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[EVDL] ac box

3K views 18 replies 1 participant last post by  EVDL List 
#1 ·
I'm about ready to re-configure my ac wiring and relay for my new 10kw
charger and I need to find a box, probably suitable plastic, to house
the relay, power supply for the relay, and related stuff. Up to 50 amp
240vac going in and up to 50 amp ac going out. Also, low power up
240/120vac relay signal going in and out. Something like 8"x6"x4", I
think. Maybe bigger. Will someone suggest a source for such boxes?

I'll look for 10ga wire for the 50 amp path but may have to settle for
12ga.

--
Willie, ONWARD! Through the fog!
http://counter.li.org Linux registered user #228836 since 1995
Debian3.1/GNU/Linux system uptime 91 days 4 hours 52 minutes

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#2 ·
Willie McKemie wrote:

> I'm about ready to re-configure my ac wiring and relay for my new 10kw
> charger and I need to find a box, probably suitable plastic, to house
> the relay, power supply for the relay, and related stuff. Up to 50 amp
> 240vac going in and up to 50 amp ac going out. Also, low power up
> 240/120vac relay signal going in and out. Something like 8"x6"x4", I
> think. Maybe bigger. Will someone suggest a source for such boxes?

Our local Lowe's and Home Depot stores have them. They're nice gray
plastic boxes, in several sizes - 6x6x4 is a common size.
Thanks,
Josh


>
> I'll look for 10ga wire for the 50 amp path but may have to settle for
> 12ga.
>
> --
> Willie, ONWARD! Through the fog!
> http://counter.li.org Linux registered user #228836 since 1995
> Debian3.1/GNU/Linux system uptime 91 days 4 hours 52 minutes
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
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> |
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#3 ·
Check your local Radio Shack for "project boxes". They may have something
of a suitable size.

- Peter Flipsen Jr


Willie McKemie <xxx@xxx.xxx> wrote:

> I'm about ready to re-configure my ac wiring and relay for my new 10kw
> charger and I need to find a box, probably suitable plastic, to house
> the relay, power supply for the relay, and related stuff. Up to 50 amp
> 240vac going in and up to 50 amp ac going out. Also, low power up
> 240/120vac relay signal going in and out. Something like 8"x6"x4", I
> think. Maybe bigger. Will someone suggest a source for such boxes?
>
> I'll look for 10ga wire for the 50 amp path but may have to settle for
> 12ga.
>
> --
> Willie, ONWARD! Through the fog!
> http://counter.li.org Linux registered user #228836 since 1995
> Debian3.1/GNU/Linux system uptime 91 days 4 hours 52 minutes
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere. Thanks.
> |
> | REPLYING: address your message to xxx@xxx.xxx.edu only.
> | Multiple-address or CCed messages may be rejected.
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>
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#4 ·
Gary Krysztopik wrote:
> http://zwheelz.com/1957-VW-Bug.html

LOTSA of good ideas there! Even the rejected ideas seem good. You've
been busy! Should I consider coming to the July plugin San Antonio
thing to see the completed project?

--
Willie, ONWARD! Through the fog!
http://counter.li.org Linux registered user #228836 since 1995
Debian3.1/GNU/Linux system uptime 91 days 6 hours 19 minutes

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#5 ·
Thanks. No show for me at PlugIn2012 - it's just for the big boys. I
wanted to bring a new trike there but they were not offering any local
discount rates or even non-profit space for our EAA chapter. I'm still
excited that it's coming here and I'm sure all the speakers and programs
will be well worth attending. Maybe I could even find an EV company
that's hiring! Found a bunch of crowdfunding sites so I'll be trying
that angle next.

