Installing a fuse

[erict]

Is it recommended to install a fuse for safety? If so, how and where does one install one? Also, which one is recommended? Links would be great


I was thinking of the CNN250 Fuse in the link below. Would this be for a stock cart? Looks like I would need the fuse holder they show as well.

http://www.evdrives.com/accessories.html#Fuse


I also see they have this and wonder if this would be something to install?
http://www.evdrives.com/contactors_ED250.html

[dougmcp]

A fuse is always recommended for the battery string, for a stock cart use a 250 amp fuse like an ANN250
Fuses protect the wiring and should always be installed as close to the power source (battery) as possible.
Example: A lot of automobile fires are caused by amplifiers that have the fuse installed by the amp in the trunk while the whole cable running from back to front remains unprotected and that's what starts the fire.

Here is the best fuse primer I can find: http://www.alltraxinc.com/files/Doc1...tall-Guide.pdf

IMO you don't really need a fuse holder but if you really want one, you can use this to hold the ANN250 fuse: http://www.ebay.com/itm/Battery-Fuse...item5add3db7ad
The same company also has the 250 amp fuse: http://www.ebay.com/itm/CNN-250-Fuse...item3efed87f21

I consider the emergency disconnect switch redundant as the fuse will protect the wiring. The only time you would need a master shutdown is if you were in a modified cart with extreme amperages or for racing applications where it is required in case of contactor failure.

Update: Oops, I just looked at your links and they are the same company as the ones I posted.

[erict]

A fuse is always recommended for the battery string, for a stock cart use a 250 amp fuse like an ANN250
Fuses protect the wiring and should always be installed as close to the power source (battery) as possible.
Example: A lot of automobile fires are caused by amplifiers that have the fuse installed by the amp in the trunk while the whole cable running from back to front remains unprotected and that's what starts the fire.

Here is the best fuse primer I can find: http://www.alltraxinc.com/files/Doc1...tall-Guide.pdf

IMO you don't really need a fuse holder but if you really want one, you can use this to hold the ANN250 fuse: http://www.ebay.com/itm/Battery-Fuse...item5add3db7ad
The same company also has the 250 amp fuse: http://www.ebay.com/itm/CNN-250-Fuse...item3efed87f21

I consider the emergency disconnect switch redundant as the fuse will protect the wiring. The only time you would need a master shutdown is if you were in a modified cart with extreme amperages or for racing applications where it is required in case of contactor failure.

Update: Oops, I just looked at your links and they are the same company as the ones I posted.

If I used the fuse holder then I would need a short cable (jumper), correct? How secure does it hold the main pos battery cable when connected to the fuse without a holder?

Also, why doesn't the cart manufactures have these installed at the factory if it's a good safety measure?

[dougmcp]

If I used the fuse holder then I would need a short cable (jumper), correct? How secure does it hold the main pos battery cable when connected to the fuse without a holder?

Also, why doesn't the cart manufactures have these installed at the factory if it's a good safety measure?

If you used a fuse holder you would also need a small jumper. IMO the less connections you have the better so I would just attach a fuse directly to the battery which eliminates 2 connections.

Over 90% of the carts made are leased to golf courses and fuses would just add more confusion to the maintenance or lack of that they get at the course.
"Value Engineering" is the main reason cart manufacturers do not put fuses on their carts.
Think of it this way:
If it costs $5 to install a fuse on every cart, not installing one on the 100,000 carts manufactured every year would save 100,000 X $5 = $500,000 directly to the bottom line of the profit sheet.

Golf cart fires are rare in stock carts and from a Risk Management standpoint, golf carts are used outdoors with an easy exit if there is a problem, the company is saving $500,000. The cost of any malfunctions created by the lack of a fuse in a cart is easily offset by the savings.

[erict]

If you used a fuse holder you would also need a small jumper. IMO the less connections you have the better so I would just attach a fuse directly to the battery which eliminates 2 connections.

