Where to buy BMS or LVC???

[Jay64]

I have been looking for a BMS or LVC for some of my lithium packs. So far, I have only found one place that sells them. The problem is that each cell in series needs it's own bms. The one pack I am planning is going to be 38 cells. The BMS modules seemed really cheap at GBP 12.76 ea., but when you need 38, that starts adding up. That's about $743 for the BMS on the pack. I don't know, I havn't found anyone else selling any, so I don't know if that is a good price or not. But I also want to try to get one for my 16 cell lifebatt pack, which would be another $312. I only paid $800 for the pack, LVC, and charger. Does anyone on here know where I can get some BMS modules or LVC modules, and what the prices are?

 

[fechter]

Get them here:
http://www.tppacks.com/products.asp?cat=26

I see they're currently listed as out of stock, so bug Gary about making some more.
This would be perfect for a 16s pack, but I don't see any reason that 38s would be a problem with a separate 12v control circuit power supply.

Our next version board should be fine for up to 40s without mod.

Check the BMS thread for the latest updates.

 

[thomas]

i know steve and co from jozzbikes already made a bms specific for bigger motorcycle packs I think they are planning to sell them at some point.

 

[mn_aerorider1]

You could try this Australian site for pre-built BMS/LVC boards up to 16 cell:

http://www.evpower.com.au/-DIY-Small-LiFePO4-Battery-packs-.html

Note that these prices are in Australian dollars - check the current exchange rate - a month ago it was 0.6 of a U.S dollar.

I got quick turnaround on a 4 cell LiFEPO4 BMS - for $25 U.S. including shipping which took about 1 week.

Brian

 

[Jay64]

yeah, I have been talking to Steve from jozzbikes on pm since I posted this. They are coming out with some, but they are not quite ready for market. Sounds like it will be real soon though. I hope to get some of those for my race E motorcycle. However, I am also looking for some in the mean time for my lifebatt and a123 cells. Maybe I'll try that company in Australia. I'll at least check it out. Thanks for the info.

 

[Jay64]

I just checked out the Australian site. Great price from what I have been seeing so far. Unfortunately I think this is the reason why:

15A continuous / 30A burst discharge rate

I think my intended use is a bit out of this range.

 

[pgt400]

Jay, I'm going to use the one on this site, (2) set up for 12 cells each (36v). And use (2) 36 volt 5 amp on board chargers. They did a nice job on the design.

 

[fechter]

Those look about the same as a Ping BMS.

I think with a little reverse engineering, you could bypass the active cutoff and make a throttle or ebrake interface to get around the discharge current limit. Charging current would still need to be limited.

Seems to me that Ping told me one of his 16 cell BMS circuits sells for around $50 plus shipping.

 

[Jay64]

Jay, I'm going to use the one on this site, (2) set up for 12 cells each (36v). And use (2) 36 volt 5 amp on board chargers. They did a nice job on the design.

From what site? The one from Australia?

Fechter, cool, I'll check in with them.

 

[pgt400]

No, the Fechters BMS. For my 24S4P pack I will split them into (2) 36v 40ah packs (12S4P). Each will have a 12 channel BMS and a 36 volt 6 amp charger.

 

[Jay64]

are you building it yourself?

 

[Jay64]

On that Australian site it states:
$94
16 Cell BMS with wiring loom
48V (51.2V) nominal
Complete cell level protection from overcharge, over-discharge and over current
15A continuous / 30A burst discharge rate

Is that 15a total for the whole 16 cell pack, or would that be 15a per cell?


Anyone on here built one of the BMS boards from the work of Gary and Fechter? Interested in building some more? I'll pay you.

 

[Jay64]

Ah, I guess I neglected to go all the way to the bottom of the page. Once I got to the last BMS, I stopped scrolling down.

Can the BMS units be used for higher peak current draw than 30A.


A. Yes. The terminals of the battery can be tapped directly to draw any current required within the limits of the cells. If required the BMS can be used to control an external relay which will cut power if one or more cells go outside the safe voltage range. In this way the internal current limit is bypassed but voltage limits are still applied.

 

[pgt400]

are you building it yourself?

Yes, as I think its only in kit form now? Seems like the board is always out if stock too. Should only take a couple of hours.

 

[GGoodrum]

Seems like the board is always out if stock too...

The boards will be available again by Friday:

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=5416&st=0&sk=t&sd=a&start=900#p124349

 

[steveo]

Get them here:
http://www.tppacks.com/products.asp?cat=26

I see they're currently listed as out of stock, so bug Gary about making some more.
This would be perfect for a 16s pack, but I don't see any reason that 38s would be a problem with a separate 12v control circuit power supply.

Our next version board should be fine for up to 40s without mod.

Check the BMS thread for the latest updates.

Did you say 40s bms board!!!!!

please tell.... release date?? could i still use the 24cell and maybe buy a second one?

-steveo

 

[GGoodrum]

Did you say 40s bms board!!!!!

please tell.... release date?? could i still use the 24cell and maybe buy a second one?

-steveo

No, what he meant is that you can "tearoff" 16 channels from a second board, and wire four jumpers so that it can be used with the charger control logic on the 1st board.

-- Gary