Gary Krysztopik
ZWheelz, LLC - www.ZWheelz.com
Alamo City Electric Auto Association - www.aceaa.org
blog - http://voices.mysanantonio.com/drive_electric_san_antonio/
San Antonio, TX

On 6/19/2012 11:18 AM, Willie McKemie wrote:
>
Gary Krysztopik wrote:
>> http://zwheelz.com/1957-VW-Bug.html
> LOTSA of good ideas there! Even the rejected ideas seem good. You've
> been busy! Should I consider coming to the July plugin San Antonio
> thing to see the completed project?
>



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#6 ·
On 19 Jun 2012 at 9:57, Willie McKemie wrote:

> Will someone suggest a source for such boxes?

If you need something of an exact size to fit a particular spot, there's a
small business fabricating custom aluminium boxes about an hour north of
here, in Elyria, Ohio They do respectable work at surprisingly reasonable
prices. You can email or fax them a dimensioned drawing, either rough or
detailed; they'll make the box and ship it to you.

I commissioned them to make battery boxes for a scooter I was working on
last winter, and was pretty well satisfied with the result. IIRC, it took
them a couple of weeks. They stay pretty busy.

http://customaluminumboxes.com/

> I'll look for 10ga wire for the 50 amp path but may have to settle for
> 12ga.

Even AWG 10 would be undersized unless you're stringing it overhead in free
air. Even then, loss from resistance could be significant unless it's a
very short run. Enclosed, #10 shouldn't carry more than 33 amps; #12, not
more than 23a. Normally #12 is protected (fused) at 20a and #10 at 30a.

For 50a, I'd go with at least AWG 8, which IIRC can be protected at 50a when
insulation is rated 75 deg C and in conduit (I'm sure Roland W will have the
final word on this). AWG 6 would be better, safer, with lower loss.

David Roden - Akron, Ohio, USA
EVDL Administrator

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EVDL Information: http://www.evdl.org/help/
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#7 ·
I used the same company for my battery box, they did a great job and
are quite affordable.



EVDL Administrator <xxx@xxx.xxx> wrote:
> On 19 Jun 2012 at 9:57, Willie McKemie wrote:
>
>> Will someone suggest a source for such boxes?
>
> If you need something of an exact size to fit a particular spot, there's a
> small business fabricating custom aluminium boxes about an hour north of
> here, in Elyria, Ohio They do respectable work at surprisingly reasona=
ble
> prices. You can email or fax them a dimensioned drawing, either rough =
or
> detailed; they'll make the box and ship it to you.
>
> I commissioned them to make battery boxes for a scooter I was working on
> last winter, and was pretty well satisfied with the result. IIRC, it t=
ook
> them a couple of weeks. They stay pretty busy.
>
> http://customaluminumboxes.com/
>
>> I'll look for 10ga wire for the 50 amp path but may have to settle for
>> 12ga.
>
> Even AWG 10 would be undersized unless you're stringing it overhead in fr=
ee
> air. Even then, loss from resistance could be significant unless it's a
> very short run. Enclosed, #10 shouldn't carry more than 33 amps; #12, =
not
> more than 23a. Normally #12 is protected (fused) at 20a and #10 at 30a.
>
> For 50a, I'd go with at least AWG 8, which IIRC can be protected at 50a w=
hen
> insulation is rated 75 deg C and in conduit (I'm sure Roland W will have =
the
> final word on this). AWG 6 would be better, safer, with lower loss.
>
> David Roden - Akron, Ohio, USA
> EVDL Administrator
>
> =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =
=3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D
> EVDL Information: http://www.evdl.org/help/
> =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =
=3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D
> Note: mail sent to "evpost" and "etpost" addresses will not
> reach me. To send a private message, please obtain my
> email address from the webpage http://www.evdl.org/help/ .
> =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =
=3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D
>
>
> _______________________________________________
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-- =

www.electric-lemon.com

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#8 ·
I have a friend who works in a metal shop.
Give him a drawing and measurements and he will make
the box or bracket you want. Alu or stainless steel is
what I have done with him. Let me know and I will get
you his contact info.

