When should recharge my LiPo starter batteries?

[frank mccune]

      When should I recharge the Li Po batteries that I use to power my Sullivan Starter? Being new to LiPo batteries, I ruined a system already and do not wish to repeat this mistake!

       I am using a 4s system and have a very good charger.

       Tia,

        Frank McCune

[John Gluth]

      When should I recharge the Li Po batteries that I use to power my Sullivan Starter? Being new to LiPo batteries, I ruined a system already and do not wish to repeat this mistake!

       I am using a 4s system and have a very good charger.

       Tia,

        Frank McCune

Hopefully a "very good charger" means a full function charger. Follow the charger's battery care instructions. Assuming you know 4S is 14.8 volts, high? Would be same as all AMP'ed-Up references.

[Dwayne Donnelly]

What did you ruin? I put my lipos into storage after every session then recharge on Balance mode the morning I go out.

[frank mccune]

     Hi:

     I “ruined” the 3s battery by draining the battery to almost zero voltage.  This killed two cells.  This led me to rethink how low in voltage may I drain these batteries to avoid damage.

     My charger has a feature that enables me to check the cells for voltage.  Thus the question of at what voltage should I recharge the battery?

      Tia,

      Frank

[Fred Underwood]

Checking the voltage on a charger can be while using a function of charge, discharge, or on some, monitor.  You can get a different reading while charging then discharging.  You can usually see the voltage before the actual cycle starts, and that is best and will be similar for charge or discharge.  While not exactly accurate or agreed upon for voltage vs percent charge, it is a reasonable approximation.  We fly down to about 20% remaining, but best for the batteries to not go that low.  In addition, a 20% charge at resting state will be lower than that under load of running the starter.  I would charge if below the 3.8v/cell range.  Lipo's last longer if not setting at full or near full charge, thus the function of storage charge.

I would charge to only about 80- 90% and recharge when about 30% for most battery cycles. 

https://blog.ampow.com/lipo-voltage-chart/

[FLOYD CARTER]

But a LiPo in an electric starter service doesn't need to be at 100% efficiency, or even very carefully balanced.  If you are able to read individual cell voltages check them periodically.  Just don't allow any cell to discharge below 3.0 volts.  Duty cycle use on a starter is nearly zero!

I have run LiPo down below 3.0 volts per cell, and they charge right up OK  However, that's risky business.

[Brett Buck]

But a LiPo in an electric starter service doesn't need to be at 100% efficiency, or even very carefully balanced.  If you are able to read individual cell voltages check them periodically.  Just don't allow any cell to discharge below 3.0 volts.  Duty cycle use on a starter is nearly zero!

I have run LiPo down below 3.0 volts per cell, and they charge right up OK  However, that's risky business.

    Exactly. What little I know about it suggests that you want to use LiPo batteries only when the performance is the overwhelming requirement, and that outweighs the fussiness. Good old cheap gel-cells are robust and work well, and very tolerant of rough treatment. OR alternately, when you don't care if they get wrecked, like, they are already too damaged to be of use for airplanes.

    But, as always, people can do what they want to do.
 
    Brett

[John Gluth]

Fred and Floyd are getting very warm...

[FLOYD CARTER]

I agree that using LiPo in an e-starter is gross overkill.  However, I do it only because I have some 3-cell LiPo left over since I switched to 5-cell for planes..  I hate to throw stuff away if there is an alternate use.

I already have a LiPo charger, so that's the hardest part taken care of.

[Doug Moisuk]

And this is why i use a 12v gel cell.

[Dwayne Donnelly]

     Hi:

     I “ruined” the 3s battery by draining the battery to almost zero voltage.  This killed two cells.  This led me to rethink how low in voltage may I drain these batteries to avoid damage.

     My charger has a feature that enables me to check the cells for voltage.  Thus the question of at what voltage should I recharge the battery?

      Tia,

      Frank

When I know I'm not flying for a few days I put my batts into storage set at 3.85 volts per cell, as stated you don't have to go to a full charge, anywhere around 4 volts volts per cell should be fine.

[John Gluth]

When I know I'm not flying for a few days I put my batts into storage set at 3.85 volts per cell, as stated you don't have to go to a full charge, anywhere around 4 volts volts per cell should be fine.

Hooray! Conservative LiPo care!

[john e. holliday]

Also a gel cell will not turn the engine through a rev when it gets low enough on battery voltage.  And I also disovered it will  not get the glow plug hot enough.

[Steve Helmick]

All the above is why I went with the $50 adapter to use 18v Makita LiIon batteries on my Sullivan starter. It's VERY zippy and I haven't come close to draining a 3 amp battery. I always take the whole set with drill/charger/2 batteries with me.  Steve

[Lloyd Oliver]

To delay them puffing up (and possibly flaming your place of storage), leave them in storage charge; ~50-60%.  They should have a balance port on them, and you use a cell meter to tell you the charge status.  Recharge at about 15-20%.   You can also get a feel for power usage by checking them after a start or two.  For example, if you use 5% of charge per start, you know how many starts before straining the battery.  The LiPO discharge curve is pretty flat...until it rapidly falls off near end of charge, so a cell meter gives a pretty good safety/longevity payback.

Cheers,