Would like Opinion/s on Voltage Drop when Starting

[tperk100]

My Garmin echoMAP CHIRP 94sv was powering down when starting the engine......not unusual from my experience with 6 previously owned boats. I have corrected this in the past by installing a DC to DC Voltage Regulator. So I just installed a SVS1212050.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

My Garmin still powers down. The following dialogue comes from an email string I am having with the manufacturer. I have not received a response to this yet, but am looking for other's opinion on the documented voltage drops.

"I put a load tester on my fully charged starting/main battery and it read Good.
I disconnected kill switch so I could crank starter without actually starting up.
I put DVM on BATTERY terminals and cranked the engine for about 10 seconds. The voltage remained steady at 11.0 volts
SVS INPUT is connected to my power distribution and ground busses near instrument cluster in my main console.
I put DVM on the busses. Cranking engine showed a steady 10.0 to 10.1 volts.
I powered up SVS with my ?Accessories ? console switch I have it connected to. The green light only was lit up.
I put DVM on INPUT Terminals of the SVS, cranked engine and read steady 9.8 to 9.9 volts. Yellow ?Low Input? LED was flashing.
I put DVM on OUTPUT side of SVS with my Garmin echoMAP 94, my VHS radio, and my Sony stereo attached. Cranked engine and read a steady 12.3 volts. So it seems the SVS works in my garage with a 9.8 V input.

I have to wonder if a 1.0 volt drop from the battery to the power distribution panel in the console where the SVS input is connected and then another .2 volts from the buss through the switch to the SVS input terminal is too much. I do not know. I do not think this should matter though because your Amazon ad says ?Highly stable under a range of input conditions (8 ? 16 VDC input).? I am confused though because your website spec sheet says ?Input 11V to 17V (will dip to 8V)? This suggests to me that the constant 9.8 volts at SVS input when cranking the engine is not acceptable??even though I was getting 12.3 output.

So why did my Garmin power off when starting my engine on the water. Keeping the Garmin powered up was the main reason I purchased the SVS."

I am thinking about running the power and ground for the SVS directly to the battery.

Thanks for any help with this.

 

[Scott Danforth]

get a bigger battery or get a second battery, leave the starting battery alone and move the electronics to a house battery

the current required to spin your motor takes X number of amps. (between 200 and 400) so your battery voltage is going to dip a bit during cranking.

your choice is to add more capacity or change how your boat is wired.

also, a 1 volt drop between the battery and helm indicates you have a poor connection somewhere

 

[tperk100]

get a bigger battery or get a second battery, leave the starting battery alone and move the electronics to a house battery

the current required to spin your motor takes X number of amps. (between 200 and 400) so your battery voltage is going to dip a bit during cranking.

your choice is to add more capacity or change how your boat is wired.

also, a 1 volt drop between the battery and helm indicates you have a poor connection somewhere

Scott ,

Thanks for your response. I had not really thought about a bigger battery. Believe it or not my starting battery is an Optima manufactured in 2003 and is still going strong. Don't know the cranking amps on it but a bigger battery is a solution I had not thought of. Will keep this in mind.

House battery is out. Have three batteries now and do not have the room or weight capacity for another.

Are you sure the 1 volt drop is too much? I have checked connections, but will check again. The only connections are at the battery and through my battery switch and the push on connectors for the +/- busses.

On another forum I was advised to put a 2 Farad capacitor across the positive and negative busses in the console, and that the capacitor and the SVS combined "are sure to work." I have ordered the capacitor.

 

[Scott Danforth]

Optima batteries suck

 

[tperk100]

Optima batteries suck

Why do you say that?

I agree. I bought this 1997 boat in 2009. It had the current Optima starting battery and 2 other Optimas for the 24v trolling motor. Both TM batteries were defective. I looked into buying Optima. They cost almost THREE times as much and offered NO BETTER WARRANTY than the Advanced Auto brand. I am still running the Advanced Auto TM batteries that I bought in 2013....forgot Brand Name, but it is a common one.

They also suck because AH ratings are miserable.

 

[dingbat]

You have me scratching my head. You have 3 batteries and can't isolate the Garmin from the starting circuit?

Put meter on "peak read" then run your crank test. Bet your monentarily dropping under 10vdc threshold of the 94

What else do you have hooked to the regulator? Only rated to 60w, Garmin takes 20w min. Did you load test? What else do you have connected to it?