Regards,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: xxx@xxx.xxx Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203

-----Original Message-----
From: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu] On
Behalf Of EVDL Administrator
Sent: Tuesday, June 19, 2012 1:18 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] ac box

On 19 Jun 2012 at 9:57, Willie McKemie wrote:

> Will someone suggest a source for such boxes?

If you need something of an exact size to fit a particular spot, there's
a small business fabricating custom aluminium boxes about an hour north
of here, in Elyria, Ohio They do respectable work at surprisingly
reasonable prices. You can email or fax them a dimensioned drawing,
either rough or detailed; they'll make the box and ship it to you.

I commissioned them to make battery boxes for a scooter I was working on
last winter, and was pretty well satisfied with the result. IIRC, it
took them a couple of weeks. They stay pretty busy.

http://customaluminumboxes.com/

> I'll look for 10ga wire for the 50 amp path but may have to settle for

> 12ga.

Even AWG 10 would be undersized unless you're stringing it overhead in
free air. Even then, loss from resistance could be significant unless
it's a very short run. Enclosed, #10 shouldn't carry more than 33 amps;
#12, not more than 23a. Normally #12 is protected (fused) at 20a and
#10 at 30a.

For 50a, I'd go with at least AWG 8, which IIRC can be protected at 50a
when insulation is rated 75 deg C and in conduit (I'm sure Roland W will
have the final word on this). AWG 6 would be better, safer, with lower
loss.

David Roden - Akron, Ohio, USA
EVDL Administrator

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL
Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = =
= = = = = = = = = = = =
Note: mail sent to "evpost" and "etpost" addresses will not reach me.
To send a private message, please obtain my email address from the
webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =


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#9 ·
Lee Hart wrote:
> On 6/19/2012 9:57 AM, Willie McKemie wrote:
> > I'll look for 10ga wire for the 50 amp path but may have to settle
> > for 12ga.
>
> I think you want to go heavier; like 6 gauge. 12 gauge is only rated for
> 20 amps continuous. Even 10 gauge is only rated at 25 amps continuous!

This:
http://www.powerstream.com/Wire_Size.htm
tells me 10' of 10ga copper wire conducting 50 amps at 240vac will
have a ~1v drop or about .43%. 12ga, ~1.6v, .68%.
They don't say anything about wire heating; I wonder if that is an
issue.

I think wire gauges larger than 10 will be too difficult to manage for
my purposes.

Thanks, all, for the box suggestions!

--
Willie, ONWARD! Through the fog!
http://counter.li.org Linux registered user #228836 since 1995
Debian3.1/GNU/Linux system uptime 91 days 13 hours 41 minutes

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#10 ·
Willie McKemie wrote:

> This:
> http://www.powerstream.com/Wire_Size.htm
> tells me 10' of 10ga copper wire conducting 50 amps at 240vac will
> have a ~1v drop or about .43%. 12ga, ~1.6v, .68%.
> They don't say anything about wire heating; I wonder if that is an
> issue.

Yes, it is an issue ;^>

~1V @ 50A is ~50W of heat being dissipated in that wire.

Try this ampacity table; it gives values based on 75C conductor temperature in 30C ambient and provides derating factors for higher ambient conditions. Bear in mind that if the cable is enclosed inside a conduit, then its ambient will be hotter than the outside air temp due to heat dissipated by the cable being trapped inside the conduit.

<http://www.okonite.com/engineering/nec-ampacity-tables.html>

Cheers,

Roger.


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#11 ·
Willie,

As Roger said, 1V drop at 50A is 50W, which will cause quite a bit of heating.

I use this 8AWG wire for various projects in my lab; it's very
flexible and easy to work with:

http://www.powerwerx.com/wire-cable/power-wire-automotive.html

-Morgan LaMoore

Willie McKemie <xxx@xxx.xxx> wrote:
> ...
> They don't say anything about wire heating; I wonder if that is an
> issue.
>
> I think wire gauges larger than 10 will be too difficult to manage for
> my purposes.
> ...

