What charger to get?

[Jay64]

I got a question about getting a charger. I have a couple of packs of EIG batts. As far as I can tell this is the ones that I have.
http://www.eigbattery.com/

Right now my 2 packs are built as 22s packs. Which would put my Max charge voltage at 91.3v and my Nominal Voltage at 80.3v according to the specs on their website. I have a battery charger that came with these packs and it is a 72v charger and the max charge voltage seems to be about 84.7v. I seem to recall being told that it was originally a SLA charger that was modified. So I'm not getting the full potential into these packs. Can someone recommend a charger that will get the 22s packs to max charge voltage?

Follow up on that, what if I decide to try to max out the 100 v controller and reconfigure to a 24s pack? That would put my Max charge voltage at 99.6v and a nominal voltage of 87.6 v. I found this charger on hobby king that says it can do 4x6s. If I make the 24 pack into 4 sub packs for charging, would this work? I would be able to have one 24s pack with charge leads every 6s and charge it while still hooked up as 24s, right?

http://www.hobbyking.com/hobbyking/store/__10327__HobbyKing_Quattro_4x6S_Lithium_Polymer_Multi_Charger_.html

 

[amberwolf]

Copied from my reply in your thread:
http://www.endless-sphere.com/forums/viewtopic.php?p=473367#p473367

The link on your battery just goes to the EIG main site. Which battery is it that you've got? (they make a few, including different chemistries like NMC, LiFePO4)

EDIT (added): These are the three spec sheets for the cells:
C020: http://www.eigbattery.com/eng/product/3.jpg
F007: http://www.eigbattery.com/eng/product/6.jpg
F014: http://www.eigbattery.com/eng/product/5.jpg
In the numbers printed on the cells will be one of the four character codes above left, which will match the datasheet link to it's right.

I would not use a regular charger, but rather something like a lab adjustable-current-limit adjustable-voltage supply, and then some other high-current supply in series with that that can add to the lab supply's voltage to give you more than the total you want now (so you can up it later).

LiveForPhysics has said in a thread or two that he uses some HP server supplies in series with a large rackmount lab supply to do this. I have plans to do something similar on a smaller scale for my own LiCo packs from reclaimed laptop cells, as I have a 55V 55A Sorenson that I can eventually series with a non-current-limited supply once I find one with a high enough current rating.

Depending on the max current you wanna pump into those packs, you might not need something so large. Ebay and other places often have lab supplies like this for not too expensive (nothing like their original cost), and electronics surplus warehouses local to you (if any) may get them in now and then, too. The server supplies are apparently plentiful and relatively cheap, based on some recent threads about such things.

Anyway, it's something you could box up into a single more portable unit, with cooling, and it'd almost certainly be more reliable than most of the chargers available out there, and way simpler to adjust voltage and current limits on as your pack evolves.

 

[Jay64]

AW, sorry, I missed your post in my build thread. Yes, the cells that I have are the 20ah ones.
C020: http://www.eigbattery.com/eng/product/3.jpg

I don't know if I really want to do any high current stuff. I believe these cells are only rated for 0.5C for charge according to the spec sheet. I will do some more work learning about voltage supplies. I've heard of power supplies, what are lab supplies? Is there a difference?

 

[amberwolf]

Well, compared to the typical chargers for bikes, a 10A charger (0.5C for 20Ah cells) is pretty high current. :lol:

Typical power supplies are fixed voltage, and some have current limiting, while some don't. Some of the current limiting is useful to us, by simply lowering the voltage output till the current drops below the limit, based on whatever load is on there--that's what we're after for battery charging. Some of the current limiting is not useful, being the "hiccup" style, or worse, the shutdown style. Sometimes you don't know which one it is until you try it, like with various MeanWells and clones.

Lab power supplies are just like I said-- they have both adjustable voltage and adjustable current limiting, usually from 0 to the max spec of either. This is what Liveforphysics uses to control his charging with, plus server supplies in series to make up the rest of the voltage needed whenever it's higher than his lab supplies can put out. These lab supplies current-limit by lowering voltage output until current drops below the limit, whcih is what we want. Then any other supply in series with the lab supply will automatically be limited to the same current.

Most of the big ones run on 220V, though some can run on 110V as well (at much lower total power levels). The Sorenson DCS 55-55 I have on loan from a friend is like that; I run it off my dryer outlet.

MEdium and small ones run on 110V, usually, like the little old Sorensons I use for lots of testing and small pack charging. They're 40V or 60V max, the smaller pair are 750mA max, and the larger are 1.5A and 2A (but the 2A one is blown right now).

There's pics of the big one over in my laptop-cell pack build thread, and pics of the little ones over in CrazyBike2 and DayGlo Avenger threads, and my Vpower pack repair thread (probably also in teh Volgood pack repair thread, not sure).

