BMS/Battery - one that must reset by itself.

[CleanLivin]

I am returning 4 of the Redodo 100Ah Mini SMART batteries because several three times in 6 weeks one or the other of the 4 batteries shuts down. To find which battery is "locked out" and then resting it is not fun due to the fact the four Redodo 100Ah Mini just fit BUT my installation is 2 batteries stacked in back corner of compartment and two stacked in front.

I only have 11" X 18" floor space, 18.5" high to place 4 LiFePO4 batteries.

To reset per Redodo:
"Hello John,

Thanks for the detail information!
It is the normal phenomenon for Smart batteries. The batteries have been protected for fully charged.
Please connect the battery with a load (current>2A) for just 2 mins, then disconnect the connections, wait 30 mins, the voltage of the batteries will recover to around 13.33V.
Best Regards,"
------------------
To even check which battery or batteries of the four has shut down requires removing the front stack of batteries by disconnecting all of the parallel cables, unstraping the 2 front batteries and removing them from the compartment, then using a voltmeter hoping to find what battery is locked out. I've done this 3 times now and it is not fun.

Their tech support has been fine to work with but now returning batteries and need to find 4 batteries that will reset on their own after a few seconds or even a few minutes.

Of course Victron and my distributor have reviewed my settings and said this is a problem apparently specific to the batteries I have. (I've noticed Redodo is no longer offering the 100Ah Mini Smart on Amazon or their own website.)

I see SOK has:

12V 206Ah LiFePO4 Lithium Iron Phosphate Battery Pack​

SKU: SK12V206

Seems expensive but "Will" seems to like it. But I would like to find a couple of competitive companies to review.
I will call SOK tomorrow and see if this unit BMS will reset automatically.

Suggestions welcome.

 

[pollenface]

Most generic brands I have played with will "reset" by themselves after over-discharge so long as no load is attached. I've never experienced full charge disconnect.

Redodo "smart batteries" sound like a P.I.T.A.

Out of curiosity, what charge voltage are you using? I wonder if lowering it slightly would trick the "smart battery" to not go into full charge protection?

 

[400bird]

A better solution is to avoid taking the batteries to fault states. Most commonly this is just needing to keep them from discharging fully.
If you've tripped the a battery for low cell voltage 3 times in 6 six weeks, I'd recommend reviewing the design of you system and settings.

If you have an SOK question, Current Connected is a dealer, @HighTechLab (Dexter) may be able to answer your questions.

 

[HighTechLab]

Are you connecting the batteries in series or parallel? If you are putting them in series, you should use a 48v battery, so only one BMS is in charge versus four of them fighting each other.

Otherwise, if you are putting them in parallel, the 206ah SOK's will work great - if for any reason you get to the point of a low-voltage shutdown, simply charging the battery bank will reset the protection within a couple of seconds.

It's critical that all four batteries are wired properly. It will likely require a bus bar and equal length cables going to each battery. Far too often cabling issues cause problems that the batteries get blamed for.

 

[CleanLivin]

Most generic brands I have played with will "reset" by themselves after over-discharge so long as no load is attached. I've never experienced full charge disconnect.

Redodo "smart batteries" sound like a P.I.T.A.

Out of curiosity, what charge voltage are you using? I wonder if lowering it slightly would trick the "smart battery" to not go into full charge protection?

 

[CleanLivin]

Are you connecting the batteries in series or parallel? If you are putting them in series, you should use a 48v battery, so only one BMS is in charge versus four of them fighting each other.

Otherwise, if you are putting them in parallel, the 206ah SOK's will work great - if for any reason you get to the point of a low-voltage shutdown, simply charging the battery bank will reset the protection within a couple of seconds.

It's critical that all four batteries are wired properly. It will likely require a bus bar and equal length cables going to each battery. Far too often cabling issues cause problems that the batteries get blamed for.

Parallel, 12V, 30Amp shore power.
Cables are all equal and well under Victron spec.

 

[CleanLivin]

A better solution is to avoid taking the batteries to fault states. Most commonly this is just needing to keep them from discharging fully.
If you've tripped the a battery for low cell voltage 3 times in 6 six weeks, I'd recommend reviewing the design of you system and settings.

If you have an SOK question, Current Connected is a dealer, @HighTechLab (Dexter) may be able to answer your questions.

Redodo - my impression and test say BMS in the Smart series on 100Ah is flawed. Their support has been excellent and they now are taking the batteries back. Just shipped back this morning.

 

[mikefitz]

Parallel, 12V, 30Amp shore power.

It's probable, if the charge voltage is 14.6, the BMS will shutdown. This will happen to many lithium batteries on the market.
Changing to a more realistic charge volts of 14.2 volts most likely will solve the issues. With some batteries it's necessary to use an even lower charge volts, 13.8. Over time the cells become better balanced. It's not a fault, just the manufactures saving costs to offer a competitive product.

There was no need to access each battery, after a short time, with some discharge of the complete pack. the BMS would recover.

I fear you have wasted your and Recodes time. It's very likely your replacements will suffer similar issues if you use high charge voltage.

Mike

 

[CleanLivin]

It's probable, if the charge voltage is 14.6, the BMS will shutdown. This will happen to many lithium batteries on the market.
Changing to a more realistic charge volts of 14.2 volts most likely will solve the issues. With some batteries it's necessary to use an even lower charge volts, 13.8. Over time the cells become better balanced. It's not a fault, just the manufactures saving costs to offer a competitive product.