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#12 ·
You have to de-rated any conductor to 80% of the ampere rating of the
conductor of the actual ampere load.

For example: A single stranded copper No. 12 AWG wire on a 20 amp circuit
breaker is rated for 16 amps with acceptable voltage drop.

A single stranded copper No. 10 AWG wire on a 30 amp circuit breaker shall
have no more than 24 ampere load on it.

A single stranded copper No. 8 AWG wire on a 40 amp circuit breaker shall
have no more than 32 ampere load on it.

And a single stranded copper No. 6 AWG wire on a 50 amp circuit breaker
shall have no more than 42 ampere load on it which is to protect a thermo
circuit breaker from overheating.

A single stranded copper No. 6 AWG wire rated at 90 C. has a 55 ampere
rating on a 60 ampere circuit breaker will be require for a 50 amp in and
out as you stated.

Now if you bundle these single stranded copper wires in three or more wires
in a cable, you have to de-rated the rated current carrying another 20%.

Example: the No 6 stranded copper wires that are rated at 55 amps on a 60
amp circuit or 55 x .80 = 44 amps for a conductor length of 50 feet. If
your length is about 25 feet of conductor, than your maximum ampere is about
49.5 amps or as close to 50 amps as you want with a voltage drop range
between 1 and 3 percent.

Your breaker size shall be 1.25% over the actual current rating of the
conductor and the conductor shall also be 1.25% over the rating of the
conductor.

There should be at least 2 inches of space around the size of a 2-pole AC
contactor that will have a actual 50 amp load should be rated for 60 amperes
which will be a definite purpose AC contactor. The size of these contactors
are about 2.5 inches wide by 3.5 inches high by 3.75 inches deep.

The enclose for this type of contactor should have at least 1.5 inches on
each sides of the contactors, making the enclosure size 5.5 inches wide by
7.5 inches high. You could get by with a 6 inch wide by 8 inch high by 4
inches inside depth.

Roland





----- Original Message -----
From: "Willie McKemie" <xxx@xxx.xxx>
To: "Electric Vehicle Discussion List" <xxx@xxx.xxx.edu>
Sent: Tuesday, June 19, 2012 8:57 AM
Subject: [EVDL] ac box


> I'm about ready to re-configure my ac wiring and relay for my new 10kw
> charger and I need to find a box, probably suitable plastic, to house
> the relay, power supply for the relay, and related stuff. Up to 50 amp
> 240vac going in and up to 50 amp ac going out. Also, low power up
> 240/120vac relay signal going in and out. Something like 8"x6"x4", I
> think. Maybe bigger. Will someone suggest a source for such boxes?
>
> I'll look for 10ga wire for the 50 amp path but may have to settle for
> 12ga.
>
> --
> Willie, ONWARD! Through the fog!
> http://counter.li.org Linux registered user #228836 since 1995
> Debian3.1/GNU/Linux system uptime 91 days 4 hours 52 minutes
>
> _______________________________________________
> | Moratorium on drag racing discussion is in effect.
> | Please take those discussions elsewhere. Thanks.
> |
> | REPLYING: address your message to xxx@xxx.xxx.edu only.
> | Multiple-address or CCed messages may be rejected.
> | UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> | OTHER HELP: http://evdl.org/help/
> | CONFIGURE: http://lists.sjsu.edu/mailman/listinfo/ev
>

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#13 ·
On 19 Jun 2012 at 23:50, Roland Wiench wrote:

> You have to de-rated any conductor to 80% of the ampere rating of the
> conductor of the actual ampere load.

I may be wrong, but my understanding of the NEC is that the 20% derating
applies only with sustained loads.

This might indeed be the case with a charger. However (again my
understanding), normally this load factor is only applied to dedicated
circuits in home or industrial wiring, not to general purpose circuits.

Nor is it (to my knowledge) applied to an electrical device to be connected
to the mains (in this case an EV).

