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Battery mod thread

These are Lion batteries. Not LiPo batteries. They have different chemistries and different voltage ranges. The big advantage to using Lion is that they can be stored on full charge indefinately and can be discharged to 0 without significant damage unlike LiPos. Their only downside is that they cannot supply the same high current that a LiPo can. But in the case of this lightweight drone, current supply is not a big issue.
There are variations in chemistry for both LiION and LiPO. Generally speaking a LiPO is a LiION cell, it is the electrolyte and packaging options that are different. What you say about current delivery is true. LiION also has a higher energy density. Your claim that LiION can be kept at full charge without detriment is demonstrably wrong. Both suffer equally from long periods at rated max terminal voltage and deep discharge (accelerated ageing). Operating voltages are also the same with identical charging requirements and discharge curves. 18650 & 21700 LiION cells are also available in 4.35V variants (the same as HVLoPO cells).
 
Okay, I was able to figure out how to just use the battery board off the factory battery and hook it up any external battery I'd like... This week and weekend will be full of testing.... I guarantee we shall see close to a hour flight time soon... I don't have the factory battery weighting me down now.

I figured out a way to revive the factory board after it is bricked from removing the factory cells. I will do some more testing , then I'll post my findings
 

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Decided I would make my battery mod look a little better.
 

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Made some new batteries to make things look more clean... So far my best time is 37:07....
 

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For anyone following this thread and are interested in swapping out the factory cells and using the stock bms without bricking it, DONT DO THE BATTERY UPDATE!!!!!
I've sacrificed 4 batteries to figure this out. After doing the battery update, and you open up a battery to put in bigger capacity cells it will brick the battery. So don't do the battery update!. If you have done it, then don't mess with your battery. You can add externals, but don't do a cell swap. I've even tried live swaps. It doesn't work..
 
Very cool, very cool indeed... i've been checking out your progress from the shadows for a bit and normally don't post much (first post here) but i've been very impressed with what you've accomplished so far and am intrigued to see if you can reach that 60 min mark...
I also dig that you are actually doing real flight tests vs just static hover tests, whats the weather conditions like there?
Are you still using the 2 sanyo 3450 mah cells from the first post? and if so how many flights have you done with them so far?
 
I think all are interested to know how close to 60 you will get. Maybe we can have a poll with a prize for the person who gets the closest to the number... Prize could be one of the dead BMS boards for a play.

What do you have added for the last flight- mah and weight (including mounting and wiring).
 
For anyone following this thread and are interested in swapping out the factory cells and using the stock bms without bricking it, DONT DO THE BATTERY UPDATE!!!!!
I've sacrificed 4 batteries to figure this out. After doing the battery update, and you open up a battery to put in bigger capacity cells it will brick the battery. So don't do the battery update!. If you have done it, then don't mess with your battery. You can add externals, but don't do a cell swap. I've even tried live swaps. It doesn't work..

Justinswidebody, have you tried equalizing cell voltages, prior to hotswap? There might be some trigger, for the "unexpected" voltage changes.
 
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Anyone trying solar panels to help charge the batteries a little bit for longer flight times?
Seems like a great idea. It won't get anywhere though. Consider that with good sun you might get 15w per square foot of panel and you will also need a charge controller. No where to put the panel and the extra power required to carry the weight would be significantly more than any energy contributed by the panel.
 
The problem may be that the BMS is designed to cut out when the battery voltage goes too low. A li-Ion, particularly LiPo should not get too low otherwise the components degrade.

Solution is to be sure you always have over 3v on the battery leads as you swap batteries. Many laptop batteries have the same low voltage shutdown.
 
Which SOC is the brains in the BMS board in the mini?

If it is one of the TI family or similar there will be an electro cap, probably around 2.2uf that will maintain the ram contents for long enough to survive a cell swap.

The issue might be a chem type mismatch. Did you try leaving the cell tap connector off the board with just B+ and - connections hooked up for before reconnecting? Often this will get them to wake up.
 
I already stated that if you don't do the battery update you can swap out cells all you want. Only requirement is after you swap them you have to plug it back in the factory charger. This resets it for the new cells.

I even have a bms that is plug and play with other batteries. This allows me to over charge the batteries, then plug into the bms, plug into factory charger, it will flash, then plug into the back of the mini and you're good to go. With this I am able to get 35min of flight time just on 2 cells
 

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The main key is to plug back into factory charger after the swap....

But if you did the initial battery update then this won't work....

I think the initial firmware on the battery didn't count how many charge cycles the battery did... I think this is why there was a new firmware released
 
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