There was no need to access each battery, after a short time, with some discharge of the complete pack. the BMS would recover.

I fear you have wasted your and Recodes time. It's very likely your replacements will suffer similar issues if you use high charge voltage.

Mike

I had posted 2 times here and 2 times on Victron forum, not any advice. Thus I have NOT heard what you suggest. I will go with that.

I do need the resting voltage at 13.8 to start a trip as I must sleep on hybred of CPAP, VPAP and it uses quite a lot of energy.

 

[CleanLivin]

Working in this space is for a very strong tiny person, 13" wide and 20" high:

 

[CleanLivin]

Working in this space is for a very strong tiny person, 13" wide and 20" high:View attachment 177546

But I am 6'4" and 220#'s!!! Imagine 4 x 100 Redodo Minis in there on 11" x 18" of floor space in the nose of a BaseCamp 16X, 2022! Front is rounded so battery space is nil.

 

[400bird]

I agree with mikefitz, trying to charge to 14.6 volts is likely to cause problems.
14.6v/4cells= 3.65 volts/cell
This is only possible with the unachievable perfectly balanced cells. It's much more likely that you have at least once cell hitting the high voltage protection limit.

14 volts would be 3.5 volts/cell on average, and a much easier voltage to reach with imbalanced cells.
14.2 volts is 3.55
Either should be a reliability improvement over 14.6 volts.

What is your low voltage cut off set to? That can also cause problems.

Do the Redodo batteries have Bluetooth? That would allow you to see the cell voltages and read the alarm/reason for the disconnect.

 

[CleanLivin]

I agree with mikefitz, trying to charge to 14.6 volts is likely to cause problems.
14.6v/4cells= 3.65 volts/cell
This is only possible with the unachievable perfectly balanced cells. It's much more likely that you have at least once cell hitting the high voltage protection limit.

14 volts would be 3.5 volts/cell on average, and a much easier voltage to reach with imbalanced cells.
14.2 volts is 3.55
Either should be a reliability improvement over 14.6 volts.

What is your low voltage cut off set to? That can also cause problems.

Do the Redodo batteries have Bluetooth? That would allow you to see the cell voltages and read the alarm/reason for the disconnect.

No the do not and even when the battery is turned "off" they are still showing 3.35v at the terminals.

 

[CleanLivin]

My settings during the Redodo problems with their smart BMS:

 

[Q-Dog]

I would run absorption voltage lower, like 14.2v ... or maybe 14.0 until the batteries are better balanced..

 

[CleanLivin]

I would run absorption voltage lower, like 14.2v ... or maybe 14.0 until the batteries are better balanced..

Have returned batteries this morning. Battery was only on Amazon factory website when first introduced, no longer as of last time I looked, yesterday. But tech was very good, however what I am finally learning in this thread, all brand new. More than Victron offered and far more than my dealer did!

Thus, thanks for all! Keep ideas coming. Big challenge is finding batteries, ideally BlueTooth, that can put 400Ah's in 11" by 18" of floor space.

 

[mikefitz]

need the resting voltage at 13.8

You won't get that with lithium no matter how high the charge voltage or battery model.
After the charge stops the voltage will quickly fall to around 13.35 volts, with loading expect a further fall.
See,

LFP voltage readings

Fully charged up six (new) LFP batteries individually using charger. (Charger made for LFP batteries). All after charging and sitting overnight read 13.4 to 13.6 volts. Hooked up as 24 volt. Controller reads 26.3 and shows 100% charge. Battery manual has a chart that says 13.35 volts is 60%...

diysolarforum.com

 

[CleanLivin]

It's probable, if the charge voltage is 14.6, the BMS will shutdown. This will happen to many lithium batteries on the market.
Changing to a more realistic charge volts of 14.2 volts most likely will solve the issues. With some batteries it's necessary to use an even lower charge volts, 13.8. Over time the cells become better balanced. It's not a fault, just the manufactures saving costs to offer a competitive product.

There was no need to access each battery, after a short time, with some discharge of the complete pack. the BMS would recover.

I fear you have wasted your and Recodes time. It's very likely your replacements will suffer similar issues if you use high charge voltage.

Mike

You won't get that with lithium no matter how high the charge voltage or battery model.
After the charge stops the voltage will quickly fall to around 13.35 volts, with loading expect a further fall.
See,

LFP voltage readings

Fully charged up six (new) LFP batteries individually using charger. (Charger made for LFP batteries). All after charging and sitting overnight read 13.4 to 13.6 volts. Hooked up as 24 volt. Controller reads 26.3 and shows 100% charge. Battery manual has a chart that says 13.35 volts is 60%...

diysolarforum.com

Mike, Makes sense from my past experience.

 

[CleanLivin]

Multiplus II, Minimum # of batteries required? One 400Ah 12v OK?
Victron system, question:
I previously had 4x100Ah 12.8v, Parallel setup.
Had problems with batteries. Return allowed by manufacture.

I read months ago "somewhere" and have the impression that MPII requires at least 3 or 4 battereis
to run properly.

Is that valid?
Prices have come down and for the very limited space I have in the Basecamp ONE 400Ah would be far easier to work, or just 2 x 200Ah's if I must have more than one.

 

[mikefitz]

have the impression that MPII requires at least 3 or 4 battereis

If you have the 12/ 3000, then at full power needs a battery or battery bank to supply in the region of 250 amps. A 12v system at these power levels needs heavy gauge cables, quality parts and high instalation standards, to prevent volt drops and associated issues.