Again, I may be mistaken, but I think that in this case it's probably safe
for the builder to take the following maximum loads as reasonable and
acceptable :

AWG 14 - 15a
AWG 12 - 20a
AWG 10 - 30a
AWG 8 - 40a
AQG 6 - 50a

AWG 12 or AWG 10 wire is definitely too small for a 50a load.

David Roden - Akron, Ohio, USA
EVDL Administrator

= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
EVDL Information: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to "evpost" and "etpost" addresses will not
reach me. To send a private message, please obtain my
email address from the webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =


_______________________________________________
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#14 ·
Indeed.
Look at (certified - not cheap crap) extension cords.
NEMA 5-15 cords typically have 14 ga but long cords can
be had with 12 ga to reduce voltage drop (which may easily be
as bad as losing 15V in a 100 ft cord)
The 10 gauge is typically used for 30A "generator" cords
but also to connect 30A clothes driers.
6 gauge is used for stoves drawing 50A.
I once had a 3-wire 6 gauge extension cord to bring 240V 50A
to my driveway. I used it once and gave it away with my truck
when I sold it, because it would typically only be used for
EV (or RV) connection.

Regards,

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: xxx@xxx.xxx Private: http://www.cvandewater.com
Skype: cor_van_de_water XoIP: +31877841130
Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203

-----Original Message-----
From: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu] On
Behalf Of EVDL Administrator
Sent: Tuesday, June 19, 2012 11:13 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] ac box

On 19 Jun 2012 at 23:50, Roland Wiench wrote:

> You have to de-rated any conductor to 80% of the ampere rating of the
> conductor of the actual ampere load.

I may be wrong, but my understanding of the NEC is that the 20% derating
applies only with sustained loads.

This might indeed be the case with a charger. However (again my
understanding), normally this load factor is only applied to dedicated
circuits in home or industrial wiring, not to general purpose circuits.

Nor is it (to my knowledge) applied to an electrical device to be
connected to the mains (in this case an EV).

Again, I may be mistaken, but I think that in this case it's probably
safe for the builder to take the following maximum loads as reasonable
and acceptable :

AWG 14 - 15a
AWG 12 - 20a
AWG 10 - 30a
AWG 8 - 40a
AQG 6 - 50a

AWG 12 or AWG 10 wire is definitely too small for a 50a load.

David Roden - Akron, Ohio, USA
EVDL Administrator

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#15 ·
Willie McKemie-2 wrote
> ...
> I think wire gauges larger than 10 will be too difficult to manage for
> my purposes.
> ...
>

I can't believe no one has suggested the obvious solution here: use two #12
wires in parallel.

--
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#16 ·
Jeffrey Jenkins wrote:
> I can't believe no one has suggested the obvious solution here: use two #12
> wires in parallel.

That can be a viable solution. I used 4-conductor #10 for 50amp
quick-charger on a fleet of Zap Xebras for a Pizza delivery business. It
was an expedient solution because I couldn't get ultra-flexible
2-conductor #6 cable in the time frame allowed.

The risk is that if one wire breaks, the other one is left carrying all
the current. It can overheat, and start a fire without the fuse blowing.
This can be handled by putting a separate fuse in each wire, properly
sized for the wire's current rating.
--
If we knew what we were doing, it wouldn't be called research, would it?
-- Albert Einstein
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart at earthlink.net

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#17 ·
Willie McKemie wrote:

> I think wire gauges larger than 10 will be too difficult to manage for
> my purposes.

I've been making some progress on this project. I didn't find any
flexible "appliance" cord greater than 10ga so I ended up using 10ga
for the 240vac path. I did get stiff single conductor 8ga wire for the
~165vdc path.

I used a plastic electric box from Lowes to contain the ac stuff:
two "120 amp" relays and a 120/240vac wallwart 12vdc power supply.
One high current cord coming in, one going out. One low current cord
going to the BMS, one coming back in to the wallwart.

