What is causing my electricals to reboot?

iflyvfr

iflyvfr

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I have a 66G model 172 with a Plane Power Alternator conversion. My ammeter was showing a slight charge yesterday which is normal. However, when I pressed the PTT to respond to tower's instructions, my avionics shut down like a fuse blew. After a full second, everything came back on. It happened so quickly I didn't have a chance to troubleshoot. I called tower, landed and taxied in normally.

At the time I was running at 2300 RPM and everything seemed normal, including a neutral to slightly positive charge showing on the ammeter. Anyone experienced this before? I know electrical gremlins can be a bear. I plan on calling Plane Power and my mechanic tomorrow to tell them this tale of woe.
 
What was the battery voltage and what did your ammeter say when you keyed up the radio?
 
denverpilot said:
What was the battery voltage and what did your ammeter say when you keyed up the radio?
Click to expand...
My GPS displays voltage and it's regularly around 12.3 - 12.6 when I'm just cruising along. Now I *think* that's low, but my mechanic and an electrical engineer I know don't agree with me.

As far as what my ammeter said, it's part of my scan and it was normal up until the event, but for the 1-2 seconds that everything shut down, I honestly couldn't tell you what it did. I was mentally forming my reply to tower and then, nothing.
 
At first glance, it seems like you were really just running on battery power, and the alternator wasn't charging the battery or providing power for high current draws at all. Key the radio, high current draw, voltage drop, radio dies, voltage returns to nominal, everything reboots.
 
iflyvfr said:
I have a 66G model 172 with a Plane Power Alternator conversion. My ammeter was showing a slight charge yesterday which is normal. However, when I pressed the PTT to respond to tower's instructions, my avionics shut down like a fuse blew.
Click to expand...

This sounds like high resistance in either the power supply wiring or in the ground wiring. Open up as many relevant connections as you can and clean them, reassembling when they are clean and bright.

-Skip
 
Nate, I was going to reply that if that were the case, I would think I wouldn't get a restart out of my battery. Except that I keep it on a Battery Minder all the time so it's getting recharged in between flights. Battery is 2 YO, BTW. I need to check the voltage at the battery next time. I did win a $100 gift certificate toward a new set of 172 cables so if Skip is onto something, that might help having brand new cables.
 
This problem is not related to current draw at all. It has to do with the Plane Power electronic voltage regulator, which requires only a few microamps from the system to measure the voltage level. The older electromechanical regulators required quite a few milliamps to do the same thing.

The source of the problem is a dirty or corroded antenna cable connection somewhere between the comm radio and its antenna. That allows RF to escape when you key the PTT, and the airplane's wiring picks it up and turns it into voltage spikes just big enough to make the regulator think there's an overvoltage condition, and it trips off. The old regulators were immune to that sort of thing because they drew so much current, which means their resistance was low, so they'd just sink such spikes without reacting to them.

Cessna started using solid-state ACUs in the 1980s and that RF was a problem. The phenomenon can be found in the troubleshooting chart in the maintenance manual.
 
iflyvfr said:
Nate, I was going to reply that if that were the case, I would think I wouldn't get a restart out of my battery. Except that I keep it on a Battery Minder all the time so it's getting recharged in between flights. Battery is 2 YO, BTW. I need to check the voltage at the battery next time. I did win a $100 gift certificate toward a new set of 172 cables so if Skip is onto something, that might help having brand new cables.
Click to expand...

Yeah check stuff. Battery voltage at rest is the first thing. Skip's idea is valid too... a loose power connection would often exhibit high resistance. Etc.

It's pretty much just an exercise of splitting the problems up and testing each possibility. Tedious but not difficult.
 
KIS. Start with the easiest items first. Remove the battery and clean it and the cable ends. Service the battery if able. Check the positive and negative cables for bulges and corrosion and tightness of connection. Remove the alternator regulator plug and re-install, just because you never know. Check the wiring going to the alternator and regulator, should be tight. Reassemble and run it, checking the voltage as specified. If it is low, turn it up to spec. Certify and go fly.
 
iflyvfr said:
My GPS displays voltage and it's regularly around 12.3 - 12.6 when I'm just cruising along. Now I *think* that's low, but my mechanic and an electrical engineer I know don't agree with me.

