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relay Q for headlight loom upgrade (its broke)

StylerG

NAXJA Forum User
Location
Oklahoma City
my high beams stopped working after a couple of months of running my GoJeep inspired headlight loom upgrade with the IPF Lenses and Fatboy bulbs. When looking at the system i can pin 30 on the relay (power from battery) and one of the pin 87's (Power from relay to lights) the lights come on. I find this odd because i only jump one pin 87 and both headlights come on
Any help on this before i go pick up a relay (which has to be tomm.)???
 
not really understanding what your saying about the pins

your feeding one pin and your getting lights?

Either way, I am pretty sure there are 2 dif relays, one where both 87 and 87a are live at the same time, and one where they are live seperately (when relay is fed 87 is open, 87a is closed)

If you have any other relays around it would be simple to toss one in, otherwise they are pretty cheap so picking one up wouldn't hurt the bank.

Only problem I ever had with the wiring upgrade was my daytime running lights (Canadian option).
 
i just re-read that, if i cross my power from battery (pin 30) to a single power to the lights (one of the two 87 pins) both headlights turn on
I found that odd because i wasnt jumping both 87 pins to turn both lights on, does that make more sense?
 
well if each headlight is wired independantly (2 relays, total, one relay controls hi/low beam of one headlight) and everything had been working upto this point, new relays may be in order.
seems odd that closing one relay turns both lights on (both headlights or both beams of light?)

wait a little longer, someone with more elec savvy than my limited mind can give you will chime in here.
 
There are three versions of the DIN relay:

1) Four-pin, SPST (Single Pole, Single Throw.) A simple "ON/OFF" relay. Usually numbered 30/85/86/87

2) Five-pin, SPDT (Single Pole, Double Throw.) Usually used as an "ON/OFF" relay, but can be used to switch to "one of two" circuits, powering one or the other. Usually numbered 30/85/86/87/87a

3) Five-pin, DPST (Double Pole, Single Throw.) Used to power two circuits "ON/OFF" at the same time. Usually numbered 30/85/86/87/87

Of the three, type (2) is the most common and easiest to find. Any of three can be used as a simple "ON/OFF" relay, but type (2) and type (3) may not be substituted one for the other.

DIN/ISO relays - the small 1" cubes - are typically rated for 30A per circuit - meaning that type (1) and type (2) can be used to supply a single 30A circuit, while type (3) - supposedly - can be used to feed two circuits at 30A. I've been loath to try it until I can set up controlled circumstances for evaluation. I've no trouble, however, using a DPST relay (type (3)) to feed 15A per circuit, and it can probably do 20A safely - I've just not tried it.

The DIN relay specification calls for the schematic of the relay to be stamped or inked on the side of the relay case - and the terminals on the bottom to be numbered. However, if the schematic is inked on the side of the cube, it can wear off.

Typical uses for the terminals:
Pin 30 - Mains Power Feed for the circuit
Pin 85 - "Trigger" lead for relay coil
Pin 86 - Earth for relay coil (direct ground will serve.)
Pin 87 - NO (Normally Open) accessory lead (OFF until the relay is turned triggered)
Pin 87a - NC (Normally Closed) accessory lead (ON until the relay is triggered.)

beakie said:
not really understanding what your saying about the pins

your feeding one pin and your getting lights?

Either way, I am pretty sure there are 2 dif relays, one where both 87 and 87a are live at the same time, and one where they are live seperately (when relay is fed 87 is open, 87a is closed)

If you have any other relays around it would be simple to toss one in, otherwise they are pretty cheap so picking one up wouldn't hurt the bank.

Only problem I ever had with the wiring upgrade was my daytime running lights (Canadian option).
 
5-90 your absolutely correct, i used a "type 3" relay with two 87 pin connectors. Tracked down someone and tested the relay, and the relay had gone bad. The stamping on the relay insenuates that the 30 amp rating is split between the two 87 pin connectors.
Should this concern me that my high relay went out (obviously i'll be upgrading to a 40 amp to see if that works) with 80 watt bulbs in (IPF Fatboys)?

On a seperate note, 5-90 this is my daily driver and doesnt have your wiring upgrade on it yet and everytime i work on it i think about ordering one up from ya...best upgrade i ever did to my trail rig.

