Charge amperage significantly below standard for battery

[abeness]

With a failing ReLiON Group 31 LiFePO4 12V 100Ah battery at 3.5 years despite regular and reasonable use, I'm disabused of costly batteries with built-in BMS and exaggerated claims about expected longevity and number of cycles. I'm now planning v2 of my DIY portable power box with a 4S prismatic setup with EVE LF230 cells, whose standard charging current spec is 0.5C, or 115A. I'm brand-new to prismatic cells and configurable BMS, but quite comfortable with DC circuits. The 49-page thread on compression is a fun one, especially when @ghostwriter66 gets notes direct from EVE engineering. Feeling a little trepidation at the rabbit hole of separate BMS and balancing, but surely game!

While it would be fun to recharge in less than 2 hours, I'm not anxious to add a high-amperage charger at this time, after updating the primary wiring in this box for full power to a 1500W inverter, building a compression setup, etc. Since I've been quite happy with my Victron gear, my next step would likely be a Multiplus II, but that would be super overkill for a portable power box...

My current mains charger is just 25A, solar charger is 30A. Normally only one or the other is available. (I only get 30A out of the solar charger when its power source is my van alternator via DC-DC boost converter. Otherwise, max 200W with my DIY portable panel kit.) This was fine for 100Ah, but will be a bit slow for 230Ah.

I mostly recharge starting at 30% SOC, which in this case will initially leave ~161Ah to restore to 100% SOC. At 25A, that will take about 6.5 hours. This is within the EVE datasheet "BMS Protection" spec to terminate charging after 8 hours.

Are there any problems with always charging these slowly at 0.11C? Battery degradation? Balancing issues?

If I were to discharge all the way, it would take over 9 hours to recharge. Would I be better off keeping a BMS "too long charge time" setting at 8 hours in case of weirdness, and reset charging after auto cut-off? Or set it to 9 hours? I mean, there will be over-voltage protection too. What does a Daly Smart BMS 250A BT do when disabling charging for a "too long" condition, assuming it has such a setting? Does it just break the battery connection, or only disable inbound current flow?

Thanks for any input!

 

[mikefitz]

failing ReLiON Group 31 LiFePO4 12V 100Ah battery at 3.5 years

Common with Region batteries when operating on too high a charge and float voltage. Try claiming on their warranty

Warranty Information Registration or Claim Submission | RELiON

Learn more about RELiON's manufacturers warranty, register your warranty, or make a warranty claim with us.

relionbattery.com

here any problems with always charging these slowly at 0.11C

No issues providing the absorbtion voltage is not too high, charge to 14.0 volts , 30 minutes absorbtion period, then float at 13.4 volts.

What does a Daly Smart BMS 250A BT do when disabling charging

The BMS has protection levels for voltage and current. If the protection levels are exceeded, it disables the charge or discharge path.
It's not intended to control the charge process, although if the cells are unbalanced, and a high charge voltage is used, it will disable the charge path, if any cell volts exceed the protection voltage level.

It's the charger that ideally terminate charging . If you have Victron chargers it's easy to set up a suitable charge profile.

 

[MiSh]

I just had a 4 year old Relion 12v RB100 that was not taking a charge properly. Called the tech to troubleshoot the issue, he blew off the troubleshooting part and just sent a brand new battery out. Great service.

 

[abeness]

Thanks, mikefitz and MiSh.
MiSh, fascinating experience, mine very different: I actually did submit a warranty claim, and they referred me to their three-year free replacement policy, followed by offering to sell a new one in year 4 at 20% off. Who did you speak with and what did you say?

This is what I got back from the warranty department after I asked about repair, after they offered only prorated purchase:
"I received an update. Due to the factory seal and described battery issue, it is determined that the battery is unable to be repaired.
The Manufacturer’s Limited Warranty offers a Prorated Purchase Program of 20% off of MSRP."

mikefitz, ReLiON actually advised me to change my charge profile to 14.6V for bulk back in 2021. I did note this in the claim form. Their specs do have that as upper charge range, though. Maybe they fried it for me? Float set to 13.6V, bulk time limit 5h. Victron does have a minimum absorption time of 1h. Thanks for the Daly notes! After it disables the charge/discharge path, what's the reset process?

I'd love a replacement RB100 that would get me more mileage out of the current config, but there's definite appeal in a capacity upgrade.