I did my first test charge with the 10kw charger this morning. The
charger was painful to get, but I did eventually receive it:
http://www.diyelectriccar.com/forums/showthread.php/10kw-60a-diy-charger-open-source-59210p59.html
http://is.gd/nk8puX
I had a foot or two of 12ga wire in my 240vac path which I was
monitoring closely; I will normally bypass that segment with 10ga wire.
Over a few minutes, the charger ramped up to about 50 battery amps and
the 12ga segment got a little warm. My battery was very near full so
it only charged maybe 5 minutes. I need to the the car out and use it
some; we've been driving the Leaf primarily.

I've put in two "120 amp" relays to break both ac power legs. My
thinking is that, with a not isolated charger, it might be safer.
Even though I don't know the risks of using a non-isolated charger. I
understand that they can't be used in series. Do they pose a risk
running in parallel with other chargers?

Anyway, the 10kw charger looks very promising at this point. If only
it is reliable! With that one charger, I should now be able to charge
at the rate of about 30 mph. One comment on the charger: the provided
terminal strip is too small to accommodate the size wire and terminals
indicated by the currents expected.

BTW, using a 12vdc universal wallwart power supply seems to be a very
good way to control 12vdc coil relays. My BMS controller contains a
"20 amp" relay which I use to turn my wallwart on/off. The
wallwart performed well controlling a "40 amp" relay for several months
and now it is controlling the two "120 amp" relays. I first off-loaded
the BMS relay when my charging currents approached 20 amps.

--
Willie, ONWARD! Through the fog!
http://counter.li.org Linux registered user #228836 since 1995
Debian3.1/GNU/Linux system uptime 107 days 3 hours 35 minutes

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#18 ·
Willie McKemie wrote:

> On Tue, Jun 19, 2012 at 06:49:12PM -0500, Willie McKemie wrote:
>
>> I think wire gauges larger than 10 will be too difficult to manage for
>> my purposes.
>
> I've been making some progress on this project. I didn't find any
> flexible "appliance" cord greater than 10ga so I ended up using 10ga
> for the 240vac path. I did get stiff single conductor 8ga wire for the
> ~165vdc path.
>
> --
> Willie, ONWARD! Through the fog!

Hi Willie,

You could put singe core, heavy-gauge conductors in a piece of flexible conduit... MW

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#19 ·
Lee Hart wrote:
> > I did my first test charge with the 10kw charger this morning. The
> > charger was painful to get, but I did eventually receive it:
> > http://www.diyelectriccar.com/forums/showthread.php/10kw-60a-diy-charger-open-source-59210p59.html
> > http://is.gd/nk8puX
>
> I'd be interested in continuing feedback on how this charger works out.
> It's very cheap, but from the photos I expect they have a lot to learn.

Well, I got good advice here on the wire size. I started with 8ga on
the dc side and 10ga on the ac. At 40+ battery amps, the ac wires got
pretty hot. The dc side seems ok. I just put 8ga on the ac side (4
segments, two big plugs) and things are better. At 45+ battery amps,
the ac wire gets warm. My goal is to put in ~50 amps from the new
charger plus ~8amps from my 1500w onboard charger. That would be about
34 mph. Right now, I'm fairly comfortable with ~40 amps from the new
charger plus the onboard charger. The BMS controlled relays appear
reliable; I'm about ready to try turning my back on them.

No trouble with the new charger; I've gotten about 200ah out of it, all
pretty closely monitored. The display uses four colors and two of
those have poor contrast. It needs a bigger screw terminal strip
(where ac goes in and dc comes out) that will take bigger wire with
bigger lugs.

Two things I'm looking for:
1) the afore mentioned screw terminal strip
2) 6ga multi strand flexible three conductor cable

--
Willie, ONWARD! Through the fog!
http://counter.li.org Linux registered user #228836 since 1995
Debian3.1/GNU/Linux system uptime 115 days 15 hours 48 minutes

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