JB 1100 charger

[kit]

What charge currents are available for the JB 1100 charger? And how many nimhs can it charge?
Do you have any connectors to fit the lipo sockets on the charger?

https://www.unitedhobbies.com/UNITEDHOBBIES/store/comersus_viewItem.asp?idProduct=3824

[CSO#1 @UHobbies]

1-9cells NiMH
500mA to 1100mA charge current.
The balance plugs on the charger suit Align/Hextronik/Dualsky packs.

[kit]

Thanks for the reply. You should have that info on your web description.

[CSO#1 @UHobbies]

We do now.
Thanks.

[Andy2No]

Which way are the balancing ports wired up? Which side is + and which is - ?

Have you got a picture that shows that part of the case clearly?

Is it possible to set a lower cut off voltage for li-po? E.g. 4.1V per cell instead of 4.2V?

[kit]

As mentioned in one of the reviews on the UH web site, the voltage for lipo charging can be set to 4.15, 4.25, or 4.35 volts.
Here's a photo of the lipo charge connectors

[Andy2No]

Thanks, kit.

Why would anyone want to charge a lipo above 4.2V? Is it so the charger can be used to make a cheap incendiary device?

[Andy2No]

Okay, after looking at a few other chargers, I've decided to buy this one. It seems to meet my basic requirements and is a good price.

I'll be very careful not to use the settings that are above 4.2V. Since it has three settings, it's a shame they're not three useful settings but all the affordable chargers I've looked at have some shortcomings, and most stop at 4.2V. 4.15V seems a better voltage to stop at.

If the final voltage turns out to be slightly off, is there any way to adjust it? I'm used to a cheap Esky charger which has a small potentiometer inside it to adjust the end point voltage (very useful). If I like the JB-1100, I may try setting the Esky one to 3.85V per cell and use it to charge batteries for long term storage - if I was designing a charger with 3 settings, that would be one of them.

For reference, here is the most detailed description of the JB-1100 charger I've found so far:

http://www.huayu-group.cn/product.asp?id=208

One more question:

Does the charge time stay on the screen after charging is finished? If so, it would be useful for estimating the amount of charge put into the battery (mAh). As I understand it, that isn't shown, like it is on some more expensive chargers.

[Andy2No]

1-9cells NiMH
500mA to 1100mA charge current.Hmm... Another question:

Is it okay to use the NiMH mode for high capacity NiCd packs?

I have a big 9 D cell NiCd pack (4 Ah) that I use to power a lipo charger for indoor flight. Could I charge that if I set it to 500mA? Would it know when to stop?

[mjdoz]

The difference between Nicad and NIMH packs is the Voltage slope at the end of charge. As NiMH cells provide a much smaller change, charging NICD on NIMH settings will generally work but may terminate early.

Older NICD chargers sometimes have issues in detecting the voltage fall off on NIMH packs so would miss the end of charge indication and keep going.

Keep an eye on it the first few times but it should be fine.

Michael

[Andy2No]

Good. Thanks, Michael.

I made a 150mAh trickle charger for that pack a while ago, which works okay but requires checking by hand to see when it's finished. I don't really need a full charge, I guess.

[rick121x]

First - all of the info is listed in the referenced threads or in the links, but here are my comments;

I was very interested in a charger that handled each cel independently. I firmly believe that to be absolutely basic for a LIPO charger and that no, repeat no other, type of charger can safely and accurately charge a multicel LIPO.

The charger comes without adapter cables - and believe me that is a problem, for most of my batteries are Thunderpower - and I had to make an adapter cord. Luckily I had a connector in my old parts box with the pins having narrow spacing... and wired that to a wide connector to plug into the charger. Time consuming and pain in the a--.

Andy2no: The port polarity is marked on the case. Plus is on the left of each connector. I, too, object to the 4.25 and 4.35 charge voltages. That could become dangerous - one error in setting the voltage and pouf!

I notice there are four adjustment pots inside on the PC board. I hope those are voltage adjustments - for I will mess with them in a few day... I intend to set them all to 4.2 volts ! No mistakes from then on....

Hi Cap NIMH's... I have not done this yet, but the charge capacity is indeed limited by the power supply - but I imagine it will not go above the 1100 ma level, because of the internal component ratings. Not sure about this, but it is logical.

