Author Topic: rare earth magnets next to a battery?  (Read 684 times)

Online ratguzzi

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rare earth magnets next to a battery?
« on: April 10, 2021, 04:01:42 PM »
My 68 loop has a 2003 EV motor in it. So it has the 2003 alternator and regulator. About 8 weeks ago, I bought an expensive lithium ion battery and it just went 100% dead while riding it shutting down the bike. So I bought an AGM battery and that lasted until earlier today with the same 100% dead and shutting off the bike. After installing both batteries, I measured around 12.8 volts at idle and about 13.4 when the rpm brought up. Like I usually see on my other Guzzis. I installed another AGM today and kept checking battery temp where I could easily reach the battery while riding. I got back to the hotel and on the battery tray, I have a big rare earth magnet stuck there so the battery doesn't slide back on me. The part of the battery near the magnet was 20f (easily) hotter than the rest of the battery.
Oh, and also nothing draining the battery when the key is off. I tested that.
JB
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Offline Aaron D.

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Re: rare earth magnets next to a battery?
« Reply #1 on: April 10, 2021, 04:16:45 PM »
A big rare-earth magnet can really make things happen!
I haven't heard of anyone with this problem or any practical experience with magnets next to batteries, , but I can think of reasons why it isn't good to have that magnet next  to any electrical gear.

Offline Two Checks

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Re: rare earth magnets next to a battery?
« Reply #2 on: April 10, 2021, 04:36:30 PM »
Your charging voltage needs to be higher than 13.4.
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Re: rare earth magnets next to a battery?
« Reply #3 on: April 10, 2021, 04:47:44 PM »

     The lead in a battery is not a magnetic attractant however depending on the strength of the magnet and polarization it will effect electrical flow. Can you flip the magnet over and see what happens?   :popcorn:

      Paul B :boozing:
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Re: rare earth magnets next to a battery?
« Reply #3 on: April 10, 2021, 04:47:44 PM »

Online ratguzzi

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Re: rare earth magnets next to a battery?
« Reply #4 on: April 10, 2021, 05:55:32 PM »
Your charging voltage needs to be higher than 13.4.
Well, that was just above idle and a brand new fully charged battery. Old needle voltmeter.
At idle, headlight ok, bring up the gas, it gets brighter.
JB
John Boettcher
Wonder Lake, IL


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Re: rare earth magnets next to a battery?
« Reply #5 on: April 10, 2021, 05:56:48 PM »
     The lead in a battery is not a magnetic attractant however depending on the strength of the magnet and polarization it will effect electrical flow. Can you flip the magnet over and see what happens?   :popcorn:

      Paul B :boozing:
This magnet is powerful enough to hold itself to another through my forearm.
JB
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Re: rare earth magnets next to a battery?
« Reply #6 on: April 10, 2021, 08:14:41 PM »
  I can't verify this , but I've heard many newer batteries are basically lead that is adhering to metal plates ( maybe magnetic )
and if that's the case then it's possible the plates are being pulled against each other and self discharging . Polite suggestion
to get the magnet far from the battery and see how that goes . Peter

Online Wayne Orwig

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Re: rare earth magnets next to a battery?
« Reply #7 on: April 10, 2021, 08:16:33 PM »
Nothing about a magnet should alter a lead acid battery. You could put a steel plate in there to shield much of the magnetic field if you think it is an issue.
Yes, you need more than 13.4 to put anything. 13.4 would be OK for full time standby, but won't recharge the battery.
You need to attach a battery monitor to the battery full time. If you have a smartphone, you just turn on the phone and it shows a graph of what the battery voltage had been in the past, and the current voltage of course. You can see if the charge goes up or down or whatever after you go for a ride.
 
« Last Edit: April 10, 2021, 08:18:04 PM by Wayne Orwig »
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Online Kiwi_Roy

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Re: rare earth magnets next to a battery?
« Reply #8 on: April 11, 2021, 08:48:05 AM »
I assume you have the Ducati Energia regulator then.
It's very important to have a good ground connection to the case, the AC alternator current makes its way back that way to the other yellow wire.
The regulator also needs a good Voltage reference on to the black wire, it's usually via the headlight relay.
You could try a wire direct from some point downstream of the ignition switch to the black wire.
You are probably familiar with testing diodes. From each yellow wire there is a diode to the red wire, sometimes as the regulators fail you will find one has gone open, you can actually use a discrete diode outside the case.
Those potted bridge rectifiers are a good way of getting a pair of diodes you can bolt them onto something as a heat sink. Here's what's inside, you can see the diodes upper left, the lead has melted off, I was able to solder it back.

