Safety for Jab alternator


Jay Scheevel
 

Just saw this in this month’s Sport aviation. Seems like a no brainer to add this and avoid a meltdown.

Jay


Mark Dunstone
 

Jay, I agree that a part of the solution to the problem of burnt out stators is a better regulator and a fuse on the AC Input side.  But regulating voltage is not enough....it needs to limit current as well...particularly if your battery (lithium or lead) can absorb a charge current greater than the stator coil wiring can take.

I remain a little sceptical about the self resetting circuit breaker.  When you have an over-current situation it will switch off, then on again after it has cooled down, and then off again, etc, etc, etc, until the battery no longer takes a charge.  I don’t think they are designed for that.  And unless you are very observant of your voltage and charge current, you in the cockpit won’t be aware of the fault, perhaps not until the blue smoke comes out of tge resetting breaker.  That’s why I like a fuse....if the fuse blows, charge goes to zero, voltage drops to 13.something and you will notice and make an informed decision.  Unless you have EFI or an electrical cabin heater, you should have plenty of time to complete your flight or land at an alternative.


wmax351@...
 
Edited

Has anyone used a Voltage/Current limiting regulator from a motorcycle? This is a common issue on some bikes, and has been for a long time. On my old sportster I used to have, the generator can put out 30-40 amps at freeway rev's, but the generator will burn out with over 10-15 amps. Other permanent magnet alternators have similar problems. 


Marc Halcomb
 

Mark,
Over voltage is bad for the down stream items: EFIS, EIS, Comm/Nav radios, ... etc. and over current is bad for the up stream items, in this case the Jabiru stator.  I install the vertical power box in my build which has over voltage protection built in, and easy to configure and use.  But for over current I installed inline fuses for each stator lead.  I wish I would have run them to a resettable circuit breaker, but live and learn. :)

with my new EarthX battery, I find if I do not allow the battery time to mostly charger before WOT takeoff run, I will get an over current alarm, have not blown the fuses yet, but makes the EarthX battery a bit dodgy.


Rob Turk
 

Nothing dodgy about this. LiFePO4 batteries have much lower internal resistance than regular batteries. That helps for start as it can provide more starting current without sagging, but it also means that the charge current will be higher when it's partially empty and th alternator is providing max power.

On 5/4/2021 8:44 PM, Marc Halcomb wrote:
...

with my new EarthX battery, I find if I do not allow the battery time to mostly charger before WOT takeoff run, I will get an over current alarm, have not blown the fuses yet, but makes the EarthX battery a bit dodgy.


Pete Twissell
 

If fitting a lithium battery is producing over current issues, I would suggest fitting an appropriate regulator for the battery.
Lead acid batteries are quite resilient and will simply gas if over charged.
Lithium batteries can get nasty if the charge current and maximum voltage are not properly controlled.
Some "replacement" lithium batteries have a built in BMS (battery management system), but I have seen these fail.
The last thing any of us want is a lithium fire.
Pete.

On Tue, 4 May 2021, 19:44 Marc Halcomb, <marchalcomb@...> wrote:
Mark,
Over voltage is bad for the down stream items: EFIS, EIS, Comm/Nav radios, ... etc. and over current is bad for the up stream items, in this case the Jabiru stator.  I install the vertical power box in my build which has over voltage protection built in, and easy to configure and use.  But for over current I installed inline fuses for each stator lead.  I wish I would have run them to a resettable circuit breaker, but live and learn. :)

with my new EarthX battery, I find if I do not allow the battery time to mostly charger before WOT takeoff run, I will get an over current alarm, have not blown the fuses yet, but makes the EarthX battery a bit dodgy.


glen english LIST
 

you wont get a fire from a lithium phospate battery

they are very different to "lithiun ion "

On 5/05/2021 5:08 am, Pete Twissell wrote:
If fitting a lithium battery is producing over current issues, I would suggest fitting an appropriate regulator for the battery.
Lead acid batteries are quite resilient and will simply gas if over charged.
Lithium batteries can get nasty if the charge current and maximum voltage are not properly controlled.
Some "replacement" lithium batteries have a built in BMS (battery management system), but I have seen these fail.
The last thing any of us want is a lithium fire.
Pete.


Jay Scheevel
 

The batteries that I have (EarthX) include a BMS module that will do a hard break if the voltage or current gets out of bounds and also serve to balance the charging per cell. These batteries actually have 2 BMS circuits per battery for redundancy. Nevertheless, I built sealed battery metal boxes vented to the exterior of the aircraft just in case.