Over 90% of the carts made are leased to golf courses and fuses would just add more confusion to the maintenance or lack of that they get at the course.
"Value Engineering" is the main reason cart manufacturers do not put fuses on their carts.
Think of it this way:
If it costs $5 to install a fuse on every cart, not installing one on the 100,000 carts manufactured every year would save 100,000 X $5 = $500,000 directly to the bottom line of the profit sheet.

Golf cart fires are rare in stock carts and from a Risk Management standpoint, golf carts are used outdoors with an easy exit if there is a problem, the company is saving $500,000. The cost of any malfunctions created by the lack of a fuse in a cart is easily offset by the savings.

With the installation pdf you sent, I would use the same hardware on both battery post and pos battery cable to fuse to secure it as far as lock-washer, washer and nut, correct?

[dougmcp]

With the installation pdf you sent, I would use the same hardware on both battery post and pos battery cable to fuse to secure it as far as lock-washer, washer and nut, correct?

Yes.
The reason for this is because there is a certain amount of heating with connections, as the heat and cool, they will loosen up and create a poor connection.
Also the possibility of vibrations from driving the cart and loosening up your connections are substantially reduced.

[erict]

I looked for the fuse locally and they all wanted $32 for it I ended up just placing an order with evdrives and for (3) 250amp shipped to my door was $22 I figure I might as well have spares

http://www.evdrives.com/accessories.html#Fuse

[dougmcp]

I looked for the fuse locally and they all wanted $32 for it I ended up just placing an order with evdrives and for (3) 250amp shipped to my door was $22 I figure I might as well have spares

http://www.evdrives.com/accessories.html#Fuse

Now you'll have 2 spares. You should really never blow a fuse so if a neighbor needs one and you sell them for $11 each yours is paid for.

[erict]

Now you'll have 2 spares. You should really never blow a fuse so if a neighbor needs one and you sell them for $11 each yours is paid for.

I always buy spares when it come to fuses because one never knows

I see you read about that cart that caught fire in the other forum and that's what got me thinking I just wonder why it didn't blow in time with a controller failure. It didn't help at all Makes me think what good safety measure does this provide.

[dougmcp]

I always buy spares when it come to fuses because one never knows

I see you read about that cart that caught fire in the other forum and that's what got me thinking I just wonder why it didn't blow in time with a controller failure. It didn't help at all Makes me think what good safety measure does this provide.

Yes I read that.
Your cart is a stock cart that has been properly designed with mated components that will work for a long time in most situations. Properly maintained, you should never have any troubles.

The cart that caught fire was a sepex motor cart with a 6" lift, 23" tires, modified motor, 2ga cables and a 500 amp controller. If he dialed the controller all the way up which is what most people do he was running on the ragged edge of the controller limits.


The fuse is designed to protect the wiring and the component if it draws too much amperage (in this case 400a) but if a component won't take the demand or shorts out internally it usually will smoke first and then maybe burn. As soon as it starts to melt things, the wiring shorts out and takes the fuse out.
If there was no fuse it could continue to supply current until the cables melt, the whole cart is on fire and the batteries blow up.

The fire cart was built for a customer that likely had no idea of what happens or what to avoid. The worst thing you can do to a sepex motor is stall it, the field amperage goes wild and will usually smoke the controller, motor or both. The fuse is supposed to prevent this but sometimes the amperage run up is so fast that the components fry before the fuse has time to react.

BTW you have a sepex motor, don't stall it.

[ZackMan]

If I used the fuse holder then I would need a short cable (jumper), correct? How secure does it hold the main pos battery cable when connected to the fuse without a holder?

Also, why doesn't the cart manufactures have these installed at the factory if it's a good safety measure?

Okay I followed you up to this point. What is this short cable (jumper) you referenced? Is it in addition to the negative battery cable? How is it connected?

[erict]

Okay I followed you up to this point. What is this short cable (jumper) you referenced? Is it in addition to the negative battery cable? How is it connected?

If I use a fuse holder instead of bolting the fuse directly to the battery I would need a small jumper wire from the fuse holder to the battery.


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[erict]

Yes I read that.
Your cart is a stock cart that has been properly designed with mated components that will work for a long time in most situations. Properly maintained, you should never have any troubles.

