A different approach to battery management...

[GGoodrum]

In the seemingly endless series of BMS testing I've been doing of late, one thing I've noticed is that these Turnigy and Zippy 6s-5000 packs I'm using, just don't get out of balance very easy, without forcing them out-of-balance. This has made me re-think how to manage these packs. What I really need to do is monitor each cell during charging, but not worry about balancing every time. What I've now done is use combo LVC/HVC-only boards in the pack, in conjunction with the new charge control board. What this does is use the throttling logic to hold each cell from exceeding the set point, which is about 4.16V, in my current setups. The current will drop all the way down to essentially zero, as the high cell gets full. With the cells fairly well balanced, they will all get full.

With all the BMS weirdness we were seeing, the problems were causing the cells to get as much as 100mV delta between the lowest and highest cells. What I used to re-balance the cells was my trusty Hobby City Battery Medics. These units work amazingly well, and will balance the cells to within about 5mV, but it can take quite awhile. They have 10 ohm shunts, so they should be capable of at least 300mA of balance current, but there's no fans inside, so it would be hard to believe they'd really shunt that much. As it turns out, the unit pulses the current, so that all the channels aren't all on at the same time. The duty cycle is roughly 2 seconds on and 1 second off.

I then decided that maybe it was easy enough to come up with a way to boost the shunt current, so that the balance time would be reduced. As it turns out, this was actually pretty simple. What I did was tap into the collector of the shunt transistors, and use this to drive the same KSA473 power transistors and 3.1 ohm shunt resistors we use on the full BMS. I finally am able to make use of some of the earlier version shunt boards, that have been accumulating in a big pile at an alarming rate. It took some experimenting to get the values right, and Richard made some circuit "adjustments", but this works amazingly well. There's just under 3.0V across the shunt resistors, so just about 1A of "boost" current. Here's what the schematic looks like:

Battery Medic Booster v1 0b.png

(22.63 KiB) Downloaded 2592 times

Pretty simple, really. The BM has a PNP transistor that drives a bank of ten 100 ohm resistors in parallel. This is similar to what we do on the BMS shunt boards. Anyway, a tap from the collector is inverted, and this is used to turn on the KSA473 shunt transistor. The LEDs are not necessary, but it is nice to have a visual indication of when each channel is actually on.

Next, I took the booster board, and stuck it in one of my favorite boxes. Here's what it looks like:

Battery Medic Booster-01.jpg

(200.06 KiB) Downloaded 2592 times

Battery Medic Booster-02.jpg

(166.75 KiB) Downloaded 2592 times

Battery Medic Booster-03.jpg

(156.62 KiB) Downloaded 2592 times

Anyway, I'll give this a good workout, and see how much time is cut out of the balance process.Later, I'll also post some pics of the new LVC/HVC boards, and the special version of the BMS control board I'm doing for this application. The board fits in one of the smaller versions of the boxes.

-- Gary

[mwkeefer]

Pretty darn cool there Gary... = )_

-Mike

[liveforphysics]

The hobby city battery medic is a badass little guy.

Watch out for leaving it plugged into a pack for too long though! I've had a few times I left it plugged into a pack for weeks with no problems, and a couple times that I've come back to the thing to find the battery-medic not on, and #1 cell voltage at 0.5v or so... Not sure exactly what happens with it, maybe I've just got a flawed unit, but you might want to check to ensure that it doesn't just continously drain cell #1 in the event it's left plugged in for extended periods.

[mwkeefer]

Just an idea - Gary have you seen the Atmel ATA680 IC chips?

They handle up to 6 cells each, have seperate lines for each cell in a pack and two temp probes and connect to each other and a master MCU (ie: atmega) via SPI interface...

The datasheets claim upto 1 amp per channel of possible charge pump operation (via inductor 50ma via capacitor) at 3kw operation...

