Tests for second hand purchase

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Tests for second hand purchase

Electric Vehicle Discussion List mailing list
Hi guys,

I’m off to look at, with an aim to purchase, a bunch of second hand kit: An AC-50, Curtis 1238 and 36 160Ah Thundersky.

They’re not installed in anything. I wont have the time to rig the whole kit up to bench test.

Has anyone got any suggestions for what tests can be done on a motor and batteries, within an hour or two, to check their condition?

I can easily bring an RC charger and voltmeter with me.
I also have the Curtis 1314 software on a PC and can use to look at the 1238.

Is there something that can be used as a suitable test load for the cells?

What do you guys do when buying second hand EV parts with an unknown history?

Thank you!
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Re: Tests for second hand purchase

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Matthew,
In my order of preference:
1- buy from someone you trust (and others vouch for if you have little experience with them)
2- get a written warranty
3- consider the money lost in case the quality is not as advertised.

You may be able to do some crude tests such as guesstimate internal resistance of the cells by loading them with a 100 Amp load and measuring drop,
but more important is the remaining capacity of the weakest cell and it is not likely you can determine that from 36 cells in an hour or two.

It may be possible to wire up the controller to a power source and make the motor spin, which would tell you about obvious damage to bearings or balance,
but it is not likely you can easily test it to the limits that it will see on a freeway doing redline, so again you will find out later if the motor is as good as advertised.

Testing the controller beyond the digital interface that you are already going to access with your program is the same as I wrote above.

One of the best ways to find out history is to know where the kit came from, so you can ask the previous owner about his use and experience with it.
Success and I hope this helps,
Cor.

-----Original Message-----
From: EV [mailto:[hidden email]] On Behalf Of Matthew Quitter via EV
Sent: Monday, January 29, 2018 1:13 PM
To: [hidden email]
Cc: Matthew Quitter
Subject: [EVDL] Tests for second hand purchase

Hi guys,

I’m off to look at, with an aim to purchase, a bunch of second hand kit: An AC-50, Curtis 1238 and 36 160Ah Thundersky.

They’re not installed in anything. I wont have the time to rig the whole kit up to bench test.

Has anyone got any suggestions for what tests can be done on a motor and batteries, within an hour or two, to check their condition?

I can easily bring an RC charger and voltmeter with me.
I also have the Curtis 1314 software on a PC and can use to look at the 1238.

Is there something that can be used as a suitable test load for the cells?

What do you guys do when buying second hand EV parts with an unknown history?

Thank you!
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Re: Tests for second hand purchase

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Thanks Cor!

Funny, I hadn’t even considered asking for a warranty.  Not the advice I was expecting but excellent!

The seller says it is unused equipment but I always like to double check.

Thank you for the help.



> On 29 Jan 2018, at 21:23, Cor van de Water via EV <[hidden email]> wrote:
>
> Matthew,
> In my order of preference:
> 1- buy from someone you trust (and others vouch for if you have little experience with them)
> 2- get a written warranty
> 3- consider the money lost in case the quality is not as advertised.
>
> You may be able to do some crude tests such as guesstimate internal resistance of the cells by loading them with a 100 Amp load and measuring drop,
> but more important is the remaining capacity of the weakest cell and it is not likely you can determine that from 36 cells in an hour or two.
>
> It may be possible to wire up the controller to a power source and make the motor spin, which would tell you about obvious damage to bearings or balance,
> but it is not likely you can easily test it to the limits that it will see on a freeway doing redline, so again you will find out later if the motor is as good as advertised.
>
> Testing the controller beyond the digital interface that you are already going to access with your program is the same as I wrote above.
>
> One of the best ways to find out history is to know where the kit came from, so you can ask the previous owner about his use and experience with it.
> Success and I hope this helps,
> Cor.
>
> -----Original Message-----
> From: EV [mailto:[hidden email]] On Behalf Of Matthew Quitter via EV
> Sent: Monday, January 29, 2018 1:13 PM
> To: [hidden email]
> Cc: Matthew Quitter
> Subject: [EVDL] Tests for second hand purchase
>
> Hi guys,
>
> I’m off to look at, with an aim to purchase, a bunch of second hand kit: An AC-50, Curtis 1238 and 36 160Ah Thundersky.
>
> They’re not installed in anything. I wont have the time to rig the whole kit up to bench test.
>
> Has anyone got any suggestions for what tests can be done on a motor and batteries, within an hour or two, to check their condition?
>
> I can easily bring an RC charger and voltmeter with me.
> I also have the Curtis 1314 software on a PC and can use to look at the 1238.
>
> Is there something that can be used as a suitable test load for the cells?
>
> What do you guys do when buying second hand EV parts with an unknown history?
>
> Thank you!
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>
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Re: Tests for second hand purchase

