12s2p LiPo pack kit including 12-channel BMS "Lite" Board

[gensem]

8ah zipps are awesome!
looking forward to get one lite bms from you.

 

[Nanoha]

Can I assume that 2 of these in series will do 20s with the 8ah zippys?

 

[o00scorpion00o]

With the Zephyr charge controller, there was an auto-shutoff function that monitored the charge current, and shut off the charge current, and the main LED, when the current dropped below a preset level. For the Lite variants, what will happen is that the LED will stay on, and be solid green at the end of the charge process. If the individual red shunt LEDs are off, and the LED is green, the charge process is complete. Unplugging the charger/supply, at that point, resets the circuit and the LED stays off until the next time the charger supply is connected. During the CC charge phase, the main LED will be orange. If there is an imbalance, the shunts for the high cells will come on, along with their respective LEDs. Once the main LED is green and all the shunt LEDs are off, the pack is fully charged and balanced.

-- Gary

Hi Gary,

With this bms, will the bms stop drawing current or do you (have to) disconnect the charger?

I'M assuming anyway that the charger will switch itself off when it senses the current has dropped below a certain point, correct?

Will you also sell chargers, or recomend chargers for this bms?

Please do a 16S 2P version!

Mark

 

[Spacey]

16 Cell Lipo user in need.............

 

[Fishmasterdan]

I need some of these. Put me on the waiting list!!

 

[GGoodrum]

I put in the PCB order yesterday, for the 12s2p-10Ah version yesterday. I'll get them back on Monday, and then I'll build up the first one, to test.



In the meantime, I just received the first of the 16-24 channel CellLog-based BMS lite boards. I'll be building up one of these tomorrow. I'll update the other thread with some pics, when I get them.

-- Gary

 

[theRealFury]

Hi Gary,

With this bms, will the bms stop drawing current or do you (have to) disconnect the charger?

I'M assuming anyway that the charger will switch itself off when it senses the current has dropped below a certain point, correct?

Will you also sell chargers, or recomend chargers for this bms?

Please do a 16S 2P version!

Mark

Hey Mark,

Im sure Gary will correct me if im wrong but i think the BMS is built to be used for bulk charging Lipo with a 'dumb' charger such as a PSU / meanwell. Therefore the BMS will not disconnect the battery from the charger. Basically you would have to modify the charger to have a CV of ~4.10v per cell (so around 49.5v for 12S lipo) so that once the pack gets to that voltage the charger will not be able to provide much current, then the shunts on any of the cells that are over 4.10v will open to stop that cell from charging and pass the current onto the other cells. If all cells are above the 4.10v shunt setting then all shunts will be active and burn off any excess current up to a point. Not sure how much current the shunts can handle though, i'd probably guess in the region of 200-300ma?

These boards look really tasty and would love to get one myself but the way i have to mount my lipo will mean there is not enough room to fit this board, my lipo is in a square 2x2 block lengthways. Guess you cant cater for everyone Gary Keep up the good work though

 

[auraslip]

Love it. Can't wait to start building.

On a practical note - it's gonna be a PITA to ship assembled boards with both ends sticking up like that. Probably no easy way to fix it, and it'll only cost a few dollars more to box it up safely, but it adds up ya know?

I want to echo the sentiment, "What took you so long!" This is THE ebike product that will make building a bike easy and affordable. Now I can build all my friends bikes for what? $200 for 4x lipo packs, $25 for a KP charger, and ~$50 for your board? Cheaper than a ping, much more expandable, arguably more reliable, and almost as easy. I LOVE IT.

 

[fabiograssi]

Love it. Can't wait to start building.
...
I want to echo the sentiment, "What took you so long!" This is THE ebike product that will make building a bike easy and affordable. Now I can build all my friends bikes for what? $200 for 4x lipo packs, $25 for a KP charger, and ~$50 for your board? Cheaper than a ping, much more expandable, arguably more reliable, and almost as easy. I LOVE IT.