As far as what my ammeter said, it's part of my scan and it was normal up until the event, but for the 1-2 seconds that everything shut down, I honestly couldn't tell you what it did. I was mentally forming my reply to tower and then, nothing.
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both are wrong. the answer lies with the manufacture of the battery. It varies among chemistry types, manufacture, and temp but for a flooded cell CB series battery concord says 13.5 volts to 14.75 volts depending on temp. http://www.concordebattery.com/otherpdf/ownermanual.pdf

bob
 
iflyvfr said:
My GPS displays voltage and it's regularly around 12.3 - 12.6 when I'm just cruising along. Now I *think* that's low, but my mechanic and an electrical engineer I know don't agree with me.

As far as what my ammeter said, it's part of my scan and it was normal up until the event, but for the 1-2 seconds that everything shut down, I honestly couldn't tell you what it did. I was mentally forming my reply to tower and then, nothing.
Click to expand...

Your mechanic and your electrical engineer are wrong. Your plane has a 14v system.A battery voltage of 12.5 is what a fully charged battery should be. While running, 14v is the value.
 
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Clip4 said:
Your mechanic and your electrical engineer are wrong. Your plane has a 14v system.A battery voltage of 12.5 is what a fully charged battery should be. While running, 14v is the value.
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The right value is the one specified in the airframe manufacturer's manual and is related to ambient temperature. Cessna wants it at around 14.4 to 14.8.
 
Dan Thomas said:
The right value is the one specified in the airframe manufacturer's manual and is related to ambient temperature. Cessna wants it at around 14.4 to 14.8.
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That's if he doesn't have some STCed different than stock battery, which we haven't determined. Voltage regulator may be turned back to accommodate something other than a stock lead acid battery.

And he's measuring at the radio. While personally I wouldn't want to see a two volt drop in whatever is feeding the radio at receiver only current levels, the volt meter in the radio may be quite a bit off (not usually but have seen it on other gear) and it may be reading correctly for whatever awful wiring is between his bus and his radio.

But agreed, I don't like that number showing on the radio when the engine is running at flight RPM. It should be higher. Unless someone purposefully set it back a bit.

I have a non-aviation radio here that the internal voltmeter is 0.3V off. That I could see. 2V, no.

I'd still measure it with a real VOM somewhere. Preferably a good VOM and not a Harbor Freight cheapie. That last part is just me and my pet peeves. I broke my Fluke and need to buy a new one. And that hurts. ;)
 
If the entire electrical system turned off and then on, then it could be a bad battery master relay. They sometimes cycle when they aren't supposed to.
 
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Spend your time and money chasing the battery and alternator and stuff. Then find the real problem with the RF escaping at a bad antenna shielding connection.
 
Dan Thomas said:
Spend your time and money chasing the battery and alternator and stuff. Then find the real problem with the RF escaping at a bad antenna shielding connection.
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LOL. That's been known to happen. Usually it won't reboot EVERYTHING on the panel though, only poorly shielded stuff with microprocessors in them. And the displays wouldn't usually go dark, they'd get scrambled... usually... during a high power RF "event".
 
Dan Thomas said:
The right value is the one specified in the airframe manufacturer's manual and is related to ambient temperature. Cessna wants it at around 14.4 to 14.8.
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It is a sealed Concord battery approved for my plane. I'm definitely not getting anywhere near the voltage you guys are talking about, at least as displayed by my GPS (Aera 510).
 
Interesting ideas too Dan. My 2nd Comm is an old Collins Nav/Comm that fits in a round hole. It has always been less powerful and I think it might even share coax w/ my main comm. All this hardware is old...slightly younger than me! Thanks for your thoughts, given me some things to relay as we Tshoot this coming weekend.
 
denverpilot said:
I'd still measure it with a real VOM somewhere. Preferably a good VOM and not a Harbor Freight cheapie. . ;)
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We use them in the classroom all the time and they either work perfectly or they are completely fried. Out of the box, we find accuracy of about 1% consistently and within 3% 99% of the time. I find nothing wrong with the HF meters and there is a current promo of buy anything in the store and get a HF voltmeter for free. Coupon URL upon request.

