Charging rate??

[olemetry]

Hi all. I have purchased 4 - 6s (5Ah) batteries. I will charging using a Paraboard. I also have a Accucell-6 (50W) that I use for R/C car charging that I will use at first.

Please help me with my math.

The voltage across the paralleled packs is roughly 6 x 3.7V = 22.2V
The charger would charge with a draw of 50W / 22.2V = 2.25A
The four 5Ah pack in parallel results in 20Ah
The time it would take to charge the paralleled packs is 20Ah / 2.25A = 8.88 hours

Is this correct?
How can I charge faster?

If it is safe to charge at 1C, the charging 20Ah worth would mean I could charge at 20A (5A per 5Ah pack). The wattage of the charger (and power supply) would need to be 20A x 22.2V = 444W. Is this correct? Do yall use multiple chargers or one big one? I'm thinking of running these at 12s2p (10Ah) but I may want to go higher in voltage later or add more capacity (Ah), so I may even want a bigger charger. Either way for now, what would be the best way to charge the four 5Ah packs? Get more chargers/power supplies? Or get a bigger better charger? Sorry for all the questions, but I think Im almost there in my understanding. THANKS YALL

 

[NeilP]

I think most of us with big packs 'bulk charge' using a Meanwell or similar (BMS Battery Alloy Shell ) charger.

You still need the hobby RC charger for testing packs and balancing , but for everyday charging just a bulk charge solution is used.

How it works is this:
You have a power supply that can supply a constant current.
You set its output voltage to be the final voltage you want your pack to be. So if you were going to use your 4 packs to make a 12series 2 parallel pack (12s2p) and you were wanting to charge each cell to a maximum 4.15 volts, then you would set the output of the power supply to be 49.8 volts (4.15 x 12)

As the voltage of the pack comes up as it charges, so the current goes down. Once the pack is charged up to 49.8 volts...it is the same voltage as the power supply, so no current will flow, since there i sno voltage difference between power supply and the battery pack.

Read up on Bulk charging/ Meanwell charging. Use the search function to find the threads, there are some big threads..read through them to get an idea of what to do.

Doing it like that you will not need to reconfigure your pack each time you re charge it.

Your figures looked correct...but I only glanced at them

 

[sn0wchyld]

your math looks good to me. an easier way of looking at it though is to work out the wh's of your pack, and divide it by the watts your charger can supply. in your case, 440wh of battery (22.2v x 20ah) divided by 50w = you guessed it... 8.8 hours. charging at 1c means you need a 440w charger.

i'd say get yourself a bigger charger. icharger, Hyperion and celpro's get pretty good reviews, and they range in power from 300w to 1400w! if your sticking with 12s, hyperion make a 14s charger, save you having to re-config your pack to charge.

you can also bulk charge your packs, though others will likely agree that its not a good option for 'noobs', as there is the potential to overcharge packs etc and get fireballs, or just plain damage your batteries. Dont worry, i was a bit confused by this stuff 12 months ago too, but its easy once you get some experience. untill you understand batteries a bit better stick with dedicated balance chargers, as their built in safety features will protect you while you learn.

 

[olemetry]

Hey great! I will read up on those threads today. But it sounds like in my 12s2p 10Ah can charge using a Meanwell charger that is 10A (max) and goes up to 49.8V.

I see a Hyperion 14s charger for about $130 shipped. This looks safer for me since it balances like you said. Can anyone recommend a power supply for this unit (550W i think). I would like to transport the power supply and charger with me everywhere, so light weight would be good. THanks.

 

[sn0wchyld]

Hey great! I will read up on those threads today. But it sounds like in my 12s2p 10Ah can charge using a Meanwell charger that is 10A (max) and goes up to 49.8V.

Does the Hyperion 14s balance as well? This may be safer for me as you stated.