The unit does not show the final cel voltages on the panel - only indicates the total voltage of the pack. And I believe that if you leave the battery on connected after the charge is complete - [I]that it slowly discharges the battery. Again I could be wrong, but after an hour of two, the cell voltages were lower than the set values!

I notice that each cel does not charge at the set charge value. Some higher and some lower - I guess that depends on the internal resistance of each cel.

It is my belief that the unit needs a power supply that can supply a minimum of 1 amp. I started with a 400ma supply and the results were ridiculous.

Tip: after the charge, hit the start button and you will get short indications of each battery cel voltages.

I am sorry that I bought this charger, it is really a product of a beginning designer, who didn't know the requirements fully.

Richard :cool:

[kit]

It is my belief that the unit needs a power supply that can supply a minimum of 1 amp. I started with a 400ma supply and the results were ridiculous.

Richard

Page 7 of the manual under Technical specification it says:

DC Supply - 12VDC, 6 A

[Andy2No]

kit,

I haven't seen the manual yet. Do you have a link for a PDF?

On the page I found it says

Input voltage range: 12V~15V DC
Power Supply: Input voltage: 100V~240V
Output voltage: 12V
Output current: 5ASo you can conclude it needs 5A to supply the maximum specified - 4 cells at 1100mA, but a 2.5A supply would probably do to supply two cells at the maximum 1100mA. For three cells, you'd probably need a 4A supply, or bettter, or just charge at a lower setting. The minimum is 500mA so for a 2s pack you'd need 2x500mA = 1A + a bit more to power the charger, say 1.5A minimum - my Esky charger came with a power supply that can do that.

Personally, I prefer to charge slowly to extend the life of the packs. NiMH cells like to be fast charged, provided the charger knows when to stop. Lipo cells like to be charged slowly.

Richard,

Thanks for the information. I'll be interested to hear what you find out about the 4 pots. I suspect they might be one per cell, but I guess they could be one for a reference for the current and three for the charge voltages... Or they could all be voltage settings, with one for NiMH cells. It would be nice if the manufacturer would tell us. I'd also like to set mine so it CAN'T go above 4.2V.

I believe that if you leave the battery on connected after the charge is complete - that it slowly discharges the battery. Again I could be wrong, but after an hour of two, the cell voltages were lower than the set values!You could be right. Hopefully, that's just caused by voltage sag - some cells will sag by upto 0.1V within minutes of being taken off a charger. I assume the sag gets more pronounced as the cell gets older and loses some capacity.

[Andy2No]

I just found the JB-1100 manual (http://www.uce-bestbuy.com/pic/ucetech.lipoly%20charger_manual.rar) on http://www.uce-bestbuy.com/views.asp?hw_id=638, which also shows pictures of the PCB. The manual is in a RAR file so if you don't have WinRAR you may need the trial version from http://www.rarlab.com/download.htm.

[DonQ8401]

How do you know if the charger is working? I plugged in my battery that I purchased from UH and it is telling me it has to have a 3 hour charge. Holy smokes BATMAN that is alot of time. The guys in the field are charging at 45min to an hour and all I am charging is a 2C 1400mah bat. Help please. I have this charger and I don't know if it is working. I emailed UH but haven't heard anything. Help new guy here.

AA

[Andy2No]

It just means it will time out after 3 hours, if it doesn't stop first.

Press Start / Stop for the defaults - quick start, charges at 0.5A to 4.15V per cell, or stops after 3 hours if not finished.

A couple of things to note:

Pay attention to the beeps. You get a warning that it's somewhere near done, then more persistent beeping when it is. Unplug the battery packl as soon as it's done, or it will run it down again.

It charges each cell independantly and stops charging each cell when it's done. It then runs it down again, while charging the other ones, because it keeps checking the voltage for no good reason, and draws a lot of current doing it (serious design flaw #1).

It'll only start charging a cell if it's at about 4.09V or below. Once it's stopped charging it, it won't restart unless you stop it and press Start/Stop again, even if it's drained it down to below 4.09V.

If you plan to charge any 3 cell packs, you'd be advised to check that the voltage it shows for cell 3 is correct - it shows each one in turn as it's charging. Mine reads 0.07V to 0.09V too low for cell 3, but gets the other two about right. It may not sound a lot, but that means the 4.15V it should stop at becomes at least 4.22V, which will result in cell 3 having a much shorter lifespan (serious design flaw #2).

