Probably the best way.
I was always wondering why the battery is limited to 99wh but you technically could take 20 of them in one bag. If one inside start to blow the rest could start fire too.
I travel a lot and I really don’t understand some rules…like with drones in Emirates. It’s not allowed to have your drone in carry on, but batteries allowed only in carry on. So you need to check in your drone without batteries…
What? This makes no sense. I would plan to place all the batteries in fire bags with about 3 or 4 packs per bag to that the fire would be smaller. I might even double bag them. I just had one of my diy lipo packs catch on fire after one of the cells overcharged due to a BMS failure.
This would be why I am so concerned about my next pack. I was going to spot weld a 18650 pack but that is out the window.
Im more interested in seeing how this 10s battery “Transformer” that breaks into 10 - 1s packs that either shares 1 10s bms … or 10 packs with a bms each with special serial connections and keeping it all compact and chargeable…
Wow that’s poor to see! Sorry for that loss!
They will all be connected to one bms. You wire up the balance cables from each parallel pack in parallel which gets all the cells balanced. Then you wire the rest up like you normally would
As you had your own experience already you can imagine how much smoke blown up when your batteries catch fire. Even if it’s only one it could be enough in the plane.
Just for my interest as I plan my next build with lipos. How much overcharged you or the bms the batteries before they blown up?
but then how do these packs break apart for this airline travel? you would need all bms wires able to disconnect… all series cable able to disconnect and reconnect… and the same for the bms… at least one of the main wires (pos or neg) would have to disconnect so you can have your 10 individual packs you ask for.
I don’t have any of this data unfortunently. I should have replaced the BMS a long time ago when I found that the batteries were as much as .4v off. I assumed the BMS just needed to do its’ work though and left it. When I removed the BMS as it wouldn’t charge or discharge anymore, I assume that the highest cell just kept getting juice and the BMS may have been preventing it from overcharging before.
1 Like
There would be a shit ton of adapters to transform the balance cables to how they need to be to hook up to one BMS but when all those adapters get removed, the pack would be isolated after removing the xt90 main port.
I wrote this to a facebook group that i’m in but it its universal so I am copying it here.
Here’s the lesson from this whole thing: For an electric fire, cover you battery/board with wet towels.
I removed my BMS as it stopped working and I assumed that I could cycle my lipos a few times as they should have been previously balanced by the BMS and thus wouldn’t loose there similar voltages. On the very first cycle, One of the batteries overcharged when the pack was around 75% which caught me totally off guard. The battery started hissing and puffed up about an inch. I quickly took the board out to the cement pool deck at the hotel I was at. The hissing stopped so I assumed that the battery was STABLE. I got all the tools to remove my enclosure and the board burst into flames. Luckily I was unharmed and there were enough people around that knew what they were doing. There was no property damage other than a burn mark on the patio from the fire.
You would need 10 separate BMS’s.
You can’t use 1 bms… If you add splitters to the bms lines you will cause a fire… That would cause it to charge cells that are not low.
All the balance wires from the first set of cells get wired in parallel. This would not cause a fire.
k, just making sure… ive built a few packs now… personally wouldnt have a need for something like this… i think the extra bullet connectors your using for all bms wires and main leads will kill some space if space is tight…
It’s ugly cause I just mocked it up but this would condense 33 balance leads into 11 (One for the positive or negative lead)
All the 1s’ would have a voltage of 3.7v 2’s would have 7.4 and 3’s would have 11.1
Yea. So if cell #1 is low on one of the packs and it goes to charge it, it’s going to charge the other #1’s that are not low…
That is why you wire all the packs in parallel because packs placed in parallel will balance each other. So all the cell 1’s would have the same voltage after a few hours of being connected, depending on how different the voltages are to start. They should never become different than each other once connected.
i dont know what im looking at here BUT a 10s would have 10 balance wires only (plus the first neg.)