everydayflyer

It will work howeever the 1100s have higher IR and their energy density is lower.
I have ran a 4S of each in parallel and flight time was approx. 25% more and the packs did not discharge evenly.
All things considered adding a cell to the 2300 pack makes more sense as you will increase flight time as much with less cost and weight if you use Throttle management.

Note: To be able to add a cell your ESC must be able to handle the higher voltage.


Charles

Max1965

Charles:
25% more and the packs did not discharge evenly.

Did the batteries get hot because of the uneven discharge?


All things considered adding a cell to the 2300 pack makes more sense as you will increase flight time as much with less cost and weight if you use Throttle management.

I am using the MEC packs and I can't add a fifth cell so I figured a 2s 1100 would work...course I guess I could rig up a one cell 2300mah battery.
Throttle management? Not me I'm a nonconformist and speed demon.[>:]

The question was just "I wonder" type. Thanks

Mr.Pibb

You'd need to make it a 4s1p 2300 and a 4s1p 1100 hooked up in parallel or you'll start some fireworks!

dirtybird

My Feedback: (5)

I have been charging my 3c 1100 battery directly from a 12V lead acid battery with a 1 ohm 10 watt resistor in series to limit the current. I have a sw that shorts out the resistor. I throw that sw after the pack has charged a few minutes. I can recharge in about 10-15 minutes. It seems to work OK.

everydayflyer

One ohm sounds high and 10 watts sounds to low.

What gauge and length leads are you using. What is the pack voltage and 12Pb voltage before start of charge and during charge and what is the starting amp. rate?


pack at 8 volts and Pb at 12 volts 1 Ohm resistence = 4A flow and 16 watts.

Charles

dirtybird

My Feedback: (5)

#20 wire about 3' long
Pb start voltage 12.2V
Pack start voltage 9.6
With resistor in the line charge rate is 1.8A, that is 3.24W
When the resistor is switched out the charge rate is 3-4 amps. When it drops to .2 amp I consider it fully charged.
These are measured valuse not calculated. (Except for the W)
If the pack is fully depleted the voltage will recover to 9.6 when the load is removed. That is if you have not ruined a cell

everydayflyer

I know how to charge with resistor and wire I just wondered why you were using such a high Ohms resistor. I see you are slow charging.

I charge a 3S 2300 pack in 5-8 minutes.

http://www.rcuniverse.com/forum/m_6477096/tm.htm


Charles

kent_man

I was thinking of picking up a couple of the BD vxp packs to make 2s or 3s batts for my 1/18th brushless truck. I have no experience with lipo's though. I have a Dynamite Prophet Plus charger that will charge 6-7 cell NiMh. What charger should I buy? I'm probably asking for the impossible, but I want a relatively inexpensive balancer charger that would be good for these batts and possibly other lipo's down the road. I would like one that had it's own power supply for ease.(unless it is better and relatively comparable price wise to buy a seperate power supply) Should the balancer be seperate or built into the charger?

What would you recomend?

Thanks in advance,

kent_man

Red Scholefield

My Feedback: (9)

CellPro 4S

kent_man

What power supply should I get for the CellPro? Pyramid? How many amps?

kent_man

Ok I guess I need a minimum of 5 amps 25 amps is a little overkill. So which power supply would you recomend? Maybe I should get a high amp one in case I get a different charger.

SS Pede

You should probably get something like a 15 amp power supply. I have a Radio Shack one that works well, but there are many choices.

thaus

My Feedback: (2)

There is an ad on rc universe which offer a 10 amp supply for $22. I have one and really like it. This is the best kept secret in the rc hobby.

SinCityJets

I wouldn't call 10amps the best kept secret.....Jacked Up Customs makes a great 25amp unit. (available below)

1100mah packs are not going to be good for the 1/18th....well, it will for about 3 minutes. Just an fyi.

thaus

My Feedback: (2)

I use a cell pro 4s to charge a 2s a123 but do not get balance. Toward the end of the charge and during balancing the cells are at 3.6 and 3.33v. This is 270 mv diffenent while the company claims there should be no more than 10 millivolt difference . The voltage disparity remains even 8 hours into bhe balance cycle.What is wrong . Do I have a bad cell or a bad charger?

coro_sk

Dont wast a time by waiting for the balancing circuit to heat out the charge from the higher cell - If You can, connect just a single (lower cells or both one by one) cell to Cellpro and let it fully charge. then repeat ordinary balance charge.
Well, Cellpro a accuracy had nothing in common with this issue - the difference is way too high and it takes ti time.. You have to restart and wait again. Bad cell is possible but not probable, at first leave a time to a charger to equalize the cells.

yarom

My Feedback: (82)

I got to be doing something wrong...