I can't remmeber all the other companies that make these supplies, but Sorenson, B&K both make them, and there are dozens of others out there, including the typical Chinese no-name stuff. Personally, for what I would consider precision needs of pack charging, I'd go for the name brand ones--even well-used like mine, they're probably more reliable than the no-names.


Nice thing about the lab supplies vs typical bulk charger, is you can also use them for single-cell or cell-group charging, at any current limit you like up to max. Makes manual balancing easy, so you don't have to deal with a BMS, just cell-level LVC (and HVC if you charge high enough to need it).


There is a recent thread about seriesing several smaller server supplies with 12V outputs to get higher voltages, too, so doing that plus a lab supply in series to adjust the top of the voltage range precisely, along with adjusting the current limit, is a lot easier than dinking around inside the server supplies to find the adjustments for those (if they have any).


BTW, those cells are the NMC type lots of people here on ES have been talking about lately, so you should collect as much data as you can on their performance during charge and discharge as you can, and post it up on ES. Should be interesting to see! I may have missed it, but where did you get them from? I know people are looking to buy this kind of cell....

 

[neptronix]

That hobbyking charger is actually 4 cheap & junky 6S chargers in one box. Do not expect it to operate as a 24S charger.

Doctorbass has covered this.. modded it for isolated outputs.. but doesn't seem to be using it anymore and gave up on it.

Anyway, how the hell did you get those EIG cells?!!

 

[Jay64]

Ok, bear with me guys, haven't been following any of this power supply stuff. I've seen people mention it before, but I was too busy looking up other stuff to follow the different threads they were referring to. Some of the terminology and concepts you guys are talking about is still a little foreign to me. I think I'm starting to catch on a little, but it looks like I'm going to have to ask quite a few questions to clarify some of the stuff you guys are talking about.
I've heard it mentioned a few times to get a set of power supplies, and then get another set of power supplies. This kind of confused me quite a bit. I wasn't sure why you would hook up one set of power supplies to another set of power supplies. AW, you did sort of clear up a lot of stuff with what you said, especially this part

plus server supplies in series to make up the rest of the voltage needed whenever it's higher than his lab supplies can put out.

Ok, but why can't you just have more of the lab power supplies in series to get the voltage needed? Can it not be done, or is it just cheaper to get a few good lab power supplies units and then add in cheaper power supplies since the few lab power supplies will help to control the cheaper ones? If this is the case, do you only use 1 lab power supplies unit and all the rest be the cheaper power supply units?
And in reference to lab power supplies.....is that the brand name, or is that a category of power supplies? It sounds like just a category. If it is a category, does anyone have any brand names on them to help search for them?
It sounds like the lab power supplies are better than meanwells. I do really like the idea of being able to change the voltage. I can really see how that will benefit my situation. I'm sure I will end up trying both the 22s and the 24s, so having one setup that can handle both will definitely come in handy. And being able to charge one cell when needed is huge too. I think I have decided to stay away from that one I linked to in the OP.
I also think I should try and find a setup that can work on the 110v input. I have a dedicated 220v line in my carport for welding and EV stuff, but if I'm going to be travelling around, it is a pain to have to lug a huge 220v generator to events and distant testing areas. As I'm writing this back a lot of it is making a lot more sense. Thanks for spelling it out for me AW. That really helped to clarify things.

Anyway, how the hell did you get those EIG cells?!!

My uncle Vinny tol' me dey fell offa truck........

I actually got them about a year ago as a package deal. I forget the name of who I got the deal from, but it was from an ES member in the for sale section. I pretty much got all the electronics for a whole build. A mars motor, Altrax controller, 44s of 20ah EIG cells, and a few other things. If I remember correctly the price was pretty damn good. I justified it that if I bought a new Mars and new Altrax it would have been about the same price as the whole package. These batts are what I put in the hurricane motorcycle build to push it from 45mph to 65mph. But that was with them only only charged up to 84 volts instead of the 91.3 that they can potentially be charged to hot off the charger. Now I'm just trying to find uses for them. I was going to try to buy some turnigy batts for this current build, but I figured I should try and use these since I already had them.

 

[amberwolf]

Ok, but why can't you just have more of the lab power supplies in series to get the voltage needed? Can it not be done, or is it just cheaper to get a few good lab power supplies units and then add in cheaper power supplies since the few lab power supplies will help to control the cheaper ones? If this is the case, do you only use 1 lab power supplies unit and all the rest be the cheaper power supply units?

Cost. Lab power supplies ain't cheap, compared to these hefty server supplies, which are out there as salvage, "scrap", etc., by the tens of thousands, maybe millions. Even if you were to buy them new, they'd be way cheaper than the equivalent voltage/current lab supply. Possibly by a couple of decimal places depending on what you are after, but at least by a few hundred dollars.