Electric Vehicle Discussion List mailing list
If it is truly unused then you can remove terminal screws and check for marks of previous wire/lug attachments
on a motor you can inspect the mounting holes and axle for any marks of mounting or set screw tightening that will leave markings,
besides general scuffing.
If cells have been sitting on a shelf they look similar dusty but quite different worn then when they have bounced around
in a vehicle for a while.
If the controller was installed, it will show as markings around mounting holes and on screw terminals.

Besides physical inspection of the goods, check a person's history - typically online or by contacting other customers.
There is a reason that employers ask for references. Yelp can be handy at times, but take it with a grain of salt as it
can easily be tricked to have lots of great reviews or have a single whiner lay out all the negatives that he endured...
Google can be your friend, so use it to build a consistent picture if you have no other references.
Success!
Cor.

-----Original Message-----
From: EV [mailto:[hidden email]] On Behalf Of Matthew Quitter via EV
Sent: Monday, January 29, 2018 1:53 PM
To: Electric Vehicle Discussion List
Cc: Matthew Quitter
Subject: Re: [EVDL] Tests for second hand purchase

Thanks Cor!

Funny, I hadn’t even considered asking for a warranty.  Not the advice I was expecting but excellent!

The seller says it is unused equipment but I always like to double check.

Thank you for the help.



> On 29 Jan 2018, at 21:23, Cor van de Water via EV <[hidden email]> wrote:
>
> Matthew,
> In my order of preference:
> 1- buy from someone you trust (and others vouch for if you have little
> experience with them)
> 2- get a written warranty
> 3- consider the money lost in case the quality is not as advertised.
>
> You may be able to do some crude tests such as guesstimate internal
> resistance of the cells by loading them with a 100 Amp load and measuring drop, but more important is the remaining capacity of the weakest cell and it is not likely you can determine that from 36 cells in an hour or two.
>
> It may be possible to wire up the controller to a power source and
> make the motor spin, which would tell you about obvious damage to bearings or balance, but it is not likely you can easily test it to the limits that it will see on a freeway doing redline, so again you will find out later if the motor is as good as advertised.
>
> Testing the controller beyond the digital interface that you are already going to access with your program is the same as I wrote above.
>
> One of the best ways to find out history is to know where the kit came from, so you can ask the previous owner about his use and experience with it.
> Success and I hope this helps,
> Cor.
>
> -----Original Message-----
> From: EV [mailto:[hidden email]] On Behalf Of Matthew
> Quitter via EV
> Sent: Monday, January 29, 2018 1:13 PM
> To: [hidden email]
> Cc: Matthew Quitter
> Subject: [EVDL] Tests for second hand purchase
>
> Hi guys,
>
> I’m off to look at, with an aim to purchase, a bunch of second hand kit: An AC-50, Curtis 1238 and 36 160Ah Thundersky.
>
> They’re not installed in anything. I wont have the time to rig the whole kit up to bench test.
>
> Has anyone got any suggestions for what tests can be done on a motor and batteries, within an hour or two, to check their condition?
>
> I can easily bring an RC charger and voltmeter with me.
> I also have the Curtis 1314 software on a PC and can use to look at the 1238.
>
> Is there something that can be used as a suitable test load for the cells?
>
> What do you guys do when buying second hand EV parts with an unknown history?
>
> Thank you!
> -------------- next part -------------- An HTML attachment was
> scrubbed...
> URL:
> <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180129/85
> 55c748/attachment.html>
> _______________________________________________
> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> http://lists.evdl.org/listinfo.cgi/ev-evdl.org
> Please discuss EV drag racing at NEDRA
> (http://groups.yahoo.com/group/NEDRA)
>
> _______________________________________________
> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> http://lists.evdl.org/listinfo.cgi/ev-evdl.org
> Please discuss EV drag racing at NEDRA
> (http://groups.yahoo.com/group/NEDRA)
>
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_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
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