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Over voltage required for EarthX battery

Not to insert myself into this fun little back-and-forth too deeply - but this thread is fundamentally NOT about internally regulated alternators. It's about the requirement for overvoltage protection with Earth-X batteries - by any suitable method.

It devolved into some deep alternator and regulator voodoo, but that's not the point of this thread.

I agree, I'm moving my posts back to the other thread: http://www.vansairforce.com/community/showthread.php?t=154377&highlight=charging
 
Previously I wrote:

The ND alternators Ross, Blain, and Mickey have checked apparently do not have an internal stator-to-field connection. It appears the only source of field current is via the IG terminal. An OV device installed in the IG lead will shut them down if the regulator goes nuts for any reason.

I've since been doing some research, gathering information about ND units, and dismantling a spare Plane Power alternator. Right now I have a question in with the ND tech line, and learning continues.

At this time I'm pretty sure the above statement is wrong.

I do not yet have a schematic for the ND regulator's IC chip. However, after looking at the TDS for a few voltage regulator IC chips in the open marketplace, it seems likely that the Denso regulator's electronics are actually powered full-time (at very low current) via a tap to the B terminal's rectifier bridge, and the IG terminal is fundamentally an ON-OFF switch for the IC, not a field power supply. More research to come; God is in the details. For sure the typical ND has a very direct stator-to-field connection, with the regulator on the ground side of the field.

Greg is right; this thread was about a requirement for OV protection with an EarthX, not alternator control. Future posts regarding alternator control will go to the other thread.
 
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High output Alt

Have been holding off and trying to educate myself on this.

Due to my large electrical load, (electrically driven air conditioner) I have a unique system. 24 volt system with a 150 amp 28 volt alternator.

Using the provided "crow bar" incorporated over voltage protection that is integrated into the external regulator, What would happen if I change my current duel odyssey firewall mounted setup to earthX? I would be capable of exceeding the maximum current rating for the EarthX batteries.

I still fail to understand why this is any worse than say a 60 amp alt. in a failure mode scenario.
 
Have been holding off and trying to educate myself on this.

Due to my large electrical load, (electrically driven air conditioner) I have a unique system. 24 volt system with a 150 amp 28 volt alternator.

Using the provided "crow bar" incorporated over voltage protection that is integrated into the external regulator, What would happen if I change my current duel odyssey firewall mounted setup to earthX? I would be capable of exceeding the maximum current rating for the EarthX batteries.

I still fail to understand why this is any worse than say a 60 amp alt. in a failure mode scenario.


Sorry for the delay in response, I missed this question. The size limit on the alternator is not about failure scenarios; it is about stressing the battery by exceeding its recommended charge rate, thus shortening the life of the battery.

If you use (2) ETX900, then the combined charge rate could be 150amp. Plus, you can account for your large electrical load. For example, if the plane uses 20amps, then the batteries could only see 130amps. Please let us know if you have other questions or you can always contact us directly as [email protected] for your specific needs.
 
Overvoltage EarthX

Kathy, I?ve installed an EarthX battery in my RV4 (not the newer EarthX) w/lights. I have a 40a alt with external voltage regulator. I?ve started getting spikes of 15.6 to 15.8 volts for a second or two via Warning on my efis and then it returns to 14.2 or so. I usually don?t see the overvoltage until after climb out and I level off to cruise. I replaced my voltage regulator thinking it was going out, but I?m still getting short spikes. Is this the lithium battery? Bad ground on case of regulator, or what? I haven?t fried my electronics yet, because I think it does have a little protection built in but I really don?t want to keep pushing it. Any advise is appreciated. I never saw any spikes with my mat gel battery and didn?t know if this was just a coincidence or not. Thanks
 
Kathy, I?ve installed an EarthX battery in my RV4 (not the newer EarthX) w/lights. I have a 40a alt with external voltage regulator. I?ve started getting spikes of 15.6 to 15.8 volts for a second or two via Warning on my efis and then it returns to 14.2 or so. I usually don?t see the overvoltage until after climb out and I level off to cruise. I replaced my voltage regulator thinking it was going out, but I?m still getting short spikes. Is this the lithium battery? Bad ground on case of regulator, or what? I haven?t fried my electronics yet, because I think it does have a little protection built in but I really don?t want to keep pushing it. Any advise is appreciated. I never saw any spikes with my mat gel battery and didn?t know if this was just a coincidence or not. Thanks

Sounds like a LOOSE field connection.

Several years ago, I spent 3-months finding an intermittent over voltage trip. The contacts in the connector for the field were loose. (Not tight like new contacts.) Replacing the contacts fixed the intermittent over voltage trip.

Loose contact made high resistance that needed higher field voltage to maintain output voltage. When good contact was made, the high resistance was gone raising field voltage that raised output voltage creating the over voltage event.
 
more details needed

Kathy, I?ve installed an EarthX battery in my RV4 (not the newer EarthX) w/lights. I have a 40a alt with external voltage regulator. I?ve started getting spikes of 15.6 to 15.8 volts for a second or two via Warning on my efis and then it returns to 14.2 or so. I usually don?t see the overvoltage until after climb out and I level off to cruise. I replaced my voltage regulator thinking it was going out, but I?m still getting short spikes. Is this the lithium battery? Bad ground on case of regulator, or what? I haven?t fried my electronics yet, because I think it does have a little protection built in but I really don?t want to keep pushing it. Any advise is appreciated. I never saw any spikes with my mat gel battery and didn?t know if this was just a coincidence or not. Thanks

Hi Mike,
More details are needed to be able to answer your questions better. First, what engine do you have? What charging system do you have? (B & C, Plane Power, etc.). What battery model do you have? The EarthX aircraft line has been out for over 3 years now, so how old is the battery? If you are not sure, there is a letter and number on the backside of the negative terminal, what is it? Does the battery hold a charge after flight above 13.3V?
 