 

Jay

 

From: main@JabCamit.groups.io <main@JabCamit.groups.io> On Behalf Of Pete Twissell
Sent: Tuesday, May 04, 2021 1:09 PM
To: main@jabcamit.groups.io
Subject: Re: [JabCamit] Safety for Jab alternator

 

If fitting a lithium battery is producing over current issues, I would suggest fitting an appropriate regulator for the battery.

Lead acid batteries are quite resilient and will simply gas if over charged.

Lithium batteries can get nasty if the charge current and maximum voltage are not properly controlled.

Some "replacement" lithium batteries have a built in BMS (battery management system), but I have seen these fail.

The last thing any of us want is a lithium fire.

Pete.

 

On Tue, 4 May 2021, 19:44 Marc Halcomb, <marchalcomb@...> wrote:

Mark,
Over voltage is bad for the down stream items: EFIS, EIS, Comm/Nav radios, ... etc. and over current is bad for the up stream items, in this case the Jabiru stator.  I install the vertical power box in my build which has over voltage protection built in, and easy to configure and use.  But for over current I installed inline fuses for each stator lead.  I wish I would have run them to a resettable circuit breaker, but live and learn. :)

with my new EarthX battery, I find if I do not allow the battery time to mostly charger before WOT takeoff run, I will get an over current alarm, have not blown the fuses yet, but makes the EarthX battery a bit dodgy.


Mick O'Connor
 

Those that insert fuses in the alternator output, what value do you use ?
Mick

Sent from my Commodore 64 TerraTurbo

On 4 May 2021, at 21:55, Jay Scheevel <jay@...> wrote:

The batteries that I have (EarthX) include a BMS module that will do a hard break if the voltage or current gets out of bounds and also serve to balance the charging per cell. These batteries actually have 2 BMS circuits per battery for redundancy. Nevertheless, I built sealed battery metal boxes vented to the exterior of the aircraft just in case.

 

Jay

 

From: main@JabCamit.groups.io <main@JabCamit.groups.io> On Behalf Of Pete Twissell
Sent: Tuesday, May 04, 2021 1:09 PM
To: main@jabcamit.groups.io
Subject: Re: [JabCamit] Safety for Jab alternator

 

If fitting a lithium battery is producing over current issues, I would suggest fitting an appropriate regulator for the battery.

Lead acid batteries are quite resilient and will simply gas if over charged.

Lithium batteries can get nasty if the charge current and maximum voltage are not properly controlled.

Some "replacement" lithium batteries have a built in BMS (battery management system), but I have seen these fail.

The last thing any of us want is a lithium fire.

Pete.

 

On Tue, 4 May 2021, 19:44 Marc Halcomb, <marchalcomb@...> wrote:

Mark,
Over voltage is bad for the down stream items: EFIS, EIS, Comm/Nav radios, ... etc. and over current is bad for the up stream items, in this case the Jabiru stator.  I install the vertical power box in my build which has over voltage protection built in, and easy to configure and use.  But for over current I installed inline fuses for each stator lead.  I wish I would have run them to a resettable circuit breaker, but live and learn. :)

with my new EarthX battery, I find if I do not allow the battery time to mostly charger before WOT takeoff run, I will get an over current alarm, have not blown the fuses yet, but makes the EarthX battery a bit dodgy.


glen english LIST
 

when considering fuse value, consider the fuse curve
I've covered this in the past.

A 20A fuse doesnt blow at 20 amps. and it might take 5 minutes to blow at 25 amps.

I used LITTLEFUSE watertight inline ATO size fuseholders in series with each stator wire
MFR PN FHAC0002LXN


https://www.mouser.com/ProductDetail/Littelfuse/FHAC0002LXN?qs=Y6HSjCmVMmv5rLPHhiQk9A%3D%3D

On 5/5/2021 6:59 AM, Mick O'Connor via groups.io wrote:
Those that insert fuses in the alternator output, what value do you use ?
Mick
Sent from my Commodore 64 TerraTurbo


David Amsler
 

The current limiting function of the circuitry in EarthEx batteries protects the battery, not our alternators, at least not for the size 900 that I was using, might be lower current limit for a smaller battery.

David A.

On Tue, May 4, 2021 at 4:56 PM Jay Scheevel <jay@...> wrote:

The batteries that I have (EarthX) include a BMS module that will do a hard break if the voltage or current gets out of bounds and also serve to balance the charging per cell. These batteries actually have 2 BMS circuits per battery for redundancy. Nevertheless, I built sealed battery metal boxes vented to the exterior of the aircraft just in case.