The thing that interests me, these are basically CellLog8 minus the dodads but for about 2.50 each... for a 20-24S pack you would need 4 of the ICs so 10.00 and the balance implementation could be done in a multiple stage fashion... somthing very similar to your booster as stage #1 but an upgraded version down the road for actual active balancing via inductor for large packs and super efficient balancing...

The master MCU can work at high level - monitoring for LVC, HVC and OOB interupts then triggering balance if needed or... it can just accept the data sent from the multiple slaves (up to 16 ICs) and then output it via (if were talking arduino mini here) the serial port for LogView use or to SD card...

Point is - with resistive balancing of 18S packs:

3 x ATA680 @ 2.50 ea
15 x Transistors (to turn on current drains) @ 5.00
15 x Resistors @ 10.00
15 x Diodes @ 10.00

So for 37.00 + PCB you have a simple MCU controlled full BMS with a few more transistors or relays and perhaps some parallel fets, you have charging control... intelligent charge and balance management (it's not too difficult, when cells > 15mv OOB and < 4.1v then turn on balancer... when 4.1v engage balancer, CV mode hits and as current tapers... balancer does it's job... A shunt on the balancer could even alert it when current has reached it's maximum dissipation level and begin at that moment (1A would leave about 10-15m of taper off on a 10AH pack for balancing).

I am personally heading down this path (though I will be borrowing your idea for the HobbyCity medics... they do work well enough)... BTW: Although I doubt we want multiple chargers / supplies... I have succeeded in using an S-145-48 configured for 62.50v and current limited to about 100w - this gives me a nice CC/CV charger fixed at 1.728 A... The thing was 11.00 and would be perfect with a 1A drain HK balancer to accomplish proper balancing.

What's your take on bottom end balancing versus top end? I guess if all cells are matched and healthy they should hit their knee at the same time?

One last thing... the reason I like the IC method better is the I2C bus of all series cell clusters... this means you can get the highest resolution across much larger cell packs (24s with +- .03mv) and that alone seems worth the weight in gold... the basic functions are easy to code up...

The thing I find difficult would be the inductor version as a charge pump... They claim (data sheets) caps are only good for about 50ma of balance current but I would think a large low ESR/Voltage cap which was allowed to charge to the same voltage as the source cell (when that drain is fired off, the cap is switched into parallel with the high cell) then discharge into the lowest cell in the pack (same thing paralleled) until it's voltage matched that of the cell it was dumping into (the current would be 0) then... it would be capable of transferring much more current...

This got me thinking... and I would really like your opinion on this one...

In my experience if I take a 5S pack at 90% SOC and connect it in parallel with a pack at 80% SOC via the discharge leads there is a burst of current transfer for a moment which slows rather quickly (and seems dependent on the difference in voltage between high v and low v) but it equalizes... the same seems true at the cell level when using balance taps to parallel the cells up.

Since we are DIY anyway... why not turn this a bit sideways:

Instead of a capacitor between each cell (seems a waste) to be switched into parallel, we construct a simple circuit which boosts the voltage of the highest cell (call it 3.9v) to 4.25v via somthing like an LM317 using a PWM transistor for current limiting to about 1A of charge rate (maybe more for faster balancing) we transfer more current into the circuit and store it in a 2S LiPo pack kept at nominal voltage (5AH is more than adequate)...these can accept up to 2C for normal charging right so 10A.

In either case... using the MCU... identify the median cell voltage and first discharge the higest cell to the median using the charger into our 2S for the load then disconnect it and connect to the lowest voltage cell and transfer enough energy until it hits the median...

In this way we use not an inductor nor a shunt nor resistors or caps but Lipo and in such a small amount (a few amps in bursts) even on the worst packs and a tiny amount (a few ma) on real balanced packs for the isolation charge pump?

What do you think of an idea like that? It complicates circuit layout due to the voltage conversion and current limiting but...