Other people have complained about one cell being overcharged. In a charger like this that typically runs off 12V, there's a voltage doubler that drives the charger for cells 3 and 4, so the charger for those cells doesn't necessarily behave the same way as the first two. There seems to be a problem with that bit. There certainly is on mine.

I don't hate this charger but I wouldn't trust it with a 3 cell pack - I tweaked my cheap orange plastic Esky chargers (the sort that come with a Lama heli) to make sure they're safe for 2 cells or 3 cells, and that's what I now use for 3 cells.

The seller I bought mine from agreed with me there was a problem with them, and gave me some of my money back. If you're in a position to return yours, I'd check it out and give that some thought. I seriously wouldn't risk a 3 cell pack on it, unless it's a really old one you were considering throwing away. That would be the best way to see if it overcharges cell 3 (if you have a way of measuring them). Checking the voltage of each cell, then seeing how much the JB-100 disagrees by is the second best way.

[topgun101]

I there, If the load stop before the battery done,it is that kept charge too mutch low. Minimum has haft to capacity of the battery.


One the other thing,to correct the final voltage of 4.15 volte of every cell,has the end of the load you decharge 5 minutes with a 1157 light(small element).After to be able to reload every cell egale in 5-10 min.


Eric.

[whilrybird]

The beeps you hear at the near the end of the charge cycle are the individual cells that completed. Say cell 1 has hit its max voltage you will hear a beep. The problem is that there is a slow drain on the completed cell, the charger does not come back on if that cell has dropped.

I believe the max specs on lipos are 4.25. But I guess people just use 4.2 as an easier base line. My charger does not over charge any of the cells. I charged my packs to 4.25 with no ill effects. I then use them in the esky charger afterwards and seem to get longer flight time. Kinda of like a battery break in or unlock full potential of the pack.

[Andy2No]

4.2V is the maximum that's considered safe for the cell. You'll shorten their life by charging them to 4.25V because the anode builds up a permanent coating, which reduces the capacity of the battery each time it happens. 4.15V is a lot healthier than 4.2V.

http://www.slkelectronics.com/lipodapter/tut8.htm

I think the higher voltage options on the JB-1100 may be to deal with packs that have protection diodes, or other built in circuitry.

[whilrybird]

http://en.wikipedia.org/wiki/Lithium_polymer
The specifications in the wikki says from 2.7 volts all the way to 4.235
.015 volts is not going to hurt anything. Blinking my eye uses more energy.

Funny thing is I hear people saying charge it to 4.15. do not discharge below 3.7.
Before they used to say do not dischage below 3.2 v per cell, then 3.4 now they say 3.7. pretty soon they will say do not charge above 3.7 and do not discharge below 3.7 so dont use the battery more than 50 seconds. Whats the point all batteries break down. I liked to see the emperical proof that charging to 4.15 is going to give me 100 more or even just 50 more cycles of the battery. Even if it does and I'm losing like 2 or 3 minutes of use of the battery each cycle because of these conservative suggestions, say 3 minutes x 100 extra cycles equals 300 minutes. In the end it probably all balances out. Reduced flight times = more charge cycles, normal flight times = reduced flgiht times, total duty cycle probably is probably the same in the end.

[Andy2No]

It's 3.2V or so under load but if you're measuring it after a flight, 3.7V because it will be higher than it was under load.

I can offer some empirical evidence in the form of a small pile of knackered 800mAh 2s lipos I flew my Lama with. I was careful not to over discharge them (I made an in-flight voltage monitor with some LEDs), but I regularly charged them to about 4.22V, apparently, because the charger wasn't set quite right. I also tended to store them fullly charged though, and that's another killer, apparently - it's okay for a couple of weeks, maybe, but not long term.

It's true, batteries are consumable items. It's just a question of how fast you're happy with consuming them, I guess. Personally, I'd like them to last as long as they can because they're fairly expensive. Treating them well is supposed to make the difference between 30 flights or maybe 200 flights. I've got some 1600mAh 10C Welgard Lipos which I was running at 12A WOT in my Cub and they seemed fine at first. Now they're almost useless - like 2 minute flights instead of 10 minutes +. The mistreatment in that case was running them too close to what the manufacturer claimed they were capable of. The 20C 1300mAh ones I bought around the same time are still going strong in the same application, because they're not running too close to their limit.

I think it's safe to assume that whatever most manufacturers claim for the C rating should be halved.