Where can I get one of these bad boys? It looks like there are quite a few different links when I search. Some on eBay too. Thanks for the quick reply. WHO DAT

http://www.ebay.com.au/itm/HYPERION...pt=Radio_Control_Vehicles&hash=item53e8af83c0

thats just one I found with a quick search... but there pretty common in the USA i think... yes it will balance at the same time, hence why a bit safer than bulk charging.

meanwells can be bought at different power levels, so you can probably find one that'll put out 20a at ~50v. or go to BMSbattery.com, and get a dedicated battery charger. I still recommend getting/starting with a high power balance charger though.


edit
sorry that link wasn't for a 14s... but yea, they're easy to find on the bay...

 

[dogman dan]

Your math is close enough, It will take forever with a 50w charger. For those uncomfortable with bulk charging, or unwilling to spend a lot on lvc hvc balance boards, the middle ground is not so bad a solution.

350 watt meanwell power supply, plus one or even two chargers that have better wattage. The idea is to hook up about 200-300w of charger to the meanwell.

My personal setup is one meanwell, and two 150 w chargers. Not super fast, but fast enough to charge your pack in two hours or less. total cost was a bit over $200. Dual chargers comes in handy when I want to balance em, twice as fast for balancing as one charger.

Guessing yall means you are USA, you might want to look at this charger place. http://epbuddy.com/

http://epbuddy.com/index.php?main_page=product_info&cPath=17_9&products_id=29 Could shave the cost a bit, by starting with a meanwell, and just one of this charger. It's a clone of the pair I use.

 

[NeilP]

you can also bulk charge your packs, though others will likely agree that its not a good option for 'noobs', as there is the potential to overcharge packs etc and get fireballs, or just plain damage your batteries. Dont worry, i was a bit confused by this stuff 12 months ago too, but its easy once you get some experience. untill you understand batteries a bit better stick with dedicated balance chargers, as their built in safety features will protect you while you learn.

I'd have to disagree with that..I was a total noob when I started with bulk charing. There is probably less potential to make a mistake with voltage setting with a bulk charger. With bulk charging, you have one adjustment..that of setting the voltage to exactly the same or slightly less, than your final full charged pack voltage..one setting and that is it and you only have to do it once...when you first set up the charger.

With a hobby charger, you have multiple settings on the charger.Cell chemistry, cell number, basic charge, balance charge, fast charge, and charge rate, balance or not..plus the added danger of having to possibly re configure the pack each time you charge, so unplugging and re plugging those pesky JST connectors, with the possibility of pluggin them in wrong and short circuiting something.

if there is any worry about bulk charging...then set it to a lower voltage to give yourself more leeway as the cells go out of balance.

If you get a big balance charger, like the Hyperion or the iCharger 3010b, you are going to need a big power supply to run it...they do not just plug in to the mains. What you can do is get a Meanwell to power the iCharger...and also configure it to bulk charge. That is what I did with mine, a switch that flicks voltages on the Meanwell, one voltage for bulk charging, one voltage to run the iCharger.

Just do a bit of reading and get setup to bulk charge and balance charge to

 

[olemetry]

OK sportsfans! Thanks for the all the ideas! Im thinking about this combo deal from EP Buddy:

http://epbuddy.com/index.php?main_page=product_info&cPath=17_20&products_id=169

It is a 350W Meanwell with a iCharger 206B (300W). I already have a paraboard and 2 sets of parallel balance connectors. With my new math:

22.2V x 20Ah = 444Wh
444Wh / 300W = 1.48 hours to charge?

I'll have to change the plugs over to the paraboard, but hey, that aint too bad. What yall think? Any better deal? I would love to have one plug to charge but that would mean a 600W power supply ($130) and a 12s charger ($140). Thanks yall. [and yes, im in new orleans and yes, i am about to have the only electric bike i ever seen in this city].

edit:
regarding bulk charge, could this be used:
http://www.bmsbattery.com/alloy-she...po4li-ionlead-acid-battery-ebike-charger.html

is it adjustable to say, dial it in at 12 x 4.15V = 49.8V ?? or am I limited to 48V only (4.00V per cell)??

either way, it is a cheaper power supply. I am wandering If I should just get this and the 14s Hyperion charger for a one-plug charge solution.