Jim
 
weirdjim said:
We use them in the classroom all the time and they either work perfectly or they are completely fried. Out of the box, we find accuracy of about 1% consistently and within 3% 99% of the time. I find nothing wrong with the HF meters and there is a current promo of buy anything in the store and get a HF voltmeter for free. Coupon URL upon request.

Jim
Click to expand...

I hear ya. Good for a classroom. I have two or three here since they're so cheap for a quick and dirty check of something, but I never quite trust them.

Of course if I really need a nice big analog needle for watching for dips, the Simpson 260 comes out of the drawer...!

But I still feel naked without my Fluke. And I damn sure wouldn't trust those HF junkers with my life doing anything with mains.

The cheap Chinese crap flooding eBay has been torn open time and time again to find their "safety ratings" for 600V to be absolute BS. Which anyone who knows what a proper test lead looks like and how thick the insulation is, besides actually opening up the meter and seeing that isolation is near zero and even the fuses are made of glass, and not rated for exploding inches from one's hand through improper non-reinforced plastic cases...

I guess the good news when I get around to replacing it is that I can get a nice AC/DC clamp for it. I've only ever had AC non-contact stuff. The new power distribution in the ham shack could probably do some arc welding if something went wrong in there, so non-contact measuring gadgetry would be nice. Especially since it's a bear to get my wedding ring off.
 
denverpilot said:
I hear ya. Good for a classroom. I have two or three here since they're so cheap for a quick and dirty check of something, but I never quite trust them.

Of course if I really need a nice big analog needle for watching for dips, the Simpson 260 comes out of the drawer...!

But I still feel naked without my Fluke. And I damn sure wouldn't trust those HF junkers with my life doing anything with mains.

The cheap Chinese crap flooding eBay has been torn open time and time again to find their "safety ratings" for 600V to be absolute BS. Which anyone who knows what a proper test lead looks like and how thick the insulation is, besides actually opening up the meter and seeing that isolation is near zero and even the fuses are made of glass, and not rated for exploding inches from one's hand through improper non-reinforced plastic cases...

I guess the good news when I get around to replacing it is that I can get a nice AC/DC clamp for it. I've only ever had AC non-contact stuff. The new power distribution in the ham shack could probably do some arc welding if something went wrong in there, so non-contact measuring gadgetry would be nice. Especially since it's a bear to get my wedding ring off.
Click to expand...

Ah, the Simpson 260. You're showing your age (and so am I) by talking about that beauty. A true VOM. Loved that thing (back in the late 1960s). I'd love to have a good Fluke meter, but for now I settle for something better than HF, but not a Fluke. Then, there's the Heathkit VTVM sitting in the garage. I should fire that thing up and use it.

Since having to have my wedding ring cut of for surgery a few years ago and having it remade a bit larger I can take it off again (for the first time in decades). You might try that. :D
 
.

The cost of a clamp on DMM capable of measuring DC current has dropped an incredible amount since the late 80s, when I owned a company that did third party maintenance and repair on large UPS systems.

I had a couple of bookshelves of binders (they were pirated copies of copies jealously guarded by those in my field of endeavour) which contained schematics along with the voltage, current, resistance values and settings for the various manufacturer's products that Liebert, Exide, EPE, Piller, IPM, etc. built at the time. TTL boards ran the systems, and the logic was actually quite simple.

In those days, a DC clamp on meter capable of measuring 1,000 amps DC was a must have tool, and the technology of the time was a separate clamp on which plugged into a conventional DMM like my then state of the art Fluke 8020b (the Fluke 8020b cost around $500 when first introduced). The DC meter contained a Hall effect transducer that produced a 0-200 millivolt signal.

Because the sampling I was doing required the ability to make precision measurements, I simply had to buy the equipment. The DC unit cost around $400 at the time.

