Bantam e-Station BC8HP any good?

[357mag1]

I'm looking for a hobby charger that can handle all of my single cells and battery packs.
I'm considering the BC8HP. If anybody has experience with this charger I would be interested to hear.

http://www.rcaccessory.com/BC8HP.aspx

 

[core]

I don't have any experience with that one but I gave it a look.

$200? Yikes.

Do you have any 8S packs? Or ever plan on having any? Because this seems to do the exact same things that the cheaper $30-$60 6S chargers do, with the exception of being able to do 8S.

That's a lot of extra $$$ if you don't need 8S. I know the power output is higher too, but really. I think if I was going to spend $200+ I'd get one of those fancier iChargers. The ones that can do your laundry and chill your beer.

 

[baudsenseless]

I've worked with bantam chargers for quite some time, they are a nice solid charger that had very few returns (warranty etc) like the above poster said tho they are quite expensive for what they do.
The bit you are paying for is the 280w and 12A for example the bantam bc6 is 50w and 5A

 

[357mag1]

Thanks for the replies.
I really don't need that much capability but was thinking about future needs. I'm open to any recommendations for a quality charger that will do at least 4-5 Li-ion or LifePO4 cells and at least 15 Nimh. I'm more concerned with good quality than saving a few dollars but don't want to spend money needlessly

 

[Justin Case]

The iCharger line looks just as capable or more so as the Bantam in terms of wattage, max charge current, etc and is also less expensive.

 

[core]

I'm open to any recommendations for a quality charger that will do at least 4-5 Li-ion or LifePO4 cells and at least 15 Nimh.

15 NiMH at once? In series? With (obviously) no balancing? You are joking, right?

Hell even just 2 NiMH at once cannot be properly charged on your average run-of-the-mill modern hobby charger. The $200 Bantam e-Station included. There is no "NiMH Balance" mode on there like there is LiXX balance. Might as well throw those NiMH cells in an Energizer 15 or something; they might even turn out better.

 

[SilverFox]

Hello Core,

NiMh balancing is done differently than Li-Ion balancing. My Schulze charger does 30 NiMh in series, and if done properly all the cells end up balanced. I don't believe any of the chargers offer cell balancing when charging NiMh cells.

The problem comes from trying to charge cells in series that are discharged to different levels. In that case, and independent channel charger would be better. However, it can also be done with a hobby charger but the process is a little more involved.

Tom

 

[core]

My Schulze charger does 30 NiMh in series, and if done properly all the cells end up balanced.

The problem comes from trying to charge cells in series that are discharged to different levels.

I'm having troubles understanding how those two statements can jive. We'll assume that a person builds a 30S pack with cells matched on measured capacity. (Do commercial pack builders even take the time?)

But not all cells are created equal, and some will have higher self discharge rates than the others, higher internal resistance, and so on. Especially over time.

How can you not have cells discharged to different levels?

 

[45/70]

Hi core. I think what you may be missing is that NiMh cells are balance charged in series. There is no setup with balancing leads as is used for Li-Ion cells, as it is not necessary. This is due to the nature of nickel based chemistry.

When NiMh and NiCd cells are charged in series, they are capable of evening out, or balancing, whereas Li-Ion chemistry is not. I think what Tom meant was with radically different states of charge, within a group of cells in series, the only way to properly balance the cells, is to use a slower charge rate such as 0.1C, for example. If the cells are close in SOC, they can be charged in series at a fast rate without any problem.

Hope this helps.

Dave

 

[357mag1]

I have some battery packs by Fivemega and threw some batteries in them with and charged them in series using the 4.8v -10.8 volt Nimh pack charger off Battery Space that is selectable for 1 or 2 amp charge rate. Then I took them all apart and the batteries measured within .008 volts of each other. That was three separate packs one using Eneloops and two using Elite AA batteries. Of course the Elites are new and the Eneloops were only 6 months old. Perhaps age and several cycles would tell a different story.

Core probably has a ton more experience with this than I do but aren't all Nihm battery packs for power tools charged the same way (In series with no balancing)? I've taken these packs apart before and don't see any provision for balancing.

 

[core]

aren't all Nihm battery packs for power tools charged the same way (In series with no balancing)? I've taken these packs apart before and don't see any provision for balancing.

Yeah, they are... power tools, cordless phones, you name it. And I've had to replace more of those two types of packs than I think is healthy. I highly doubt pack manufacturers want their stuff to last 5 years anyway?

I'm just still trying to get my head around how you can present a voltage to a drained pack of cells with slightly differing SOC and it will automagically balance itself before reaching 100% SOC. (If you're relying on tolerance of overcharge well that's cheating.)

I know, I know, "it's the chemistry" right? How exactly? Because when it comes down to it it's just one cell seeing a voltage; I didn't know chemistry causes interactions between cells.

And can someone explain how -deltaV works with a boatload of cells in series? Some are on the rise, some are on the downside of the peak, all looks like a fairly static voltage to the charger, no? Only after most all of them have peaked and dropped, and some have likely gotten a good toasting, would the charger actually see a V drop.

