Storage charge, what's best to do over winter?

[Pj1969]

As like many of you, now winter in creeping upon us, I for one won't be flying as much with a baby and other commitments, so what's best to do with my lipo's?? I normally just put them in a box after each flight and leave till I fly again. They normally are run down to 25% lowest after a flight
t, so will they be ok as is? Or is best topping up and putting into storage mode? I did try a few packs last night, but on my PL6, it showed 56% completed in storage charge, but when I checked on battery checker, they were down too 36%?????


Also, as storage charging takes ages, is it ok to do a high power charge as normal, then when it reaches 60%, stop and switch to storage charge mode?? I found I did over 14 packs in only around an hour, which I like lol. I've also been told that packs need to be kept at a decent room temp and they don't like the cold, so I'm thinking putting then all in a flight box and putting under the stairs??
Any tips would greatfuly be appriceatted
Pj

[George J]

Storage charge programme on charger, 3.8v/cell and no issues over longer periods.

[trillian]

If they're going to be sitting for some time before flying again the best storage charge is 3.83 volts per cell. It's fine to leave them at 25% charge after flying till the next time if it's not too long before you fly again but if it's going to be weeks then going up to a storage charge is probably better. The thing about temperature is fluctuation, ideally you don't want them warming and cooling very much. It won't hurt them to get cold when they're being stored but make sure you warm them up before using them. Also don't go to a full charge in temps less than 8 degrees because if you do they will exceed the safe voltage when warmed up, so ideally you want to charge at a reasonably warm temp and keep them at that temperature until you fly them.

Not sure why it would take longer to do a storage charge unless it's automatically going to a lower amp charge rate. I have a Hyperion and it's just as fast in storage charge mode.

[sparky 2]

My multi chem and PL8 chargers only charge to 4.1v per cell when below 10degc

[George J]

Storage charge cycle on my PL8 Duo takes about 4 or 5 hours to do 6 x 6s packs and thats on the max possible discharge rate it allows.

[SaneAdam]

Charge up to storage charge and it will take no time at all. If your packs are currently charged and you want to discharge them to storage charge on your charger it will take hours and hours.

[Grumpy]

There isn't anything 'magic' about storage charge voltage, the main thing is that they are not fully charged and not over-discharged. Anything in the 3.7-3.9v range is fine. To further reduce degradation put them in a tupperware box or sealed plastic bag and put them in the fridge.

[cjcj1949]

Just to add to Grumpy's words. The lower the voltage and temperature the less degradation. Lipos lose a bit of charge all the time, but it is very small on good lipos. The lower the volts the greater the chance of over discharge. I'd say 3.7V was a bit low, but on the other hand if a lipo went from 3.7V to lower than 3V during storage then it would probably have been on the way out anyway. There is no magic figure.

[trillian]

I'd say 3.7V was a bit low, but on the other hand if a lipo went from 3.7V to lower than 3V during storage then it would probably have been on the way out anyway. There is no magic figure.

There probably is nothing magic about a certain number but the 3.83 volts comes from Andy at Optipower as the best storage voltage so I'd say there is some knowledge / research behind it, it is not just plucked out of the air arbitrarily.

[Varelco]

Yeap as everyone has suggested bung them on storage charge to 3.85v, store in a cool, dry place, out of direct sunlight otherwise they start sprouting.

Ok maybe that last bit isn't true, but out of direct sun light is still probably a good idea.

[hedge]

double post

[hedge]

...out of direct sunlight otherwise they start sprouting.

Ok maybe that last bit isn't true, but out of direct sun light is still probably a good idea.

Actually I believe it was snowy on here but his hobby room went up in flames - lipo in direct sunlight.

http://www.rcheliaddict.co.uk/main-d...tted-fire.html

[Grumpy]

There probably is nothing magic about a certain number but the 3.83 volts comes from Andy at Optipower as the best storage voltage so I'd say there is some knowledge / research behind it, it is not just plucked out of the air arbitrarily.

No it's not arbitrary, they pick it because that voltage represents precisely 50% charged... But again there isn't anything really special about 'precisely' 50% charged. FWIW Thunder Power suggest 3.8 -3.9v: http://www.thunderpowerrc.com/core/m...cb0782&whence=

[cjcj1949]

Using a 50% figure is arbitrary. The main thing to avoid is a combination of high temperature and high voltage. For minimum degradation use 3.7V in the fridge and check frequently. That's why leaving them at 20% charge when in frequent use works, there isn't enough time for the volts to drop to a level that might damage the lipo.

[Pj1969]

Storage charge it is then and I'll keep them down in my man cave workshop, nice and cool down there. Cheers guys