Fix for slow Fiat wipers

turbofiat124

turbofiat124

True Classic
I mentioned this awhile back because I read on here where someone had done this except with a 12 to 16.5 step up voltage converter. I found the thread in the archives but they never posted any photos, diagrams, videos, etc. Then they just disappeared.

I've owned my 124 Spider for almost 24 years and the one thing that has always bothered me are the wipers on this car. I "upgraded" to a Bosch wiper motor from a VW/Audi which is a step above the Marelli unit but it still did not suit me.

So I finally installed a 12 to 15 volt step up converter. So far so good.

It has been suggested using a couple of relays to compensate for the voltage drop across the wiring and switches in the wiper motor system and all and I'm not saying anybody is right or wrong but I had already started on this project so I wanted to see how well this device was going to work.

Also there is not much more wiring involved in this step up converter versus a relay anyway. I bought this item off Ebay.

OK so I finally got my elusive 8 amp circuit breaker from a company called Crimp Supply. It seems none of the auto part stores sold these circuit breakers below 15 amps. The converter itself is rated at 5 amps which should be sufficient since both the blower motor and wiper motor operate off an 8 amp circuit. I don't know how much current each individual component pulls.

I went back and rewired my converter (to and from) using 14 AWG wire which is good for 15 amps. 14 AWG wiring might be overkill... I don't know right off hand what the metric equivalent is to AWG.

I ran the input and output wires through the grommet on the passenger side then behind the dashboard and to the ignition switch. There are two yellow/black wires that go to the column switch which are connected to the yellow output (15 volts) wire. The red input (12 volt) wire is connected to a wire coming directly off the ignition switch instead of the fuse box. The box is grounded using the original ground wire that went to the motor and the motor is grounded using the 15 volt ground wire.

The reason for using the 8 amp circuit breaker initially was, with the engine was not running, the wiper motor would make one swipe then blow a 7.5 amp fuse. My guess is because the less voltage you feed into a step up converter, the more amps it pulls. But with the engine running, it would not blow fuses.

But the voltage drop was not that low. I tested the voltage with the engine not running and it was around 12.4 volts and somewhere between 13.5 and 14 volts engine running. I did not test the voltage directly at the wiper motor by the time power went through all the switches and such.

It seems at one time the circuit breaker tripped for a second or two but that was it. I may have accidentally had it on intermittent mode and didn't realize it. I may be upgrading to the 10 amp version of this device if this occurs again.

Here are some photos. I found a indention about the same size in the center of the cowl panel where I decided to mount the converter which is "supposedly" water proof. I figured it being mounted in a heat sink, it would get plenty of airflow in this location and help cool it.

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Here's a couple of video's I shot:

http://vid222.photobucket.com/albums/dd148/turbofiat/Videos/fast wipers2_zpsvs2hdn5v.mp4

http://vid222.photobucket.com/albums/dd148/turbofiat/Videos/fast wipers_zpsnkfbuq2i.mp4

One thing about it, unlike before when the headlamps and heater motor fan are switched on, they do not affect the speed of the wiper motor at all. So far I'm impressed with the result. Also I should point out there is no Rain-X on the windshield whatsoever. Before Rain-X was a must or the wipers would otherwise stop and I'd have to help them return to rest.
 
Nice results!:D

Could you post a link to the voltage booster you got on eBay?

I don't know a lot about Spiders, but I think I recall someone saying that the entire car runs on four circuits. If that's true, it's well into Lucas "Prince of Darkness" territory!!!
 
I'm as dumb as a box of rocks when it comes to electrickity stuff (but it doesn't stop me!) but wouldn't ramping up the voltage to the wiper motor further tax the charging system (that was barely adequate when new and in good order)? I added relays which made a huge difference and now wiper speed is "normal". Even so, when wipers are on the volt meter tells me things are being stretched and I run a 100 amp GM alternator! (not to say that it's set up perfectly!)
This is a cool solution though.
Does the wiper motor care that it's getting more volts then designed for?
 