 

Jay

 

From: main@JabCamit.groups.io <main@JabCamit.groups.io> On Behalf Of Pete Twissell
Sent: Tuesday, May 04, 2021 1:09 PM
To: main@jabcamit.groups.io
Subject: Re: [JabCamit] Safety for Jab alternator

 

If fitting a lithium battery is producing over current issues, I would suggest fitting an appropriate regulator for the battery.

Lead acid batteries are quite resilient and will simply gas if over charged.

Lithium batteries can get nasty if the charge current and maximum voltage are not properly controlled.

Some "replacement" lithium batteries have a built in BMS (battery management system), but I have seen these fail.

The last thing any of us want is a lithium fire.

Pete.

 

On Tue, 4 May 2021, 19:44 Marc Halcomb, <marchalcomb@...> wrote:

Mark,
Over voltage is bad for the down stream items: EFIS, EIS, Comm/Nav radios, ... etc. and over current is bad for the up stream items, in this case the Jabiru stator.  I install the vertical power box in my build which has over voltage protection built in, and easy to configure and use.  But for over current I installed inline fuses for each stator lead.  I wish I would have run them to a resettable circuit breaker, but live and learn. :)

with my new EarthX battery, I find if I do not allow the battery time to mostly charger before WOT takeoff run, I will get an over current alarm, have not blown the fuses yet, but makes the EarthX battery a bit dodgy.


Jay Scheevel
 

That’s true, David, but I have the Rotec external belt driven alternator modification. I did not use the alternator that Rotec sent, going instead with a B&C 40 amp alternator of the same design and an external regulator. There is more protection built into my system as a result. My Jab stator did do some good, though. I donated it to a guy on the field that had burned up his original. Seems to be a common problem.

 

Jay

 

From: main@JabCamit.groups.io <main@JabCamit.groups.io> On Behalf Of David Amsler
Sent: Tuesday, May 04, 2021 4:06 PM
To: main@jabcamit.groups.io
Subject: Re: [JabCamit] Safety for Jab alternator

 

The current limiting function of the circuitry in EarthEx batteries protects the battery, not our alternators, at least not for the size 900 that I was using, might be lower current limit for a smaller battery.

 

David A.

 

On Tue, May 4, 2021 at 4:56 PM Jay Scheevel <jay@...> wrote:

The batteries that I have (EarthX) include a BMS module that will do a hard break if the voltage or current gets out of bounds and also serve to balance the charging per cell. These batteries actually have 2 BMS circuits per battery for redundancy. Nevertheless, I built sealed battery metal boxes vented to the exterior of the aircraft just in case.

 

Jay

 

From: main@JabCamit.groups.io <main@JabCamit.groups.io> On Behalf Of Pete Twissell
Sent: Tuesday, May 04, 2021 1:09 PM
To: main@jabcamit.groups.io
Subject: Re: [JabCamit] Safety for Jab alternator

 

If fitting a lithium battery is producing over current issues, I would suggest fitting an appropriate regulator for the battery.

Lead acid batteries are quite resilient and will simply gas if over charged.

Lithium batteries can get nasty if the charge current and maximum voltage are not properly controlled.

Some "replacement" lithium batteries have a built in BMS (battery management system), but I have seen these fail.

The last thing any of us want is a lithium fire.

Pete.

 

On Tue, 4 May 2021, 19:44 Marc Halcomb, <marchalcomb@...> wrote:

Mark,
Over voltage is bad for the down stream items: EFIS, EIS, Comm/Nav radios, ... etc. and over current is bad for the up stream items, in this case the Jabiru stator.  I install the vertical power box in my build which has over voltage protection built in, and easy to configure and use.  But for over current I installed inline fuses for each stator lead.  I wish I would have run them to a resettable circuit breaker, but live and learn. :)

with my new EarthX battery, I find if I do not allow the battery time to mostly charger before WOT takeoff run, I will get an over current alarm, have not blown the fuses yet, but makes the EarthX battery a bit dodgy.