The battery cannot cause a spike into the 15+ volt region, physics simply doesn't allow it. Only one device can do that - the charging system. High likelihood suspects are a loose wire on the "sense" line or a bad ground on the alternator such that it sees a "floating ground" voltage and tries to adjust system voltage to 13.8 above that floating ground.
 
The battery cannot cause a spike into the 15+ volt region, physics simply doesn't allow it. Only one device can do that - the charging system. High likelihood suspects are a loose wire on the "sense" line or a bad ground on the alternator such that it sees a "floating ground" voltage and tries to adjust system voltage to 13.8 above that floating ground.

Unless the battery's protection circuit is repeatedly disconnecting/reconnecting, and the regulator isn't quite keeping up with the load of battery charging being switched off & on abruptly.
 
Unless the battery's protection circuit is repeatedly disconnecting/reconnecting, and the regulator isn't quite keeping up with the load of battery charging being switched off & on abruptly.

That's still not the battery causing the problem - it's the regulator. The regulator should be quite capable of reducing the output voltage faster than the battery protection will isolate it. If it's not doing so, then the regulator or some associated wiring is faulty.
 
And we should all be able to afford a Ferrari. :)

There's a long history of 'load dump' issues with both automotive and aviation qualified (FAA blessed) alternators/regulators. I can testify; I've killed one via load dump. Most truly modern automotive products have licked the problem, but any old tech could still have the issue, and anything FAA-blessed will *likely* still have an issue, if it did when certified. No regulator was specified, but with a 40A alternator, it could well be a very old tech automotive regulator.

And it might not be an actual issue. If he were to hook up a storage o-scope to the alternator output, he might see the voltage only get to that 16V level for a few milliseconds, but long enough for the EFIS voltage monitor to see it. And the EFIS display software may have a time constant of a second or two, to keep the display stable enough for the pilot to read the digits.

edit: I should say that it's most likely a bad connection, but since the battery is capable of disconnecting itself (something new and different), that can't be ignored.
 
Over voltage warning led.

Hi

I have been trying to buy from you or source in the UK a battery problem warning light.

Firstly your site does not allow real international shipping so I cannot buy fr9m you, unless I get it shipped to a US friend and ask them to forward to me which is not convenient.

Your web page does not allow contact for any questions to be asked which is really unhelpful. You should reconsider this option as I think you will find vendors who cannot be contacted through their web page are not highly regarded by their customer base. I should be able to ask these questions dir3ctly without resorting to VAF.

In the Uk I have found lights but with only a 390 ohm resister, yours is 500ohm. Not being an electrical geek I have no idea whether a 390 will work or whether I will get erroneous warnings from such a light, please advise.
 
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Ohms

Mark

Thanks for the information however I do not see any mention of what resister value is fitted to the light. I presume you don?t know that either?

Can you tell me how it works when in use and howl you dertimined it?s working ok?

Regards
Steve
 
I don't know what rating the internal resistor is but I tested it by simply connecting it to the battery. It's made for auto use so 12v works fine. The way you'd test it is to ground it out. The battery turns on the led when it internally ground the connection.
 
Culprit Found

Thanks to all who had input on trying to find the voltage spike, along with the efis dropping the ahrs. It took nearly a month of changing everything out-battery,alternator , wiring, replacing wiring, grounds you name it. Sitting in the hanger with the nose out the door going back through all of the pin ins and outs I turned and leaned over the side of the cockpit to turn a page on the wiring layout book laying on the wing and my leg bumped the keys in the ignition switch mounted left of panel.
My canopy light goes out. Wiggling the keys caused all kinds of issues.The switch was bad. Replaced it and wa la everything works like it should. I?m keeping my fingers crossed. I?ve flown about 5 hrs and 30-40 landings without loosing the ahrs or any voltage issues.
While some of the responses didn?t fix my problem, I?ve learned of many potential problems and have possible answers for them now.
Thanks again to all who answered.
 
i will also take dumb luck any time.
probably a good idea to not have any more weight hanging from the key than necessary.
 
Key ignition switches are just a problem waiting to happen.

Two ignition toggle switches and a push button to crank is the only way I?ll wire a plane.

Carl
 
12V LED

Hi

I have been trying to buy from you or source in the UK a battery problem warning light.

Firstly your site does not allow real international shipping so I cannot buy fr9m you, unless I get it shipped to a US friend and ask them to forward to me which is not convenient.

Your web page does not allow contact for any questions to be asked which is really unhelpful. You should reconsider this option as I think you will find vendors who cannot be contacted through their web page are not highly regarded by their customer base. I should be able to ask these questions dir3ctly without resorting to VAF.

In the Uk I have found lights but with only a 390 ohm resister, yours is 500ohm. Not being an electrical geek I have no idea whether a 390 will work or whether I will get erroneous warnings from such a light, please advise.

The 390 ohm resistor is just fine. We do ship all over the world but as this is such a variable with shipping lithium batteries, we do not allow international orders via the website. We have you contact us with your shipping address and what you want and we quote it that way but for an LED light, any 12V LED light will be fine to use.
 
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