Now I have two of these Craftsman PN 82369 AC/DC multimeters pictured below that measure DC current up to 400 amps. While AC clamp on multimeters can be purchased for literally a few bucks, finding an accurate but reasonably priced DC unit is harder to do. This meter around $60 new, it's versatile and easy to use. It comes with two probes and leads, and a thermocouple.

I found both of mine at pawn shops, and paid less around $30 each for them. One of them appeared to be new and unused.

A clamp on DC ammeter allows one to take certain measurements and perform troubleshooting that's impossible to do otherwise. If you are qualified to use the device and find a DC clamp on ammeter for a reasonable price, buy it.

You can use it to check the alternator charging current, the current the battery is receiving, the amperage draw of individual components like the radios, find stray ground currents, and other helpful measurements of the DC system in your aircraft and automobile.

Edit: I found a similar DMM that's really inexpensive-$34.00. It's the second link below.

.


714CoigzdYL._SL1280_.jpg


Overview
Digital clamp-on ammeter. Measures AC/DC current up to 400 amps with 3.0 percent (VAC) accuracy without breaking the circuit. Also measures AC/DC voltage, resistance, frequency, capacitance, continuity and diode. Type K thermometer allows for surface or air temperature measurements. Display is an extra large 4000 count LCD screen. Also includes one-touch auto zero, belt holster, molded rubber holster, auto on/off, test leads and thermocouple. Category III - 600 volt.
Click to expand...

.

https://www.searsoutlet.com/Digital-Clamp-On-Ammeter/d/product_details.jsp?pid=19004&mode=seeAll


https://www.amazon.com/gp/aw/d/B00O...rent+clamp&dpPl=1&dpID=41sD0XebR4L&ref=plSrch
 
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3393RP said:
.

I have two of these Craftsman PN 82369 AC/DC multimeters that measure DC current up to 400 amps. While AC clamp on multimeters can be purchased cheaply, finding a reasonably priced DC unit is harder to do. This meter around $60 new, it's versatile and easy to use. It comes with two probes and leads, and a thermocouple.

I found both of mine at pawn shops, and paid less around $30 each for them. One of them appeared to be new and unused.

A clamp on DC ammeter allows one to take certain measurements and perform troubleshooting that's impossible to do otherwise. If you are qualified to use the device and find a DC clamp on ammeter for a reasonable price, buy it.

You can use it to check the alternator charging current, the current the battery is receiving, the amperage draw of individual components like the radios, find stray ground currents, and other helpful measurements of the DC system in your aircraft and automobile.

Edit: I found a similar DMM that's really inexpensive-$34.00. It's the second link below.

.


714CoigzdYL._SL1280_.jpg




.

https://www.searsoutlet.com/Digital-Clamp-On-Ammeter/d/product_details.jsp?pid=19004&mode=seeAll


https://www.amazon.com/gp/aw/d/B00O...rent+clamp&dpPl=1&dpID=41sD0XebR4L&ref=plSrch
Click to expand...

The Craftsman looks like it's just a re-branded Uni-T. They have some design flaws, but they're an "okay" meter. And certainly usable.

An awful lot of the middle of the road meters are just re-brands of a few manufacturer's meters, but then there's the ones that perfectly mimic the middle of the road stuff, and when you open them
up, you find they're just dangerous copies without much, if any, protection.

Bad barrel connectors, no minimum trace distances for high voltage use, no proper current protection or dangerous exploding current protection devices, cheap switches not rated for the current right under your fingertips...

Sorry. I can really get off on a rant on cheap test gear. It worries me that people will be hurt by this stuff, and completely unnecessarily just to make them ten times cheaper than the real deal.

Seeing a creep up of stories of cheap power supplies setting houses on fire, too.

And LOTS of great teardown videos on YT of these cheap things too, by folks who have no problem telling you they're tearing it apart to show how dangerous the thing is, and it's going in the trash can as soon as they're done shooting the video.
 
denverpilot said:
The Craftsman looks like it's just a re-branded Uni-T. They have some design flaws, but they're an "okay" meter. And certainly usable.