Mark Dunstone
 

Marc, yes.  I bought and installed a ‘Powermate’ voltage regulator.  It limits alternator charge current to 8Amps so it may not be suitable for some folks with high electrical power needs.  I find at take-off and then for about 10 minutes charging is pegged at the maximum 8A and voltage around 13.7, and then the DC voltage stabilises at 14 to 14.2V. I run a lithium battery.  In terms of electrical needs I run an MGL Extreme EFIS/EMS, a vhf radio, a class C ssr transponder (with an RS232 to Gilliam code converter), a SkyEcho ADSB, a MGL Blaze ASI/VSI, an electronic G-meter, an LED strobe (wing tips and tail), and a couple of fuel pumps (boost and wing tank transfer).  The 8A charge current seems more than adequate.
I agree the lithium batteries are more likely to accept excessive current than lead acid, but that does not mean lead acid batteries will not also accept excessive current....it’s just that it’s not as common.  My in-flight meltdown of the alternator was with a lead acid battery.

Glen, I’ll think you will find that lithium iron phosphate batteries belong in the class of ‘lithium ion’ batteries....but not all lithium ion batteries are lithium iron phosphate.  My understanding is that the major fire risk are those lithium batteries where you can get lithium metal dendrites growing on the electrodes,,,and these can cause shorts. This isn’t a high risk for lithium iron phosphate.


Marc Halcomb
 

Mark,
Which specific “Powermate VR” did you use?  Interesting idea.  BTW I misstated my installation, the fuse is in the VR output to the battery (per the Jabiru installation manual). Noting like a aircraft wiring document review and physical inspection to correct oneself! :) 


Ron Milan
 

Glen:  Please educate me why you use a fuse in "each stator wire"?  Is the stater not a strand of continuous wire--a loop if you will--one continuous circuit?  Unless there was a short to ground causing an open in the loop would not one fuse in this circuit cause the "circuit" to open, thus preventing any further current flow from the loop?   I would appreciate your explaining to me why two fuses are required to protect this circuit!

Thank you in advance for the education on this issue!

Ron M


-----Original Message-----
From: glen english LIST <glenlist@...>
To: main@JabCamit.groups.io
Sent: Tue, May 4, 2021 5:05 pm
Subject: Re: [JabCamit] Safety for Jab alternator

when considering fuse value, consider the fuse curve
I've covered this in the past.

A 20A fuse doesnt blow at 20 amps. and it might take 5 minutes to blow
at 25 amps.

I used LITTLEFUSE  watertight inline ATO size fuseholders in series with
each stator wire
MFR PN FHAC0002LXN


https://www.mouser.com/ProductDetail/Littelfuse/FHAC0002LXN?qs=Y6HSjCmVMmv5rLPHhiQk9A%3D%3D


On 5/5/2021 6:59 AM, Mick O'Connor via groups.io wrote:
> Those that insert fuses in the alternator output, what value do you use ?
> Mick
>
> Sent from my Commodore 64 TerraTurbo
>






Mark Dunstone
 

Seems ‘Powermate’ are no longer in business....they were at Powermate.com.au but that doesn’t seem to work. It was a bit of a backyard business....a shame it’s gone.


David Amsler
 

Mark,
Thanks for the reminder, checked my wiring diagram and it shows a 20 amp fuse installed in one line from alternator, added to drawing in Jan of last year.  WITH A NOTE:  NOT YET INSTALLED. (too cold to work in hangar in Jan.)  So today I have a project.

David A.

On Tue, May 4, 2021 at 10:57 PM Marc Halcomb <marchalcomb@...> wrote:
Mark,
Which specific “Powermate VR” did you use?  Interesting idea.  BTW I misstated my installation, the fuse is in the VR output to the battery (per the Jabiru installation manual). Noting like a aircraft wiring document review and physical inspection to correct oneself! :) 


jabcamit@...
 

Attached is a simple circuit to  prevent alternator coils or regulators burning out due to over-heating (due to excess alternator current output).  The circuit works as follows:


1) When the sense input on  the regulator is shorted to zero volts, or open circuit, the regulator turns off ( check it does this on your regulator (if not a slight circuit tweak is required).

2) The circuit works by thermal switches attached to the regulator, and to an alternator coil, disconnecting the voltage to the regulator sense input if either get too hot.

3) An optional pilot switch is also included (eg if the  pilot sees a high current warning on his instruments).  The pilot switch has an optional OK LED. When glowing the circuit is working normally. It also acts as a reminder to switch the switch off when parking the aircraft (the sense wire drains a few mA from the battery).

4) As the sense wire only  consumes a few mA low current, low hysteresis, thermal switches are used (mechanically and thermally bonded to the parts they  are sensing). Switching on and off of the alternator current (10 amps plus) is performed by the regulator (which is what it does anyway in normal operation). So the new circuitry (in red in picture) only needs low current (eg 1 amp) rated wiring.