Thumbs Up... fabiograssi "like it!"

 

[gensem]

I think this is going to be a game changer for most builds

 

[GGoodrum]

On a practical note - it's gonna be a PITA to ship assembled boards with both ends sticking up like that. Probably no easy way to fix it, and it'll only cost a few dollars more to box it up safely, but it adds up ya know?

The end plates attach to the ends of the pack, once it is assembled, and then the whole packs gets shrink-wrapped. The plates aren't pre-attached to the main board at all.

-- Gary

 

[auraslip]

The end plates attach to the ends of the pack, once it is assembled, and then the whole packs gets shrink-wrapped. The plates aren't pre-attached to the main board at all.

Ok, very cool. I was about having to ship assembled boards, and having that plates snap in transit.

 

[o00scorpion00o]

Im sure Gary will correct me if im wrong but i think the BMS is built to be used for bulk charging Lipo with a 'dumb' charger such as a PSU / meanwell. Therefore the BMS will not disconnect the battery from the charger. Basically you would have to modify the charger to have a CV of ~4.10v per cell (so around 49.5v for 12S lipo) so that once the pack gets to that voltage the charger will not be able to provide much current, then the shunts on any of the cells that are over 4.10v will open to stop that cell from charging and pass the current onto the other cells. If all cells are above the 4.10v shunt setting then all shunts will be active and burn off any excess current up to a point. Not sure how much current the shunts can handle though, i'd probably guess in the region of 200-300ma?

These boards look really tasty and would love to get one myself but the way i have to mount my lipo will mean there is not enough room to fit this board, my lipo is in a square 2x2 block lengthways. Guess you cant cater for everyone Gary Keep up the good work though

Thanks Fury!

 

[GGoodrum]

Im sure Gary will correct me if im wrong but i think the BMS is built to be used for bulk charging Lipo with a 'dumb' charger such as a PSU / meanwell. Therefore the BMS will not disconnect the battery from the charger. Basically you would have to modify the charger to have a CV of ~4.10v per cell (so around 49.5v for 12S lipo) so that once the pack gets to that voltage the charger will not be able to provide much current, then the shunts on any of the cells that are over 4.10v will open to stop that cell from charging and pass the current onto the other cells. If all cells are above the 4.10v shunt setting then all shunts will be active and burn off any excess current up to a point. Not sure how much current the shunts can handle though, i'd probably guess in the region of 200-300ma?

This is almost right, but the shunts are set for about 4.15V. We made a couple of changes in how the charge control is done, in this newest version, The HVC is set a bit higher than that. The charger/supply voltage can be set at around the same point as the sum of the HVC voltages, or even a bit higher. It isn't critical now, and is also dependent on what the max current the charger/supply is capable of putting out. Basically what will happen now is that the first time a cell hits HVC, it will cut the charge current off and the shunts will then pull all the cells down to 4.14V. Once the HVC is hit, the main LED will turn green. Once all the red shunt LEDs go out, the cells are all balanced, and the charge cycle is complete. If a pack has some cells that are really out-of-whack, you might have a case where the HVC is tripped, but not all of the shunt LEDs are on yet. In those cases, the cycle might have to be repeated. You'll have a pretty good general indication of the overall health of the pack, just by watching the red LEDs. In most cases, the red LEDs will all come on pretty close to the same time and then the main LED will go green. Watching when the red LEDs then go off will also be a general indication of the relative balance/health of the cells.

These boards look really tasty and would love to get one myself but the way i have to mount my lipo will mean there is not enough room to fit this board, my lipo is in a square 2x2 block lengthways. Guess you cant cater for everyone Gary Keep up the good work though

We are also doing another variant that might work better for you. In this one the layout is similar to the basic LVC/HVC/parallel adapter boards we've done in the past. This adds the balancing function, which makes it a complete BMS solution. The charge control section is done in a way where it can be left attached to the cell circuits, or it can be detached, and put into the small Hammond extruded aluminum box. For that option, custom end plates are provided.