If your charging a 10AH pack and a 2S5AH is connected to be charged at a 2.5A - it could draw naturally (shunt) as much as 25% of the charge current from the higher cell, then burst transfer it to the lower cell.. I think this pump needs more than my attention but I think it would be a great tradeoff (no transformers required, no caps for storage, no bleed resistors and minimal support components).

As always ... feedback welcomed and appreciated.

-Mike

[GGoodrum]

Luke, the Battery Medics have two modes, balance and discharge. In the balance mode, the high cells are brought down to level of the low one, just like every other RC balancer we've used for years. The discharge mode works like our BMS shunt circuits, where each cell is brought down to programmable set point, like 4.10V. For the BMS testing, I've been using 4.00V. Anyway, when all the cells are discharged to that point, the unit stops. In the balance mode, it gets all the cells down to the level of the lowest, but I think sometimes it can overshoot a bit, and this cell now becomes the lowest, so all the rest are brought to this level. The cells all seem to stay within 4-5mV, but I have seen them "keep going" like this. I guess I'll really have to watch this, with the booster connected, because it certainly will take a lot less time. What I will do is only use the balance mode if I happen to be using these while charging the pack. Otherwise, I'll use the discharge mode, set to something like 4.10V.

Mike, are you talking about the ATA6870 chip? This looks similar to the LT chip that Patrick (methods...) has been using in his 36-channel monitoring system he's working on. I went through the 6870 datasheet, and I see how it can be used to drive a standard shunt circuit, but I didn't see any reference to a charge pump-type setup.

As for top vs. bottom balancing, all I can say is bottom balancing is not something I would ever consider. Even with cells that are closely matched in capacity, etc., there will always be one that will "jump off the cliff" first, so trying to catch them right at that point is risky, at best. This whole top vs bottom balancing is really more applicable to larger capacity cells like the ThunderSkys, which seem to have quite different capacities, RIs and temp coefficients. This causse them to get out-of-balance, in relation to each other, quite fast, sometimes with every cycle if they are discharged far enough. For these types of cells, doing "top balancing" doesn't really make a lot of sense, because what happens is that the lowest capacity cells have to wait around, shunting current, while the high cells get fully charged. As long as you do cell-level low voltage protection, to keep the "cliff jumpers" at bay, you don't really need to do top balancing. What many BMSs used with these cells seem to do, though, is simply stop the charge when the first cell hits the HVC point. The problem with that is that the cell really isn't getting full charge. In order to get full, the voltage needs to be held at the HVC point, and the current allowed to taper off. This is exactly what our charge controller does. It uses the HVC signal to keep the cell right at that HVC point. Without any shunt circuits, the low capacity cell will control the current tapering down, so this way at least it is getting full. There is one problem with this "no balance" approach, however, and that is the case where you may have cells with similar capacities, but different states of charge. What happens is the "usable" capacity is reduced, so you end up with less range. To fix this, you still need to do periodic balancing, of some sort, but it doesn't have to be top balancing. You could use something like this boosted Battery Medic to balance the cells, after a charge, either to a fixed point, or to the low cell, so that they are all at the same point, and then charge them to where the low capacity cell is fuil.

The LiPo packs we've all been using are a different animal. For the most part, the differences we see in voltages between cells are due to differences in state of charge. Eventually, the cells will drift apart more, but even then most of the deltas are going to be because the cells are unbalanced, not because one cell has a significant difference in capacity and/or internal resistance. For these, balancing is a good thing, but it doesn't need to be done with every charge, because the cells just don't get that far apart, under normal use. What will get them a bit unbalanced, is discharging them down to the LVC point. While the LVC circuits will stop the cliff jumping, the first one to get close to the ledge, so to speak, will not be allowed to commit suicide, but this cell will end up farther out-of-balance with the rest of the pack.

