Electric Vehicle Discussion List
>Subject: Re: [EVDL] wiring and fusing battery box?
>
>Hello Tehben,
>
>The ampere is going to be the same anywhere in the circuit when you
>cannot these batteries up all in series.
>
>Using fuses or circuit breakers, the ampere should at least be 125
>percent over the maximum amount you may use. The voltage of the fuse is
>at the rated voltage that is use. If you have a 250 volt circuit, than
>a 250 volt rating fuse will work.
>
>Make sure you use DC fuses on a DC circuit. It does not matter if you
>use a higher voltage fuse, unless the fuse size in the higher voltage
>may get too large for installation.
>
>In my EV, I use a 500 v Limitron rated fuses that is the size as a 12
>volt fuse. The fuse holders are all 600 v rated that accepts the same
>size fuse down to 0.1 amp.
>
>At one time, I had a battery box in the front and in the back. I used
>the 400 amp Anderson Connectors to connected these battery boxes in
>series and have only one 400 amp semi-conductor fuse in the circuit.
>
>Roland
>
>
>
>
>----- Original Message -----
>From: "Tehben Dean" <[email protected]>
>To: "EV mail list" <[email protected]>
>Sent: Friday, August 17, 2007 10:58 PM
>Subject: [EVDL] wiring and fusing battery box?
>
>
> > If I have 3 battery boxes, #1 48v(4 cells), #2 120v (10 cells) and #3
> > 144v (12 cells)
> > Should I wire them so each box is a big battery and string them up
> > with a return cable? Or should I have each box split with the to and
> > from, so that there isn't a long return cable?
> > If I fuse each box can I use all fuses rated for 312v (should I use
> > 400v fuse?) or do the fuses have to be different sizes depending on
> > where they are in the string?
> > would it be a good idea to have breakers instead so I can break up the
> > pack while performing maintenance?
> > With less than 300amp current draw what size cable should I use? Is
> > gauge 4 the same as AWG 4?
> >
> > Thanks,
> > --
> > Tehben
> > '90 Toyota 4x4 Pickup
> > 'hElix EV'
> > Website: www.helixev.com
> > evalbum: http://www.austinev.org/evalbum/1225
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
>_______________________________________________
>For subscription options, see
>http://lists.sjsu.edu/mailman/listinfo/ev
>
>_______________________________________________
>For subscription options, see
>http://lists.sjsu.edu/mailman/listinfo/ev

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Discussion Starter · #7 ·
Hi Tehben,

Some new comments inserted.....

--- Tehben Dean <[email protected]> wrote:

> > > If I have 3 battery boxes, #1 48v(4 cells), #2
> 120v
> > > (10 cells) and #3
> > > 144v (12 cells)
> > > Should I wire them so each box is a big battery
> and
> > > string them up
> > > with a return cable? Or should I have each box
> split
> > > with the to and
> > > from, so that there isn't a long return cable?
> >
> > I'm not clear what you mean. But I would advise
> to
> > figure out cable runs to minimize total cable
> length
> > and maximize safety.
>
> Ok, ummm let me try to phrase that better.
> If I have 3 boxes and treat them like 3 batteries
> and string them up
> in series I will have the negative cable left over
> at the back of the
> truck. WHich means a long run back to the
> controller.
> But If I spit the two front boxes into 2 groups of
> batteries and
> string one group in each box on the way to the rear
> box and then
> string the other group on the way back to the
> controller I won't have
> the long run.

O.K. Better explained, no clear answer, from me at
least. More than one school of thought on the
subject. And it depends how the batteries are
arranged inside the boxes. But like I said, it is
good to minimize total length of cable. But safely.
It may not make a difference in total cable length by
having a longer negative run.

Now, some might say it is best to have both cables,
pos & neg, side by side. This can minimize stray
inductance on the source side of the controller. And
reduce electrical interference. Some would say to
twist the two cables. I feel that is difficult and
unnecessary. However, for some commercial vehicles I
do, I run both cables together inside a liquid tight
conduit (safety and RFI). Boils down to your
decision.

> >
> > > If I fuse each box can I use all fuses rated for
> > > 312v (should I use
> > > 400v fuse?) or do the fuses have to be different
> > > sizes depending on
> > > where they are in the string?
> >
> > I recommend a fuse in each battery compartment.
> That
> > way each is protected in case of an incident. And
> > each fuse must be rated for the total battery
> system
> > voltage and current.
>
> So if I have a 48v battery and a 120v battery
> connected in series I
> would use the same fuse for each box?

When you end up with all the batteries connected in
series and any one fuse blows in the circuit, it sees
312 volts. So the safe answer is "all fuses rated for
312 volts."

Now, if it makes sense, you can get fancy and use a
main fuse rated at 312V say at 300 amps, and then
battery pack fuses rated at pack voltage (120, 48,
144V) with a higher current, say 400 amps. That way
an operational overcurrent condition takes out the
main 312V,300A fuse. But accidental shorts take out
the lower voltage, higher current fuses in the battery
boxes. I think this is risky and advise against it.

Now, my volts and amps are just examples. You should
consult your controller manual or supplier for
requirements. And there are many types of fuses, fast
blow, slow blow. You need to protect the equipment
like the controller and also the people in the car.
This is done by using the fuses for protection against
so high a current that it melts wire insulation or
batteries when an unforeseen incident occurs, such as
a dead short.

> > > would it be a good idea to have breakers instead
> so
> > > I can break up the
> > > pack while performing maintenance?
> >
> > Up to you. Breakers can be hard to come by or
> > expensive. I think Roland mentioned an Anderson
> > connector. Using a few of these in the right
> places
> > might be a good way to isolate battery boxes for
> > service.
>
> Do you have to worry about arcing when you plug and
> unplug Anderson connectors?

No...you should never unplug when current in flowing.
But Anderson connectors are very robust and will break
current if necessary. If you have some capacitive
load, you may see an arc when connection is made.
This can be eliminated with a precharge. Some
occasional small arcing will probably not damage the
functionality of the Anderson contact.

> > > With less than 300amp current draw what size
> cable
> > > should I use?
> >
> > Figure your average current and size it a for
> little
> > higher than that. Less than 300? Would that be
> 299?
> > Could be looking at 2/0 AWG. And remember,
> especially
> > if you have long cable runs, the larger gauge will
> > have less voltage drop. If you can afford it and
> it
> > fits in, bigger is better.
>
> Well my controller says it has 282 max amp in. But
> with a heater and stuff...

Should be in the controller manual. If not, ask the
guy who sold it to you.

But your heater should not be on the controller fuse.
It needs to be fused at the proper ampacity for the
wires you use for it.

Fuses in the battery line would have to have an
ampacity for the combined value of the branch
circuits.

Hope that helps.

Jeff M

> --
> Tehben
> '90 Toyota 4x4 Pickup
> 'hElix EV'
> Website: www.helixev.com
> evalbum: http://www.austinev.org/evalbum/1225
>


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Discussion Starter · #8 ·
Thanks for all the info,
So 2/0AWG should be fine for a max current of 300amps?
Any more current will just mean more loss?

Thanks

--
Tehben
'90 Toyota 4x4 Pickup
'hElix EV'
Website: www.helixev.com
evalbum: http://www.austinev.org/evalbum/1225

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