Thanks for your help
 
StylerG said:
5-90 your absolutely correct, i used a "type 3" relay with two 87 pin connectors. Tracked down someone and tested the relay, and the relay had gone bad. The stamping on the relay insenuates that the 30 amp rating is split between the two 87 pin connectors.
Should this concern me that my high relay went out (obviously i'll be upgrading to a 40 amp to see if that works) with 80 watt bulbs in (IPF Fatboys)?

On a seperate note, 5-90 this is my daily driver and doesnt have your wiring upgrade on it yet and everytime i work on it i think about ordering one up from ya...best upgrade i ever did to my trail rig.

Thanks for your help

Thanks for the kind words! Sounds like I should flesh out that design for the relay tester I'm thinking about, tho...

As far as the relay current ratings, I'm of a divided mind on the literature. For the SPST and SPDT relays, having a 30A/circuit rating makes sense (since it only powers one circuit from the off.) However, the DPST relay being rated for "30A per circuit" seems a bit vague to me - which is why I don't push them past 15A or so...

For your lighting - 80W x 2 = 160W. 160W/12V = 13-1/3A. So, plenty safe margin there. Your relay may not have been pressed to capacity - relays usually end up failing (if the applications are properly designed) due to arcing of the contacts. You can actually tell when a relay is on the way out by testing resistance of the contacts with the circuit CLOSED - resistance will increase as carbon builds up due to arcing (I've seen this with high-power relays - a couple hundred amperes - but the condition is similar with lower-power relays. Same thing happens with toggle switches and house lamp switches as well - unless at least a "debouncing" diode is included, there's going to be a bit of sparking when the circuit closes. I've seen old toggle switches in houses where the switchbat would flash due to the sparking - I usually replaced those first.)

A 30A relay should carry up to 3600W (nominal - it will be a bit lower with operating voltages, which I usually take as "safe margin." W=V*A, and using the 12 nominal volts gives you a little wiggle room at the actual operating voltage of 13.6-14.4VDC.) So, no reason you can't use a 30A relay - or even a 20A relay, if that's all you can find. As long as it's a DIN relay, or you'll have to adapt the socket...
 
5-90 said:
There are three versions of the DIN relay:

1) Four-pin, SPST (Single Pole, Single Throw.) A simple "ON/OFF" relay. Usually numbered 30/85/86/87

2) Five-pin, SPDT (Single Pole, Double Throw.) Usually used as an "ON/OFF" relay, but can be used to switch to "one of two" circuits, powering one or the other. Usually numbered 30/85/86/87/87a

3) Five-pin, DPST (Double Pole, Single Throw.) Used to power two circuits "ON/OFF" at the same time. Usually numbered 30/85/86/87/87

Of the three, type (2) is the most common and easiest to find. Any of three can be used as a simple "ON/OFF" relay, but type (2) and type (3) may not be substituted one for the other.

DIN/ISO relays - the small 1" cubes - are typically rated for 30A per circuit - meaning that type (1) and type (2) can be used to supply a single 30A circuit, while type (3) - supposedly - can be used to feed two circuits at 30A. I've been loath to try it until I can set up controlled circumstances for evaluation. I've no trouble, however, using a DPST relay (type (3)) to feed 15A per circuit, and it can probably do 20A safely - I've just not tried it.

The DIN relay specification calls for the schematic of the relay to be stamped or inked on the side of the relay case - and the terminals on the bottom to be numbered. However, if the schematic is inked on the side of the cube, it can wear off.

Typical uses for the terminals:
Pin 30 - Mains Power Feed for the circuit
Pin 85 - "Trigger" lead for relay coil
Pin 86 - Earth for relay coil (direct ground will serve.)
Pin 87 - NO (Normally Open) accessory lead (OFF until the relay is turned triggered)
Pin 87a - NC (Normally Closed) accessory lead (ON until the relay is triggered.)

Times like these I don't mind being wrong at all. Corrected my mistake, informed with right info, and without 'tude or 'above ye' tone. Love it.
I had forgotten about the 3rd (4pin). Don't mind adding to the knowledge base though, thanks.

Told ya someone with better knowledge would chime in, was right on that one. Ah ha!
 
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