An awful lot of the middle of the road meters are just re-brands of a few manufacturer's meters, but then there's the ones that perfectly mimic the middle of the road stuff, and when you open them
up, you find they're just dangerous copies without much, if any, protection.

Bad barrel connectors, no minimum trace distances for high voltage use, no proper current protection or dangerous exploding current protection devices, cheap switches not rated for the current right under your fingertips...

Sorry. I can really get off on a rant on cheap test gear. It worries me that people will be hurt by this stuff, and completely unnecessarily just to make them ten times cheaper than the real deal.

Seeing a creep up of stories of cheap power supplies setting houses on fire, too.

And LOTS of great teardown videos on YT of these cheap things too, by folks who have no problem telling you they're tearing it apart to show how dangerous the thing is, and it's going in the trash can as soon as they're done shooting the video.
Click to expand...

The equipment I used when working on 6-8 megawatt 4 kV data center systems was quite a bit safer than my Sears stuff. I still have five or six Fluke devices along with my four channel 150 mHz Textronix oscilloscope, but they don't get used much.

Fortunately the only electrical work I do since retiring is the 120/240/1 around the house, and DC current measuring is no more than the 20 or 30 amps of my autos. I rent aircraft, so I don't mess with those systems.

I still do the annual online CE courses to keep my MEL (that's Master Electrician, not Multi Engine :D. ) license current but haven't looked at NEC and NFPA documents in a while.
 
Clip4 said:
Your mechanic and your electrical engineer are wrong. Your plane has a 14v system.A battery voltage of 12.5 is what a fully charged battery should be. While running, 14v is the value.
Click to expand...

2X. I agree that it appears that your alternator is not charging and you are running on battery alone. With no load (everything off) your battery should be 12.5+ for a good battery (check at battery). When the engine is running in flight you should see 13.5+ volts (this would validate charging). I am also an electrical engineer and same applies to boats, cars, etc.

When you key the mic the DC bus voltage drops further until the voltage is too low for the radio to operate. Transmitting uses the most power. The radio recovers when you stop transmitting (removes load) because the battery voltage goes up again.
 
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Baron62 said:
2X. I agree that it appears that your alternator is not charging and you are running on battery alone. With no load (everything off) your battery should be 12.5+ for a good battery (check at battery). When the engine is running in flight you should see 13.5+ volts (this would validate charging). I am also an electrical engineer and same applies to boats, cars, etc.

When you key the mic the DC bus voltage drops further until the voltage is too low for the radio to operate. Transmitting uses the most power. The radio recovers when you stop transmitting (removes load) because the battery voltage goes up again.
Click to expand...

Aircraft systems use different specs than cars, boats, etc. Cessna, in their alternator/regulator manual, specifies 14.1 to 14.6 volts at an ambient temp of 75 degrees F. This tapers down to 13.3 to 13.8 at 175 degrees F. At a cool 50°F, it's supposed to be 14.3 to 14.8 volts. Vastly different than ground-bound vehicles. It likely has to do with the slightly higher specific gravity of aircraft battery acid (1.285). Setting things too low will only result in battery sulfation and shorter life.
 
Dan Thomas said:
Aircraft systems use different specs than cars, boats, etc. Cessna, in their alternator/regulator manual, specifies 14.1 to 14.6 volts at an ambient temp of 75 degrees F. This tapers down to 13.3 to 13.8 at 175 degrees F. At a cool 50°F, it's supposed to be 14.3 to 14.8 volts. Vastly different than ground-bound vehicles. It likely has to do with the slightly higher specific gravity of aircraft battery acid (1.285). Setting things too low will only result in battery sulfation and shorter life.
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I'm sure your correct on the exact voltages per temperature, but unless he has 13.5+ with the engine running, then I suspect the alternator is not charging and he is running on the battery. My piper indicates 13.6 volts while running. Seems to be charging my 7 year old Concorde battery nicely.
 
Baron62 said:
I'm sure your correct on the exact voltages per temperature, but unless he has 13.5+ with the engine running, then I suspect the alternator is not charging and he is running on the battery. My piper indicates 13.6 volts while running. Seems to be charging my 7 year old Concorde battery nicely.
Click to expand...

