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Reconditioning Dynon Backup Battery

RudiGreyling

Well Known Member
Reconditioning Skyview Backup Battery

Ok my 2 Skyviews are 5 years old +/- 200 hours of operation and the backup SV-BAT-320 packs did not pass its annual 45min run check.

Horror to my surprise they cost $180 each I need x 2 = $360 and I am situated on the other side of the globe South Africa, so add another $75 for HAZMAT shipping and this is getting a bit expensive...So I needed to make another plan.

So for the sake of Experimental and cost (my Skyview is out of its 3 year warranty in any case) I embarked to recondition them and share here what I have learned....

The SV-BAT-320 pack is simple to open with 4 screws.
IMG_5840

Inside is a simple 6 cell Lithium-Ion 18650 cell (3.7V) battery pack in (3S2P - 3 Series x 2 Parallel) configuration. These look like No-Name brand and the capacity is not listed, but an internet search revealed they are 2200 mah if you can trust the internet.
IMG_5842

On the one side, closed by some covering is a small PCB board, a BMS (Battery Management System) to manage the pack.
IMG_5841

So I had 2 new packs made up with quality branded SANYO cells of 3400mah capacity (50% more capacity). It cost me $50 locally and no special HAZMAT shipping required since it was local in South Africa.

I soldered the BMS board exactly like the orginal but I added an additional touch. I soldered balance lead, standard used in radio control LIPO batteries, to each pole of the BMS and battery pack. Now I can monitor the condition of each cell in the pack, by simply plugging in a Radio Control battery measurement device.
IMG_5845

I balance charged the Battery Pack on my Radio Control Balance Charger on the bench, then I taped the BMS closed and fitted everything back into the Dynon SV-BAT-320 housing.

The battery packs went back into the airplane and each of them passed the annual 45-minute duration test successfully.

I also have the added benefit to check the health of each pack during the annual inspection, by the way of the balance leads on each battery pole. If the cell voltages are different I have the means to balance them back into alignment with the means of simple a Radio Control LIPO balancer, to extend the battery pack life.

So in Summary:
This is a simple standard 3S2P pack than any good Battery Repacking Company can repack for you with higher capacity branded cells, with a cost saving...and if required can easily add a balance monitoring lead for you to inspect the health and balance the cells occasionally to extend its life.

I hope this helps some of you..

Kind Regards
Rudi
 
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Rudi,

Thanks for the detailed instructions. I've done similarly on my PLB Li battery. All the "official" battery replacement places wanted over $100 to replace the batteries, so I bought new ones and made my own battery pack. Someone is getting rich on these battery replacement schemes.
 
Good to see you on here Rudi! We miss you!

Met a guy at Osh from South Africa that said he knows you.

I did not get his last name but him and his son are named Arie and Kian.

LIsoQOj.jpg

Photo shamelessly stolen from Mike Bullock :)

Oh, and thanks for the write up on the batteries! Great stuff and saves people money!
 
Good going Rudi!
I tried doing the same thing with my D-180 backup battery, but gave up. The problem is that the battery pack fits inside of the D-180. I could not get the new batteries and circuit board and insulating tape all compacted enough to fit back inside of the D-180. If you ever removed the boxed contents of a newly purchased product, then tried unsuccessfully to pack everything back into the package, you will understand the challenge. Not wanting to risk a lithium battery fire, I broke down and bought a new Dynon backup battery pack.
 
I wanted the backup battery mainly to prevent rebooting during engine cranking brownout. An added benefit is backup in case the aircraft electrical system fails. I had considered a DC to DC converter to maintain Dynon voltage during engine cranking. But buying a new battery was easier.
 
As option, design your power distribution scheme so you eliminate the need for backup batteries.

Carl

you can never eliminate the need for backup batteries if you want redundancy. you either have independent batteries for the units or a two battery system like you advocate. it a single large backup vs smaller backups. to each his own.

bob burns
RV-4 N82RB
 
Good going Rudi!
I tried doing the same thing with my D-180 backup battery, but gave up. The problem is that the battery pack fits inside of the D-180. I could not get the new batteries and circuit board and insulating tape all compacted enough to fit back inside of the D-180. If you ever removed the boxed contents of a newly purchased product, then tried unsuccessfully to pack everything back into the package, you will understand the challenge. Not wanting to risk a lithium battery fire, I broke down and bought a new Dynon backup battery pack.