Here's what the new combo LVC/HVC-6s4p Parallel Adapter boards look like:

6s LVC-HVC-01.jpg

(144.02 KiB) Downloaded 2521 times

6s LVC-HVC-02.jpg

(205.96 KiB) Downloaded 2521 times

There are several "external" connection options, a standard 7-pin JST-XH pigtail, a Molex MicroFit 3.0 connector, or a 3.5mm mini-terminal block. I mostly use the Microfit 3.0 plugs and connectors, which are a lot more robust than the JST-XH connectors, and can take 18-gauge wires. I'm also able to use the same ridiculously expensive crimping tool, with these, that I bought for use with the larger Tyco/AMP VAL-U-LOK 4.2mm PE Series connectors. I'm also in the process of having some "pre-crimped" wires made made up, so I can offer cables with matching MicroFit plugs on each end. Finally, because my next LiPo pack is probably going to based on the new Turnigy 8s-5800 packs that HC is now selling, I'm going to do an 8s version of the LVC-HVC board. I just got a bunch of 9-pin JST-XH, 9-pin MicroFit connectors and 9-pin 3.5mm terminal blocks in this morning.

-- Gary

[recumbent]

... Finally, because my next LiPo pack is probably going to based on the new Turnigy 8s-5800 packs that HC is now selling, I'm going to do an 8s version of the LVC-HVC board. I just got a bunch of 9-pin JST-XH, 9-pin MicroFit connectors and 9-pin 3.5mm terminal blocks in this morning.

Hobbyking is shipping 4 of these 8s-5800 to my door, i"ll do a review of how balanced they are when i receive them.

I'm already in the market for a few of those 9pin jobbers your going to be makin-up. The 9 pin JST (or anything with similar spacing) fit perfectly in the CellLog and my icharger 208. When i saw these batteries for sale, I snatched 4 of them up for 60 volts of power to boost my speed well over 50KM/H (30mi+)

If you have a few of the 9 pinners already made-up, i have Paypal...Pal.

[dogman]

I found it very interesting that you mention that the packs stay balanced pretty good. That sure does make bms issues a bit of a moot point. If the pack tends to stay balanced all you need to do is not overdischarge. Use the method of your choice for that.

My first v1 ping went 2500 miles without the bms ever balancing the pack. I was using a too low voltage sla charger so the bms couldn't start balancing. How did it stay so balanced in 200 cycles? Low discharge rate. I wasn't forcing them out of balance. Pretty simple, but nobody wants to do it because it means spending more money and more weight to carry. It worked fine for me though, discharging at .75c average.

[icecube57]

I have two battery medics. I charge in a 10s 2p with thundersky packs. The charger sees a 18.5v 40AH pack. On a good day the medics make quick work of top end balancing the pack. About an hour if i didnt do a full DOD. I have my charger set to 37v-37.1v. I set the battery medics to discharge mode to discharge down to 3.7v. I still have some strong guys in the pack that have lower IR and like to hog all the voltage to themselves but the battery medic puts them in line with the rest eventually. Im lucky I can set my pack on the charger and forget it. I peek on it every few hours.

If i could get my meanwell to not drift on voltage this would work out great as a charging system. I swapped out SVR1 from a 1k pot to a 10k on my meanwell. You barely blow on it and it changes the voltage. I recently glued the pot its help alot it only shifts around .1v depending on temperature and other variables. .1v This is still alot for these balancers to deal with and they cant barely shunt away enough current at that much variation. I plan to buy 2 more medics so each of my (4) 18.5v 20AH pack has their own dedicated medic. That way one medic isnt trying to balance and shunt current for (2) 18.5v 20+20=40AH pack.

I do need an lvc board but then again i dont. Im getting stronger in my riding to where i dont need no where near the same amount of AH to go the same distance. So my DOD should be around 50-75% at most. The last 2-3AH or 10% of discharge sucks. Talking about saggy. Barely able to hold a 0.5-1C load. Ive only been their twice. Its enough to convince me not to flirt around past 17-18AH. Its no fun. And not to mention the cells no longer are in balance. During the actual working/usable discharge curve all cells sit exactly at the same level but on the top and bottem end of of SOC they are all over the place without balancing.

