Would you trust or somehow test this eBay Daly BMS?

Terrapin

Solar Enthusiast
Joined
Jan 4, 2021
Messages
315
Location
New England, USA
I bought his for a second battery build from Ebay. It is for a battery for a trolling motor on a boat and I selected it based on
the water proof/resistant comments VS what else I could find.

I noticed just now it didn't say LiFePO4 like some others, but they may be the smart ones, this is
not

The seller clearly listed it a for 4S LiFePO4. Knowing a little more than I did when I got it several months ago I decided to check on the Daly site and saw this picture as listed for LiPO. But MANY of the photos on their site are messed up and the rather poor translation to English did say it could be ordered configured for any charging profile. I can't read most of the writing on it. It came from over there so it will get used or trashed.

It does have the correct number of leads to balance a 4cell 12V LiFePO3 build.

How would you treat this/ trust it, test it somehow, trash it?

I am stumped on how to proceed. with it.
 

Attachments

  • output_image1617659346632.jpg
    output_image1617659346632.jpg
    82.1 KB · Views: 19

Terrapin

Solar Enthusiast
Joined
Jan 4, 2021
Messages
315
Location
New England, USA
Just to confirm a few things
1. You suggest using it and watching closely. as it tops off right?
2.
The dumb DALY are typically set for 3.75±.05V. I would test it to that. If it hasn't shut off by 3.8V, to the bin it goes.
OK so there could be the risk I am worried about.

My thoughts on testing it are to charge the existing battery after adjusting the onboard overkill BMS settings shut down when the highest cell hits 3.65v, I will then let the voltage settle and replacing the BMS with this unknown then begin a slow power supply charge and watch the cv/cc display closely to see what/if this charges past that 3.7- 3.8. Honestly I am not liking that 3.75, let alone 3.8. I want long life, not necessarily full 280ah capacity.

Do you think a capacity test is needed to find the low volt shut off as well. I have been searching the interweb and cant find a simple answer on the parameters of a 12v Lithium ion BMS, Well the problem is actually there are so many lithium chemistries I can't tell what's what..

Any comments or suggestions?
 

Cdkipp

Photon Sorcerer
Joined
Jul 29, 2020
Messages
1,599
Just to confirm a few things
1. You suggest using it and watching closely. as it tops off right?
2.

OK so there could be the risk I am worried about.

My thoughts on testing it are to charge the existing battery after adjusting the onboard overkill BMS settings shut down when the highest cell hits 3.65v, I will then let the voltage settle and replacing the BMS with this unknown then begin a slow power supply charge and watch the cv/cc display closely to see what/if this charges past that 3.7- 3.8. Honestly I am not liking that 3.75, let alone 3.8. I want long life, not necessarily full 280ah capacity.

Do you think a capacity test is needed to find the low volt shut off as well. I have been searching the interweb and cant find a simple answer on the parameters of a 12v Lithium ion BMS, Well the problem is actually there are so many lithium chemistries I can't tell what's what..

Any comments or suggestions?
It should jump to 3.75 3.8 really fast. They don't mess around once they get over 3.4. Just be ready to shut it down and attach a load.
 

Terrapin

Solar Enthusiast
Joined
Jan 4, 2021
Messages
315
Location
New England, USA
It should jump to 3.75 3.8 really fast. They don't mess around once they get over 3.4. Just be ready to shut it down and attach a load.
Thanks. I will set the overkill to bring it to 3.45 or so and let it settele down a bit from there as the start point. It really does freak me out a bit that it could go to 3.7 or 3.8. But since I am using good chargers with auto shutdowns already it may work. I really do need a waterproof BMS for the boat and on the tongue of the camper at a later date. I thought this could do it. Fingers crossed.
 

JoeHam

Photon Sorcerer
Joined
Dec 30, 2019
Messages
2,671
But since I am using good chargers with auto shutdowns already it may work.

Just be honest with yourself. If you are using the chargers auto shutdown to protect the battery you might as well pitch the BMS anyway.

Either be certain it works properly or replace it if you want to protect your battery investment.
 

Terrapin

Solar Enthusiast
Joined
Jan 4, 2021
Messages
315
Location
New England, USA
Tr
Just be honest with yourself. If you are using the chargers auto shutdown to protect the battery you might as well pitch the BMS anyway.

Either be certain it works properly or replace it if you want to protect your battery investment.
Very true. One charger is the Aims 75a and the other is a PD4645 converter going into the trailer. Both have specific LFP profiles. I am pretty knew to all this and completely forgot about the shutoffs on the chargers. So I comes down to knowing the low cell cut offs way more than the high.... Maybe a top balance check once a year to make certain I don't cook one then...

This is an expensive hobby.
 

Gazoo

Dumb Dumb
Joined
May 12, 2020
Messages
2,811
Location
Texas
Any BMS should be checked to make sure the HVD and LVD are working. Even the infamous Overkills, which I am using and love, should be tested before final assembly. Remember the BMS is used for the last line of defense to protect the cells in case a charger or something malfunctions.
 

Terrapin

Solar Enthusiast
Joined
Jan 4, 2021
Messages
315
Location
New England, USA
Lol....yes it is. And at times it's painful. But it's been fun for me and definitely have learned so much. Plus I am still way ahead of the cost of battleborns.
👍 👍 I've gone through about 6 group 29 deep cycle FLA trolling motor batteries in the small 15' grumman boat. And now with the addition of a camper that has a converter that just sits at 3A charging to cook another deep cycle. I might be a little over cautious but my retirement plan doesn't have buying batteries in the math. I am doing this once and right. Damn good to have the recourses here and the personalized help to walk me through. I probably wouldn't have taken the leap at $1000 for 100ah.
 

Diysolar123

Photon Sorcerer
Joined
Feb 28, 2021
Messages
663
the BMS is stop any damage to individual cells, even smart chargers, unless they have a wire to each individual cell, are only monitoring the total voltage which absolutely does NOT protect your batteries unless you keep the top charge voltage very low.
I agree that the high voltage cell disconnect is much too high for my comfort level.
The daly over charge p[rotection specs are 3.75 +/- 0.05..
which means the high voltage disconnect can be as high as 3.75+0.05 = 3.8V!!!!
For a low cost battery pack, sure, the cheap daly dumb BMS are better than nothing and do offer low voltage/short circuit disconnect as well.
For an expensive large pack, you absolutely need a smart BMS so you can actually set the voltage numbers for disconnects.

that picture does not look like a real daly lifepo4 4S BMS... the part number looks wrong.
 

Diysolar123

Photon Sorcerer
Joined
Feb 28, 2021
Messages
663
if you look at the "daly official store" on aliexpress, all of the smart BMS models are waterproof.
 
Top