The low voltage problems in a FIAT rarely have anything to do with the charging system. The low voltage problems in a FIAT are the result of age on a barely adequate distribution system.

One problem is the use of those spade connectors everywhere, some of which are exposed to weather. These will tarnish/corrode (even those out of the weather) and provide a voltage drop.

Next is the use of those bullet fuses on early cars. Not only do they tarnish, the holders also lose their grip over the years. Often the fuses end up spinning freely in their sockets. There's another big voltage drop.

Then there is tarnishing/pitting of the switches, primarily those switching large loads. Not only does that create a voltage drop, the voltage drop creates heat which tends to melt the plastic supporting structures. This creates more voltage drop, more heat, eventually leading to complete switch failure.

Another thing to consider are motors which are not spinning as freely as they did 30+ years ago. These will place an even greater demand on the struggling power distribution system.

Finally, FIAT used the minimum wire gauge in most of the circuits and this wire is not up to the task of handling now sluggish motors or upgraded lights.

The best thing you can do is to use relays to offload power from various switches like the keyswitch, headlight switch, and wipers.

The next thing, if you have bullet fuses, is to clean the tarnish off the fuses and holders, then pinch the fuse holders together so they hold the fuse tightly again.

Finally, disconnect and reconnect each spade terminal to give them a fresh bite, especially those ground ones in the weather. Don't forget these are also used on all the bullet type fuse holders, though it can be a challenge to mess with them. They are also used on the main distribution point coming from the battery.

jvandyke said:
I'm as dumb as a box of rocks when it comes to electrickity stuff (but it doesn't stop me!) but wouldn't ramping up the voltage to the wiper motor further tax the charging system (that was barely adequate when new and in good order)? I added relays which made a huge difference and now wiper speed is "normal". Even so, when wipers are on the volt meter tells me things are being stretched and I run a 100 amp GM alternator! (not to say that it's set up perfectly!)
This is a cool solution though.
Does the wiper motor care that it's getting more volts then designed for?
Click to expand...
 
Dan Sarandrea (Phila) said:
Nice results!:D

Could you post a link to the voltage booster you got on eBay?

I don't know a lot about Spiders, but I think I recall someone saying that the entire car runs on four circuits. If that's true, it's well into Lucas "Prince of Darkness" territory!!!
Click to expand...

Here is the step up voltage booster:

http://www.ebay.com/itm/161898374968?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

Here is the 8 amp circuit breaker:

http://www.ebay.com/itm/251731060100?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

I couldn't find these from any of the local autopart chains below 15 amps. I did not check with NAPA which is on the other end of town. Just my local Autozone, Advance and O'Reilys.

You'll need to get one of those ATO in-line fuse holders and cut two of each tab off. I like to over do everything so I used a fuse holder with 12 AWG wire rated for 30 amps.

After checking the current draw with a meter I can understand why the fuse blows with the engine not running. Initially when the system is switched on, there is a huge increase in current for about one second then the current draw tapers off. By using a self resetting circuit breaker, takes care of this.
 
geekdaddy said:
Looks like this is a good solution that worked well for you.
I followed the insertable relay approach and also acheived good results. I think the relay may provide an additional benefit because it offloads the ignition switch. Before and after video here.
https://www.youtube.com/watch?v=n0Aa-NFMxIc
Click to expand...

Either way seems to work.

Like I mentioned there is not much wiring involved in the step up voltage converter than using the relays.

I actually did install a relay on my Fiat 131 between the fusebox and column switch and didn't see much increase.

Question:

Since you are using two relays, I'm assuming one relay is for the slow speed and the other relay is for the fast speed? So the park and intermittent functions do not see "battery" power but power otherwise?

