Dual Battery Mod

[shockwave199]

I had the horizon modded battery and used it to charge the split 5200 via Dji charger. It never would power the external past 4.25v and ended up damaging a cell and breaking the battery. Had to send back to Horizon to fix, he had to strip the Dji battery down and rebalance each cell individually. I stopped using that method, I will only power via my proper charger now.

Did horizon advise that this is the better way, acknowledging there's a problem with using the dji charger? I've used the dji charger so far without a problem, so much as I know. I'd have to buy another charger that can properly charge the 5200's, more money. My current charger doesn't have a setting to charge them. I'm just wondering if you had an isolated incident or what, and what horizon says about it.

 

[Digdat0]

Did horizon advise that this is the better way, acknowledging there's a problem with using the dji charger? I've used the dji charger so far without a problem, so much as I know. I'd have to buy another charger that can properly charge the 5200's, more money. My current charger doesn't have a setting to charge them. I'm just wondering if you had an isolated incident or what, and what horizon says about it.

Horizon did not acknowledge a problem charging in this method, nor did they advise on other ways. I have no proof that is what caused it, but i only charged it twice and both the same manner via the DJI charger. Its probably speculation on my behalf. Tom at Horizon was very helpful, he had me send it back and he did troubleshooting and fixed, then sent it back to me a few days later. It could have been a freak thing to be honest, and I dont have any more DJI batteries with balance leads to test either. I'm hoping its a fluke, definitely not pointing a finger at Horizon.

 

[Digdat0]

Did horizon advise that this is the better way, acknowledging there's a problem with using the dji charger? I've used the dji charger so far without a problem, so much as I know. I'd have to buy another charger that can properly charge the 5200's, more money. My current charger doesn't have a setting to charge them. I'm just wondering if you had an isolated incident or what, and what horizon says about it.

Here's what the thread with Tom looked like. Looking back, i had a test hover flight and took down to 10% and landed. Could have been that, not the power/charging. Anyways, you can see below Tom was super helpful in fixing.

Digdat0: HI there - i dropped a line on the website via the contact page last night, not sure if it went through. I ordered the Phantom 3 battery mod and external packs about 2 weeks ago. I managed to get 3 flights from them, then after charge yesterday the DJI battery shows BATTERY ERROR and says "cell damaged". I tried to discharge the battery and recharge, but same issue. I'm at a loss of whats going on. Do you have any ideas or options?
Tom: If voltage dropped below 3v on any of the cells it could of damaged a cell, If you want to send it to me. I'll see what I can do with it.
Digdat0: Thanks Tom. If ya don't mind I'll send it over. The last flight i did a hover test, flew for 26mins and auto landing kicked in and it landed. I let it sit that night, charged next morning with the balancer and then found this when i tried it again. I'll ship it over, hoping you can do something
Tom: few back and forth with shipping info
digdat0: Did you get the battery in the mail yet? Any ideas on what's going on?
Tom: Yes I received it and plan to break it down tomorrow to see if there is an internal problem.
digdat0: Thanks Tom. Keep me posted.
Tom: Nothing so far. It is really out of balance, 3.73 3.74 3.77 4.00 its the cell thats 4.00v is causing the error. the smart board is picking up on it being out of balance with the other 3. I'm going to replace the smart board with a new one and try charging it again to see if it balances out. the smart board is supposed to monitor each cell when charging to keep them balanced but when I tried charging it that 4th cell increased faster then the others.
digdat0: Thanks! Keep me posted please.
tom: I removed the smart board and while it was off I put the battery on my charger and cycled it a few times and was able to get the cells balanced. I soldered a new board on it and charged it with the DJI charger and it stayed balanced. I do not have a P3 in house to test it so I will send it back to you. Keep your test flights low and close to you for a few cycles and let me know if the cells remain balanced. I'll be sending a battery monitor with a lead so you can keep an eye on each cells voltage as it charges.

 

[Strat]

Looking for bits for my battery mod i found this on ebay

Anyone used something like this??

Looks simple as to make from the pics.. not sure how much i trust it shorting ?

 

[Silverwingflinx]

I've been eyeballing those thunder power for some time, please do report back on how they work. They, for the weight/mah almost seemed too good to be true. Their 7000mah lihv weighs as much as the multistar 5200 lihv. Do report back silverwing!