If he was running solely on the battery, its voltage would continue to drop. The regulator is not set right, apparently, and the alternator is being fed only enough field current to maintain whatever he's getting. It's working ok, but the regulator prevents it from raising the system voltage to the correct level.

A calibrated voltmeter, connected directly to the bus, is the only way to determine actual system voltage. If whatever voltmeter you're using is connected to some downstream load's B+ input, there is easily possible a drop in the supply wire. AC43.13-1B specifies wire sizes for various lengths and current levels to limit voltage drop to 0.5V. And some panel-mounted stuff might not be too accurate, either. The OP's GPS is indicating in the 12V range, which violates the first condition (it's attached to a downstream load input), the input might be taken from a dirty/corroded old cigarette lighter socket, and the GPS voltmeter is probably not all that accurate.

You should check your mechanic's Piper service manual to see what your system voltage should be. 13.6 is low. It might be charging OK, but if it's not at the desired level, you end up with less starting capacity, less alternator-failure endurance, shorter battery life, and so on.
 
First, I'm really liking this Dan Thomas guy.

Second and along the same lines - If you changed out the old alternator with a Plane Power I'm assuming you changed out the voltage regulator with same. If not, you could have low charging issues. (I did because I didn't change the regulator at the same time. The Plane Power voltage regulators are adjustable. Now how one person can do this without a little trial and error is beyond me, meaning I'd have to have the engine running with my feet on the brakes to see the charge and then shut it down and make adjustments as necessary.

Having said that and not to revive all the trickle charger threads - I don't think a car battery minder charges as high as an aircraft charger. I don't know for sure but although it keeps it above 12v, I come back after a flight with a higher charge than with what I started with.
 
Timbeck2 said:
First, I'm really liking this Dan Thomas guy.

Second and along the same lines - If you changed out the old alternator with a Plane Power I'm assuming you changed out the voltage regulator with same. If not, you could have low charging issues. (I did because I didn't change the regulator at the same time. The Plane Power voltage regulators are adjustable. Now how one person can do this without a little trial and error is beyond me, meaning I'd have to have the engine running with my feet on the brakes to see the charge and then shut it down and make adjustments as necessary.

Having said that and not to revive all the trickle charger threads - I don't think a car battery minder charges as high as an aircraft charger. I don't know for sure but although it keeps it above 12v, I come back after a flight with a higher charge than with what I started with.
Click to expand...
A bit of browsing on the BatteryMinder website should yield their explanation for higher voltage aircraft batteries along with specific voltage for battery type. Their claim is that aircraft batteries use higher acid concentrations that auto batteries. The chemist in me sorta has a problem with that until they explain how the higher concentrations are achieved. Just to add clarity, I'm not claiming BatteryMinder has it wrong at all. Just saying that electro-chemistry training indicates to me that something different has to be done with aircraft batteries to achieve the cell voltage they claim.
 
I just surfed pics on my phone and found photos of my GPS displaying 12.8, 13.0, 13.2, 13.0 v. so I reported my numbers as being lower than what they are, but they still sound low. I did install the new regulator when I did the conversion. I will have my mech check voltage at the battery and on the bus. I have long suspected that my voltage is set too low, but I know nothing of this stuff so I get talked out of setting it any higher. I am confident that we used the appropriately sized wire because there was a lot of referencing the diagram, running wires and we pulled a lot of old wire out when we removed the generator.
 
Clark1961 said:
A bit of browsing on the BatteryMinder website should yield their explanation for higher voltage aircraft batteries along with specific voltage for battery type. Their claim is that aircraft batteries use higher acid concentrations that auto batteries. The chemist in me sorta has a problem with that until they explain how the higher concentrations are achieved. Just to add clarity, I'm not claiming BatteryMinder has it wrong at all. Just saying that electro-chemistry training indicates to me that something different has to be done with aircraft batteries to achieve the cell voltage they claim.
Click to expand...