Hi Joe,
I have not tried to recon batteries for D-180 yet, I have one in my other airplane, so might consider tackling them at a later stage.

Just a comment on lithium fire risk vs. stock Dynon battery. Having opened and deconstructing the original Dynon supplied SV-BAT-320, I have noticed Dynon has not taken any special measures in constructing their LIPO pack, and actually did the least amount of effort and least cost route.

The pack I reconstructed used quality branded cells of higher capacity, proper battery spacing trays and insulated wires from the battery poles to BMS. In addition, I enhanced it with the balance monitoring lead.

So, in a nutshell, my reconditioned pack is superior to the original pack in many ways. I am happy with my decision to recondition, your mileage might vary.

Kind Regards
Rudi
 
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you can never eliminate the need for backup batteries if you want redundancy. you either have independent batteries for the units or a two battery system like you advocate. it a single large backup vs smaller backups. to each his own.

bob burns
RV-4 N82RB

Ditto Bob! The smaller Dynon SV-BAT-320 backup is a simple drop in redundancy without the need to worry about other decisions like keeping the aux backup battery charged and healthy. The Skyview unit makes that easy for you with a SV-BAT-320.
 
The Dynon pack does indeed make it easy for you, but it never balance charges all of the cells, and that's a major cause of failure in LiPo battery packs. Lazy cells kill off the harder working cells.

It's all due to variance in production of the battery cells.

Storing LiPo cells with a full 100% state of charge is a good way to kill all the batteries. They do much better in storage, which is how your plane sits, most of the time, at a 50- 60% state of charge, long term. A Li Po cell stored at 3.9V will last easily 10 years, if not stored in extreme heat or extreme cold.
 
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Dynon has stated in the past that the battery charge state is controlled by the Skyview display, which is how the battery is charged. If that is the case have you considered how the increased pack capacity might impact Skyview during the charge cycle?
 
The Dynon pack does indeed make it easy for you, but it never balance charges all of the cells, and that's a major cause of failure in LiPo battery packs. Lazy cells kill off the harder working cells.

It's all due to variance in production of the battery cells.

Storing LiPo cells with a full 100% state of charge is a good way to kill all the batteries. They do much better in storage, which is how your plane sits, most of the time, at a 50- 60% state of charge, long term. A Li Po cell stored at 3.9V will last easily 10 years, if not stored in extreme heat or extreme cold.

The Dynon battery is Lithium Ion. Nobody should have a LiPo battery in their airplane, IMO.
 
The Dynon battery is Lithium Ion. Nobody should have a LiPo battery in their airplane, IMO.

LiThium Polymer (LiPo) batteries are lithium ion batteries. The polymer aspect is a manufacturing technique, and technically other differences also that allow them to overheat easier. The chemistry can vary, but Lithium Colbalt is common. Anything but LiFePo have are less safe. I test batteries under FAA qualification testing. The results make you wonder about carrying a phone in your pocket.
 
The Dynon pack does indeed make it easy for you, but it never balance charges all of the cells, and that's a major cause of failure in LiPo battery packs. Lazy cells kill off the harder working cells.

It's all due to variance in production of the battery cells.

Storing LiPo cells with a full 100% state of charge is a good way to kill all the batteries. They do much better in storage, which is how your plane sits, most of the time, at a 50- 60% state of charge, long term. A Li Po cell stored at 3.9V will last easily 10 years, if not stored in extreme heat or extreme cold.

It depends on the capabilities of the built in balance circuit.

Does it keep every cell at the same voltage as the battery is charged....

Or just prevent each individual cell from overvoltage.

You could get long live by keeping each cell at the same voltage and then limiting pack voltage to a multiple of 3.9 (in your case).
 
