Bryan

Unlike NiMH batteries, which will usually run down and die without undue ceremony, LiPo batteries have been known to go unstable if they are allowed to discharge below 3.1V/cell. This will create a lot of heat!

For that reason you'll find that any decent brushless speed controller will have a cut-off voltage which can usually be programmed on initial set-up. On the types I've used there is a default value of 3.4V. An audible alarm is triggered as the battery approaches this voltage; ignore that and the power is cut off before any damage is done.

If you intend to use a LiPo battery on a speed controller which doesn't have this facility then the simple answer is don't.

Dave M

Bryan. You can buy little voltage monitoring widgets that plug into the charge monitoring battery lead, and will bleep when the voltage drops below (I think you can set this ) whatever. They are small and cheap.

Means you can use a non lipo esc.

Ashley

"Lipo voltage alarm" seems to find them.

I suspect Dave's comments in bold are code for "it's a no brainer"

An overly discharged LiPo is likely to have been ruined and good ones are not cheap.

Tim R

Hi All,

This sounds a very cautious approach, I've been flying and floating maybe for 10 years now, never had a Lipo go completely flat , surely I watch for the signs of the aeroplane not wanting to climb, or the boat comes off the plane, than it's time to land or head for the jetty 😀

Regards Ray

Edited By Ray Wood 2 on 20/12/2019 21:00:12

Whilst it is important not to over discharge LiPos it is apparently also not good practice to store them at full charge so if you are not using the boat for a while they need to be partially discharged. My LiPo charger has a 'Storage' mode facility which will discharge the battery to the appropriate level.

As a relative newcomer to LiPo batteries, I can appreciate their combination with brushless motors to provide the performance in fast prototype models that would previously only been achieved either by I/C power or very sophisticated and expensive conventional electric setups.This is just what you need for the SLEC Fairey Huntsman and Swordsman models I have been building.

But for the more sedate scale models I nornally build, my preference is still for the conventional brushed motor/NiMH battery installation which gives adequate and responsive power without the need to actively manage the batteries to avoid some sort of potential meltdown. They don't sell fire resistant LiPo battery storage pouches for no good reason and I do wonder if I've got potential firebombs in the workshop!

I'm used to the situation that when a battery is neglected it just dies. The idea that if it falls below a certain voltage it spontaneously self combusts is something I find a bit alarming. Being more used to Lead Acid or NiMH batteries where the requirement is to maintain a minimum level of charge when not in use I do find the high maintenance needs of LiPos a bit difficult to come to grips with.

Colin

Hi Colin,

Lithium polymer batteries in my experience are fine no issues, many scare stories not heard of combustion at low voltage?? I charge them on a fire brick for safety. They don't last that long before they start venting and need throwing away, I have nicad s that still work 25 years old.

Regards Ray