 

[NeilP]

Regarding your link to the BMS battery charger. If you look back up this page two of my posts back, first line, you will see that is what I said to get in the first place

What exact pack configuration are you going to use on your bike? I cant see if you have actually stated that
You told us how many packs. Four 6s 5 Ah packs. I guessed you were going to run as 12s2p, and you did justmention 12s charging in your last post,BUT so far you have not actually said what you will be running the bike at.

The EP BUDDY meanwell and charger deal is only OK, if you do not plan on bulk charging
The Meanwell in that deal is only 12 volt and if you are running a 12 s pack, you need 50 volts
I do not know anything about the charger in that deal, and what input volts it can take, BUT I can tell you a iCharger 3010b can handle up to 38 volts input. But only 10s charging. So you would have to charge 6s
You may wonder why having a 38 volt input is so great,...it means you can have one 48 volt Meanwell for use as power supply for the charger (you turn the supply down to 36 volts) , and when you want to bulk charge you turn it up to 50 volts

 

[amigafan2003]

I have the same pack set up as you and have an Icharger 106b, 250psu and paraboard that I use to balance the pack in 6x4p config.

I then have a Meanwell NES-350-48 that I use to charge the pack in 12s2p config - I trimmed the shunt to output 7.2amps and it peaks at 353watts. PSU stops charging at 49.9 volts.

I balance charge probably every 10 charges but tbh I've never seen an inbalance more than 25mv.

 

[nonlineartom]

I just ordered a 1200W BMS battery alloy shell charger for my LiPo bulk charging, based on Neils advice I went with 49.8V charging voltage to charge my 12s 2p pack. When it comes to charging my 24S trike pack I will just charge it in two sections I guess.

Does anyone know how easy it is to tweak the voltage output on the BMS battery chargers? is there a way to easily add voltage / amps display to the charger to get a better feel for whats going on?

 

[nonlineartom]

I just did the maths and realised charging a 12S 10ah pack at 1200W is going to exceed it's charge C rate right?

What do?

 

[NeilP]

Well that will be about a 2.5C charge rate, so that is nto too bad. should be OK, I am sure up to 5C is fine. I have seen m y Nano tech packs have a 10 C charge rate on them.

 

[nonlineartom]

I'm using regular Turnigy packs. I can easily make my commuter pack up to 15ah but seeing as I only ever use 6ah max on my daily rides it's a bit of a waste of LiPo. I was under the impression Turnigy Lipo was 2C

 

[NeilP]

Yould could be correct...I do not have any with labels on that are still intact to be able to read them.

If that is too much for them , then I guess you will have to buy another couple of packs and make it 3p

 

[Ykick]

I'm using regular Turnigy packs. I can easily make my commuter pack up to 15ah but seeing as I only ever use 6ah max on my daily rides it's a bit of a waste of LiPo. I was under the impression Turnigy Lipo was 2C

My nearly 2 yr old 20C Turnigy label sez 2C charge rate but that's 1P brick. 12S2P would allow double the suggested rate since current would be divided equally between parallel bricks. Based on my experience 10A or slightly more is fine and my Turnigy bricks actually cool during charge at those rates. Btw, these bricks still retain nearly 90% of original capacity and have seen well over 500 charge cycles. I do adhere to 4.15/cell or less top charge and never discharge below 3.6V/cell unloaded. They do sag a bit more than when new but that gets better as they warm a little from use.

 

[NeilP]

I'm using regular Turnigy packs. I can easily make my commuter pack up to 15ah but seeing as I only ever use 6ah max on my daily rides it's a bit of a waste of LiPo. I was under the impression Turnigy Lipo was 2C

I would not say that was a waste to have 15Ah but only use 6.
I have 20 Ah (20s4p) and my daily commute is between 10 and 12Ah, and I would not want my pack to be any less than 20.