[whilrybird]

My question was proof that over charging the battery by .015 is having a detrimental effect and charging batteries to 4.15 increasing life span of the battery.

of course over discharging and improper storage will have detrimental effects and no one is questioning that. The point was that this charger was being slammed on because it allowed slightly higher charge voltages. I think charging at higher than 1c would have a more negative effect than .015 volts. I have charged 2 of my batteries to 4.25 and have seen a drastic increase in flight time. This might not occur for all batteries, but it has worked on 2 of mine. Maybe the battery was never borken in properly, and this kicked it in. IDk

[Andy2No]

I don't have a problem with it having higher charge voltages because it defaults to 4.15V, which is what I use. I don't think they're intended to be used with a bare cell though.

My problems with the charger are

a) that it drains whichever cell finished first so the pack is never balanced

b) that it misreads the voltage for cell 3 and overcharges it by at least 0.07V, which takes it over 4.2V (4.22V or a little more) when I'm aiming for 4.15V.

Conventional wisdom has it that charging above 4.2V is a bad idea and that staying below it is a better one. Personally, I don't feel like taking the risk.

I adjusted my Esky chargers so they charge 2s and 3s lipos to below 4.2V per cell. I now use those exclusively for 3 cell lipos and I've taken to using them most of the time for 2 cell ones too, though I'm okay with using the JB-1100 for that.

I bought the JB-1100 because I thought it would do a proper job of balance charging, better than the Esky chargers. It doesn't. It's useful for smaller packs due to the 500mA charge rate (default), but that's about the only advantage it has over the Esky chargers, which were a lot cheaper.

[whilrybird]

I bought it because it can bring an over discharged pack from the dead without puffing it. I have no over charging error on any of the cells. I think the discharging after a cell completes sucks but maybe a relay circuit between each cell could solve that. use a momentary button to prime the circuit when starting the charge and when voltage stops the relay breaks contact stopping the discharge. Might need some kinda circuit that adds the required voltage if there is any voltage at all to keep the relay working. Or you could put the relays with manual toggle switches and shut them off once charging is complete on a certain cell.

More than likely you got a bum charger or need to open it up and fine tune one of those pots inside.

4.235 is the max voltage per the battery design specs. I doubt .015 volts is gonna be the straw that breaks the camels back.

[Andy2No]

I'd forgotten about the cell recovery feature, because I've never used it. I've needed to do it with small single cell lipos but I just used 2xAA cells and a resistor to bring the voltage back to 3V, then charged them normally.

I'm fairly sure I've read other complaints about one cell being overcharged by the JB-1100, though not in this thread. Fiddling with the pots is certainly worth trying, though there's no way of knowing if they adjust the voltage or something else til someone tries it.

Possibly just making a lead with switches in and doing it manually would be the solution to the dicharging problem, though it would be a bit of a pain. I started trying to design something to report the cell voltage to the charger and isolate the cells (via transistors) so they can't be discharged by the charger after it stops charging them. I didn't get very far with it because it started to not seem worth the effort. It's possible, I think, because a transistor that's conducting can have a very low voltage drop between the collector and emitter (e.g. 0.05V to 0.1V). It would probably mean using one of the higher voltage settings to compensate for that drop.

I'm tempted to think that my Lama batteries mostly died due to being charged to 4.22V, before I adjusted the charger... It may have been 4.25V, now I think about it. I certainly didn't over discharge them, or charge them above 1C as far as I know (or at least I charged them with the 800mA charger). I did tend to store them full, but they were in use every few days so I'm not sure that counts. I found the flights got shorter and shorter before the LED voltage monitor told me to stop. Still, they're you're batteries so you charge them how you want :) It's hard for the likes of us to do enough testing to see what really happens in different circumstances, so I rely on what I've read.

[Andy2No]

Well, I finally managed to fix my JB-1100 charger so I can use it to charge 3 cell lipos, without it overcharging cell 3. It still has the problem of running down the cells that finished first, of course.

There may be different revisions of the circuit board, but here's the details of mine.

The main chip is a Holtek HT46R64 8 channel A/D converter with built in MCU. Four of the channels are used to monitor the cell voltages. The four presets on the front/top side of the PCB aren't involved in this process - I fiddled with those for some time before deciding they don't affect it. Possibly they adjust the current sensing, which I guess is what the other four channels are used for.

There's a small group of SMT resistors close to the main chip, not far from the white plastic socket that the fan plugs into.

R4 and R3 form a potential divider which is used to read the voltage on cell 4.