From http://www.gillbatteries.com/faqs.aspx

...we read:

  • Can I use automotive electrolyte in my battery?

No……not recommended! Automotive electrolyte is only 1.260 Specific Gravity. By using automotive electrolyte the battery will not function to it’s intended capacity because the cell electrolyte balance would not be up to the required levels. Gill electrolyte is 1.285 Specific Gravity. Warranty will be void if the proper specific gravity electrolyte is not used.


  • What is good battery voltage on a new fully charged battery?

On a newly charged battery the voltage should read:
12 volt battery…13.00 to 13.20 volts. 24 volt battery…26.00 to 26.40 volts.

Same chemistry than the automobile's battery, but stronger acid to give a slightly higher voltage of 2.2 volts per cell, or about 13.2 volts fully charged.

The battery uses sulfuric acid and lead and lead peroxide plates. We test the specific gravity of the acid in a battery to see the state of its charge. 1.285 is fully charged. 1.1 is essentially stone-dead. 1.0 is nothing but water. All the sulfuric acid has broken down to water and lead sulfate.

The chemistry: https://www.av8n.com/physics/lead-acid.htm
 
Dan Thomas said:
From http://www.gillbatteries.com/faqs.aspx

...we read:

  • Can I use automotive electrolyte in my battery?

No……not recommended! Automotive electrolyte is only 1.260 Specific Gravity. By using automotive electrolyte the battery will not function to it’s intended capacity because the cell electrolyte balance would not be up to the required levels. Gill electrolyte is 1.285 Specific Gravity. Warranty will be void if the proper specific gravity electrolyte is not used.


  • What is good battery voltage on a new fully charged battery?

On a newly charged battery the voltage should read:
12 volt battery…13.00 to 13.20 volts. 24 volt battery…26.00 to 26.40 volts.

Same chemistry than the automobile's battery, but stronger acid to give a slightly higher voltage of 2.2 volts per cell, or about 13.2 volts fully charged.

The battery uses sulfuric acid and lead and lead peroxide plates. We test the specific gravity of the acid in a battery to see the state of its charge. 1.285 is fully charged. 1.1 is essentially stone-dead. 1.0 is nothing but water. All the sulfuric acid has broken down to water and lead sulfate.

The chemistry: https://www.av8n.com/physics/lead-acid.htm
Click to expand...
Nice stuff. You should read it carefully instead of citing it as a reference. There is a voltage in the lead acid reaction which is defined by the lead-acid cell. No credible mechanism is offered which changes that voltage.

In other words your post simply echos what I have already said about what batteryminder claims.
 
Today's observations:

Location Voltage on GPS | RPMs Master Switch | Avionics Status
On ground at TZR: 13.6v, + deflection on Ammeter, 800 RPM, Master Switch ON, Avionics Master OFF;
On ground at TZR: 13.5v, + deflection on Ammeter, 800 RPM, Master Switch ON, Avionics Master ON;
In flight, 1800' MSL, 12.7v, + deflection on Ammeter, 2500 RPM, Master Switch ON, Everything ON;
In flight, 3500' MSL, 12.6v, slight + deflection on Ammeter, 2400 RPM, Master Switch ON, Everything ON;
On ground at TZR: 12.1v, - deflection on Ammeter, 0 RPM, Master Switch ON, Avionics Master OFF;

The issue did not repeat itself today. On the ground after 45 minutes in the air with everything shut down, my battery read 14.4v on a multi-meter. Battery leads were perfect & clean. I did clean up some leads on the starter solenoid but that's all I was able to accomplish today.

I don't understand why, after the battery had been on the BatteryMinder for a week, it read a full volt higher on the ground than in the air before flight - unless that VR isn't set right (as some surmised) and it's drawing down the battery. Yet the ammeter showed neutral to slightly positive deflection the entire time. I also keyed the mic several times in flight and watched the voltage on the GPS change in reaction to the power draw. Back on the ground after the return leg, with engine off, avionics master off and master switch on, the GPS read only 12.1v.

I plan to return tomorrow to take another reading of the battery after having let it rest for 24 hours without the BatteryMinder recharging it.
 
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