The cart that caught fire was a sepex motor cart with a 6" lift, 23" tires, modified motor, 2ga cables and a 500 amp controller. If he dialed the controller all the way up which is what most people do he was running on the ragged edge of the controller limits.


The fuse is designed to protect the wiring and the component if it draws too much amperage (in this case 400a) but if a component won't take the demand or shorts out internally it usually will smoke first and then maybe burn. As soon as it starts to melt things, the wiring shorts out and takes the fuse out.
If there was no fuse it could continue to supply current until the cables melt, the whole cart is on fire and the batteries blow up.

The fire cart was built for a customer that likely had no idea of what happens or what to avoid. The worst thing you can do to a sepex motor is stall it, the field amperage goes wild and will usually smoke the controller, motor or both. The fuse is supposed to prevent this but sometimes the amperage run up is so fast that the components fry before the fuse has time to react.

BTW you have a sepex motor, don't stall it.

OK Doug, what is a sepex motor and what do you mean by don't stall it?

[ZackMan]

If I use a fuse holder instead of bolting the fuse directly to the battery I would need a small jumper wire from the fuse holder to the battery.


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Thanks for the explanation.

[erict]

Thanks for the explanation.

It seems the better choice is to just hook the fuse directly to the battery post to avoid needing the jumper wire and fuse holder

[dougmcp]

OK Doug, what is a sepex motor and what do you mean by don't stall it?

A sepex or regen motor is a separately excited motor that uses the field coils to alter the state of the motor to give it a different performance curve from the old style series motors. They are also the only ones that produce regen braking which limits the speed of the cart.

Stalling is when you try to start out and the cart doesn't want to move, like against a curb, wall, steep incline, heavy load etc. The current created when you stall a sepex motor is enough to cook it if you don't release the throttle.

Here is some info from the Curtis site which would probably make more sense than me trying to explain it:

I am not familiar with SepEx, what can you tell me about it?
SepEx or Separately Excited DC motor belongs to the family of the wound field DC motors including; Series, Shunt, and Compound. It is a 4 terminal motor where the armature (A1 and A2) and field windings (S1 or F1 and S2 or F2), are brought out the like a Series motor. But unlike a Series motor, a SepEx motor field is wound with finer gauge wire of many turns, and has to be independently driven by a SepEx motor speed controller. Since all Curtis SepEx controllers offer full bridge control of the motor field, this will make changing in direction of travel quiet and seamless without the use of direction contactors.

I heard that Series motors produce more torque than SepEx motors.
This is not true when an electronic motor controller is used. A motor controller will limit the current to a Series motor, effectively limiting its torque to the controller’s maximum current rating. A Series motor will only provide more torque than an equivalent SepEx motor if the Series motor is connected directly to a battery without any current limiting. In this case, the stalled motor current would be very high due to zero armature back EMF. However, once the motor got spinning, the torque would rapidly decrease.

[erict]

A sepex or regen motor is a separately excited motor that uses the field coils to alter the state of the motor to give it a different performance curve from the old style series motors. They are also the only ones that produce regen braking which limits the speed of the cart.

Stalling is when you try to start out and the cart doesn't want to move, like against a curb, wall, steep incline, heavy load etc. The current created when you stall a sepex motor is enough to cook it if you don't release the throttle.

Here is some info from the Curtis site which would probably make more sense than me trying to explain it:

If you stall it can it damage or cook it right away? Also, is this only when you apply full throttle?

[dougmcp]

If you stall it can it damage or cook it right away? Also, is this only when you apply full throttle?

It's difficult to explain but I would just say if you step on the gas and the cart doesn't move, take your foot off the gas and find out why. It certainly won't blow out immediately but it could happen within 5-10 seconds.
Usually people push on the throttle and if the cart doesn't move they push harder, I know I do.
If the motor is not spinning at least a little and power is being applied, there will be a problem.
I sometimes drive my truck with 2 feet, 1 on the gas and 1 on the brake, this is not a good idea in a golf cart.