Top Balancing "How to"

Just John

Photon Sorcerer
Joined
Aug 15, 2020
Messages
2,576
It seems to me that this process takes so long because us DIY guys can only afford low voltage/low amperage power supplies. If we could buy a low voltage, high amperage power supply then the process would be much faster.
Apparently Riden has now released their 24 amp power supply, so for approximately $173 you can get a 24 amp supply that works for top balancing as well as pack charging. That's a pretty good deal. I haven't tried the 24 amp version yet, but the 12 and 18 amp versions are very reliable and easy to use. I highly recommend them.

RD6024 link
 

Just John

Photon Sorcerer
Joined
Aug 15, 2020
Messages
2,576
DOH! After I just pulled the trigger on the 6018W. 😲😲😲

Just order the $70 part, it will use the same case and power supply.
Yes, right after I ordered the RD6012, they came out with the RD6018.

I just ordered the RD6024 myself.
 

Browneye

Dr. WattSon
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Nov 2, 2021
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Southern California
Now it's charging at 10.0A CC. When the voltage gets a little closer it switches to CV - it's set for 3.62V constant volts.
I'll keep an eye on it, should be mostly there. Probably tomorrow.

Day four...16 hours later it's STILL charging at 10A. Cell voltage is up to 3.386. :oops:
 

Browneye

Dr. WattSon
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16?

4 x 24 = 96

10A x 96 hours = 960 Ah

For the first three days it was mostly at 5A. I'm guessing maybe I got about 350Ah in them.
Yesterday I reset to 3.62V on the supply and it's been 18 hours at 10A. My guess is I've got about 8 more hours to go.

Estimated 30% SOC on arrival - 4@230A cells - I will need about 600Ah +/- total. Getting close now...cell voltage is finally coming up.
3.382
3.369
3.369
3.377

The connect terminals are 3.391
Talk about watching paint dry. 🙃

As of now I'm a big advocate for pre-charging. This is nearly ridiculous. LOL
Fortunately I don't have anything else to do, nothing pressing - no rush for a RV battery. (y)

Also worth noting...the power supply cooling fan ran intermittently when it was putting out 5A. At 10A it runs continuously. Noisy but not enough to hear in the next room. I'm glad I started this in the office and not in the shop - it's 70* in here, shop is probly 50.
I'm happy with the Longwei unit, for a one-time project (well, maybe LOL) and it was $60 from amazon.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
10,678
The suitors of Ulysses wife?
She told them she would select one after finishing the tapestry she was working on.
Each night, she unraveled what she had woven the day before.
 

Browneye

Dr. WattSon
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Well it took another ten hours from when I said up-thread I probably needed another 8 hours of charging. It took FOREVER. Top balancing without pre-charging them is not recommended, it just takes way too long, even for four cells. I can't imaging doing it that way with those bigger 8 and 16 cell packs. Wire them up with your bms and charge them to 3.4 or so and THEN do the top balance.

Started building once they were done top balancing. First step was to VHB tape them together, and cut the compression case ends and bottom:



 

Oldtoad

Solar Enthusiast
Joined
Jun 22, 2020
Messages
190
Location
ME to AZ
It seems to me that this process takes so long because us DIY guys can only afford low voltage/low amperage power supplies. If we could buy a low voltage, high amperage power supply then the process would be much faster.
Whoa Nelly! I take exception to this. This is the hinternet, I am rich, handsome and a legend, if only in my own mind. I choose to buy a thrifty power unit so I can agonize over the impressive charging curve. After all, why rush quality...and money. :cool:

Brownie,
Nice build!
Remember, magic smoke just takes a second but lasts forever.
 

HRTKD

Boondocker
Joined
Apr 24, 2020
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Somewhere South of Denver
Whoa Nelly! I take exception to this. This is the hinternet, I am rich, handsome and a legend, if only in my own mind. I choose to buy a thrifty power unit so I can agonize over the impressive charging curve. After all, why rush quality...and money. :cool:

Brownie,
Nice build!
Remember, magic smoke just takes a second but lasts forever.

I top balanced in parallel from start to finish. So I understand the concept of patience. On the other hand, if low voltage, high amperage chargers were readily available to the unwashed masses, we assuredly would be melting more cells than we are now. So, low amps is probably a good thing.
 

Browneye

Dr. WattSon
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I cringed when i saw this. VHB is pretty permanent. Battery cell configuration changes and reassembly are nearly assured in the 10 year lifespan of these. Hopefully it works out for you!
It's fine. Fishing line cuts right through it if necessary. Steve at Overkill actually recommends it. And I like that it ties everything together. I ordered cutting mat material but it hadn't arrived yet and my day to build the pack was yesterday. 😊
I won't be taking it apart unless it fails.
 
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Browneye

Dr. WattSon
Joined
Nov 2, 2021
Messages
1,073
Location
Southern California
I placed a 1/8" thick sheet of medium density rubber under the pack. The VHB provides a nice cushion and insulation between the cells.
Once clamped in and compressed it sets up really solid.



 

atti

Solar Enthusiast
Joined
Jun 28, 2021
Messages
35
I am in the same boat, due to the huge capacity (280Ah) I am unable to top balance my cells. I wish I had something like 50-100A charger at 3.2v. Can I use buck converter charger like this and make it charge faster? Any experience of using these sort of products?
 
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