So, what we plan to have are three variants, initially at least, for the basic "lite" BMS design, the standalone 12s2p "kit" package, the 4x6s standalone variant shown above, and special version that uses either two or three CellLog units, along with the cell shunt circuits. All three have a PCB-based relay for completely isolated LVC functionality. There's actually two indepenent sets of double-throw relay contacts (DPDT...), so a variety of LVC control options are available. For instance, one set of normally closed (NC) contacts can be used in series with the throttle signal line. Normally, the throttle stays connected to the controller, but when the LVC trips, it breaks the connection. This is a lot simpler than pulling down the throttle lne to ground, which requires a current limiting resistor. You could also use a set of connections to drive a buzzer, or maybe a contactor. Lots of options this way.

I should be receiving the first of the 12s2p boards today. I just put in an order this morning for the CellLog and 4x6 variants. I'll receive these later this week.

-- Gary

 

[modern_messiah]

I got into the EV game because the motors interested me greatly...I'm on my way to build (or modifying) my own motor and only remembered yesterday that I will need some way to power the thing. Queue me wondering over to the battery thread for the first time and becoming completely overwhelmed in about 5minutes. The battery and power side of EV’s is going to take me longer than the motor side to understand, and that makes me sad :lol:.

Long story short I’m so happy I found this thread because this BMS “pack” is going to save me so much time and trouble. I can’t wait to see the results (and of course price).

Question – the thread title is “12s2p LiPo pack kit including 12-channel BMS "Lite" Board”. This to me implies it’s the full caboodle – batteries plus BMS. Is this correct? No skin off my back either way, I’m just trying to clarify because as I’ve said I’m a little lost at the moment!

I’m also keen to know what charger you would recommend for use with this.

Patience is a virtue…apparently.

 

[stingray17]

Gary, really excited to see this. Getting started out with LiPo is complicated. The complexity involved in recharging & balancing medium/large packs was enough to discourage me from going LiPo for my first ebike. LiFePO4 weight and C rate might not be the best, but it's easy to recharge a Ping pack without isolating cells, connecting and disconnecting multiple cables, etc.

Nonetheless I really want to try LiPo. So I'm biting the bullet and ordering four of the Zippy 6s-8000 packs. Before too long I will definitely need a 12s2p BMS, so as soon as your kit/PCB is available in a size for the slightly larger 8000mAh packs... sign me up!!

 

[gensem]

I got into the EV game because the motors interested me greatly...I'm on my way to build (or modifying) my own motor and only remembered yesterday that I will need some way to power the thing. Queue me wondering over to the battery thread for the first time and becoming completely overwhelmed in about 5minutes. The battery and power side of EV’s is going to take me longer than the motor side to understand, and that makes me sad :lol:.

Long story short I’m so happy I found this thread because this BMS “pack” is going to save me so much time and trouble. I can’t wait to see the results (and of course price).

Question – the thread title is “12s2p LiPo pack kit including 12-channel BMS "Lite" Board”. This to me implies it’s the full caboodle – batteries plus BMS. Is this correct? No skin off my back either way, I’m just trying to clarify because as I’ve said I’m a little lost at the moment!

I’m also keen to know what charger you would recommend for use with this.

Patience is a virtue…apparently.

batteries are not included.

patience is mandatory not a virtue.

 

[GGoodrum]

I got into the EV game because the motors interested me greatly...I'm on my way to build (or modifying) my own motor and only remembered yesterday that I will need some way to power the thing. Queue me wondering over to the battery thread for the first time and becoming completely overwhelmed in about 5minutes. The battery and power side of EV’s is going to take me longer than the motor side to understand, and that makes me sad :lol:.

Long story short I’m so happy I found this thread because this BMS “pack” is going to save me so much time and trouble. I can’t wait to see the results (and of course price).

Question – the thread title is “12s2p LiPo pack kit including 12-channel BMS "Lite" Board”. This to me implies it’s the full caboodle – batteries plus BMS. Is this correct? No skin off my back either way, I’m just trying to clarify because as I’ve said I’m a little lost at the moment!