[GGoodrum]

I found it very interesting that you mention that the packs stay balanced pretty good. That sure does make bms issues a bit of a moot point. If the pack tends to stay balanced all you need to do is not overdischarge. Use the method of your choice for that.

My first v1 ping went 2500 miles without the bms ever balancing the pack. I was using a too low voltage sla charger so the bms couldn't start balancing. How did it stay so balanced in 200 cycles? Low discharge rate. I wasn't forcing them out of balance. Pretty simple, but nobody wants to do it because it means spending more money and more weight to carry. It worked fine for me though, discharging at .75c average.

Yep, this tracks with my experience as well, both with LiPos and with a123-based packs. If you don't pull them down to the cell-level LVC, the cells stay pretty close together. One way to do this is to set the controler, or CA, pack-level LVC point so that under normal conditions you don't discharge the cells to the point they become unbalanced. The cell-level LVC is still needed, in my opinion, to catch those instances when the cells do get out-of-balance, for some other reason. There's been lots of cases where there are cliff-divers, ready to make the leap, even though the pack level LVC hasn't tripped.

While not as critical with LiFePO4 cells, over-voltage protection, during charging, is just as important, in my opinion. Simply shutting off the charger, when the first cell hits the HVC point will do that, but it doesn't let the low capacity cell get full either.

[number1cruncher]

I have a question, although it is somewhat rhetorical. I built a 12s Lipo battery. Works great. Its set up in series(2 6s, duh). I use two BatteryMedics(BM) while charging with a MW S350-48. So far so good, right? Well I've noticed that they are not quite in sync with each other. One will say 25.02, while the other will say 24.98. This is still okay. Then I switch them and one now says 24.98 and the other, you guessed it 25.02. It would be great if some how both were linked, because if they were wildly off, I can forsee some really crazy situations arising.

Maybe my question isn't completely rhetorical: Is there a standard that all this electronics stuff should comply with? Now don't say the Chinese Standard, lol. But it seems when I go from BM to DMM to WattsUp to BM6 I get different values.

One other "issue" I've noticed, relating to the above issue is that even if they were perfectly calibrated to each other, it seems some packs increase in voltage faster than others. So, I've noticed that one 6S section is all 4.16V and the other is half 4.15V and half 4.16V. The split side is knocking the 4.16V guys down to 4.15V, while the other side is letting the 4.16V jump up to 4.17V and not bleeding them. It almost seems better from my limited exposure to just let them self-balance, because they seem to do it better than using outside influences.

Thank you Gary for your dedication! Those LCV/HCV boards look outstanding!

[GGoodrum]

I think the differences you are seeing are normal variances. While the overall "real" voltage they are reporting are slightly different, the relative balancing they are doing seem consistent between units. I have four of these, and they all will balance the cells within 4-5mV of each other.

I just tested the booster/BM combo on several 6s-5000 packs, and it is a ton faster now. Somewhere between 5-10 times faster. Well worth the effort, I think.

I have I already have a bunch of the 6-channel LVC/HVC boards right now, and I should have the 8-channel version by early next week. Tomorrow I should receive a run of the new small control boards. Here's what they look like:

Simplified Controller-v4.0.6.png

(134.79 KiB) Downloaded 2460 times

It is sized to fit in the smallest size Hammond box, which I happen to have a bunch of, and I did new end plates for these as well. The control board doesn't have the fan switch, which it doesn't need, and it doesn't have the balance timer, which it also doesn't need. In place of the timer, there is a new shutoff feature that will shut down the charge current when it drops below a certain level. Initially, I'm going to try .3A. Again, this is just to get the low capacity cell full, so once the current drops to that level, it is goig to be about as full as it is going to get.