I purchased two VPX packs, took them apart, left the bottom tabs on, removed the top tabs, soldered 14G wires to the positive (button) and negative (flat), added a deans connector at the end and my charger refuses to acknoledge the battery packs.

Same charger charges my other packs (Triton using a 'dapter'), which are 2s 2300mah packs I purchased already made. I just modified the current down the 1100mah on the charger.

Anybody has any idea what is going on?

coro_sk

Can You check voltages using any DVM? Preferably each cell. It should tell us more.
I see that You have noticed that positive and negative are reversed against big 2300mAh cells, so I have no idea..

everydayflyer

Set the Triton to Li Ion 2 cell 7.2 volts and see if the charger will start. Perhaps there is aproblem with the Dapter. Like coro posted ,can you check at deans to make sure there is voltage there. There have been reports of lose connections on some of thes batteries.


Charles

yarom

My Feedback: (82)

Checked the batteries with a volt meter. Both show 6.62V, which is a good sign.

Guess I have to figure out the charging thing...

Kraeuterbutter

hey
question: why use A123 and not lipos
1.) longer lifetime
2.) safer
3.) easy in use, more robust when it comes to overcharging/overdischarging
4.) fast charging

just want to point your attention also to other LiMangan-Cells, which are maybe also to considere

i mean the Konion1300 cells and the First Connect Li-Mn
http://www.elektromodellflug.de/akku...onion-1300.htm
http://www.elektromodellflug.de/akku...rstconnect.htm

Safety:
you can drill a hole in them or overheat them -> no fire

Long Lifetime:
if you don´t treat them with disrespect, on normal use:
where Flightpower, Thunderpower, ... live 100-150cycles (heli) the Konions have showed over the years that they can stand 250cycles and more in same condition

the First Connect-Cell is relative new, so no data for that one

easy in use:
they don´t need a balancer.. there are no other cells (no lipos, no Fepos) that do drift as few as the Konions does

fast charging
you can fill them in ~35min.. not more, thats the maximum...
charged with normal Lipo-Mode to 4.2V per cell

so: why do i mention this cells, when A123
* lives (on paper sofar) longer,
* is maybe even safer,
* and can be charged a lot faster ??

so why considere Konion1300 ?
capacity !

from the first post of everydayflyer i see:
A123 1100:
~40g weight of a single cell ?
at 18A discharge ~900-970mah
at 2.5-2.6V

to compare with Konion1300:
43g weight of a single cell
at 19A discharge ~1280mah

(at a discharge with mixxed loads between 5C and 20C even 1400mAh)

so at virtually same weight you have about
2.4Wh vs. 4.1Wh
so about 70% more energy in the Konion1300

the Konion1300 is good for ~20A continous and peaks up to 30A

if you are realy on a budget:
get the older Konion1100
still more capacity and energy than the A123 1100mah
18A continouse and 22A peak are ok
you can get this cell in the BOSCH 36V battery-packs
i payed last time 58 Euro for one pack (a pack has 10s2p cells)
--> so only 2.9Euro per cell
http://www.elektromodellflug.de/akku...iIonM-1100.htm

just wanted to state this here for the once who think, A123 has to few capacity for them and think there is no other alternative

everydayflyer

Well in the first place this is not the general Batteries and chargers Forum area.

IT IS THE A123 RACING SUPPORT FORUM and as such is intended for questions / answers on these cells only.

Yes there are other LiMangan-Cells but like with most things there is #1 / the best and then all the rest.


Charles

yarom

My Feedback: (82)

I think you could assume that like everything in this hobby, people tend not to jump in until the product is available, well supported and has been tested by people who took a risk.

These Konion are virtually unknown to most people and likely hard to come by.

aman_74

What do you feel is better about the A123 versus Konion and Saphion2 in the 18650 size?

Clearly the A123 in the 2300 version is the best in it's class, but from what I've seen this is not the case in the smaller sized cells.

aman_74

I've heard about them quite a bit, just because something can be easily purchased at Walmart doesn't make them the best.

There seems to be a lot of cells in this size and it is harder to know which are the right ones to buy when looking on US websites. We can get Konion and Saphion to make sure it's the right cell, just seems we have to order from the UK. Bummer, because I'd like something better than A123 in this size.