Battery recharge times

[rick]

What sort of time should I be able to recharge a 2200 3s lipo in?  I have a charger that seems to have little in the way of settings and it takes ages - an hour plus to recharge them.  Surely there's a faster way?

If I get a different charger will that help?  What chargers are you guys using and what time does it take to recharge your batteries?

[papa_lazerous]

Ok a quick rule of thumb, if you charge at 1C it should take one hour if you charge at 2C it should take half an hour.

1C means 1 times the capacity of the pack, so a 2200mah pack means charging at 2.2Amps so you will replace the full capacity in 1 hour

2C means charging at twice the capacity of the pack so that would be 4.4Amps so you would replace the capacity in half an hour.

A few things that make the above only a rule of thumb and not gospel is that firstly you dont ever full empty your lipo so you are not putting in the full capacity, so that should lean towards a shorter charge time, but here is where your mileage will vary, balancing!  different chargers have different methods of balancing cells and achieve different times.  A knackered pack thats getting tired might take longer to balance than a nice new pack

[rick]

The charger I have only lets you set the capacity of the battery and that's it - I assume then that it's charging at 1C.

Does your charger allow you to alter this then?  I also guess that the amount that you can charge at must be relative to the discharge rate of the battery?  I'm a bit wary of getting it wrong too - don't want to set the damn thing on fire!

[papa_lazerous]

post up what charger you have and I will give you some more info on it.

My charger is the iCharger 3010b - you can configure just about every aspect of charging with it, its a serious piece of kit.  It's good for 1000watts!  there are other lesser rated iChargers which are good and well priced.

I will explain the figures on your battery so its completely clear,

the capacity of your battery is either displayed as 2200Aah or 2.2Ah  both means the same, as 1000mAh = 1Ah
Basically this means if you where to draw 2.2Amps continually from the pack it would last 1 hour.  Thats a perfect world figure as we always leave energy left in the pack.  so thats your capacity or 'C'

you have a discharge rating for example given as 25C  this means your continous discharge current is 25 times the capacity so its 25 x 2.2amps = 55Amps sometimes packs will have 25 - 35C which would mean a constant discharge of 25C is ok but a burst of 35 is ok too.  going over this mans you will damage your pack and will get a poor life and most likely puffing of the pack too.

somewhere else it will say on your pack the charging rate, so if it says charge at 1C then charge at 1 times capacity = 2.2Amps if it says 2C then you guessed it 2 times capacity 4.4Amps if it says 5C then its 5 times capacity then its 11amps.  If in doubt charge at 1C your pack will last longer and you wont set anything on fire.

Long term you may want to look at a charger thats got a few more features, but thats a whole other post I guess

[londonguy]

charging at 1c doesn't equal an hour because the charger will slowly ramp down the ampage as it fills up.

[papa_lazerous]

charging at 1c doesn't equal an hour because the charger will slowly ramp down the ampage as it fills up.

Yup, thats why I said a rule of thumb and not gospel

[rick]

Thanks
making sense so far. The charger is an old ultramat 14.  I am using standard turnigy 2200 batteries though I've ordered some nano-tech's to give them a try as well and I think they are a bit better rated for a little more discharge and possibly may give a better charge rate (if I get a better charger).

I did have a look at one of these a while ago - not sue if they're worth the money - pretty cheap though!

http://www.giantcod.co.uk/imax-balance-charger-clone-p-406640.html

or one of these?

http://www.giantcod.co.uk/power-b606-balance-charger-lipo-nimh-battery-p-406285.html

cheers

Rick

[papa_lazerous]

you have a 50W charger at present and I think both are 80W,what you buy next is entirely down to how deep your pockets are and what you actually want out of a charger. I charge upto 6s packs for my heli's and wanted the ability to parallel charge so I am not waiting all day and night to get all my packs full again so got a big powerful charger.  If you only have half a dozen 3s packs you may not have the same requirements.  Its all down to what you are going to want to charge longterm.

It appears that giantcod is your preferred place to buy, perhaps consider this http://www.giantcod.co.uk/icharger-106bplus-250w-balancecharger-p-404527.html It's only a few £'s more than what you linked but is 250w which is triple the power near enough of the units you linked.  All you would need then is a power supply, for something this power modifying an old computer PSU is the cheapest simplest option.  probably best to look at what your needs are long term and then weigh it all up, not something I would jump into as a charger is an expensive investment and something you have to live with for a few years

[rick]

thanks

I see what you mean - they don't actually have a lot more grunt than the one I have.  I'm not stuck to GC - they were just ones that I had been looking at.  I have some old PC power units to sorting that out wouldn't be a problem.

I'll have a look around and see what's out there with more power.  I've got some big 5s 8000mah jobs which I may be using soon so it may be worth investing in something more powerful.

thanks for you help/advice

Rick

[jiberjaber]

Rick - it depends on how much you are flying and what as to how much you want to invest.  If you are just flying 2200mAH batteries on some planes and thats about it, then you might be better getting a few more batteries and living with the the charger you have. 

I exclusively fly electric now, though I still have one nitro heli, it hasn't been flown for a year.  I plumped for a PL8v2 charger, similar to Papa's charger it does loads of stuff and is 1000W+ capable.  I charge my 3000mAH in parallel in about 15 mins.

The other problem you need to consider when you start charging high current / short time is having a suitable main power supply to run it off.  I use a converted power supply from a server.  But in the field, a car battery is fine, however you struggle to get a lot of battery charge cycles out of them... its worse if thats the same battery you need to start the car off to get home LOL.

The answer is a compromise between the charger and the number of batteries you have

I have always used Revolectrix chargers, I have a couple of others, but I trust these chargers to be able to leave the batteries unattended because of the way they charge them.  Here's a link to them on Midland Heli's

http://www.modelhelicopters.co.uk/chargers/revolectrix.html?p=2

Not used the icharger's which I think Papa has, but here's a link to them:

http://www.modelhelicopters.co.uk/chargers/icharger.html

Other suppliers and chargers are available

[rick]

Wow - £200 odd quid for a charger!   

You guys are right though - it's a balance of what you do and what you can afford.  I was really just looking at something that would enable me to do a quick/er charge of lipos - and if I was going to change charger then it may as well be one that will charge two at once at the higher rate.

I'll do some more looking.  Got a birthday coming up soon so might use that as an opportunity to upgrade.

thanks

Rick

[MrBen]

I use one of these

http://robotbirds.com/catalog/product_info.php?cPath=9_268&products_id=5877

there is a new one out now that is 500w+500w and does 2x7s (instead of 300w+300w 2x6s)

Its all the charger I will ever need, I can charge a pair of 4s 3300 in 25mins

[rick]

That's a beast of a machine too! Guess now I've spent my money on your Naza Ben I'll have to make do for a while!