Newbie BMS basics and tppacks BMS boards

[NeilP]

Hello all
First ...who i am...Newbie with very basic electronics ability. I could if pushed do some of these 'beef up the controller' mods I have seen, and did ant one time make two or three PCB's...many years ago. If I was to build a circuit and it did not work I would be screwed...I could follow a schematic and build it, but theory and fault finding were never a strong point.

Totally new to electric vehicles and am considering building an electric bike. Not a super fast racer...25 -30 mph would be just great.

Two questions here really, one about BMS units in general and the second about the tppacks unit. have read a thread on here entitled "BMS units are BS", so amy not after info on if I SHOULD use one or not.

So....PIng battery packs.
http://www.pingbattery.com/servlet/the-21/60V-30AH-V2.5-LiFePO4/Detail
..from what I have read I thought they contained some sort of BMS system....but they look rather compact when compared to the separate battery pack and BMS units I have seen elsewhere, so do these packs have a BMS function, and you just plug in a charger (bought with the pack ) and off you go...or is the BMS section perphaps built into the supplied charger? any one any experience?



Secondly
I downloaded a book the other day (Greg Daveys pdf on electric bike building) and saw mention of tppacks BMS boards. I see a post or two from Gary (GGoodrum) and from what I read, he seem to be involved in tppacks, so may be he can clarify things for me

I looked at their site and cant see any mention of just BMS boards. I saw the 8/12/16/18-Channel CellLog-Based Balancer Unit which I am assuming would do a same or similar job...but the page
http://www.tppacks.com/proddetail.asp?prod=EBKE-x-CMS-BAL
does say Cell log units are not supplied...and cant see any mention or a link to the seperate Cell units and how many are needed...is it one per cell? and where to get them/


Thanks,for your patience with these probably v.basic questions,

Neil

 

[dogman dan]

The pingbatteries come with a signalab bms that is usually adequate. Failures do happen, and can be an expensive bummer, but Ping has pretty good CS, and helps you with the repairs on a warantee defect. Upgrading to the 5 amp charger is good, and you merely plug it in to charge. However, monitoring the battery performance with a wattmeter like a Cycleanalyst is highly recomended.

Also more stringent monitoring of the first few cycles is a very good idea, checking voltage of each paralell string of cells as they charge, and making sure that you don't ride too far the first few cycles. The new pings typically need a bit of extra time on the charger to balance. After that, they typically stay balanced fairly well if discharged no more than 80%

The typical pack is 48v 15 ah, which on many hubmotor kits reaches 25-30 mph. The kits have 20-25 amp controllers, and the battery can put out 30 amps continuous. It's recomended though, to keep discharges down closer to 20 amps continuous on that size pack. Normal riding on a 20 amp controller does that.

 

[NeilP]

I was going thinking of there 60 volt 20 Ah battery, with a 72 volt 60 amp Crystalyte controller and Cycle analyst and 5304 motor? any comments on that setup?

 

[dogman dan]

Too much motor and controller for a 20 ah ping. The pings work best with less power hungry motors than the 5304, paired with controllers around 20-25 amps.

Have you looked into lipo batteries? For a hot rod bike like a 5304 with a 60 amp 72v controller they are just the ticket.

 

[AndyH]

<snip>
Secondly
I downloaded a book the other day (Greg Daveys pdf on electric bike building) and saw mention of tppacks BMS boards. I see a post or two from Gary (GGoodrum) and from what I read, he seem to be involved in tppacks, so may be he can clarify things for me

I looked at their site and cant see any mention of just BMS boards. I saw the 8/12/16/18-Channel CellLog-Based Balancer Unit which I am assuming would do a same or similar job...but the page
http://www.tppacks.com/proddetail.asp?prod=EBKE-x-CMS-BAL
does say Cell log units are not supplied...and cant see any mention or a link to the seperate Cell units and how many are needed...is it one per cell? and where to get them/


Thanks,for your patience with these probably v.basic questions,

Neil

Hi Neil,

Here's a post that gives a 'functional overview' of the V2.6 Goodrum/Fechter/E-S BMS that Gary Goodrum of TPPacks once sold:
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=13380&#p200076

I built these for customers that didn't want to build their own - I have circuit boards in stock and still build and support them:
http://www.rechargeablelithiumpower.com/oscommerce2/catalog/index.php I don't recall if Greg Davey built his own or if I built one for him, but I provided the battery pack for his bike when he was writing his e-book.

The 6S and 12S CellLog based balancers use one CellLog for every six cells - so two CellLog devices for a 12 channel balancer. In addition to a CellLog-based balancer, one would need a charge controller (either one of Gary's stand alone units, or an add-on board for a MeanWell power supply), and one would also need cell-level low voltage protection for the pack. Geoff57 is or will soon be selling surface-mount versions of Gary and Richard's LVC/combiner boards:
http://www.endless-sphere.com/forums/viewtopic.php?f=31&t=21695
Or you can get the boards from Gary: http://www.tppacks.com/proddetail.asp?prod=EBKE-8s-LVC

Please note that of you desire a single-board solution, the V2.6 BMS provides cell-level LVC, cell level high voltage (HVC) and balancing, and charge control.

The E-S/Goodrum/Fechter BMS designs are different from the Chinese imports in one significant way - they do not limit or restrict power to the motor controller in any way. This removes a common failure mode of the less expensive BMS units, but requires that one either chooses a battery pack more than capable of powering the motor, or uses a current limiting device like a CycleAnalyst to keep a lower-performing battery from being discharged at too high a rate.

Welcome to E-S - you've found a great place to learn about e-vehicles!