I’m also keen to know what charger you would recommend for use with this.

Patience is a virtue…apparently.

Not quite the "full caboodle", as it does not include the actual four 6s-5000 LIPo packs, but it does include everything else needed to make a sealed 12s2p 45v/10Ah battery pack, with full BMS protection. You basically just plug in the 6s-5000 packs to the PCB, and shrink wrap the whole assembly.

For charging, all you need is a surplus 48V current limited power supply. There's usually plenty of these available on eBay. There's also lots of different 48V SLA and/or LiFePo4 chargers that can be used. All the smarts are in the BMS, so there doesn't need to be a lot of "smarts" in the charger/supply. After we get these going, I may look to source a good candidate charger/supply.

I will be posting pics in the next day, or so. I built up the first board today, and will test it in the morning. After that I'll put the pack together and take some pics.

-- Gary

 

[GGoodrum]

Gary, really excited to see this. Getting started out with LiPo is complicated. The complexity involved in recharging & balancing medium/large packs was enough to discourage me from going LiPo for my first ebike. LiFePO4 weight and C rate might not be the best, but it's easy to recharge a Ping pack without isolating cells, connecting and disconnecting multiple cables, etc.

Nonetheless I really want to try LiPo. So I'm biting the bullet and ordering four of the Zippy 6s-8000 packs. Before too long I will definitely need a 12s2p BMS, so as soon as your kit/PCB is available in a size for the slightly larger 8000mAh packs... sign me up!!

As soon as I test the first article, and verify everything is working properly, I'll submit the boards for the 12s2p version that uses the 8Ah packs.

-- Gary

 

[VoKuS]

Any pix for us yet?

 

[GGoodrum]

Soon. I had a couple of errors on the first test boards, and its caused a bit of a delay. Testing continues, however.

-- Gary

 

[Crash Machine]

Ok I am in too. I have shyed away from Lipo because having a catastrophic failure on one of my long road trips is not an option. This setup would also allow me to carry just the meanwell.

 

[GGoodrum]

As I said, testing continues. A couple of issues, beyond the wiring errors, have arisen that I'm dealing with right now. The first is that the shunts are coming on a little low, like around 4.09-4.10V, instead of the predicted 4.14-4.15V. I'm tweaking the values a bit to raise this up. The other issue is that with the shunt current at around 180mA, there's a bit more heat than I was expecting, so for this embedded board I either need to reduce the shunt current, or add some thermal protection for the cells.

What I'm doing now is moving a new variant to the front burner, which still supports the notion of a complete kit of parts to build a 12s2p pack, but this version will also support higher capacity setups, like 12s4p, packs made with the 8Ah Zippys and configurations with 6s packs oriented vertically. What I'm doing is moving the shunt circuits and the charge control section to a small 1" x 3" x 4.7" box. This way, the higher current shunts are not a problem. There is a single 18-pin VAL-U-LOK connector that sticks out of one end of the box. This marries up with a single 18-pin plug coming from the pack that has the paralleled balance plug connections, along with the charger + and - main charging leads. The only other wires coming out of the box are the two leads going to the supply/charger, and then two wires for the LVC function.

There will be two parallel adapters provided that will allow up to a 4p configurations, but this could be expanded, really, just by using additional parallel adapters. These two adapters are connected to the single 18-pin plug using AWG 18 wires. These adapters are "buried" with the packs, and just the single plug brought out to the outside. Here's what this harness/adapter setup will look like:

View attachment 2

This one doesn't yet have the two 12-gauge wires for the main charge +/- connections, nor does it show the other end of these which will have the 4mm or 5.5mm bullet connector parallel adapters. Both 2p and 4p versions will be available.