I used a single relay on my Brava which boosted power to everything on the wiper motor circuit.
 
jvandyke said:
I'm as dumb as a box of rocks when it comes to electrickity stuff (but it doesn't stop me!) but wouldn't ramping up the voltage to the wiper motor further tax the charging system (that was barely adequate when new and in good order)? I added relays which made a huge difference and now wiper speed is "normal". Even so, when wipers are on the volt meter tells me things are being stretched and I run a 100 amp GM alternator! (not to say that it's set up perfectly!)
This is a cool solution though.
Does the wiper motor care that it's getting more volts then designed for?
Click to expand...

I wouldn't think so.

Really, if the voltage drop between the ignition switch and wiper motor wasn't so bad, in reality I'd only be bumping up the voltage by 1.5 volts which isn't enough to burn the motor up. I'm just more less compensating for the voltage drop in the system.

If there was no voltage drop in the system then the true voltage would be between 13.4 volts and 14.3 volts.

If the battery is strong, then the alternator doesn't put out more than 13.4 volts. If the battery is slightly weak, the alternator puts out around 14.3 volts.

By the way. Some people have said that bumping the voltage up will increase current and require heavier wiring. On the contrary. If you plug in these numbers in an electrical calculator you will discover a 12 volt 60 watt light bulb will pull 5 amps but a 110 volt 60 amp light bulb will pull .5 amps.
 
turbofiat124 said:
By the way. Some people have said that bumping the voltage up will increase current and require heavier wiring. On the contrary. If you plug in these numbers in an electrical calculator you will discover a 12 volt 60 watt light bulb will pull 5 amps but a 110 volt 60 amp light bulb will pull .5 amps.
Click to expand...

It doesn't quite work that way.

For a 100% efficient converter, watts must be balanced on both sides. The calculation is P=IE (watts=amps*volts)

So, for 60 watts out at 15 volts it's supplying about 4 amps. HOWEVER, the converter is actually creating those 60 watts with 13.5 volts by using about 4.4 amps. While the engine is off it's creating those 60 watts with 12.5 volts using about 4.8 amps.

In reality, no converter is 100% efficient. For a 90% efficient converter a 60 watt load will be causing a 66.7 watt draw on the input side. Therefore with the engine off, to create 60 watts out at 15 volts the converter will be using 66.7 watts in at 12.5 volts with about 5.3 amps.

Ugh, now my head hurts. :)
 
sdlsaginaw said:
It doesn't quite work that way.

For a 100% efficient converter, watts must be balanced on both sides. The calculation is P=IE (watts=amps*volts)

So, for 60 watts out at 15 volts it's supplying about 4 amps. HOWEVER, the converter is actually creating those 60 watts with 13.5 volts by using about 4.4 amps. While the engine is off it's creating those 60 watts with 12.5 volts using about 4.8 amps.

In reality, no converter is 100% efficient. For a 90% efficient converter a 60 watt load will be causing a 66.7 watt draw on the input side. Therefore with the engine off, to create 60 watts out at 15 volts the converter will be using 66.7 watts in at 12.5 volts with about 5.3 amps.

Ugh, now my head hurts. :)
Click to expand...

That was probably a poor example I gave.

When I checked the current draw of the converter, I noticed the current draw was higher based on voltage output from the alternator and with the headlamps and heater fan on. Don't quote me on these numbers because I didn't write them down, this is just from memory.

By the way. I rigged up an Autometer ammeter gauge in place of the fuse because my multi-meter only reads in milliamps.

Engine not running (at 12.6 volts measured before converter)

wipers on : ~ 5 amps
wipers+headlights+heater fan : 10 to 15 amps

This time the 8 amp breaker did not trip.

Engine running (~13.3 volts before the converter)

wipers on ~2 amps
wipers+headlamps+heater fan : ~ 5 amps

So as long as the engine is running and the alternator is producing enough voltage all should be fine.

Although it would take more wiring, one idea could be to take the supply voltage directly off the battery instead of the ignition switch and use a relay to reduce the current draw when the engine is not running.

On the other hand, who's going to be running the wipers,headlamps and heater fan when the engine is not running?
 