So one used current-limited variable votlage/current lab supply, for a couple hundred dollars or less (since you only need 10A max), and a fixed-voltage/current server supply for probably less than $50-$100, depending on shipping. If you use the apparently popular Hewlett-Packard/Compaq 48VDC out 220VAC in unit, and a 55VDC 10A out 220VAC in lab supply, you now have a 48V-103V 0A-10A charger, that if your wall AC can support it, can charge any pack you have at up to 1KW. Should work fine even with just a dryer outlet.

And in reference to lab power supplies.....is that the brand name, or is that a category of power supplies? It sounds like just a category. If it is a category, does anyone have any brand names on them to help search for them?

It's jsut a category, lab being short for Laboratory. Sometimes people call them Bench supplies. Usually they're in the Test Equipment section of places that sell such things.

Sorenson, B&K, for sure. Tektronix, Lucent, and other places probably make them, too. TTI in the UK. I've only personally used Sorenson and once a B&K. Well, I also have a Heathkit but it's not even 15V 1A capable. :lol:

I've seen other brands that are much cheaper, but are also probably made more cheaply, too. Most are probably Chinese clones of something else, or each other, but some might be "original" designs. Whether that makes them better or worse would have to be tested. Tenma, Madell, Pyramid, Mastech, I forget the others.

It sounds like the lab power supplies are better than meanwells.

More versatile, at least.

 

[Jay64]

Thanks for taking the time to walk me through that AW.

 

[Jay64]

I found this one on ebay. This would be considered one of the cheaper fixed power supplies correct? It is 200-240v input though, so I would have to carry a larger generator around with me to go testing/racing with.

 

[Jay64]

Am I reading this one right? It can have 110 or 220 input?

 

[Jay64]

Ok, another question. I've been searching for different power supplies and one thing I have been coming across on a few is that it states Input: 105-125VAC and then it also states Input Wired For: 200-240VAC 210-250VAC. What does the wired for mean? They look like there are almost blank check boxes in front of ea, but neither is checked.

 

[marty]

7,209 Linear & Switching Power Supplies here:
http://www.mouser.com/Power/Linear-Switching-Power-Supplies/_/N-8s82a/

239 Bench Top Power Supplies here:
http://www.mouser.com/Power/Bench-Top-Power-Supplies/_/N-wp4b/

More here http://www.newark.com/
More here http://www.alliedelec.com/

 

[Jay64]

Obviously 10a is a better unit, but would a 5a unit be acceptable? I know it would take longer to charge, but wouldn't that also be better for the batts in the long run? If I get a lab power supply that is 5 a, and hook it up in series to regular power supplies that have more than 5a, the lab supply will limit the current to 5 a, correct?

 

[amberwolf]

Yes, the lower current limit will limit everything in series with it. If you don't mind the longer charge time, you can use as low a limit as you can afford.

Since your pack is 20Ah, though, it'd take up to 4 hours to recharge it at that rate. If you're looking to be able to recharge at a race, I'd want to charge a lot faster than that--even the two hours minimum it'd take is a long time at an event.

At-home charging wouldnt' matter much, at least to me, since I typically only need the bike for one trip a day (and I have more than one bike and more than one pack, although they are not all as capable as each other). Probably true for you as well.


Regarding the input wiring, some supplies have a switch on them that allows use at either 110 or 220, and some are cheap and don't use the switch, but instead just wire across the spots on the PCB inside that the switch would have gone to, and thus are pre-wired for either 110 or 220. If it's marked inside as to which is which, you could change that. Otherwise, you'd have to partly reverse-engineer the input section to be sure what goes where for the other voltage before changing it.

Still other supplies have different components (input transformer, caps, surge suppression, diodes, etc.) for 110 vs 220. That you probably couldnt' just change over, unless you happen to have all the right parts to swap over. Fortunately for your use if you had a 220-made supply, most parts would be fine (even better!) at the lower 110V use, however the transformer probably would ahve to be changed so that it would output the full voltage. It's possible that it might still start and run on 110V, but only output half the voltage it was intended to, or the full voltage but only at half the power level; it would depend on how they designed it. More likely, it wouldn't even start correctly, without changing something on th estartup circuit inside. I don't know enough about SMPSs to say for sure.

 

[Jay64]

I'm just having a hard time finding a lab power supply that is 10a and not $400. I found a bunch that were about 6a.

 

[Jay64]

Just curious, is it possible to parallel these to get the amps up?

 

[Jay64]

How does the power supply charging know when to stop? It's been a while since I looked into chargers, but I seem to recall something about the power getting scaled back in stages towards the end of the charge cycle or something like that.