Hi DIgdat0 will do! Hope I have some nice whether...???

 

[Strat]

Ru kidding look at that!!!! I would not trust it!!!!! parts are .. 50cents and selling it for 30.00????? WHAT!!!

Yes lol's for the price.. maybe he zapped himself when he decided on price

 

[petermeter]

But the DJI manual says to only use DJI batteries...doesn't it?

Since this thread discusses batteries, I thought it might be helpful if I were to share and recap some of the information I learned from other forum members on various threads here over the past 8 months. Some of these are counter-intuitive so it's good that we have these forums available to us and so many members that are smarter than us and willing to share their knowledge!

- You are guaranteed to crash if you use non-DJI batteries

- DJI will go bankrupt and fail as a company if they are not allowed to sell ALL of the Phantom batteries that people want to buy - at $150 each.

- using non-DJI batteries causes a greater likelihood that any crash will land on and seriously injure a person - most likely a child.

- when using non-DJI batteries you are 12 times more likely to crash land in a school yard during recess as you are to land anywhere else. (This is somehow true even on weekends and during summer vacation.)

- only people with low-IQ's that don't understand how warranties work would even consider using a non-DJI battery

- it is impossible for any company to build a better battery than DJI

- when a DJI battery fails, the drone drops out of the sky straight downwards, but when an aftermarket battery fails, the drone flys away and is drawn to the largest congregation of people within a 7 mile radius and will crash into the center of them

The scariest thing is that only one or two of the above "pearls of wisdom" are completely made up by me. The rest were either implied or stated explicitly to be true by one or more of our fellow pilots....


Sent from my iPhone using PhantomPilots

"Some of these are counter-intuitive" lol

 

[petermeter]

I had the horizon modded battery and used it to charge the lit 5200 via Dji charger. It never would power the external past 4.25v and ended up damaging a cell and breaking the battery. Had to send back to Horizon to fix, he had to strip the Dji battery down and rebalance each cell individually. I stopped using that method, I will only power via my proper charger now.

ok so it might be better to charge both dji batt and ext batt with good non-dji hv charger,
which seems to maximise usable dji batt capacity in some cases and helps preventing dji batt switching to charge mode when attaching the ext batts,
but still, i want to use the dji charger... has someone with horizon modded battery looked inside?
is the smartboard utilized for charging the externals somehow, or is there complete new extra electronics added?
or ist the dji charger "intelligent" enough to recognise the state of the externals which seem directly connected to it in the dji batt,
and does he regulate the charging process himself,
and the parallel to the internal dji cells connected balancing contacts of the the ext cells doe the balancing while charging, despite the smart board is turned off?
How does it... um... how does it work? don´t want to build a holy hand grenade...

 

[Irepairapples]

Looking for bits for my battery mod i found this on ebay

Anyone used something like this??

Looks simple as to make from the pics.. not sure how much i trust it shorting ?

Hh

Looking for bits for my battery mod i found this on ebay

Anyone used something like this??

Looks simple as to make from the pics.. not sure how much i trust it shorting

No its not simple to make as it has a protection circuit build into the connector

 

[Strat]

Hh

what does this mean ?

 

[Digdat0]

ok so it might be better to charge both dji batt and ext batt with good non-dji hv charger,
which seems to maximise usable dji batt capacity in some cases and helps preventing dji batt switching to charge mode when attaching the ext batts,
but still, i want to use the dji charger... has someone with horizon modded battery looked inside?
is the smartboard utilized for charging the externals somehow, or is there complete new extra electronics added?
or ist the dji charger "intelligent" enough to recognise the state of the externals which seem directly connected to it in the dji batt,
and does he regulate the charging process himself,
and the parallel to the internal dji cells connected balancing contacts of the the ext cells doe the balancing while charging, despite the smart board is turned off?
How does it... um... how does it work? don´t want to build a holy hand grenade...

I have opened the Horizon modded stock battery. He solders the power lead onto the same place as the rest of us. The only thing he does differently is that he also hooks in/solders balance leads to the 4 balance connectors and ground. He is using the same setup as stock, just with balance connectors attached. There is absolutely no additional smartboard or electronics otherwise included. By piggybacking the externals to the t60 power lead and the balance connectors, you basically charge both at the same time equally via the smartboard itself (or, thats the theory).

edit: their modded bat looks like this

charging:

Here's what the stock battery looks like under the cap:

 

[petermeter]

He solders the power lead onto the same place as the rest of us.

you mean on the switched side or the unswitched side?