I'm completely not following this...

turbofiat124 said:
Engine not running (at 12.6 volts measured before converter)

wipers on : ~ 5 amps
wipers+headlights+heater fan : 10 to 15 amps

Engine running (~13.3 volts before the converter)

wipers on ~2 amps
wipers+headlamps+heater fan : ~ 5 amps

So as long as the engine is running and the alternator is producing enough voltage all should be fine.
Click to expand...

Why would the wipers draw less amps whether the engine is running or not? I am no Tesla, but it seems to me that the amps are "drawn" by the device, not pushed from the power source. Having a better or worse power source should not change the draw. I am wondering if gauge accuracy is at play here, especially if the gauge is calibrated for, say, 50 amps and you are reading in the bottom 10% of the gauges ability.

I do agree with Jeff and Steve's assertion that the "extra" power is not free. To create more volts requires pulling more amps. Since amps (not volts) dictate wire size, you are asking more current to be drawn across the same size wires (and through an already-taxed ignition switch and all points upstream back to the battery).

It's a clever mod, and I'm glad it's working for you. But personally I would go with a relay modification.

Pete
 
I don't want my posts to sound like I'm raining on his parade. I think this is a very cool upgrade for the simple fact that the wipers wouldn't slow down sitting at a stoplight because they are now being fed a regulated voltage rather than whatever the alternator outputs at idle.

I *would* advise getting the headlights off the circuit. At 110 watts they are using the bulk of the converters capability all by themselves.

I'd hate to be on the freeway on a drizzly night with the heater and wipers going, hit my high beams (130 watts), and suddenly find myself in the dark.

I'm also not sure the headlights will last running at 15 volts all the time.
 
Pete Whitstone said:
Why would the wipers draw less amps whether the engine is running or not? I am no Tesla, but it seems to me that the amps are "drawn" by the device, not pushed from the power source. Having a better or worse power source should not change the draw.
Pete
Click to expand...
The wiper motor is fed a constant 15V from the DC-DC converter, and the current draw of the wiper motor would not change with the battery voltage of the car. The current that the DC-DC converter draws from the battery does change with the battery voltage. As sdlsaginaw said, the power delivered by the DC-DC converter to the wiper motor stays constant, the power delivered by the car electrical system to the DC-DC converter stays constant too (as a good first order approximation; DC-DC converter efficiency changes with supply voltage). Power equals current times voltage, so if the supply voltage drops, the current draw of the DC-DC converter increases to keep the power constant.
 
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Gruffalo said:
I=U/R
Less voltage equals less current
Click to expand...
Yes, for a resistive load Ohm's law is fine, but a DC-DC converter is not a resistive load. In this case it is a device that draws constant power, so as supply voltage drops, current drawn from the supply goes up.
 
Introducing a DC DC converter only, without upgrading the wiring, connectors and such, is a workaround at best. The same old crappy circuitry will still have to carry all the load (and more, adding the loss in the converter).

I don't wanna sound like a smartass or anything, but there's no magic to it, really.

:)
 
sdlsaginaw said:
I don't want my posts to sound like I'm raining on his parade. I think this is a very cool upgrade for the simple fact that the wipers wouldn't slow down sitting at a stoplight because they are now being fed a regulated voltage rather than whatever the alternator outputs at idle.

I *would* advise getting the headlights off the circuit. At 110 watts they are using the bulk of the converters capability all by themselves.

I'd hate to be on the freeway on a drizzly night with the heater and wipers going, hit my high beams (130 watts), and suddenly find myself in the dark.

I'm also not sure the headlights will last running at 15 volts all the time.
Click to expand...

I'm not running the headlamps off the thing! Just the wiper motor.

The only reason I mentioned headlights and heater fan was because these two circuits would drop the speed of the wipers. Now that I have regulated power going to the wiper motor, the headlamps and heater fan no longer effect the speed of the wiper motor.

My headlamps and auxiliary lamps are running off relays so they take the load off the ignition switch.
 
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