 

[MiSh]

Thanks, mikefitz and MiSh.
MiSh, fascinating experience, mine very different: I actually did submit a warranty claim, and they referred me to their three-year free replacement policy, followed by offering to sell a new one in year 4 at 20% off. Who did you speak with and what did you say?

This is what I got back from the warranty department after I asked about repair, after they offered only prorated purchase:
"I received an update. Due to the factory seal and described battery issue, it is determined that the battery is unable to be repaired.
The Manufacturer’s Limited Warranty offers a Prorated Purchase Program of 20% off of MSRP."

mikefitz, ReLiON actually advised me to change my charge profile to 14.6V for bulk back in 2021. I did note this in the claim form. Their specs do have that as upper charge range, though. Maybe they fried it for me? Float set to 13.6V, bulk time limit 5h. Victron does have a minimum absorption time of 1h. Thanks for the Daly notes! After it disables the charge/discharge path, what's the reset process?

I'd love a replacement RB100 that would get me more mileage out of the current config, but there's definite appeal in a capacity upgrade.

I don't remember the tech's name. I called, no one answered. I did not leave a message and the guy calls me back from caller I.D. Who does that these days? Anyway, I explain issue (would not charge fully) and he says sounds like a bad cell. Orders me a new battery. All I had to do was fill out online form. Apparently they may have more leeway in deciding if a new battery is warranted?

 

[mikefitz]

After it disables the charge/discharge path, what's the reset process?

It should not disable the charge path if you use a suitable charge voltage. Once in protection mode due to cell overvolts , usually set at 3.65 volts, the voltage needs to fall below the recovery voltage, example 3.50 volts ( actual protection and recovery volts depend on BMS settings).

One disadvantage of using a high charge voltage where BMS protection is cutting off the charge current, is that voltages spikes may occur, if the charger cannot respond fast enough. These voltage transients may effect system parts.

You don't have to charge the cells to 3.65 unless you are carrying out capacity testing. With the battery used in a typical application , and has a low charge current compared to battery capacity , 'full' is reached by the time the cell volts reach 3.5 volts , 14.0 volts for a 12v battery

 

[abeness]

I don't remember the tech's name. I called, no one answered. I did not leave a message and the guy calls me back from caller I.D. Who does that these days? Anyway, I explain issue (would not charge fully) and he says sounds like a bad cell. Orders me a new battery. All I had to do was fill out online form. Apparently they may have more leeway in deciding if a new battery is warranted?

Sadly, when I called today I got the same person that I was emailing with, and she said they had to rely on the warranty department for the decision. So I left a message on the warranty person's vm, and did not hear back today. Not especially hopeful.

You don't have to charge the cells to 3.65 unless you are carrying out capacity testing. With the battery used in a typical application , and has a low charge current compared to battery capacity , 'full' is reached by the time the cell volts reach 3.5 volts , 14.0 volts for a 12v battery

That charge curve graph is illuminating; thanks. Regarding disconnect, I mean once charge time limit has been reached, what happens? EVE recommends max time of 8h, and I can foresee a day--e.g. during capacity testing--when charge time at 25A exceeds 8h. I suppose if I have my voltage set up correctly, it won't matter if charge time exceeds 8h. Victron gear is very robust--though I wish they would enable less than an hour float! (It's been requested, I'm pretty sure, but hasn't been implemented.)

 

[yodamota]

Sadly, when I called today I got the same person that I was emailing with, and she said they had to rely on the warranty department for the decision. So I left a message on the warranty person's vm, and did not hear back today. Not especially hopeful.

That charge curve graph is illuminating; thanks. Regarding disconnect, I mean once charge time limit has been reached, what happens? EVE recommends max time of 8h, and I can foresee a day--e.g. during capacity testing--when charge time at 25A exceeds 8h. I suppose if I have my voltage set up correctly, it won't matter if charge time exceeds 8h. Victron gear is very robust--though I wish they would enable less than an hour float! (It's been requested, I'm pretty sure, but hasn't been implemented.)

why not float at a voltage which is lower than the battery's voltage. My battery resting voltage when full is 13.35vdc. So I have the float set to 13.2vdc. Therefore the battery isn't being floated because it is higher than it needs to be in order to float.

 

[abeness]

Just getting back to this: Yes, yodamota, setting float to lower than battery's resting voltage works.