Newbie Battery Questions

[luckyrc]

Hi All,

Bought my son a stadium truck for x-mas, took him to the local club track two days later. Two days after that, bought myself a staduim truck and we are both addicted!!!

We are just learning and being fairly mechanical, we have firgured out all the suspension, motors, tires, etc...but the most confusing to us is the batteries and chargers, we see so many variations at the track. so here are a few basic questions....

1) What is the benefit of the single cells soldered together, verses the pre made packs?

2) The mAh numbers have me confused. I would think you would want the highest (3300mAh, 3800mAh) but I see some 1100mAh being used at the track and also selling for a fairly high price.

3) What is the benefit to one of these sophisticated programable chargers verses a simple charger that has a 2 & 4 amp setting only?

4) How important is it to discharge your batteries? Should it be done before each charge? What is the best method for a reasonable cost?

I know its a lot of questions, but any input you can give us to any or all of these questions would certainly be appreciated.

Thanks Guys,
Ron & Riley

[SS Pede]

1. Sets of unassembled cells are typically "matched" by voltage and run time. Pack performance is a bit better if all the cells have similar properties. You can buy matched assembled packs as well, though. Some packs are assembled better than others. "Stick packs" typically have higher resistance than "side by side" packs.

2. mAh is a measurement of capacity. Higher is better (gives you more run time). 1100 mAh packs are used for mini vehicles or nitro receiver packs. Go for GP3300's (or higher) cells for a full-size electric vehicle.

3. Fancy chargers just give you more options, and might charge your packs a little better. But generally you're just getting more flexibility like a discharge function, adjustable peak-detect settings, and possibly faster charging.

4. NiMH batteries do not need to be discharged after each run, but it won't hurt because they CAN develop a memory over time (though not nearly as much as older NiCd's). There are various dischargers to take the energy out of your pack. Some ("tray" type) discharge each cell individually if you have a side by side pack to keep cell voltage equalized. Others are less precise and just discharge until the pack is down to 5.4 volts.

[luckyrc]

Thanks for the info.

One more question...

Should batteries be stored charged or discharged? Is it different if it is going to be a day or two or maybe a week or longer?

[tadium54]

nicds, always discharged. nimhs, if memory serves- partial charge if being stored for a few weeks, and less charge if being used in the next few days

[Grizzbob]

Prety much right. Today's NiMh cells can be treated somewhat like NiCd's in that you can store them discharged IF it won't be all that long before you use them again(say a week or two at most). But if they'll have to sit unused for any longer, then you should put a charge in them before storing(if just a few weeks, a half charge should be fine but if it's long-term, then I'd fully charge them first).... :cool:

[strcstreetcar]

When you have a quick charger (around 20 mins) is it worse for the battery than the slow chargers (6hours) Sorry newbe, thanks.

[ErikRC10]

I've never heard of anybody charging "hobby grade" batteries at 6 hours that's just for toy's bc it's easier to make then a charger that only takes a couple of minutes. But it will give the batteries a longer lifetime if they aren't charged as fastly but most likely you wont notice the difference between of lifetime if charged slowly or fastly.

[strcstreetcar]

Thanks, and the charger i got came with the car so its nothing special, planning on upgrading.