Charging Batteries

[SteamPunkSultan]

Hi All,

Been a long time since I have been to a site, but I have recently bought myself some batteries and a charger.

The charger has a Charge Rate Selection which can be 0.5, 1, 2, 3.5 and 5A. Which is the best option for charging?

Thanks!

SPS

 

[Dan Robinson]

Very much depends on what battery you have, both in terms of chemistry and size. 

The setting equates to how much you're jamming into the battery at a time.  With NIMH its not so critical.  With a lipo then it's vital not to over do it. The higher the number the faster the charge speed which can cause a fire if not careful. 

If you're charging lipo's then send the charger back and get a smart charger that you can select the exact battery type and let it sort things out. 

It will also help you track battery health by monitoring the amount of juice going in and out..... Lipo's need to be stored at a certain voltage too, which means getting them to that level if you're storing for more than a few days. 

 

[SteamPunkSultan]

Hi Dan,

Thanks for the reply. Its all NIMH batteries. Based on what you have recommended I think middle of the road at 2A would be a good place to be.

Thanks again!

 

[Dan Robinson]

2A is what my smart charger defaults to for NIMH so you should be fine. ?

 

[Adolf Hamster]

Good rule of thumb is try to avoid charging more than 1c.

Take the capacity of the battery eg: 1600mah, divide by 1000 gives you 1c or 1.6 amps.

If in doubt slower is the safer option to go for, given the usage of airsoft there shouldnt be any need to go fast just charge up before game day and if you run out mid-day then buy more batteries.

 

[EDcase]

Yep, slower is better for the life of the battery

 

[Rogerborg]

Its all NIMH batteries

Is there a particular reason that you went with NIMH?  I mean, they work, but it's old technology.  It's also surprisingly tricky for chargers to deal with since they don't know what voltage they're charging to, they have to look for the battery resistance to spike / the current to drop off.

I know that lithium cells can get a little explodey, but the performance advantages outweigh that for me.

 

[SteamPunkSultan]

I should have asked before I splurged. I will be looking at Lithium in the near future though.

Is there specific chargers etc. required for LiPo batteries? Dischargers etc.?

Thanks,

Rob

 

[Rogerborg]

Full disclosure, I made that mistake too, having bought a CYMA with a nimh battery, then gone deeper down that hole before climbing out.  It's not a disaster, some folk still swear by them for their non-exploding properties.  

And yes, lithium charges differently from nimh, so it's likely you'll need a different charger unless you current one has a lithium mode.  Any remotely decent charger will also balance-charge lithium batteries to keep the cells at the same voltage.

We're currently liking the SkyRC S65 charger.

 

[EDcase]

Its certainly worth getting a good charger for Li-Po batteries. (as Roger said, 'SkyRC S65' is recommended)

An intelligent charger will properly charge to keep the batteries in best condition and reduce the risk of fire.

 

[Dan Robinson]

A Smart charger is a must for lithium batteries if only to get them to the correct storage charge. 

My son's m16 has a chunky NIMH battery in it and the performance is pretty damn impressive for a budget pew pew. 

Good thing about NIMH is it's very hard to overcharge and damage in comparison to lithium. You also dont get memory effect problems. They are twice the size though. 

I still have a Sky B6 smart charger which does everything i need. But the RC65 is the same price and I suppose easier to use, can't justify the cost of changing for the sake of it. 

 

[Floperator]

I was given the advice above, got some 7.4 LiPos and the SkyRC S65, and it worked out great. The Sky charger is a good bit of kit (though the instruction manual kind of assumes you know everything, recommend watching some YT videos) and it will also cycle charge NiMH batteries meaning they will be better off too. 

I kept hold of my NiMHs as backup, can't hurt.

 

[Adolf Hamster]

You also dont get memory effect problems

Am i reading that wrong? Because it sounds like your saying nimh doesnt have memory?

 

[EDcase]

...You also dont get memory effect problems.

Yeah, I hope you're not talking about NiMh because its completely the opposite.

NiMh DOES have memory effect so they should be fully discharged before charging to full.

Li-Po Does NOT have memory effect so they can be charged from any level to full and its actually better to re-charge them before they get too low.

The SkyRC B6 is also a good charger if its a genuine one.  If not then be very wary and charge in a Li-Po bag.

 

[Adolf Hamster]

NiMh DOES have memory effect so they should be fully discharged before charging to full.

Pretty sure i still have a discharger lying around somewhere from the bad old days......

 

[Dan Robinson]

Yeah, I hope you're not talking about NiMh because its completely the opposite.

NiMh DOES have memory effect so they should be fully discharged before charging to full.

Li-Po Does NOT have memory effect so they can be charged from any level to full and its actually better to re-charge them before they get too low.

The SkyRC B6 is also a good charger if its a genuine one.  If not then be very wary and charge in a Li-Po bag.

Old ones did, but new ones I was told, do not..... Had a quick Google to check and found this:

Q: What does NiMH stand for?


A: The material is Nickel Metal Hydride (NiMH) which has many advantages over other battery construction materials.


Q: What is meant by battery memory?


A: Older generation and batteries with other chemical make-up were subject to a memory effect. This is when a battery must be fully drained before recharge or their capacity is reduced. The New Generation of NIMH batteries do not develop a memory effect and can be recharged at anytime during usage cycle. When uncertain about battery charge level or condition, recharge it

Happy to be corrected though.  Everyday is a school day. 

 

[Adolf Hamster]

Not entirely sure how much i'd trust a source that includes a sales link.

But if there's been a reformulation of the chemistry of nimh cells to eliminate memory this is the first i've heard of it, surprising companies haven't at least re-named it to avoid the stigma of the old cells.

 

[EDcase]

Hmm, I wouldn't trust it either but you could test it out.

I did read a few articles saying to discharge to about 10% before re-charging.

 

[Dan Robinson]

My original info came from a discussion I had with a power tool company when we were re-tooling and deciding to either move to the new lithium ion range of toys or stick with the nimh and just get new batteries. 

I suppose the guy could have been trying to shift old inventory, but we decided to move over anyway.  Some of those lithium batteries are only now just starting to give up, and they have been abused in all sorts of ways; including being used as percussive maintenance implements. 

Still have a few nimh batteries powering some old tools (the ones we didn't use often enough to justify buying new versions of) that must be 16 years old now and still working.  The NiCad ones are guffed though.  Finally threw them out last year. 

As a side note, there are a lot of snide copies online, and it's a very mixed bag when it comes to capacity and runtime.  Sometimes a lot worse than oem.  Sometimes the same or betterer. 

 

[Adolf Hamster]

Hmm, as you say could be trying to shift old stock.

Curious if there is truth behind this, if only as academic interest.

Certainly all of my experiences with nimh are years old at this point given i've never had call to use them since the lipo takeover.

Ofc there are valid uses for nimh (even in its bad old form) in airsoft, when dealing with rental guns. Cant trust rentals to understand the gravity of not mashing the trigger until the gun stops cycling.