In a 12 Vdc circuit, 1 volt is almost 10%. That's 3 times best practice and twice recommend maximum voltage drop.

I have a Garmin CHIRP 94Sv and 4208, Furuno 587, Icom 502 and a 200w CD changer running of a dedicated electronics distribution panel. Connected to the battery with 10 gauge duplex wire. 12.67 VDC at the battery post, 12.67 VDC at the Garmin connector.

 

[tperk100]

I have three batteries because this is a fishing boat with a 24v trolling motor.

I can promise you that your distribution panel will not read 12.67 v if you are connected to the starting battery and are cranking the engine...as I indicated in my post.

My post also indicates what is connected to the regulator, and that I load tested the battery.

Today I am going to disconnect connections from battery to console +/- busses, clean them well, re-connect , and test the drop......while cranking.

 

[Scott Danforth]

Why do you say that?

Because I have purchased and spec'd out over a million batteries, and used to spec Optima on equipment that I was in charge of. then when Johnson Controls bought them in 2000 and move their plant to mexico, the quality went from good to horrible. the warranty went from 1 in a thousand to an average of 2 batteries per pallet.

couple the poor manufacturing along with the fact that your 14 year old optima is 9 years older than its design life, I suspect the battery is degraded.

you have a 1 volt drop to your helm which is over the acceptable rule of thumb of 5%, and about 10 times what you should ever get with good connections and properly sized wire.

voltage drop on a 10 gauge wire with 10 amps and a run of 10 feet would be 0.2 volts or 1.7%
voltage drop on a 10 gauge wire with 10 amps and a run of 40 feet would be 0.8 volts or 6.7%
voltage drop on a 10 gauge wire with 30 amps and a run of 10 feet would be 0.6 volts or 5%
voltage drop on a 10 gauge wire with 30 amps and a run of 40 feet would be 2.4 volts or 20%
voltage drop on a 4 gauge wire with 30 amps and a run of 40 feet would be 0.6 volts or 5%

 

[tperk100]

Scott,

Now this is VERY helpful. Thank you.

 

[tperk100]

Scott,

FYI, just did another load test on battery with another (newer) tester. Battery is rated at 750 CCA. I used the 800 CCA scale, loaded it until the tester started smoking (about 15 seconds), and it never even approached the yellow zone....stayed in the green zone the whole time. I don't have the experience you do with batteries but I do have a lot. I cannot believe that this 14 yr old battery is performing so well.

The tester amperage draw is 100. I suppose it's possible that cranking my engine draws more current and drops the voltage accordingly......if the battery really is weak. What do you think?


And, BTW, you realize the voltage drops I am referring to in original post are when the starter is turning......right?

 

[cjstangman]

This is what you need. I designed it to fix this very issue. https://www.myfishingdepot.com/wiring-harness

The problem arises when the voltage drops on the power bus wires combines with the voltage drop caused by the starter. This kit eliminates the voltage drop on the power bus by giving your electronics their own circuit. You still have the voltage drop from the starter, but I have installed 3 of these on friends' boats and they all reported that their devices remain running on startup.
You are smart to be worried about it shutting off though. Repeated brown-outs damage the power supply in the GPS and eventually cause it to fail. Especially on new electronics with big touch screens.

 

[tperk100]

CJ,
Thank you....NO insult intended but I almost have that now, and I can do the whole thing for WAY less than $250. In my former life I was an Electronics Tech.

 

[cjstangman]

Oh for sure. If you know what you are doing, go for it. Let me know if you want more details on how I made it. If you are building a new harness put a switch in it so that your devices don't drain the battery with standby power.
For anyone that doesn't have electrical experience, it will cost a lot more than $250 to pay someone to do it. You wouldn't believe the fire hazards I have seen in boats from guys that tried it themselves or got their buddy to do it because he claimed he knew what he was doing.

 

[Scott Danforth]

cjstangman your post is borderline solicitation.

 

[cjstangman]

I'm not trying to be sneaky about anything. I am just trying to help. Tperk's issue is a common one and I have a solution to it. Like I told him, if anyone has any specific questions about how I designed it so they can make their own, I am happy to answer them. If they just want a solution that will fix their problem ASAP, I'm happy to sell them one.

 

[tperk100]

CJ,
Good answer. Seems reasonable to me.