 

[jonescg]

Jay - seriously, get yourself a charger(s) from Nancy Loo like I did and she will have it made to do whatever voltage you want. If you want three times the current, parallel three of them together. They are all CC/CV chargers which cut themselves off when the charge current drops below 0.4 amps. They rock. They are cheap. They are dumb, but they work. TC Chargers I think is the name.

 

[marty]

Jay - seriously, get yourself a charger(s) from Nancy Loo like I did and she will have it made to do whatever voltage you want. If you want three times the current, parallel three of them together. They are all CC/CV chargers which cut themselves off when the charge current drops below 0.4 amps. They rock. They are cheap. They are dumb, but they work. TC Chargers I think is the name.

Here is a web site
http://www.tccharger.com/english/

TC Chargers 24V,36V,48V,60V,72V,84V,96V,120V,144V~420Vetc.,
In < Items for Sale - New
Don't know why topic is locked?
http://endless-sphere.com/forums/viewtopic.php?f=31&t=16602

 

[Jay64]

But are those chargers adjustable at all? My packs kind of fit in between some of their models. It looks like the closest one would be the model that does 104v 16 amp. But my max volts at 22s would be about 91v and 99.6v for 24s if I remember correctly and the max charge rate of 0.5C would be 10 amp. I'm gonna send them an email and ask, but was just wondering if anyone might already have one and could answer that quicker.

 

[amberwolf]

@marty: It is locked because the poster kept posting something, then deleting it, just to bump it back up to the top, among other things.

Just curious, is it possible to parallel these to get the amps up?

It should be, but I've never tried it. If all their voltage settings are not exactly the same, there will likely be uneven current flow from them. Some manufacturers, like Sorenson, include control pins on the back for "slaving" several of them to a single unit. I have not yet ever used that feature, but I think it is discussed in the manuals (which should be on their website, IIRC). There are also other features implementable that way, such as an external thermal override/cutoff, or even using Methods' LVC/HVC boards' output to shut off the supply if a cell is being overcharged.

If the supplies you want don't have that feature, and no protection against backfeeding power into them from a source higher in votlage than they're set to, you could also use diodes in series with them to do the paralleling, so that none of them could backfeed into the others. It might still have the current imbalance problem, where one supply is providing most of it, but as long as they're all designed for that much output it wont' hurt anythign.

How does the power supply charging know when to stop? It's been a while since I looked into chargers, but I seem to recall something about the power getting scaled back in stages towards the end of the charge cycle or something like that.

They don't know, by themselves. They just always output the voltage that you have set them to. As the battery approaches that voltage, current drops lower and lower, eventually zeroing as it reaches the supply voltage.

A regular charger is likely to have a stage at which it outputs *more* than the specified pack voltage, so that it charges at the end just about as fast as it did to start with, and so that the pack can balance using a bleed-type BMS.

If you are not using a bleed BMS, but just HVC/LVC, you don't need the charger to do that, and just letting the lab type supplies do their thing will work fine.

 

[amberwolf]

Oh, and I just remembered about the OVP on the Sorenson I have, so:

On one of the Sorensons I have, it has an OVP (over voltage protection) that you could use for end-of-charge, I guess, by setting it to the point just at full-charge. Then turn the voltage of the Sorenson up to that point, so it shuts down. Mark the knob's point of rotation on the face of the unit. Turn it a smidgen down, then power it back on, and connect the pack. Then turn it back to the marked point. Once the voltage reaches that limit, it will shut the Sorenson off.

The thing I don't know is if the pack will then drain into the Sorenson's OVP circuits--that would rquire checking it's schematic to be sure this is already prvented by design, or providing a diode on the output of the Sorenson (and compensating for it's voltage drop) to keep the pack from backflowing into the Sorenson under any conditions.

I've never tried this on mine, but in theory it should work with any PSU that has adjustable voltage output and adjsutable OVP.

 

[jonescg]

If you ask them to make you a 117.2 V charger, they will do just that :wink:

 

[Jay64]

I tried contacting them and never got a response. I did send it as a PM through ES, and it appears that they didn't check it yet. Apparently they no longer visit ES.
If I get a power supply and I have my regular charger, could I series the power supply to the charger? My charger already can do 84.5v, so that save me from having to buy a lot of power supplies.
I did end up buying 2 Meanwell S-320-24 12.5ah. I will be having them shipped to LA and pick them up when I get back up there next month. I looks like these have some voltage adjustability?

Voltage range stock is about 17.4V to 27.2V.

I still want to get one that can adjust all the way down to charge a single cell, but from what I have heard, these are pretty good supplies, and I figured a good place to start with building what I need. Does anyone know if the amps on these can be adjusted? I guess if I get another supply that can adjust the amps then it will also limit these down.