Aircraft battery inventory

LiThium Polymer (LiPo) batteries are lithium ion batteries. The polymer aspect is a manufacturing technique, and technically other differences also that allow them to overheat easier. The chemistry can vary, but Lithium Colbalt is common. Anything but LiFePo have are less safe. I test batteries under FAA qualification testing. The results make you wonder about carrying a phone in your pocket.

A while back I wondered about a situation where someone stated they weren't willing to go down the "risky" path of installing an EarthX (LiFePo*) battery, yet at the same time were happy to take off with 2 phones, 1 tablet, a Camera that included a lithium ion battery, and a panel instrument that probably also included a lithium ion backup battery. We seem to care a lot about aircraft battery safety, and rightly so, but everyone just gets on board carrying the dangerous stuff anyway...:confused:
 
Resurrecting this thread from last year...

Because my Dynon Skyview battery failed testing this year...and looking for options.

This thread seemed made-to-order, however when I called the local battery retailer, while they had the batteries I needed, they wouldn’t assemble them in packs as they said there is specialized equipment needed to solder Li-ion batteries, which they don’t have.

Anyone else run into this? What was your workaround.

While I have modest soldering skills, I don’t need a battery fire caused by improper technique or materials.

Thanks,

Rob S.
 
The 18650 cellls are not something you should fool with unless you understand the risk. That being said, if you want a custom built 2x3 pack you should find a battery shop that can spot weld the connecting tabs vs trying to solder them.

I bought a six pack of individual 18650 cell holders with wire leads and a Comidox 3S 12V 10A 18650 Lithium Battery Protection Board BMS. I used LG HG2 3000ma/h cells with that BMS. Another route is to buy a 6 cell, 12V 18650 case from Amazon such as the Cuawan DIY 6X 18650 Battery Storage Case Box 12V Power Supply (nice compact unit, however I would check the BMS).

It turned out the problem with the Dynon Backup Battery was the BMS board had failed, it was replaced and has been working fine for the past two years.

John Salak
RV-12 N896HS
 
The 18650 cellls are not something you should fool with unless you understand the risk. That being said, if you want a custom built 2x3 pack you should find a battery shop that can spot weld the connecting tabs vs trying to solder them.

If you're lucky enough to find a shop to do that, I would suggest you do NOT tell them it's for an aircraft. "Offroad vehicle" should be just fine but nobody wants the liability associated with an aircraft.
 
The 18650 cellls are not something you should fool with unless you understand the risk. That being said, if you want a custom built 2x3 pack you should find a battery shop that can spot weld the connecting tabs vs trying to solder them.

I bought a six pack of individual 18650 cell holders with wire leads and a Comidox 3S 12V 10A 18650 Lithium Battery Protection Board BMS. I used LG HG2 3000ma/h cells with that BMS. Another route is to buy a 6 cell, 12V 18650 case from Amazon such as the Cuawan DIY 6X 18650 Battery Storage Case Box 12V Power Supply (nice compact unit, however I would check the BMS).

It turned out the problem with the Dynon Backup Battery was the BMS board had failed, it was replaced and has been working fine for the past two years.

John Salak
RV-12 N896HS

John,

Thanks for the info...how does one ?check the BMS? with one of these things...swap the pigtail over to the new unit/batteries and see if the Skyview ?sees? it and charges it up? Or something else?

For instance, I found this on EBay:

https://www.ebay.com/itm/Battery-Pa...hash=item1f031f7b7b:m:msbRgRa0fH8svo1-EkBmBOg

They have a 3S2P setup, with BMS for ~$38.

If the form factor of their unit fits into the old Dynon case, it would be great (no specs for the backup battery on Dynon?s website so I gotta go out to the airport and pull the bad one to measure) to open it up, pull the old cells out, swap the pigtail and see if it works.

I like that it says it has cells made by someone I?ve heard of before...

Comments appreciated, especially in attaching the pigtail to the BMS board (soldering?)...do?s/dont?s etc..

Thanks!

Rob S.
 
Rob,

I like the 3S2P battery pack you found, that is exactly what you need. I suspect it may not fit in the Dynon battery case or will be a tight fit. You should be able to remove the lead from the old battery pack and solder to the + and - tabs on the BMS.

