Need help Figuring this FIRE out!

GSXR1000

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BMS is needed for low voltage even more then over voltage in this application I could imagine your run LifePo to dead state ie golf cart won't move. let's say 15v or 1 volt per cell
Then put at a 49v charger. not sure but I could see to those pouches start over heating and chemically breaking down.
The OP said it wouldn't charge so prolly already damaged then charger left on till poof
 

GSXR1000

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Using a BMS with this design is difficult... but so is recovering from a house fire... I know.
not really you have the golf cart control and charger current goes thru the BMS and motor only strait to the battery. would require a single bms...
 

Supervstech

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not really you have the golf cart control and charger current goes thru the BMS and motor only strait to the battery. would require a single bms...
Oh, I wasn't saying there aren't options available.
I was making an example showing that no matter how hard it is, it is NEEDED.
 

A.Justice

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OP could even use one of those little dinky 20 or 30 amp BMS's from ebay coupled with a large contactor if they wanted. Probably the cheapest route to get 500-1000a discharge current for less than a few hundred bucks.
 

GSXR1000

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Oh, I wasn't saying there aren't options available.
I was making an example showing that no matter how hard it is, it is NEEDED.
I agree. seems that budget was an big issue so just suggesting a budget friendly solution
 

Juan Gonzales

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OP ignored my request to show their mentioned new pack design with BMS. Then goes on to justify why they didn't need a BMS. This user may be trolling.
Hi Will,
Glad to hear from you personally.

Im sorry I didnt send a picture of a latest pack design with BMS, I know everybody is anxious for updates, but have been very busy lately literally procuring BMSs.


First I´ll address the questions:
golf carts are known to be driven till the battery is so drained that it slows down
Agreed, lesson learned.
do you think they ever driven the cart till it slowed down even a little bit..
Not for a Fact, but I absolutely believe so. Also, believe that is the main reason for the failure, with no BMS to stop it, cells voltage probably got spread out.
DETAILED STEP BY STEP OF WHAT YOU DID TO TOP BALANCE THE CELLS.
I already answer this, and showed a picture. all cells connected in parallel, charged to 3.65 v, let it rest 24 hrs, charged to 3.65v all at 8 Amps. FYI Followed the balancing recommendation of Professor Jay Whitacre. at this video

Then put at a 49v charger.
Actually, the charger my friend was using was a SMART Trojan Charger, that was part of the issue. it was Equalizing to 64V


Here it is:WhatsApp Image 2022-06-20 at 3.43.06 PM.jpegWhatsApp Image 2022-06-15 at 6.46.18 PM.jpegWhatsApp Image 2022-06-15 at 6.46.21 PM.jpegWhatsApp Image 2022-06-25 at 3.22.06 PM.jpeg

12V 40ah 120A BMS Cranking
WhatsApp Image 2022-06-20 at 7.28.03 PM.jpeg

48v 105ah 120A Bms Solar
WhatsApp Image 2022-06-15 at 6.46.16 PM.jpeg



Then goes on to justify why they didn't need a BMS.
I dont think I deserve this post. On the contrary, since the beginning I have been transparent about my mistake for not adding a BMS for that Pack. I also encourage tinkering to find other sources of failure.
 
Last edited:

GSXR1000

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Actually, the charger my friend was using was a SMART Trojan Charger, that was part of the issue. it was Equalizing to 64V
wow 64v to a 48v Lifepo battery... well there you go. that's 4v per cell if in balance more on a few cells if not... 3.65v MAX
 

A.Justice

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Hi Will,
Glad to hear from you personally.

Im sorry I didnt send a picture of a latest pack design with BMS, I know everybody is anxious for updates, but have been very busy lately literally procuring BMSs.


First I´ll address the questions:

Agreed, lesson learned.

Not for a Fact, but I absolutely believe so. Also, believe that is the main reason for the failure, with no BMS to stop it, cells voltage probably got spread out.

I already answer this, and showed a picture. all cells connected in parallel, charged to 3.65 v, let it rest 24 hrs, charged to 3.65v all at 8 Amps. FYI Followed the balancing recommendation of Professor Jay Whitacre. at this video


Actually, the charger my friend was using was a SMART Trojan Charger, that was part of the issue. it was Equalizing to 64V


Here it is:View attachment 101651View attachment 101650View attachment 101652View attachment 101655View attachment 101654View attachment 101653
How much current is that BMS able to handle? There's no way that's a golf cart battery.
 

Juan Gonzales

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Hi Guys, thank you for the feedbacks.

I Hope the pictures will help someone. It sure helped me when I was starting out. Im a Visual Guy.

How much current is that BMS able to handle? There's no way that's a golf cart battery.
120Amp 16S 3.2v For Solar 48v
wow 64v to a 48v Lifepo battery
Yes, we figured out later thats the charger the local dealer sells for Trojan 1275. and it has a "SMART" Equalization voltage to 65v. However the charger could be Fried, we were never able to get it back to charge again.

DIY is one thing, but building for others
Yes, you start with one, and one thing led to another and your making packs for all your friends and family.
People seem to not get enough from LifePo4. Such an improvement over Lead Acid.
 

GSXR1000

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Yes, we figured out later thats the charger the local dealer sells for Trojan 1275. and it has a "SMART" Equalization voltage to 65v. However the charger could be Fried, we were never able to get it back to charge again.
lead acid have higher internal resistance so they only pass do much current.
Lifepo is almost like a dead short, pass high amounts of current do yes could have
 
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