This version of the control board also has the new charge current limiter, which is adjustable from about 1-20A. This means no more MeanWell hacks. Any version will work, even the ones that only have the front-end hiccup mode for overload protection.

Anyway, my plan is to make the controllers and the 6-channel LVC/HVC/6s4p Parallel Adapters available by this weekend, either separate, or packaged together in a "system". There will be boards-only and assembled options, like before. I may also make the BM booster boards available, if there is any interest. Next week, when the 8-channel boards are ready, I'll make the LVC/HVC/8s4p Parallel Adapter version available. The same controller will work with any pack configuration, up to 100V, or so.

-- Gary

[icecube57]

Ive learned that when the PSU is tuned exactly to the volktage you want it the medics dont have an issue getting it right dead on where it needs to be. But let it be slightly high by .1v then the cell with the lowest internal resistance will hog the excess voltage and its impossible to get that guy to come back down.

I would be intrested to use this beefy shunter with the battery medic..

Below is my medic on a perfectly tuned power supply. All is well. It was a good day and the angels sang.

[AndyH]

I found it very interesting that you mention that the packs stay balanced pretty good. That sure does make bms issues a bit of a moot point. If the pack tends to stay balanced all you need to do is not overdischarge. Use the method of your choice for that.

Just don't add anything to the pack that will cause imbalance - like unmodified CellLogs or PakTrakr remotes.

[recumbent]

Just don't add anything to the pack that will cause imbalance - like unmodified CellLogs or PakTrakr remotes.

Good point Andy, CellLogs pull more current than we might think. And pins 7-8 are not powered, making it trickier still, I only plug them in to check instead of leaving them on all the time. I haven't tried modding mine yet, too afraid to pull them apart is it easy?

[dak664]

Mike, are you talking about the ATA6870 chip? This looks similar to the LT chip that Patrick (methods...) has been using in his 36-channel monitoring system he's working on. I went through the 6870 datasheet, and I see how it can be used to drive a standard shunt circuit, but I didn't see any reference to a charge pump-type setup.

http://www.atmel.com/dyn/resources/prod_documents/doc9184.pdf, updated 3/10. Other docs are at http://www.atmel.com/dyn/products/product_card.asp?part_id=4641

[dogman]

Been a few cells ruined by leaving a bms connected all winter on the shelf. Or leaving a controller turned on, I never do that!, much.

[mwkeefer]

Yes I was - there is an updated app note on the Atmel site but really this ASIC (application specific integrated circuit) just as any designed for this purpose could simply be adapted with a cap or inductor and an addressable bus for discharge/charge direction.

Their appnote is ok but it would be better to design from scratch after selecting the MCU and drawing up the stacking interface connectors (6s per board x 3 boards for 18S - each with it's own ADA chip tied back to the master MCU.

I am still awaiting confirmation (which doesn't usually arrive before the sample units do) on shipment and qty of samples shipped, I asked my atmel rep for a small number of samples for testing in pump balance/BMS mode for a 24S pack but he usually sends me 2x what I ask for...

We shall see... in the meantime, I am excited about the HK balance mod GGoodrum came up with on the external discharge board for higher current balancing of our packs - I have several of the units here and plan to arrange them in a similar fashion until I have somthing better to use on my big packs (hint hint gary).

In the long run, the charge pump style balance system would be best for efficiency and lowest heat generation... I believe this system could be allowed to run even durring discharge - this may seem trivial to many people, why would you want to balance while discharging? In the event of a weaker cell, the power stored in a stronger cell would transfer durring discharge at up to a 1A rate which should extend the cutout of the pack as a whole and increase the retrievable pack level energy. This could be very useful in smaller packs too (a single series string of LiPo gets more oob at end of cycle than several strings in parallel configuration) to increase their lifespan and usefulness.

PS: I just lost another iCHarger... no more for me, 135.00 each is too much to keep toasting them... I'll stick with my homebrew charger solutions from now on and hopefully a pair (up to 18S each) of GGoodrum/Fetcher BMS HVC/LVC systems when they are completed.