And here's the schematic, you can see how the diodes are connected between yellows and red, I suspect you might have one open.
Note how the current gets back from the case ground to the opposite side of the alternator winding, through the SCR shown on lower right of the picture above.
« Last Edit: April 11, 2021, 09:04:45 AM by Kiwi_Roy »
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Re: rare earth magnets next to a battery?
« Reply #9 on: April 11, 2021, 09:39:05 AM »
Just thinking here, I don't know anything.  All lead acid batteries (I believe) have Antimony in the lead plates.  Antimony is somewhat susceptible to magnets (or magnetism) so would that have any effect on the reaction inside the battery when extreme magnetic fields are placed in one area of the battery.  Like I said I do not know just asking a question.

Online DougG

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Re: rare earth magnets next to a battery?
« Reply #10 on: April 11, 2021, 10:23:52 AM »
Hi All,                                                                                                                                                              4-11-21

Theoretically, a number of interctions can occur.  Remember, neither lead, antimony, nor any other nacent element move within a battery...only charged ions.  The movement of any charged particle produces its own magnetic field.  The greater the current, the greater the field.  There can be interactions between the electromotive field and the static rare magnet field.  There are also strong magnetic fields caused by the current through the cables.  I have no idea if any of these interactions are great enough to cause the issue you are describing.  However, I'm really interested in knowing  :popcorn:

(My suspicion is that there is some other circuit related issue at the root cause.)

Good luck, and please report back.

Be well, stay well,
DougG
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Online Murray

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Re: rare earth magnets next to a battery?
« Reply #11 on: April 11, 2021, 10:35:09 AM »
It may be the various fields from the current flow interfacing with each other than direct action on the components of the battery. The question is what the hell is wrong with a piece of bicycle inner tube to retain the battery that the most obscure way as possible is sought?

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Re: rare earth magnets next to a battery?
« Reply #12 on: April 11, 2021, 05:48:05 PM »
It doesn't make any logical sense to me either. I am only struggling for clues. My comment on 13.4 was not meant to be "exact" Mostly to point out, the higher the revs, the voltage went up. I know today, I rode 470 miles across Texas with no magnet near the battery and there were no hot spots on it. But I did run my headlight which I do or sometimes not do and not sure if I was using it or not when the two batteries failed. I am running carbs so much less load on the charging system but a regulator should regulate.... Yes, the regulator is on a stock EV mounting plate and well grounded.
Ok, to add to the mystic. Both batteries, bike running down the road fine and no sputter, just like shutting the key off, total dead. Both batteries measured zero volts. A few days ago, I check the lithium battery and it has 12.4 v. Maybe it has a overheat switch in it, not sure.
The AGM stayed dead for two days and today, it will actually take a charge. I will toss a real voltmeter on it tomorrow and see the voltage at around 3500 rpm. Both failures, I was running 70-80 mph. Ambo final drive so the rpm was pretty high.
Maybe the magnet is total coincidence which makes more sense.
JB
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Re: rare earth magnets next to a battery?
« Reply #13 on: April 11, 2021, 09:05:22 PM »
  ^  Or maybe not  :evil: . Peter

Online Murray

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Re: rare earth magnets next to a battery?
« Reply #14 on: April 12, 2021, 04:55:00 AM »
It doesn't make any logical sense to me either. I am only struggling for clues. My comment on 13.4 was not meant to be "exact" Mostly to point out, the higher the revs, the voltage went up. I know today, I rode 470 miles across Texas with no magnet near the battery and there were no hot spots on it. But I did run my headlight which I do or sometimes not do and not sure if I was using it or not when the two batteries failed. I am running carbs so much less load on the charging system but a regulator should regulate.... Yes, the regulator is on a stock EV mounting plate and well grounded.
Ok, to add to the mystic. Both batteries, bike running down the road fine and no sputter, just like shutting the key off, total dead. Both batteries measured zero volts. A few days ago, I check the lithium battery and it has 12.4 v. Maybe it has a overheat switch in it, not sure.
The AGM stayed dead for two days and today, it will actually take a charge. I will toss a real voltmeter on it tomorrow and see the voltage at around 3500 rpm. Both failures, I was running 70-80 mph. Ambo final drive so the rpm was pretty high.
Maybe the magnet is total coincidence which makes more sense.
JB

The output for the Ducati charging system is 14.5 volts at 5000rpm +- 0.1 volt.