Andy

edit in blue - I'm working with 6S and 12S CMS boards at the moment so reported what I know to be fact. Sorry that the incomplete info omits the 8S variants.

 

[MitchJi]

Hi,

The CellLog based balancers use one CellLog for every six cells - so two CellLog devices for a 12 channel balancer.

The Cell-log units are 8s (and I think Andy meant either 8 cells or 8 channels of parallel Cells) per Cell-log:
http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=9282

Accurate cell voltage monitor for up to 8 cell battery packs. Voltage alarm configurable with over voltage and low voltage settings.

 

[999zip999]

Neilp, The main problem is just what you asked the ping battery on a 5304 20ah. It would be to hard on it you some head room so your not always pushing the battery at it's limit. Yes you will. A cycle analst is the best so you can adjust the controller for 22amps and see how much life is left in the pack. Going faster then 30mph is hard on a bike just for wind resitance.

 

[GGoodrum]

Hi Neil, and welcome.

Andy is correct. The CellLog-based balancers, the separate LVC boards and the two Charge Controller variants all together are the functional equivalent of a "full" BMS board. The reason for having them separate is because these are mainly designed to be used with LiPo-based setups, which typically use 6 or 8-cell 5Ah pre-wired RC-type packs as building blocks for larger ebike packs. The cells in these packs have very high "C"-ratings, which among other things, means the packs stay very well balanced, if they aren't drain down near the end of their capacity. LiPo-based packs can also be quite compact, and light. Because of both of these traits, it isn't always desirable to use a full BMS board, with it's heat-generating balancing circuits, with these setups. Of the three major BMS functions (I.e. -- low voltage protection, high voltage protection and cell balancing...), only the over discharge/low voltage protection function really needs to be resident within the pack. Balancing can be done periodically (once every 5-10 cycles...), so the balancing circuits can be part of an external unit. With the CellLogs integrated in with the balancers, they can provide the high voltage protection function, in conjunction with the Charge Controller, which is there basically to throttle back the charge current if a cell tries to go too high.

One slight change I made today is to replace the LVC/parallel adapter boards with a version that adds the HVC function for each channel as well. This allows the pack to have the HVC function resident so that bulk charging can be done without the CellLog/balancer connected, just the Charge Controller.

Now that I'm pretty close to finishing up the BMS "pieces", I will get back to finishing up the full BMS update. It is long overdue, but I think in the end, it will be a better, and more reliable unit. In the meantime, Andy will continue to offer the last "production" version, which was v2.6c.

-- Gary

 

[jondoh]

You know, 60v and a 60amp controller is probably going to go 40 mph in a bike-- maybe faster. Didn't you say you would be happy with 25 ~30 mph? Are you planning to go those speeds up the side of a mountain? Usually 48v is good for 25~30 mph on a bicycle on a flat.

Have you considered the weight for a 60v 20ah battery? Even with Lifepo4, it's going to be a pretty heavy battery pack. More suitable for an electric motorcycle than bicycle. If you have to have 60v20ah on a bicycle, you may not have much of a choice except Lipo. You can achieve 60v20ah with 8 of these:
http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10870

8 of them might even fit in a standard rack bag. Easy to mount on a rack.

Lipos have the advantage of balancing taps and sophisticated chargers. With the balance taps, you can employ a cell log directly. Just plug it in and you're done! Just don't leave the cell log plugged in when the battery is not in use. If you don't want to use a cell log, there are other cheaper units that have both low voltage and high voltage alarms. It wouldn't be a bad idea to have a cell log to check voltage of individual cells under load.

Lipos, "vent with flame," so be careful.

 

[GGoodrum]

Hi,

The CellLog based balancers use one CellLog for every six cells - so two CellLog devices for a 12 channel balancer.

The Cell-log units are 8s (and I think Andy meant either 8 cells or 8 channels of parallel Cells) per Cell-log:
http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=9282

Accurate cell voltage monitor for up to 8 cell battery packs. Voltage alarm configurable with over voltage and low voltage settings.

No, Andy was correct. We use the CellLogs with both 6s and 8s-based packs. The 8-cell balancer uses one CellLog, with all eight channels active. For the 12-channel version, two CellLogs are used, but only 6 channels are used in each. The 16-channels version also uses two CellLogs, but with all 8 channels on both. Finally, the 18-channel version has three CellLogs, with 6 channels active on each.

-- Gary

 

[AndyH]

Thanks for the correction Gary. Sorry to offer only a partial answer, Mitch.

I've only worked with the 6S and 12S CMS variants so far, so reported only what I know for sure. I've edited my post with blue to clarify.

Andy

 

[NeilP]

HI guys,
Sorry for nto getting back to this thread...I forgot to check the Notify me when a Reply is Posted box,

Well a t lot to take in, in your posts.

Yes I do realise that the motor controller combo is a lot for the Ping 20Ah battery...so yes, a CA, was also included in the system. Lyen has all that under control...I just need to put the order in now.

The reason behind going for the big motor and heavy weight controller, and then limiting it with the CA, was simply because I cant afford the big money to buy a 'heavy weight' battery pack yet.
So what I was hoping was to buy the motor and controller, and run it 'throttled back' with the CA until one day I can get the cash together for the bigger pack, and I will then not have to shell out again for another motor and controller.

Yes I will be having to push around the weight of the bigger motor for the moment, but hope I can live with that.

I'll go through the thread again and try and learn and digest what you have told me.

I have had a brief converstaion with Paul (cell man) about a A123 pack from him, but I think that that will be over my budger for the moment. Also been told of other motor choices to consider Maxi-Might and a new hall effect sensor free Crystalyte series...I want to get on and build, but also do not wnat to just jump in with an order and feel I made a mistake when I get it together