Lipo Chargers or How Not to Burn Down the Makerspace

Aerospace / RC
#41

I am not so sure about enclosing batteries that can overheat in anything that is not well ventilated. If one is to make this kind of battery bunker, they should probably find a way to assure a lot of ventilation (maybe fan table under it?) or other cooling take place while charging. If even a small fraction of batteries overheat due to being enclosed that would not be good.

How about using the cinder blocks more or less as shown with a fan table under them. Design a system using smoke detectors that shuts the fans and drops the sand? Possibly the concrete block might be permeable enough to sandbag the top and still have enough air to cool the batteries while charging? Another possible method might be to use a water chamber to charge the batteries. This would give exceptional heat transfer, the batteries are well sealed I am sure. OR possibly wet the concrete blocks before using them with the fan to gain evaporative cooling? There are plenty of possibilities to improve the safety even further.

#42

@Dirk_Jeanis much has transpired since the earlier posts. There is a brand new, in the box charger with enclosed metal cabinet that was purchased. Link and photo above.

#43

Maybe we’re overcomplicating this?

#44

I suspect direct contact with concrete is going to be far more effective at transferring heat away from the batteries than circulated air.

In any case, as @AbelRamirez mentioned, it makes no difference. The idea for a battery bunker does not have momentum.

#45

Nope.

The thermal conductivity of concrete varies from 0.1 - 1.8 W/(m K) , while the thermal conductivity of moving air starts at about 10 W/(m K)… and goes up depending upon how fast the air is moving.

Moving substance almost always has greater heat transfer since part of the equation on the speed is the difference in temperature. When two items are in permanent contact the transfer of heat slows down as the difference in temperature decreases. With a moving liquid/gas you can nearly maintain a constant differential in temperature.

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#46

I am pretty sure LiPo batteries in good working condition do not get ‘HOT’ when charging. They only get to 100+°F when there is something wrong. Usually just before they burst into smoke and/or flame. :wink:

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#47

And not only does this Venom Stronghold charger monitor the battery’s temperature while it’s charging, but it also monitors the battery’s internal resistance of each cell. When a LiPo cell’s internal resistance starts to increase, that is the #1 indicator that something is going wrong with the battery.

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#48

I used it to charge my 130mah at 1amp and it worked well, it seems fairly safe. Thanks!

IMG_20151016_030213198.jpg3358×2519 2.45 MB

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