 

[TheLightSpeedz]

I have opened the Horizon modded stock battery. He solders the power lead onto the same place as the rest of us. The only thing he does differently is that he also hooks in/solders balance leads to the 4 balance connectors and ground. He is using the same setup as stock, just with balance connectors attached. There is absolutely no additional smartboard or electronics otherwise included. By piggybacking the externals to the t60 power lead and the balance connectors, you basically charge both at the same time equally via the smartboard itself (or, thats the theory).

edit: their modded bat looks like this

Why can't they do this for the P4 Battery?






charging:

Here's what the stock battery looks like under the cap:

Sent from my iPad using PhantomPilots

 

[Digdat0]

you mean on the switched side or the unswitched side?

Switched side from the diagram in the pic above.

 

[Red Five Standing By]

Hello all!

I've spent a couple of days reading the whole of this thread and digesting the information. Very informative and you guys seem to know what you're doing, well most of you!

I've just ordered some parts to do the bird mod and a Multistar LiHV High Capacity 5200Mah 4S as the external. Fine with how to do it, charger, etc.

However yesterday I joined in a conversation on a P3 Facebook group and started debating with this guy who is an electrical engineer and uses large lipos for his work... He basically said that what we are doing is an no no, and you shouldn't mix HV lipos and standard lipos together in parallel. And even adding the DJI Lipo with another HV lipo in parallel is very bad.

This is exactly what he said:

I'm a electronic engineer and have worked for a company building large lithium ion packs and BMS systems for underwater electric vehicles for over 10 years so I work with this technology daily. Unless the cells are 100% matched, (capacity, voltage, even batch from assembly), you will damage them and oxidisation will diminish the cell chemistry, prematurely ageing them. Massive surge currents also risk puffing and fire when you short them together. I urge you to read the link I posted above, running lithium packs in parallel posses the same issues as the charging that he is describing.

Do yourself a favour before you loose the drone, spend 5 minutes on Google. The information is all over the place. Just because some RC hobbyists have been doing it does not make it good practice at all, you are tempting fate trust me. Here is a good link, "connecting cells that don't have a matched internal resistance will lead to 40% reduction in cycle life"...http://web.mit.edu/bazant/www/papers/pdf/Gogoana_2013_J_Power_Sources.pdf

The issue is the discrepancy between cells in different packs, and especially the voltage difference if you charge the dji packs to 100%. This will instantly back feed into the normal lipos and over charge them, plus drag the dji voltage down a bit. When you make a pack from scratch the cells that go in there needs to be properly binned, we don't even use cells from different manufacturers batches at work let alone different capacities / voltages.

He seems to know what he's talking about, but this mod isn't new and hundreds of people have been doing it.. So whats the deal?

 

[Ed209]

Hello all!

I've spent a couple of days reading the whole of this thread and digesting the information. Very informative and you guys seem to know what you're doing, well most of you!

I've just ordered some parts to do the bird mod and a Multistar LiHV High Capacity 5200Mah 4S as the external. Fine with how to do it, charger, etc.

However yesterday I joined in a conversation on a P3 Facebook group and started debating with this guy who is an electrical engineer and uses large lipos for his work... He basically said that what we are doing is an no no, and you shouldn't mix HV lipos and standard lipos together in parallel. And even adding the DJI Lipo with another HV lipo in parallel is very bad.

This is exactly what he said:

I'm a electronic engineer and have worked for a company building large lithium ion packs and BMS systems for underwater electric vehicles for over 10 years so I work with this technology daily. Unless the cells are 100% matched, (capacity, voltage, even batch from assembly), you will damage them and oxidisation will diminish the cell chemistry, prematurely ageing them. Massive surge currents also risk puffing and fire when you short them together. I urge you to read the link I posted above, running lithium packs in parallel posses the same issues as the charging that he is describing.