Online Kiwi_Roy

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Re: rare earth magnets next to a battery?
« Reply #15 on: April 12, 2021, 07:37:16 AM »
The magnet effecting the battery makes no sense to me either but will it stick to the battery? If so get it the hell out of there and pop rivet a piece of angle to the tray in its place.
If the battery is going flat while riding your charging system is failing, my experience of that it's usually loss of the battery voltage reference, the Ducati Energia regulator needs the reference to fire the SCRs inside.
Where does that signal come from on your bike?
On the normal wiring it's downstream of the headlight relay half a Volt less than the actual battery terminals so the battery gets boosted from the regulator setpoint 13.9 + 0.5 = 14.4 thereabouts
This is problematic because the Voltage drop through the headlight relay changes with time and the regulator gets cooked.
Stuck with a flat battery on the road I have a couple of times wired the black wire direct to the battery, that at least makes sure its getting a solid reference but it can't be left that way as the regulator draws about 15 milliamps.
Not knowing how you adapted the regulator to the loop I would say connect the black wire downstream of the ignition switch or any relay that is normally connected to the battery positive while the bike is running.
I wouldn't depend on a metal bracket to ground the regulator body there's significant current flow there, same as the red wires from regulator to battery actually, spikes of 30 Amps DC, Run a copper conductor from the regulator case to a timing cover 6mm bolt. You could even use an aluminium strap for that to keep the metals similar but whatever you do slap some grease on the joints to keep out the water and oxygen. Back when I rode a VII Sport I had everyone convinced that a ground strap was the answer, after market regulators normally come with a ground wire and no need to ground the case.
BTW if you look at the sketch I posted you will see a diode in the black wire, add another in series and it will boost the charge Voltage up by 0.6 Volts, a resistor will do similar.
The charge warning light is completely useless on this regulator, how can it light up if you lose the Voltage reference, that's what powers the light.
Check  both the diodes in your regulator, yellow to red, it should show up with your analog meter as a high resistance, I think you have to switch the leads black lead is positive, it's a long time since I had a steam powered meter.
Anyway one way you will get a circuit, switch the leads and it will be open.
« Last Edit: April 12, 2021, 08:14:26 AM by Kiwi_Roy »
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Offline PeteS

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Re: rare earth magnets next to a battery?
« Reply #16 on: April 12, 2021, 08:02:11 AM »
I wouldn’t think magnets would affect lead acid batteries but the Lithium-ion battery for vehicle applications uses iron as the ion. LiFePO, AKA lithium-iron.

Pete

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Re: rare earth magnets next to a battery?
« Reply #17 on: April 12, 2021, 09:15:39 AM »
   If I read this correctly the magnet was added at the same time the 1st lithium ion battery went in and remained in with the next 2 AGMs. I am also assuming there were no issues previously.
    Everyone is jumping all over the 13.4 V number no matter how many times you clarify it was a fast check at low rpm with an old meter to confirm that some charging was occurring.
    You may well have a less than 100% output of your charging system but not enough to cause total shutdown with a stone dead battery repeatedly. And the hot spot on the battery next to the magnet doesn't seem to impress anyone either while I think it is a major clue.
    Myself and a fellow aircraft mechanic came up with a troubleshooting method many years ago that seldom let us down. After finding too many problems developing following other maintenance we called it "The last thing touched by human hands" method of troubleshooting.
   Everything points to the magnet being the problem to me and Why would you not remove it and try. Flipping it or putting a steel plate next to it as a buffer has been suggested but I would just remove it from the equation completely. As long as the battery's haven't been damaged I expect you will be fine.
  Despite my former profession I am very far from being an electrical expert but could usually make things work. My "Joke" going away gift from my first aviation job was a very nice multi meter. I opened it and really liked it but everyone was trying not to laugh. Then I noticed the bag of 100 spare fuses they included with it.
    Those rare earth magnets are extremely powerful and I wouldn't want them in close proximity to a battery or regulator or ign. module or any electrical component. I know they sell them to stick under your motorcycle to make your bike visible to the sensors that control traffic lights but in that application hopefully they are far enough from electrical components to matter
« Last Edit: April 12, 2021, 09:17:46 AM by leroy_can »
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Offline kirby1923