R5 and R2 form a potential divider to read cell 3

R6 and R1 form a potential divider to read cell 2

Cell 1 is a bit more mysterious. R7 is the top half of a potential divider between the JST-XH socket and the Holtek chip. I didn't find the other half of the divider and I didn't need to know so I stopped looking.

In my case, I needed to adjust the sensing of the voltage for cell 3. It consistently read it as 0.07V to 0.1V below its true voltage, which meant it typically overcharged to 4.25V when it was set for 4.15V.

I just measured the resistors in circuit which gave:

Cell 4: R4= 29.5 kOhms, R3= 9.8 kOhms

Cell 3: R5= 29.7 kOhms, R2= 9.8 kOhms

Cell 2: R6= 7.2 kOhms, R1= 7.5kOhms

Cell 1: R7= 7.2 kOhms, resistance measured to ground= 11.8 kOhms

The real resistor values will be a bit higher, but that's not important. I could see that I needed to reduce R5 slightly so that the voltage at the pin on the main chip was a little bit higher. The easiest way to do it is to solder a bigger resistor across R5 (unless you're really good at soldering, which I'm not). I worked out I'd need a 1.3 MOhm resistor to correct it. I started with a 1 MOhm and a 100 kOhm resistor in series, with one end of each soldered to the pads on R5, and the other ends twisted together. That didn't quite do it, though it did improve things. I then added another 1 MOhm resistor between them. I was fairly happy with that, so I soldered the twisted ends. It would still be easy enough to change it.

The charger now reads cell 3 as 0.02V to 0.04V higher than it really is, so there's still a bit of room for improvement (I could try reducing the resistance I added a little), but I'm going to leave it like that for now. The result is that it will stop charging slightly early rather than too late, so it won't damage that cell.

It may turn out that cell 4 needs adjusting too. If it reads the cell too low, I could just do the same with R4. If it reads it too high and I'm not happy with the error, I can solder a resistor across R3.

I can see the JB-1100 can be used to charge two similar 2 cell lipos at once by just making an adaptor to plug them in to the 4 cell JST-XH socket, with one wire shared so they're in series. I may get round to trying that, in which case I'll look into adjusting cell 4. The three pins of the 2 cell JST-XH socket are wired to the first three pins of the other two sockets, so charging a 2 cell and a 3 cell at the same time woudln't be a good idea, but charging two similar 2 cell lipos should be fine, with the right leads - either make a splitter for the 4 cell socket, or an adaptor to plug a second 2 cell lipo into it, using the three pins on the left side.

I've read a couple of other people complaining the JB-1100 overcharges one cell. It's easy enough to check with a lipo meter - just take readings then plug it into the charger and start it charging. Maybe take some more readings near the end because the error might not be a fixed amount. If the readings it shows for any cell are too low, by more than 0.05V, you've got a problem.

If the charger is reading a voltage too high, there's no danger to the cell, it will just stop charging early. Unless it was way off, I'd probably just put up with that. If it's reading it too low, like mine was, it will keep charging it after it's full and damage it, so that's more serious.

If it overcharges cell 4, you need to reduce R4.
If it overcharges cell 3, you need to reduce R5.
If it overcharges cell 2, you need to reduce R6.
If it overcharges cell 1, you need to reduce R7.

- that's using the same cell numbering as the charger, counting from right to left on the JST-XH socket pins.

Here are some pictures of both sides of the PCB, with my mod on the back/lower side. There's plenty of room inside the case so I didn't bother to tidy it up. I use UHU White Tack to hold components while I solder them. In this case, I just left it on as insulation.

[Andy2No]

I made up an adapter with a 5 pin JST-XH plug to go in the charging socket for a 4s lipo, with a 3 pin JST-XH socket on the other end, wired to the three pins on the left of the 5 pin socket on the charger.

I checked the cell voltages on two 2 cell 800mAh lipos (Lama / Blade CX size) then plugged them in. The first one is in the normal 2s charging socket and the second one is plugged into the 4s socket with the adapter. When I press Start, the charger sees it as a single 4s lipo and charges it quite happily.

I got lucky on the voltage reading for cell 4 - it happens to be pretty accurate so I didn't need to adjust it with more resistors. Of course, you shouldn't assume yours is accurate if you try the same thing - take a reading first and see if the charger agrees when it starts charging.

I'm feeling too lazy to take a photo but I'm sure you can picture it.