I would have said that if you use 6Ah every day, then a 10Ah pack was a bit small.
You should not be charging to 4.2volts..so 4.15 ideal...and you should not be going down too low either, so both those factors reduce the overall capacity of the pack.
Going to 15 Ah keeps you nicely within 80% or less discharge. You could even think of charging to a slightly lower voltage..say 4.10 or so, and the extra capacity will keep the discharge further away from the 3.5v cliff. It will only benefit the pack in the long run, helping you to get more cycles on it.

 

[NeilP]

Yes, is pack will be 10Ah, so 2C will be 20amp charge rate.
His Alloy shell charge is goging be putting out 24 amps or so at 50 volts...so that is a little over the suggested 2C (20amp) rate.
Goign to a 3p pack will bring it back to below 2C

 

[nonlineartom]

Thanks Neil I will do that. At the moment my 12s 2p pack is balanced charged everyday to 4.20 across the board, it never goes more than 0.3v out per cell even when discharged to 3.5V on the edge of the cliff. The one or two times I've taken them from full to the cliff they gave out over 6ah each.

Neil do you know if my 1200W charger I've got on order can be modified by me to charge 24S or is that more than pot tweaking can achieve?

 

[sn0wchyld]

alternatively email them right away and ask them to change the order... I've had good experience with their cust. service. youll find they send it out with a lower output than 1200w anyway, rather than 24A it will be closer to say 22 or even 20A, my '900w' charger charges at 100v 8A for example.

If they're not nanotechs then chances are they're max 2c charging, though 1c is probably safer/better for pack life. You cant always trust what's said on the HK website either, my 4s packs on the international site say 5C charging, but on the AUS site say 2c (as well as on the packs themselves)...

upgrading to 15ah is probably the best idea though, using 6ah each day shouldn't present any issues, but having the extra there is always a good idea. I regularly use 5-6ah out of my current 100v 10ah pack (and sometimes want to use much more), so im building a 5ah booster to get some extra range... cant wait to get some nano-techs though and charge at 5C or more!!

You can also mod the bms chargers to output any voltage (within reason) so long as the internal components can handle it... Ie caps, fets etc... whatever they're rated at is going to be your max Vout (minus some safety margin...). The problem is figuring out what pots control the Vout and Amps... my 900w has about 15 different pots, I haven't begun to figure out whats what yet...

 

[nonlineartom]

alternatively email them right away and ask them to change the order... I've had good experience with their cust. service. youll find they send it out with a lower output than 1200w anyway, rather than 24A it will be closer to say 22 or even 20A, my '900w' charger charges at 100v 8A for example.

If they're not nanotechs then chances are they're max 2c charging, though 1c is probably safer/better for pack life. You cant always trust what's said on the HK website either, my 4s packs on the international site say 5C charging, but on the AUS site say 2c (as well as on the packs themselves)...

upgrading to 15ah is probably the best idea though, using 6ah each day shouldn't present any issues, but having the extra there is always a good idea. I regularly use 5-6ah out of my current 100v 10ah pack (and sometimes want to use much more), so im building a 5ah booster to get some extra range... cant wait to get some nano-techs though and charge at 5C or more!!

You can also mod the bms chargers to output any voltage (within reason) so long as the internal components can handle it... Ie caps, fets etc... whatever they're rated at is going to be your max Vout (minus some safety margin...). The problem is figuring out what pots control the Vout and Amps... my 900w has about 15 different pots, I haven't begun to figure out whats what yet...

Thanks for that, does anyone know if the 1200W has an amps / volts display or is there an easy way of adding them? I like to see whats going on with batteries / chargers, give you a better idea when somethings going horribly wrong.

 

[NeilP]

No idea if those chargers come with a display, but there are plenty on ebay

http://www.ebay.com/itm/3-1-2-Blue-LED-Digital-AMP-Panel-Meter-Shunt-DC-20A-/170758068243?pt=LH_DefaultDomain_0&hash=item27c1f95813

 

[olemetry]

Ok I just bought the Mean Well SE-600-48 (600W, 12.5A @ 48V). Im gonna try to get to the pot I read about in your posts Neil and tweak it to 50V. I may have questions later. Thanks again. By the way i have 12s2p.