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#1
posted to rec.boats.electronics
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Losing locator and stereo when cranking
Hi everyone!, Hey I'm having a small but irritating problem with an
electrical circuit on my 1993 OMC Sunbird. The problem is that sometimes the engine doesn't start right away and requires a few more cranks by the starter to get it going. I'm talking about a 3 - 4 second crank time altogether before it starts. When the cranking hits the 4 second mark it seems I lose power briefly to my fish locator and stereo. If the engine manages to start in the 2 - 3 second time frame this doesn't happen. I have load banked my battery and it tests really well. I have the locator and stereo connected to my accessories dash rocker switch. Is there a quick fix for this besides installing a second batery? Do I need to install a diode in the accessory circuit to prevent the started from sucking power back from the locator and stereo? Thanks. Chris |
#2
posted to rec.boats.electronics
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Losing locator and stereo when cranking
Chris Mares wrote in news:7sXGg.6579$Tl4.3557
@dukeread06: Is there a quick fix for this besides installing a second batery? Do I need to install a diode in the accessory circuit to prevent the started from sucking power back from the locator and stereo? No, what you need to do is to turn off ALL ELECTRONICS while cranking the engine to protect the electronics from the inductive kick and low voltage the starter drawing 300 amps from the poor little battery creates. Go out to your car and turn on the switch. Turn on the radio. Now, notice how your radio turns OFF while the car is cranking to protect it from the awful surges cranking produces? Do you think car manufacturers do that to spend more money building the car....or to keep owners with warranties from getting free radios? All electronics hooked to the same battery the starter is hooked to need to be OFF WHILE CRANKING! The reason for the shutdowns you're seeing is the battery voltage drops to 10V or less from the awful current drain, especially if you hold it and the battery runs low on electronics as its chemistry is under such a shock.... -- There's amazing intelligence in the Universe. You can tell because none of them ever called Earth. |
#3
posted to rec.boats.electronics
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Losing locator and stereo when cranking
300 amps? How big is the motor he's cranking?
Or, he has a dirty battery terminal. My Crown Vic 302 showed me how that works. After the dirty terminal gets warm, it's resistance starts to go up, then it gets hot. Depending on how the terminal reacts, strange things can happen in the course of a few seconds. The terminal got worse until, if the car didn't start right away, it quit trying and even the dash lights went out. An hour or two later, it was ok. Got caught downtown after a short stop, called a cab for a boost. Voltmeter was bouncing all over the place. Low idle speed, engine quits. Brownish crumbly snow around terminal connection. Clean terminals, no more probs. The battery was a little low, but OK. Terry K |
#4
posted to rec.boats.electronics
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Losing locator and stereo when cranking
"Terry K" wrote in news:1156440924.118445.64140
@p79g2000cwp.googlegroups.com: 300 amps? How big is the motor he's cranking? Or, he has a dirty battery terminal. My Crown Vic 302 showed me how that works. After the dirty terminal gets warm, it's resistance starts to go up, then it gets hot. Depending on how the terminal reacts, strange things can happen in the course of a few seconds. The terminal got worse until, if the car didn't start right away, it quit trying and even the dash lights went out. An hour or two later, it was ok. Got caught downtown after a short stop, called a cab for a boost. Voltmeter was bouncing all over the place. Low idle speed, engine quits. Brownish crumbly snow around terminal connection. Clean terminals, no more probs. The battery was a little low, but OK. Terry K I always assume they've at LEAST cleaned the terminals before posting here...(c; 300A is easy on a diesel engine with 22:1 compression ratio and cold oil. 800A if it stalls the starter motor The conductors JUMP!....(c; -- There's amazing intelligence in the Universe. You can tell because none of them ever called Earth. |
#5
posted to rec.boats.electronics
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Losing locator and stereo when cranking
In article ,
Larry wrote: "Terry K" wrote in news:1156440924.118445.64140 @p79g2000cwp.googlegroups.com: 300 amps? How big is the motor he's cranking? Or, he has a dirty battery terminal. My Crown Vic 302 showed me how that works. After the dirty terminal gets warm, it's resistance starts to go up, then it gets hot. Depending on how the terminal reacts, strange things can happen in the course of a few seconds. The terminal got worse until, if the car didn't start right away, it quit trying and even the dash lights went out. An hour or two later, it was ok. Got caught downtown after a short stop, called a cab for a boost. Voltmeter was bouncing all over the place. Low idle speed, engine quits. Brownish crumbly snow around terminal connection. Clean terminals, no more probs. The battery was a little low, but OK. Terry K I always assume they've at LEAST cleaned the terminals before posting here...(c; 300A is easy on a diesel engine with 22:1 compression ratio and cold oil. 800A if it stalls the starter motor The conductors JUMP!....(c; as well as the batteries...... |
#6
posted to rec.boats.electronics
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Losing locator and stereo when cranking
Inductive kick from switching a starter motor off does not get
transmitted to the electronics. The inductive kick comes from the induction of the windings in the starter motor when the current is interrupted. But if the current has been interrupted it is no longer connected to the battery so the spike is restricted to the starter motor side of the switch. Radios and accessories in a vehicle are turned off during cranking to minimize additional loads on a struggling battery so its full output is available for the starter motor. It has nothing to do with protecting the electronics. The problem with low voltage drop-out is when you have computer based equipment that takes forever to re-boot or radar which has to go through a warm-up delay before applying power to the magnetron. Turning these off to crank an engine and then having to wait for them to re-boot is not only frustrating but could be dangerous if you had an engine failure in an emergency situation, right when you may need that radar or depthfinder the most. Most modern marine electronics can accept a very wide range of input voltage so it sounds like the voltage is dropping too low during cranking. As suggested above this could be a bad battery connection (check the GROUND connections too) or it could be a battery failure in progress. If you have a combiner and a house battery, move the sensitive electronics to the house battery where they will not be subjected to the low voltage during cranking. |
#7
posted to rec.boats.electronics
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Losing locator and stereo when cranking
Terry K wrote:
300 amps? How big is the motor he's cranking? Or, he has a dirty battery terminal. My Crown Vic 302 showed me how that works. After the dirty terminal gets warm, it's resistance starts to go up, then it gets hot. Depending on how the terminal reacts, strange things can happen in the course of a few seconds. The terminal got worse until, if the car didn't start right away, it quit trying and even the dash lights went out. An hour or two later, it was ok. Got caught downtown after a short stop, called a cab for a boost. Voltmeter was bouncing all over the place. Low idle speed, engine quits. Brownish crumbly snow around terminal connection. Clean terminals, no more probs. The battery was a little low, but OK. Terry K The terminals are clean, I clean them every 6 monthes and I have had the problem for about 5 years now. |
#8
posted to rec.boats.electronics
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Losing locator and stereo when cranking
Is there a quick fix for this besides installing a second batery?
Do I need to install a diode in the accessory circuit to prevent the started from sucking power back from the locator and stereo? Clean the terminals to the battery. Clean the terminals on the starter. Replace the wires to the starter (both positive AND negative). This is about the extent of 'quick fixing'. Possibly use heavier gauge wire to the "locator" (chartplotter or something?). This to make sure it's getting enough juice anyway. If it's using too small a gauge wire it may not be getting the right level of voltage to begin with. But if you've got these devices on the same battery you really should be TURNING THEM OFF before cranking the starter. Your best solution is to get a second battery installed. It may be simplest to get a new one just for cranking the engine. That way you'd probably be able to leave everything else wired to the existing battery and only have to rewire for the starter/ignition. Having a second battery helps make sure you don't end up stranded somewhere after spending all afternoon/night on the hook listening to the radio... |
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