Daly BMS, read on here people had problems.

[Greg Burrows]

Have 7 on my shelf, made 3 batteries up with them with no problems, but did buy 10 over 2 years ago from the manufacturer, as (beieve at the time another china company was counterfiting Daly BMS's and these did not work) ones I have are 13S 48v 30A with common, charge discharge/port, I prefer common port as enables, single battery charge discharge with one plug.
What is the situation now with DALY BMS's reccomend or not?

 

[Nealh]

I have had two 12s 20a separate port models and both failed replace with a same port BMS without balance and it is working much better.
Cells HG2 were unbalanced with the Daly's yet with new BMS they stay in check dispite no balance feature.

I do have a same port Daly on a moli p42a pack so far it is still working .

Users on ES also seeing issues with Daly failures.

 

[Greg Burrows]

Thanks Neath, for your input, and Knowledge I have found over the years that if you find a reliable chinese product, such as controller, BMS etc.
Other chinese companys sometimes counterfiet, hence I bought those BMS's from Daly, trouble was you had to buy 10 you could not buy one.

 

[lenny]

Thanks Neath, for your input, and Knowledge I have found over the years that if you find a reliable chinese product, such as controller, BMS etc.
Other chinese companys sometimes counterfiet, hence I bought those BMS's from Daly, trouble was you had to buy 10 you could not buy one.

How can counterfeit Daly BMSs be identified?

 

[Greg Burrows]

Been so annoyed in the past building a battery, and the BMS you bought is the fault, do wish someone would invent a battery that was as safe as Nicad, wlth the same output as lithium ion, BMS are always something else to go wrong.

 

[lenny]

Buying 10 BMSs at a time from Daly is good for Daly, bad for us if their BMSs are cr*p.

 

[Greg Burrows]

Lenny I am not sure, how to identify counterfeit Daly BMS, usually counterfeit products are the cheapest on ebay and elsewhere they work when you get them, but fail soon after, leaving you stranded on your bike, counterfeit Ebike controllers have been out for years, a controller i use has just one typo mistake, between genuine an counterfeit manufacturer.

 

[lenny]

Do they fail because of bad heat management for bleed resistors? Is there a way to stress test a BMS before use in a battery? Or must we wait for a fire?

 

[Greg Burrows]

Lenny I have not had a problem with those Daly 13s 48v 30A BMS.
As far as I am concerned they are a good product, I have built three batteries with them and had no problems, they cost £8.75 each from Daly the manufacturer, am just building another battery, as one battery is getting a bit tired, so will see if next Daly BMS is OK, may just have a good batch.

 

[lenny]

Shrink wrapping is heat insulating and the BMS is usually wrapped with the cells. Do counterfeit Daly BMSs fail more often in smaller higher drain battery packs because of higher temperatures?

 

[Greg Burrows]

Lenny BMS when they stop working you have no negative, if stuck in the middle of nowhere and disabled like me, you overide the BMS, done that before today with a bit of wire.
They are a safety device, against idiots who plug in the wrong charging voltage, their main point on an ebike battery is balancing cells in a battery pack, so they last longer.
There are plenty of lithium ion Battery packs built without a BMS, I have boxes of 32v 9s 2P that were built for leaf blowers, that I got at a good price, samsung cells.

 

[Greg Burrows]

Never overide a BMS though if it has cut power, because the battery is hot or any smell is coming from battery, use common sence.

 

[Greg Burrows]

Just to add all those boxes of battery packs I have without a BMS all are Bosch 32v 9S 2P all are wired with an over temperature sensor, for safety.
Do not build a lithium battery pack for your ebike without a BMS.

 

[lenny]

over temperature sensor

Do most BMSs have those or facility for those to be added?

 

[Greg Burrows]

Neath may be able to explain more on the intricities of how BMS's function,
I have had BMS's with temperature sensors and those without, some sence the temperature through electrical resistance or whatever.

 

[WheezyRider]

Never run a pack with a bypassed BMS if you get no output. If a BMS is "not working" you need to know why it is not running. It might well not be running because there is a fault with one or more of the cell banks and it is doing its job by not letting power out!

The danger is if one or more of the cell banks is faulty, power from other good cells will be dumped in the failing cells, causing them to overheat.

BMS boards sometimes fail and need replacing, but until you have fully diagnosed the problem and checked the cell banks you don't know if it is a BMS fault or a cell bank fault.

 

[Nealh]

Unless one is an expert in microtechnology components then knowing what is wrong isn't worth wasting time on and simply replace is best.
Before my Daly failures previous issues have simply been balance or should I say cell bleed out issues where one or may two cell groups are drained sometimes beyond recovery. Typically this is a resistor issue , one that has failed to close and simply allows voltage to drain away.

With the Daly's I had some imbalance issues but the main issue was next to no output voltage, likely a mosfet failing . We see little or no voltage on the out put yet the the day before the bike rides fine.

I opted for a small footprint Daly to fit inside a waterbottle and two failed , first one lasted about 12 months and a second less then 6 months. Both the same result with next to no output .

 

[Nealh]

The current BMS I'm using has smaller footprint then the Daly and is a no balance feature BMS, it has the sense wires to solder but these are simply for HVC /LVC for charge /discharge protecttion.
BeMoreSafer is the brand name and via my checks the LG Hg2 cells once I manually balanced two cell groups after the Daly failures have stayed pretty true with little imbalance ( I'm happy they are keeping within 0.01v - 0.02v).

Most BMS use passive balance and only balance during charge, if cells are way out of balance then balance could take hours. It is not good from a safety point of view to leave a batteyr to balance without monitoring esp if left for several hours.

The other option is to go with a no balance BMS and add an active balancer , these will monitor the cells all the time and balance when a balance anomily is sensed usually 0.1v and then balance to within 0.03v.

 

[lenny]

I manually balanced two cell groups after the Daly failures have stayed pretty true with little imbalance ( I'm happy they are keeping within 0.01v - 0.02v).

Please could you explain how you manually balanced those groups?

 

[Nealh]

Manual balancing requires battery surgery to get at the Balance wires whether the BMS uses balance or not, it also requires close monitoring and frequent voltage checking.
The cheap way is an old 5v adapted phone charger and a pair of male to male arduino wires for added safety.
The slightly dearer way is a lipo balance charger that one can charge 1s with.

The forum search should show up results of how to as we have psoted many times how to carry out the process, but firstly it needs the user to have a battery working knowledge as a mistake can also kill the battery .