I made a two piece replica battery case with a larger volume for the same type of 18650 cell holders you see on the ebay battery. I would be glad to send you the 3D print file if you want to print one.

John Salak
RV-12 N896HS
 
Hi

This has been an interesting discussion, made more so by the falling Australian dollar. I think I will try to see what I can put together to replace my elderly, but not failing, Dynon battery back up pack.

Rather than cannibalise my existing battery can I ask if anyone knows the type of plug used on the Dynon Battery? I was thinking I would like to do something before the need arises.

Thanks

Peter
 
From Dynon forum:

"Dynon Technical Support Staff member
Jan 31, 2011
The connector is a Molex 43640-0301, and the pins are 43031-0007. Sorry, but we can't supply these except as part of a harness."

Googling around I think that may be a typo as it reurns 3 connector parts.
 
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Second being in Australia with a falling dollar. Haven?t tested mine as yet but are interested in the results as to if something is available locally for future reference.
 
The correct part is the 3-pinned connector which only the two outer pins are used, not the middle one. I think I purchased mine from McMaster-Carr. Dan from Reno
 
What Battery Management System on the SV-BAT-320?

My SV-BAT-320 didn't pass the test and as it is almost 9 years old (I suspect) I guess I can't complain too much. However I liked this thread and before buying a new battery I thought I try this.

However having the pack made and the old BMS soldered back on, I was told by the technician that the BMS is faulty. Does anyone have any idea what BMS to get.

It looked like Dynon used all stock parts, so I am sure that BMS is 'out there somewhere..' but I haven't been able to find it.
 
Try Amazon for a 3S 12V 10A 18650 Lithium Battery Protection Board BMS. The "3S" specification gets you the 12 volt configuration.

John Salak
RV-12 N896HS
 
Just to add a data point...I just replaced mine after 8 years of operation (so probably 9 years, if you add the time from purchase to first flight, or thereabouts).

180 bucks every 8-10 years makes this one of the cheapest annual expense items on the entire airframe.
 
My SV-Bat-320 isn't even a year old yet, and isn't charging.... think I need to open it up to see what's failed, unless it's still under warranty by Dynon.
 
Battery

Call Dynon
It’s covered for 3 years
Just got mine replaced
They will sell you one, you send yours back and they credit you if it’s bad
Dave
 
I've owned mine for 8 years and flown it 700 hours and mine just passed the check no problem which actually surprised me.
 
Same 18650 cells and arrangement as what Dynon has in the backup battery, so it should fit.

John Salak
RV12 N896HS
 
Because my Dynon Skyview battery failed testing this year...and looking for options.

This thread seemed made-to-order, however when I called the local battery retailer, while they had the batteries I needed, they wouldn’t assemble them in packs as they said there is specialized equipment needed to solder Li-ion batteries, which they don’t have.

Anyone else run into this? What was your workaround.

While I have modest soldering skills, I don’t need a battery fire caused by improper technique or materials.

Thanks,

Rob S.

I'm late to reading this old thread. Since no one gave him an answer, I will. I can recommend MTO Battery. They replace cells in all sorts of tools and other devices with Lithium cells.

https://www.mtobattery.com/
 
Skyview won't charge or detect BU Battery

I rebuilt my Dynon BU battery with these batteries, https://www.amazon.com/5200mAh-Lithi...72710400&psc=1. My skyview still shows status standby with these and the original factory batteries. If i unplug the bu battery, the text on the setup page lights with yes/no, plugged in the text is unlit. Skyview isnt detecting or charging the bu batteries. With engine running, the system voltage is 13.2v, the bu packs each show around 11.5v
 
Dynon has stated in the past that the battery charge state is controlled by the Skyview display, which is how the battery is charged. If that is the case have you considered how the increased pack capacity might impact Skyview during the charge cycle?

There should be no effect whatsoever. A proper charge cycle for a Lithium battery involves constant current, followed by constant voltage. The current limit imposed by the Skyview display will simply result in a slower recharge.
 
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