Here's what the current layout looks like, with the two 6s4p parallel adapters, the two boards that go in the box, the two custom end plates for the box and the 4mm bullet parallel adapters:

View attachment 1

Here's a basic mockup of what a typical 12s2p setup might look like:



This pack is setup right now to be used with the Hyperion charge harness, so I needed a gender reverse adapter, but the harmess shown above would plug right in. The charger/Supply simple plugs into the Deans plug. Operation is the same, as wih all these new variants. You plug in the supply/charger and the main LED comes on orange. It'll stay this way until pack is nearly full. Once the voltage gets to the point that the highest cell hits the HVC point, the main LED will turn green, and the charge current is cut. The shunts should all be on, at this point, and the red LEDs will all be on.What will happen is that the shunts will pull all the cells down to the same point, and then all the LEDs will go out. You just wait for the main LED to be green and for all the red LEDs to go out. At that point, all the cells will be fully charged and balanced, and the charger/supply can be unplugged. This will cause the main LED to go out.

There is a small relay that is used for the LVC function. Both normally open and normally closed contacts are provided, which can be used in a variety of ways. For instance, the throttle signal wire alone can be routed through the normally closed contacts so that when a cell's LVC ciruit trips, the throttle signal will be cut. The normally open contacts can be used to simply ground the throttle signal, like we do with the opto-based circuits now. Other options include using the contacts to drive a 12V buzzer/alarm, or to maybe trip a larger contactor/relay. The relay has two sets of independent contacts (i.e. -- DPDT...), so a combination of functions can be supported.

Anyway, I still need to play with the HVC trip points to try and see for a healthy pack, how far above the desired charge to point we need to go to insure that the low cell is at least up to the point its shunt/LED just comes on. This approach has the advantage that a higher charge rate is used at the end, so the cells get full faster. From what I've seen, ith then takes about 20-30 minutes to get the cells to balance. Of course, if the cells are reasonably balanced already, which will be eveident by how close together the shunt LEDs come on, you can stop as soon as the charge current cuts off, and go ride.

It shouldn't be too much longer.

-- Gary

 

[modern_messiah]

Awesome work. So if my understanding is correct the original concept was to have everything in one package, but some heating issues amongst other things have forced you to move the bulk of the circuitry to an external box? Would have been nice to have it in one simple package but whatever needs to be done for the best product makes perfect sense to me!

*cough* can't wait for a price *cough* :wink:

In all seriousness though what I plan to use these for is not even under development yet. So I'm happy to sit and watch. Exciting stuff.

Cheers.

 

[GGoodrum]

Awesome work. So if my understanding is correct the original concept was to have everything in one package, but some heating issues amongst other things have forced you to move the bulk of the circuitry to an external box? Would have been nice to have it in one simple package but whatever needs to be done for the best product makes perfect sense to me!

*cough* can't wait for a price *cough* :wink:

In all seriousness though what I plan to use these for is not even under development yet. So I'm happy to sit and watch. Exciting stuff.

Cheers.

Well, the heating issue is just postponing the single package version, but not cancelling it altogether. I've got some ideas to deal with the heat issue, and I'll get back to this variant soon.

This new "boxed" version will support a wider variety of pack configurations, not just the horizontally-oriented, end-to-end version shown above. Here's the latest PCB:



I've added the adapter board on the right, which can eliminate the need for the parallel adapters/harness. It brings out the 18-pin connector to the end of the pack. The balance plug connectors are oriented in the middle of the pack. I included support for the 8Ah Zippys as well, which are a bit longer. I like having this board-mounted connector because it makes it compatible with my Hyperion 12s charge harness. I like to use the Hyperion to cycle the cells, during tests, and for occasional checking on the general health of the packs. Anyway, it is easier for me to make connection cables with the free-hanging plugs than it is to make the harnesses, like the one shown above.

I have no idea what the costs are just yet, other than the PCB. I'm not sure how much labor will be involved as well , just yet. All of this will get sorted soon. I'm ordering boards today, which I will get back early next week. I already have all the parts. As soon as I build up the first one, and verify its operation, fit within the box, etc., I'll start making them available.

-- Gary