-Mike

[Doctorbass]

I heard alot of these problem overbleeding cells to Voltage under lvc using the MKS or any other BMS that balance to the lowest.

The best way i found to avoid that with every of my setup is to link every balancer line thru a relay contact.

Yes.. it exist some very small 6pst or 4pst relay that you can use to switch the balancer ONLY when you use or charge the ebike battery!

When i precharge the contactor on my setup and that the contactor activate.. it also activate these relay... and when the ebike is OFF and left for prolonged period or just not be used, There is absolutely no link between the BMS and the cells..( relay contacts are open) so no danger to drain all your cells !

It cost around 15$ to avoid that problem for a 24s battery.

Doc

[CamLight]

Nice setup Doc, I like it!

[AndyH]

The best way i found to avoid that with every of my setup is to link every balancer line thru a relay contact.

Brilliant! I guess that's why you're the Doc, Doc!

[AussieJester]

FANTASTIC to see progress Gary! When do you envisage
they will be available for purchase mate?

KiM

[richerson]

HI Doc

That would work well for my pack, but I can only find 24v relays, I need 75vdc. I have trashed a whole lipo pack leaving hk cell monitor conected.

I have just bought some zippy packs so i want my setup to be full proof this time.

[GGoodrum]

What Doc is doing is mainly for permanent installations of these RC-type monitoring/balancing widgets. The LVC/HVC-only boards draw microamps, and can be left connected. They draw less than the typical self-discharge rate for most cells. The charge control boards also draw nothing, when the charger/supply is not hooked up.

Using Battery Medics, boosted or not boosted, and/or other units, as external balancers is still a problem, if left connected to a pack, but at least if you use the Battery Medic in the discharge mode, all the ones I have do seem to stop when they hit the programmable set point, so at least they won''t quickly drain the pack dead.

I have the first of the new charge controller cards built (shown below...), which I will be testing today. This is the first one with the new adjustable current limiter. Later, I'm going to try this with the CellLog unit, which I've added an isolated opto output to so that the programmed HVC "alarm" output might be used with the throttling logic. I tried this before, but there was hysteresis between when this signal comes on and when it goes off, which was playing havoc with the PWM throttling logic. What I will try now is using a higher value filter capacitor on the opto signal, to smooth out the swings.

Kim -- We're getting close, buddy. My hope is to get you something by the time you have everything back together on your blinged-out cruiser.

-- Gary

[AussieJester]

Kim -- We're getting close, buddy. My hope is to get you something by the time you have everything back together on your blinged-out cruiser.

Won't be a problem there Gary I'm waiting on you now LoL..i can't go any further at this stage until i have the BMS, i can't have the battery housing painted until i know what holes i need to placed in the enclosure, its being professionally painted all openings etc must be done to it before it sent for paint alternatively if you can give
me exactly what size holes are needed for the charging/balancing plugs, LEDs or display window to see status of charge etc? etc? So i can do it before the BMS is ready? lemme know when you have one ready and ill paypal the money for one immediately, they look and sound EXCELLENT anywayz Gary fantastic effort mate hopefully i can keep my lipos 'alive' a lil longer this time round hahaha ...

cheers mate much appreciate your efforts

KiM

[GGoodrum]

The hysteresis in the CellLog alarm output is just too great to be able to use these as HVC outputs for the PWM/throttling logic. Even with a very large cap across the input, the current was jumping all over the place.

The new controller works great,however, with the LVC/HVC boards. the CC limiter also works quite well. You can set the current pretty much anywhere you want. I also tested another new feature, which is the auto-shutoff based on the current dropping down below a minimum value. Right now, it is set for about 190-200mA. As soon as the current drops down under this point, everything shuts off.

Simplified Charge Controller-v.4.0.6-02.jpg

(186.96 KiB) Downloaded 284 times