Do yourself a favour before you loose the drone, spend 5 minutes on Google. The information is all over the place. Just because some RC hobbyists have been doing it does not make it good practice at all, you are tempting fate trust me. Here is a good link, "connecting cells that don't have a matched internal resistance will lead to 40% reduction in cycle life"...http://web.mit.edu/bazant/www/papers/pdf/Gogoana_2013_J_Power_Sources.pdf

The issue is the discrepancy between cells in different packs, and especially the voltage difference if you charge the dji packs to 100%. This will instantly back feed into the normal lipos and over charge them, plus drag the dji voltage down a bit. When you make a pack from scratch the cells that go in there needs to be properly binned, we don't even use cells from different manufacturers batches at work let alone different capacities / voltages.

He seems to know what he's talking about, but this mod isn't new and hundreds of people have been doing it.. So whats the deal?

Seems to be some misunderstanding in the EE's response: He seems to be assuming the voltage is not the same with the externals. Most of us are using LiHV (15.2v) which is the same as the DJI battery. As far as the internal resistance difference and reducing cycle life, for me that's a non-issue since I tend to fly to 1% and kill the battery or deem it unusable due to too many 1% discharge cycles before I can actually see any real degradation due to mismatched internal resistance.

Also, in the document he provided it states:
"The cells used in this study were commercially available 2.2 Ah cylindrical LiFePO4 cathode, graphite anode cells, designed for use in high-C-rate applications."

I'm not a battery engineer but LiFePO4 and LiHV are batteries of different chemistries... Not saying the results would be different with LiHV but just pointing out that the study is not apples to apples.

I'm not sure how large the demographic is out there for people running battery mods who are trying to get "near-stock" reliability and longevity out of their birds. For me I don't care. I have taped up shells due to cracks, I know the extra weight puts added stress on many components, I fly for extreme distance, and many times ditch thousands of feet away and retrieve. It's like telling someone to drive slower because it's more dangerous the faster you go. Or you'll burn more fuel and wear your tires/engine by driving fast!

 

[dirtybum]

Yeah, I agree w/ Ed209
We all understand the risks and if you dont want to take risks, I suggest you leave your a/c exactly the way DJI sent it to you and fly it how DJI recommends.
These procedures in this thread are not for everyone, but for those of us that use these techniques the mishaps due to the mis-match that youre friend describes are few and far between.


Sent from my iPhone using PhantomPilots

 

[Digdat0]

I'm comfortable taking the risk. I'm already tempting fate flying out 10 miles, whats a battery explosion? </s>

that was an interesting read, but the takeaway is (IMO) decreased battery life, not really dangerous. "Mismatching of internal resistance in parallel-connected cells can lead to the more resistive cell taking a higher current toward the end of the discharge cycle." <--- outside of "it aint good", "it will lower your cycle life" and "it cause 'splosion" this stuck out as the main point, that the mismatched internal resistance could result in a higher pull of currents at the lower end of the battery available %, limiting the amount of available power left in the batteries. But, realistically, the DJI go battery drops MAH faster than the external batteries (they always have SOME juice left), so if that's the case I am not too worried to be frank. Still an interesting read, and we all need to be aware of the potential risks here.

 

[Red Five Standing By]

Yeah, I agree w/ Ed209
We all understand the risks and if you dont want to take risks, I suggest you leave your a/c exactly the way DJI sent it to you and fly it how DJI recommends.
These procedures in this thread are not for everyone, but for those of us that use these techniques the mishaps due to the mis-match that youre friend describes are few and far between.


Sent from my iPhone using PhantomPilots

Not my friend. Random guy on Facebook.

Thought I'd post his comments as after reading the whole of this thread I'd not seen any comments of mentions of this. Educational for all lol

 

[Red Five Standing By]

I'm comfortable taking the risk. I'm already tempting fate flying out 10 miles, whats a battery explosion? </s>

that was an interesting read, but the takeaway is (IMO) decreased battery life, not really dangerous. "Mismatching of internal resistance in parallel-connected cells can lead to the more resistive cell taking a higher current toward the end of the discharge cycle." <--- outside of "it aint good", "it will lower your cycle life" and "it cause 'splosion" this stuck out as the main point, that the mismatched internal resistance could result in a higher pull of currents at the lower end of the battery available %, limiting the amount of available power left in the batteries. But, realistically, the DJI go battery drops MAH faster than the external batteries (they always have SOME juice left), so if that's the case I am not too worried to be frank. Still an interesting read, and we all need to be aware of the potential risks here.

Yep, my thoughts. Already flying 6 miles out, just need more juice.