5) The fuses in the circuit are only there to protect if a component (eg the regulator) actually fails. They will reduce the risk of  short circuit fires and of resulting damage to other components/wiring.


6) An even better solution (regulates battery current and voltage as well as  providing thermal overload protection) is shown in my noddy picture last time this topic was discussed.



Simples

BobP


Rob Turk
 

I like your idea but with one remark. When the switch is open, the sense wire is not shorted to ground. It's connected through the resistor and LED. That means if there's anything inside the regulator that can source a few mA to the sense wire (either intended or through a defect), then the LED will keep that wire at ~3V. If still functional, the regulator will see this as a low, and regulate its output to way beyond 14V.


On 5/5/2021 2:24 PM, jabcamit@... wrote:
Attached is a simple circuit to  prevent alternator coils or regulators burning out due to over-heating (due to excess alternator current output).  The circuit works as follows:


1) When the sense input on  the regulator is shorted to zero volts, or open circuit, the regulator turns off ( check it does this on your regulator (if not a slight circuit tweak is required).

2) The circuit works by thermal switches attached to the regulator, and to an alternator coil, disconnecting the voltage to the regulator sense input if either get too hot.

3) An optional pilot switch is also included (eg if the  pilot sees a high current warning on his instruments).  The pilot switch has an optional OK LED. When glowing the circuit is working normally. It also acts as a reminder to switch the switch off when parking the aircraft (the sense wire drains a few mA from the battery).

4) As the sense wire only  consumes a few mA low current, low hysteresis, thermal switches are used (mechanically and thermally bonded to the parts they  are sensing). Switching on and off of the alternator current (10 amps plus) is performed by the regulator (which is what it does anyway in normal operation). So the new circuitry (in red in picture) only needs low current (eg 1 amp) rated wiring.

5) The fuses in the circuit are only there to protect if a component (eg the regulator) actually fails. They will reduce the risk of  short circuit fires and of resulting damage to other components/wiring.


6) An even better solution (regulates battery current and voltage as well as  providing thermal overload protection) is shown in my noddy picture last time this topic was discussed.



Simples

BobP


glen english LIST
 

Hi Ron

It is to cover a likely regulator fault condition.

There are two hot wires from the regulator back to the alternator stator body. Depending on the regulator style, both may be able to source battery current.

A stator  may have a short to the stator laminations or spider body- a short to ground.

This might occur from either a mechanical failure, or due to over heating.  The stator has a fair resistance. A short at the far  end of the (long) wire may only cause a 'cook' and not blow the fuse because it has high resistance.  So we cover both bases with two fuses- one at each end of the stator winding to cover the regulator being able to source current from either wire, and blowing a fuse close to it.  The fault condition make me a combination of cooking current in one section of the winding, plus maxiumum load current.

The rule of fuses as you know, the wire and circuit that is going to carry the fusing  current must be capable  carry  the current without overheating.

On 5/05/2021 8:58 pm, Ron Milan via groups.io wrote:

Glen:  Please educate me why you use a fuse in "each stator wire"?  Is the stater not a strand of continuous wire--a loop if you will--one continuous circuit?  Unless there was a short to ground causing an open in the loop would not one fuse in this circuit cause the "circuit" to open, thus preventing any further current flow from the loop?   I would appreciate your explaining to me why two fuses are required to protect this circuit!

Thank you in advance for the education on this issue!

Ron M


-----Original Message-----
From: glen english LIST <glenlist@cortexrf.com.au>
To: main@JabCamit.groups.io
Sent: Tue, May 4, 2021 5:05 pm
Subject: Re: [JabCamit] Safety for Jab alternator

when considering fuse value, consider the fuse curve
I've covered this in the past.

A 20A fuse doesnt blow at 20 amps. and it might take 5 minutes to blow
at 25 amps.

I used LITTLEFUSE  watertight inline ATO size fuseholders in series with
each stator wire
MFR PN FHAC0002LXN


https://www.mouser.com/ProductDetail/Littelfuse/FHAC0002LXN?qs=Y6HSjCmVMmv5rLPHhiQk9A%3D%3D


On 5/5/2021 6:59 AM, Mick O'Connor via groups.io wrote:
Those that insert fuses in the alternator output, what value do you
use ?
Mick

Sent from my Commodore 64 TerraTurbo