Burn Tester - UK Part Numbers

iainmsmith · June 14th, 2006, 01:15 AM

If anyone is wanting to make their own scooter burn tester, the following information may be useful:

Use the same design as shown of Jeff Bently's site:
Gavin/Irvine Scooter Burn Tester

Suitable resistors and mounting brackets can be sourced in the UK from Farnell (Farnell InOne, distributors of electronic, electrical and industrial component products. Online ordering and 24 hour delivery as standard.).

300W 3.1 Ohm Resistor (you need 2)
Farnell part: 1129440
Ohmite part number: C300K3R1E

Twin Resistor Mounting Kit
Farnell Part No: 1130257
Ohmite Part No: 6127P-8.5E

The first nice thing about Farnell is that if they have stuff in stock, overnight delivery is free.

The second nice thing about Farnel is that if they are out of stock, the chances are that their American sister company, Newark, will have them and they can get them shipped over...for a price.

The really nice thing about Farnell is that if the are out of stock, you phone them up and explain that you want to schedule a delivery for the parts in about two weeks time and could they therefore have these parts brought over from the USA and sent out to you, thus saving you a £16 shipping charge.

Farnell/Newark also do the modular Anderson connectors and the Molex connectors for connecting the burn tester, but these come in several varieties and I haven't quite worked out how to avoid ordering a thousand conductor inserts for the connectors yet...watch this space!

When it comes to soldering wire to the resistors, I found that my normal electronics soldering iron wasn't even close to being up to the job. However, a small gas soldering iron with flame head attached (ie Maplin YT73Q) worked perfectly.

Hope this is of use to someone.

Iain

*peter_steinhoff* · June 14th, 2006, 02:51 PM

Just a quick note. If you want to compare burn times with other people you should try to use 3.0 Ohm resistorns.

Best,
Peter

iainmsmith · June 15th, 2006, 12:23 AM

Quote: (Originally Posted by peter_steinhoff)

Just a quick note. If you want to compare burn times with other people you should try to use 3.0 Ohm resistorns.

With what tolerance? For what it's worth, the Ohmite resistors have a 10% tolerance, the Milwaukee resistors shown on the Bentlytech site have a 5% tolerance. My pair of Ohmites gives a burn tester with a resistance of about 1.45 Ohms, which is within the tolerance of a burn tester made of a pair of 5% 3 Ohm resistors.

The only way I can think of getting an exact 1.5 Ohm burn tester is to have two variable wirewound resistors, whose maximum resistance (with worst-case tolerance) is greater than 3 Ohms, which can then be adjusted down to 3 Ohms each. Suitable resistors from Farnell might be 1998237 or 1840393 which are the 4 Ohm and 5 Ohm variable resistor equivalents of those I listed above...and why didn't I think of this before making my burn tester...

Iain

***Bob Cooper*** · June 15th, 2006, 12:38 AM

Burn test results are always relative, relative to the actual resistor array you are using. In other words, you can use an array to burn test a set of batteries and you *might* get similar results if you use the same array with the same batteries a day later. Using a different array you *might not* get the same result with the same batteries.

Just use the array to give you an early warning of when the battery might be flagging. It is no more precise than that. In any case, the actual burn time in the water is always more than the figure you get on the burn test.

HTH

Bob

June 14th, 2006, 01:15 AM	#1 (permalink)
iainmsmith(Offline) Member Join Date: Jan 2006 Location: Glasgow Posts: 151	Burn Tester - UK Parts Source If anyone is wanting to make their own scooter burn tester, the following information may be useful: Use the same design as shown of Jeff Bently's site: Gavin/Irvine Scooter Burn Tester Suitable resistors and mounting brackets can be sourced in the UK from Farnell (Farnell InOne, distributors of electronic, electrical and industrial component products. Online ordering and 24 hour delivery as standard.). 300W 3.1 Ohm Resistor (you need 2) Farnell part: 1129440 Ohmite part number: C300K3R1E Twin Resistor Mounting Kit Farnell Part No: 1130257 Ohmite Part No: 6127P-8.5E The first nice thing about Farnell is that if they have stuff in stock, overnight delivery is free. The second nice thing about Farnel is that if they are out of stock, the chances are that their American sister company, Newark, will have them and they can get them shipped over...for a price. The really nice thing about Farnell is that if the are out of stock, you phone them up and explain that you want to schedule a delivery for the parts in about two weeks time and could they therefore have these parts brought over from the USA and sent out to you, thus saving you a £16 shipping charge. Farnell/Newark also do the modular Anderson connectors and the Molex connectors for connecting the burn tester, but these come in several varieties and I haven't quite worked out how to avoid ordering a thousand conductor inserts for the connectors yet...watch this space! When it comes to soldering wire to the resistors, I found that my normal electronics soldering iron wasn't even close to being up to the job. However, a small gas soldering iron with flame head attached (ie Maplin YT73Q) worked perfectly. Hope this is of use to someone. Iain Last edited by iainmsmith; December 14th, 2006 at 02:34 AM.

June 14th, 2006, 02:51 PM	#2 (permalink)
peter_steinhoff(Offline) Instructor candidate Join Date: Dec 2005 Location: Sweden & Florida Posts: 205	Just a quick note. If you want to compare burn times with other people you should try to use 3.0 Ohm resistorns. Best, Peter __________________ Peter Steinhoff GUE DIR-F, Tech1, Tech2, Cave1, Cave2, Cave3, RB80-1&2, DIR-F/Cave Instructor Candidate. NAUI Tec Instructor (Trimix, Technical DPV, Technical Wreck Penenetration etc) WKPP Support Diver, Halcyon Product Development Team, Gavinscooter Representative. Various IANTD, NSS-CDS, NACD, PADI & NAUI. ---------------------------------------------- http://dir-diver.com http://peter.steinhoff.se (swedish only)

June 15th, 2006, 12:23 AM	#3 (permalink)
iainmsmith(Offline) Member Join Date: Jan 2006 Location: Glasgow Posts: 151	Quote: (Originally Posted by peter_steinhoff) Just a quick note. If you want to compare burn times with other people you should try to use 3.0 Ohm resistorns. With what tolerance? For what it's worth, the Ohmite resistors have a 10% tolerance, the Milwaukee resistors shown on the Bentlytech site have a 5% tolerance. My pair of Ohmites gives a burn tester with a resistance of about 1.45 Ohms, which is within the tolerance of a burn tester made of a pair of 5% 3 Ohm resistors. The only way I can think of getting an exact 1.5 Ohm burn tester is to have two variable wirewound resistors, whose maximum resistance (with worst-case tolerance) is greater than 3 Ohms, which can then be adjusted down to 3 Ohms each. Suitable resistors from Farnell might be 1998237 or 1840393 which are the 4 Ohm and 5 Ohm variable resistor equivalents of those I listed above...and why didn't I think of this before making my burn tester... Iain

June 15th, 2006, 12:38 AM	#4 (permalink)
*Bob Cooper*(Offline) Moderator - "Don't stop me now!" Join Date: Nov 2005 Location: South East London, UK Posts: 680	Burn test results are always relative, relative to the actual resistor array you are using. In other words, you can use an array to burn test a set of batteries and you might get similar results if you use the same array with the same batteries a day later. Using a different array you might not get the same result with the same batteries. Just use the array to give you an early warning of when the battery might be flagging. It is no more precise than that. In any case, the actual burn time in the water is always more than the figure you get on the burn test. HTH Bob