When to charge race packs?

[Bill Gibson]

When is the best time to charge my packs before a race? How much will the packs lose if i charge them a week before the race! I always store them in a steel Ammo box! Would it be better to charge them 2 or 3 days before the race? Its hard to charge them just before the race! Many Thanks!

[fweasel]

Lipo batteries degrade when left fully charged. How long or when the degradation starts is debatable, but as a rule of thumb, I never leave my packs charged for more than half a day. Not only that, but they are most volatile when fully charged. From both a safety and longevity standpoint, it's best to leave them at storage voltage whenever possible.

As for peak race performance, warm batteries perform better than cold, so heating them if cold or at room temperature helps as well.

[Xrayted]

100% agreed, OP you are not doing your batteries any favor by storing them fully charged like that for any significant period of time

low quality Lipo cells can be damaged irreparably in short order by leaving them fully charged for long periods

Lipo's chemical degradation is kept to a minimum by keeping them only at storage charge which is 50%, roughly 3.8 V per cell or so, and even better if stored cold in a mini fridge, as storing lipos cold slows the natural breakdown process of the chemistry.

Mine are stored in a fridge always when not in use inside large Ziploc bags, as you want to keep them sealed up so that the batteries don't get condensation on them when you remove them from the fridge for use

One big rule is always let the Lipo sit out until they have completely come down to room temperature, as colder temperatures increase the internal resistance and the batteries can be permanently damaged if you try to pull a lot of amps out of them cold

I take mine out the day before I know that I'm going to need them, and then only charge them right before I need to use them (within a few hours)

As was already stated above, warming lipos within reason lowers their internal resistance, and increases their performance capability

80 to 100F is the sweet spot for performance, however Lipo can be permanently damaged once their temperature reaches 130 to 140 Fahrenheit

[Bande1]

alot of people dont seem to realize you can easily charge your lipos off your vehicles battery. If you dont a have DC input charger (Hota D6 is $55) then get an inverter and charge your batteries lakeside. While you are waiting for them to charge run your nitro or gas boats.

when you race you have to leave your batteries sit out in the sun. if its cold outside you need a lipo warmer or a heating pad. Your batteries need to be at least 100f to output high amps.

[Ryanj]

A week before, is too long to sit at a full charge and can cause damage to lipo as stated above. It is best to charge all your batteries just before you race as limit how long they will sit at a full charge, hours before you race of the Evening before you race. I Race as well in my local club and I will charge all my lipos the night before a race as Racing starts 8:30 am in the morning. This way I'm limiting how long they sit at a charge. I will also put all my charged batteries in a Fire safe lipo bag, all 12 Batteries for night and transporting to my race. I've been doing this for the past 4 years and havn't had any issues. Voltage loss maybe a .1 Volt loss. not enough to see a performance issue. Your main goal is charge your Batteries at a time that works best for you and at the least mount of time they will sit fully charge before Use. limit how long sitting at full charge. But a week is way too long.