Charge levels for NiMH and Lipos in storage

[TeamMishap]

I'm moving back to the states soon and have to get my batteries back to CONUS.

I'll be mailing them as movers don't want them in their shipments, so my batts will sitting in a Montgomery, AL post office for about a month and a half.

So, what percentage of capacity should I charge my NiMHs and Lipos before shipping them off?

Thanks for any info.

John

[Hughes500Bob]

Long term storage for Lipos is 50% (mAhr rating) ..... but if you expect to use them within a few months just charge them up. NiMHs .... makes no real difference. I'd charge them up full as well. Even though they are female connectors .....Tape the connectors up with insulated electrical tape so nothing can short them.

[TeamMishap]

Thanks!

[SilverFoxCPF]

Hello John,

I happen to think it makes a slight difference how you store your NiMh cells and packs.

LiPo packs should be at around 3.85 volts/cell for storage and shipping. This allows tolerance of temperature changes during transit without harming the packs.

NiMh packs can be stored either fully charged or fully discharged, or even somewhere in between. However, it is better to store them fully discharged.

A fully charged cell will self discharge, and during this process the smaller crystals of a "vibrant" cell join together to form larger crystals during the self discharge process. This causes the cells to "go to sleep."

After storage, you need to run several charge/discharge cycles to wake these cells back up.

On the other hand, cells that have been discharged at 1C to 1.0 volts and stored empty, will be "vibrant" on the next charge.

If you are storing for longer than a month, it is probably best to put a little charge back into them. Charging for around 15 minutes should do just fine.

Discharged NiMh cells will also have some self discharge, but the rate is greatly reduced with the discharged cells.

You are good to go either way, but I figured you should know what your options are.

Tom

[TeamMishap]

Glad I asked the question :)

[Pinecone]

The other thing is, I am sure that there is someone nearby where you are ending up, that you can ship your packs to and they can store them properly and check the charge rate every month or so.

If I was in AL I would volunteer.

[TeamMishap]

It's not that big of a deal. Just some ond 3300 mAh packs for my trucks and a generic 11.1V lipo pack I cannibalized from a plank for my Trex. I just didn't want to cause a danged fire or something from batteries not properly charged.