Top Balancing...Do I need to go to 3.650V?

[John Frum]

Put another way, there are 2 vendors the provide the best quality cells that we have access to.
Docan is one of them.

 

[LivingTheDream]

Here is where the first batch is sitting after an overnight stay...

 

[Electric Personality]

Good, glad its not a Daly.
At least you have a fighting chance.
If the cells drift too much you may need an active balancer.

Just found this on a search. My 280ah 4s battery has a Daly 200 amp BMS.
My trailer has been sitting over winter, but I just plugged it in, and it has now been floating at 13.64 volts for a few weeks. I took a meter to the cells, and find a variation of .15 volts.
Should I be concerned?

 

[time2roll]

Just found this on a search. My 280ah 4s battery has a Daly 200 amp BMS.
My trailer has been sitting over winter, but I just plugged it in, and it has now been floating at 13.64 volts for a few weeks. I took a meter to the cells, and find a variation of .15 volts.
Should I be concerned?

I would add an active balancer for $20

Although 13.64 is on the high side for float service. I would be looking to change the converter.

 

[John Frum]

Just found this on a search. My 280ah 4s battery has a Daly 200 amp BMS.
My trailer has been sitting over winter, but I just plugged it in, and it has now been floating at 13.64 volts for a few weeks. I took a meter to the cells, and find a variation of .15 volts.
Should I be concerned?

What is the highest cell voltage and what is the lowest?

 

[John Frum]

What is the highest cell voltage and what is the lowest?

If you start a new thread I will be happy to help.

 

[NVS]

I added a 5amp active balancer to my battery, and I like how it keeps all my cells balanced continuously. Maybe not so important if you run your bank at a 90% to 20% charge/ discharge cycles. But if you are needing to run more than that an active balancer will definitely help keep your cells balanced.

Heltec 6S 7S 8S 5A 6A Active Equalizer Balancer/8s Equalizer Lifepo4 Lithium Lipo LTO Energy Transfer Board Fit Capacitor https://smile.amazon.com/dp/B08D9D4NGW/ref=cm_sw_r_apan_i_RFBH0WTR12RYDHAJ3CEH

 

[LivingTheDream]

Ok, last night I ran to HD and got a DC light bulb. It only pulls 8.8W, which is about the best I could find. I also hooked up my air compressor that barely sputters along at 3.5V, but it's something. I turned on the charger and within a few minutes, here is where I am already. It's as if I didn't even try to bring these voltages together.

 

[time2roll]

Set the charging to stop at 27.60 and put the battery in service. Possibly put an active balancer on.

 

[John Frum]

@LivingTheDream how is your balance algorithm configured?
I would set it to balance threshold to 3.45 volts per and the delta trigger to 10mv
Until the cells come with to a delta of less than <50 mv I suggest you have it balance all the time not just during charging.
Also make your normal runtime charge profile...
boost/absorption = 3.55 volts per
float = 3.35 volts per

 

[NVS]

I would put the active balancer on it and save all the headaches just make sure you get the 5amp balancer.

 

[LivingTheDream]

Set the charging to stop at 27.60 and put the battery in service. Possibly put an active balancer on.

I would put the active balancer on it and save all the headaches just make sure you get the 5amp balancer.

I've got one on order. Should be delivered tomorrow and I'll pick it up on Sunday.

 

[DerpsyDoodler]

@LivingTheDream did you scuff the terminals with fine grit sandpaper and clean them with isopropyl before you did the final assembly? Did you use oxguard or noalox? You need good clean terminals to make good connections for maintaining well-balanced batteries. These variances can be indicative of poor connections due to dirty terminals.

 

[LivingTheDream]

@LivingTheDream how is your balance algorithm configured?
I would set it to balance threshold to 3.45 volts per and the delta trigger to 10mv
Until the cells come with to a delta of less than <50 mv I suggest you have it balance all the time not just during charging.
Also make your normal runtime charge profile...
boost/absorption = 3.55 volts per
float = 3.35 volts per

I made the changes you mentioned. However, I don't see in the settings on where to change the boost/absorption nor the float. I am using the app on an iPhone if that matters.

 

[LivingTheDream]

@LivingTheDream did you scuff the terminals with fine grit sandpaper and clean them with isopropyl before you did the final assembly? Did you use oxguard or noalox? You need good clean terminals to make good connections for maintaining well-balanced batteries. These variances can be indicative of poor connections due to dirty terminals.

No, I didn't. I'll do that now. Do I need to use oxguard/noalox? If so, is that found on Amazon or...?

 

[John Frum]

I made the changes you mentioned. However, I don't see in the settings on where to change the boost/absorption nor the float. I am using the app on an iPhone if that matters.

Those are settings for the your charger.
More precisely I mean the charger that you will use to charge the pack during normal operation at pack voltage.

 

[John Frum]

To accelerate the balancing of the pack you could float it at 3.5 volts for a couple of days.
It will cause some short term stress on the battery in order to get more capacity over the operational life of the battery.

 

[DerpsyDoodler]

No, I didn't. I'll do that now. Do I need to use oxguard/noalox? If so, is that found on Amazon or...?

Are you using tinned lugs? If not, you can probably get by without it. Doesn't hurt to use it, though. Yes you can probably find either on Amazon. I used Oxguard. Apply it after you've cleaned your terminals and bus bars. Some use a lint-free qtip, I put on a nitrile glove (non-powdered), put a dab on my finger, and spread a very thin layer across the terminal and on the busbar where it contacts the terminal. You don't need a lot, and you don't want to "goop" it on.

 

[LivingTheDream]

Are you using tinned lugs? If not, you can probably get by without it. Doesn't hurt to use it, though. Yes you can probably find either on Amazon. I used Oxguard. Apply it after you've cleaned your terminals and bus bars. Some use a lint-free qtip, I put on a nitrile glove (non-powdered), put a dab on my finger, and spread a very thin layer across the terminal and on the busbar where it contacts the terminal. You don't need a lot, and you don't want to "goop" it on.

Ok, I just sanded the terminals and bus bars. Hooked everything back up and I'm still out of whack on three of the cells. I'll work on bringing those down a bit and see what happens. I'll order some oxguard for the final build out. I'm not sure if the lugs are tinned, just what came from Doshan.

 

[LivingTheDream]

To accelerate the balancing of the pack you could float it at 3.5 volts for a couple of days.
It will cause some short term stress on the battery in order to get more capacity over the operational life of the battery.

I'll try to bring the high ones down with a load. In the mean time, I'll be getting the balancer over the weekend. Why does @Will Prowse not care so much for the active balancers? Or did I misunderstand him in his balancing video?