Am I way off, or is the explanation really "this isn't ideal, but the cells can sorta take it so let's do it this way"?

 

[VidPro]

slow overcharge within spec, balance out by spec overcharge that does very little damage, that is possible with ni-mh and ni-cd and wet PB too if you included that.

they cant perfectally do the v-drop in them, i have seen it. with ni-cd it could cope with it easier, but there is an inevitability of some cells still rising in voltage as the finished one drop in voltage, and detection being impossible, the more in series the blinder the computer becomes.
the really primo ni-my chargers will do a slowdown to a slow charge final topping balancing thing within spec for overcharge.
the others just guess and hope.
others (like some power tools) have a max voltage and slow down by default sort of like CV thing, they can still charge faster intitally, and dont rely on v-drop at all. newer things are more likly to attempt to detect a v-drop than old school stuff did.

really would ni-?? all still just love a special balance charge treating each cell like a li-ion charge is supposed to ? heck yes.
i think it is more like they did it that way for a long time, before they did balance for (anything) li-ion, and they arent about to change. want to see them cringe when someone suggests that as many times superior and faulty for not including it

Am I way off, or is the explanation really "this isn't ideal, but the cells can sorta take it so let's do it this way"?
I believe your exactally right, they can get away with it easily, and they did for eons, so they will for eons more. ahh it works , they dont way overpressure with the slow rate, and with the v-drop rate they dont die untill the pack is weak and way out of capacity balance anyways.

potentially you can configure a hobby charger to use "other" methods than its defaults too , i have been testing/trying this. like a 12V 2P10S ni-mhy pack can be put on a PB charge for 12V and it will slow down around 14.4v. and other cheap tricks to do what a person wants by reconfiguring and knowing the chargers parameters. (hopefully without blowing something) i cant think of anything stopping someone from putting 3x ni-mhy where the 1x li-ion was and balance out a ni-mhy pack 3 at a time using a li-ion alogrythm.

 

[pepko]

is it able to charge new samsung 18650 cells with 4.3V or 4.35V charging voltage ?

 

[357mag1]

is it able to charge new samsung 18650 cells with 4.3V or 4.35V charging voltage ?

Good question and I have no idea. If somebody knows if this charger or any other that will charge the 4.35v cells properly it would be nice to know.

 

[jasonck08]

I don't know if this one can or not, but hopefully we'll see more chargers able to charge next gen LiCo cells in the 4.3-4.35v range as mentioned by Pepko. I know Sanyo has a 4.3v cell and Samsung has 4.3 and 4.35v 18650 cells.

OT: With this slightly higher voltage LiCo cells, they will have a higher nominal voltage and stay at or above the LED's vf for a longer period of time.

 

[baudsenseless]

This charger has usb connection for updating software, so if that charging programme is not present i'm sure it would be something that they would add when they do a software update.

 

[SilverFox]

Hello Core,

Hobby chargers have some features that allow for the safe charging of multi-cell packs.

Here is an outline of how to take care of your battery pack...

First do a 16 hour 0.1C charge to balance the cells in the pack.
Next do a 0.2C discharge to verify the capacity of the pack.

Now that you know the capacity of the pack, you have an idea of how much you need to put back in when the pack is discharged completely.

Take the capacity and multiply it by 90% and then set the maximum charge to that amount.

Now you can charge the pack at 1C and see where you end up. The goal is to have the cells just warming up when the charger shuts off. After the 1C charge you top off with a 0.1C charge to re-balance the cells in the pack.

Once you get used to the pack, and the charger, you can tweak things so that the charger ends the charge using -dV.

If you store the pack discharged and do a charge/discharge cycle every 30 days, the cells in the pack will remain vibrant. Every 10, or so, uses of the pack you should take time to top it off with a 0.1C charge for a few hours to make sure all the cells are balanced before use.

Some people feel that this is too much effort to put in. I tell them to simply purchase a new battery pack every few years, or to consider moving to a Li-Ion pack.

Tom

 

[LuxLuthor]

If I understand core's essential question, my observation on lots of NiMH cells charged in series bears him out....unless you get perfectly matched, high QC (i.e. Eneloops), same date of manufacture, same batch of electrolytes, and use the techniques Tom has described. I would estimate that out of a box of 50 cells, there are typically 3 batches of 10-18 cells that perform very close to each other within that batch, and some number of useless turds that are best circular filed.

In reality, after cells charge at either 0.5C, "auto" setting on hobby charger, or even at 0.1C x 16 hours, (I have charged as many as 30 at a time in series) then sit for a period of time (4-36 hours), their DMM measured voltage (recognizing the limitation of that method of evaluating NiMH cells) drift apart to some degree.

When making packs, I use that feature to do several charge/discharge sortings of cells, which ends up with a high degree of reliable and reproduceable matched performance on subsequent series charges.