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Re: rare earth magnets next to a battery?
« Reply #18 on: April 12, 2021, 09:41:41 AM »
   If I read this correctly the magnet was added at the same time the 1st lithium ion battery went in and remained in with the next 2 AGMs. I am also assuming there were no issues previously.
    Everyone is jumping all over the 13.4 V number no matter how many times you clarify it was a fast check at low rpm with an old meter to confirm that some charging was occurring.
    You may well have a less than 100% output of your charging system but not enough to cause total shutdown with a stone dead battery repeatedly. And the hot spot on the battery next to the magnet doesn't seem to impress anyone either while I think it is a major clue.
    Myself and a fellow aircraft mechanic came up with a troubleshooting method many years ago that seldom let us down. After finding too many problems developing following other maintenance we called it "The last thing touched by human hands" method of troubleshooting.
   Everything points to the magnet being the problem to me and Why would you not remove it and try. Flipping it or putting a steel plate next to it as a buffer has been suggested but I would just remove it from the equation completely. As long as the battery's haven't been damaged I expect you will be fine.
  Despite my former profession I am very far from being an electrical expert but could usually make things work. My "Joke" going away gift from my first aviation job was a very nice multi meter. I opened it and really liked it but everyone was trying not to laugh. Then I noticed the bag of 100 spare fuses they included with it.
    Those rare earth magnets are extremely powerful and I wouldn't want them in close proximity to a battery or regulator or ign. module or any electrical component. I know they sell them to stick under your motorcycle to make your bike visible to the sensors that control traffic lights but in that application hopefully they are far enough from electrical components to matter

 :thumb:
         
I have witnessed some strange things caused from these rare earth magnetic fields. unexplainable?!
Easy to rule out.

:-)

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Offline Aaron D.

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Re: rare earth magnets next to a battery?
« Reply #19 on: April 12, 2021, 03:30:48 PM »
Not really inexplicable, just we aren't sure!


It would be even worse if the magnet were spinning, I bet.

Offline TN Mark

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Re: rare earth magnets next to a battery?
« Reply #20 on: April 12, 2021, 04:25:29 PM »
Why is a magnet strong enough to magnetize through your arm next to the battery in the first place? Can the magnet be stored somewhere else and use another object to keep the battery in place? With two batteries going dead so quickly the alternator, the regulator, some associated wiring is going out or the magnet is effecting things as well.

I'd first remove the battery from the motorcycle completely and then troubleshoot the charging system. It's 'possible' but not probable you have two goofy batteries in a row. 

Offline Lumpy Idle

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Re: rare earth magnets next to a battery?
« Reply #21 on: April 12, 2021, 05:14:06 PM »
     ... Can you flip the magnet over and see what happens?   :popcorn:

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Online ratguzzi

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Re: rare earth magnets next to a battery?
« Reply #22 on: April 12, 2021, 05:56:54 PM »
The magnet was used purely to keep the battery from sliding back into my right side hand shifter. It was stuck to the battery pan between the shifter slot and the battery. I'm leaning toward overcharging and the magnet was coincidental. It seems the thing in common for both situations was higher rpm and no load on the charging system, headlight off, no fuel injection on a charging system that was meant for FI. Yes, the regulator should cover it.
I appreciate all the advice!
Remember, the battery didn't slowly die as I was riding. It went to instant death. 0v instantly per a LED tail light bulb I had that uses near zero amps.
I rode 450 plus miles yesterday with no issues but I did run with the headlight on the entire day.
JB
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Online Chuck in Indiana

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Re: rare earth magnets next to a battery?
« Reply #23 on: April 12, 2021, 06:44:13 PM »
Instant death is common with AGMs. We drove our Prius home from the brewpub in a driving rain one night, and when we shut down in the garage, the battery didn't have enough power to do the shut down routine. (!) I'm *really* glad it didn't decide to do that in the brewpub parking lot.  At night. In the rain. :smiley:
Now, the question remains.. just *why* did two batteries do the instant death thing?? I have a hard time imagining it's the magnet.. but I certainly don't know. I'll just  :popcorn:
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Online ratguzzi

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Re: rare earth magnets next to a battery?
« Reply #24 on: April 12, 2021, 08:05:49 PM »
Instant death is common with AGMs. We drove our Prius home from the brewpub in a driving rain one night, and when we shut down in the garage, the battery didn't have enough power to do the shut down routine. (!) I'm *really* glad it didn't decide to do that in the brewpub parking lot.  At night. In the rain. :smiley:
Now, the question remains.. just *why* did two batteries do the instant death thing?? I have a hard time imagining it's the magnet.. but I certainly don't know. I'll just  :popcorn:
I could see a lithium ion having a safety temp switch or similar to prevent forest fires, especially after 100% dead, 2 days later, it rose from the dead. Overcharging seems most reasonable but it's really not worth much more discussion even though well appreciated.
JB
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Online AJ Huff

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Re: rare earth magnets next to a battery?
« Reply #25 on: April 12, 2021, 08:09:23 PM »
Doesn't a battery under load create magnetic field? And then you've got a more powerful magnet inside that magnetic field. So then the battery world be undercharging?

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Online LowRyter

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Re: rare earth magnets next to a battery?
« Reply #26 on: April 12, 2021, 08:30:15 PM »
Regulator?
John L 
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