Battle Born Victorious

[KITROBASKIN]

Perhaps you can adjust the title of this thread to reflect where things are now?

Maybe "Battle Born Bummer: Solution Pending"

 

[JunglePower]

Perhaps you can adjust the title of this thread to reflect where things are now?

Maybe "Battle Born Bummer: Solution Pending"

How's this for a fitting thread title?

 

[KITROBASKIN]

Maybe we can get one of the artificial intelligence programs to write a song about it.

Please let us know when the situation has become truly victorious.

 

[mikefitz]

Stringing multiple 12v batteries, each with its own BMS, for 24 or 48 volt systems, will always end badly, issues can be reduced to some extent by using additional mid point balance units.
Having more than one loose internal connection suggests the Battleborn battery is perhaps not the quality item thats perceived.

 

[JunglePower]

Stringing multiple 12v batteries, each with its own BMS, for 24 or 48 volt systems, will always end badly, issues can be reduced to some extent by using additional mid point balance units.
Having more than one loose internal connection suggests the Battleborn battery is perhaps not the quality item thats perceived.

I will say this about that:
If charging guidelines for lifepo batteries are .5C or 50% of capacity, why at 48 amps do the B+ terminals get hot enough to soften the plastic where the terminal post bolts to the bus bar?

Also, I have been charging each BB10012 individually. The charger takes forever to drop past the last 0.25adc. Is this normal or is the BMS trying to finish balancing the individual cells?

After years of adding water, doing EQ charge sessions, cleaning and checking SG with Rolls FLA batteries, I thought those days were over with LiFePo cells.

But alas, they require testing for cell balance every so often, especially if they do not reach at least 14.4vdc weekly.

Now is it possible to locate a battery with low/unbalanced cells whilst it is still connected in the full string? Like I mentioned, a low one can wreak havoc on the rest of the string and go unnoticed.

 

[HarryN]

I will say this about that:
If charging guidelines for lifepo batteries are .5C or 50% of capacity, why at 48 amps do the B+ terminals get hot enough to soften the plastic where the terminal post bolts to the bus bar?

Also, I have been charging each BB10012 individually. The charger takes forever to drop past the last 0.25adc. Is this normal or is the BMS trying to finish balancing the individual cells?

After years of adding water, doing EQ charge sessions, cleaning and checking SG with Rolls FLA batteries, I thought those days were over with LiFePo cells.

But alas, they require testing for cell balance every so often, especially if they do not reach at least 14.4vdc weekly.

Now is it possible to locate a battery with low/unbalanced cells whilst it is still connected in the full string? Like I mentioned, a low one can wreak havoc on the rest of the string and go unnoticed.

First - don't use the general guideline that LiFe batteries can be charged at 0.5 C. That is just not universal at all.

In this particular case, yes, the 50 amp max charge rate of the BBs happens to coincide, but there are MANY LiFe batteries that cannot be charged that quickly. Often it is not so much the cell chemistry, but the BMS that cannot handle it.

Within the battery case itself, the cells do need to be balanced. In older cell builds, the BMS was used to "top level" this charge after each fill if you will. This was activated by holding at or around 14.1 - 14.4 volts.

Modern / high quality cells are so consistent cell to cell that balancing does not need to be done all that often - but it does need to be done sometimes. Others will comment on exactly how often but certainly it is less than once a week. There are plenty of vans out there that probably are doing it less than 1 / month.

Once you get the batteries top balanced and matched - they will stay that way for a long time in normal use.

There are balancers and chargers that are used to "match" two batteries wired in series. For instance that dual pro company that I suggested as well as some others.

I am in no way dismissing the value of an "optimum setup" but it is very common to use those BBs in 24 and 48 volt packs for years with good success. I check mine every quarter just to look and nothing really happens - same with the Lifeline AGMs that I use.

I ask my customers to do a check or stop by once a year to take a look and within what I can measure it is hard to tell them apart.

 

[JunglePower]

First - don't use the general guideline that LiFe batteries can be charged at 0.5 C. That is just not universal at all.

In this particular case, yes, the 50 amp max charge rate of the BBs happens to coincide, but there are MANY LiFe batteries that cannot be charged that quickly. Often it is not so much the cell chemistry, but the BMS that cannot handle it.

Within the battery case itself, the cells do need to be balanced. In older cell builds, the BMS was used to "top level" this charge after each fill if you will. This was activated by holding at or around 14.1 - 14.4 volts.

Modern / high quality cells are so consistent cell to cell that balancing does not need to be done all that often - but it does need to be done sometimes. Others will comment on exactly how often but certainly it is less than once a week. There are plenty of vans out there that probably are doing it less than 1 / month.

Once you get the batteries top balanced and matched - they will stay that way for a long time in normal use.

There are balancers and chargers that are used to "match" two batteries wired in series. For instance that dual pro company that I suggested as well as some others.

I am in no way dismissing the value of an "optimum setup" but it is very common to use those BBs in 24 and 48 volt packs for years with good success. I check mine every quarter just to look and nothing really happens - same with the Lifeline AGMs that I use.

I ask my customers to do a check or stop by once a year to take a look and within what I can measure it is hard to tell them apart.

Thanks. I think I am spooked by how many of the 6 batteries for 24vdc were low and not knowing how to test them individually whilst connected.
The only true SOC/SOH test is with the entire string disconnected, testing each battery by itself.
Correct?

 

[KITROBASKIN]

A loose internal connection could be the result of very bumpy transport during delivery or use?

Could have been a single oversight by a Battle Born factory worker? These things can happen with the best of companies, right?

 

[JunglePower]

A loose internal connection could be the result of very bumpy transport during delivery or use?

Could have been a single oversight by a Battle Born factory worker? These things can happen with the best of companies, right?

Thanks for your comment. I'm not sure which came first, loose, then heat then open circuit or heat from high amps then open circuit. Whatever the case, Battle Born is steadfast in their customer support.

 

[Bluedog225]

Minor aside Jungle, I’m fairly confident double nutting is a bad idea. Instead, properly torque a single nut for more reliable connection.

 

[HarryN]

Thanks. I think I am spooked by how many of the 6 batteries for 24vdc were low and not knowing how to test them individually whilst connected.
The only true SOC/SOH test is with the entire string disconnected, testing each battery by itself.
Correct?

To some extent, yes you are a bit spooked.

I would not be too worried about the individual capacity of each battery having shifted.

If it were my setup, what I would do:
- sort out the batteries into 3 piles
- ones that you have no faith in at all
- ones that you have confidence in based on their physical attributes. (terminals are solid )
- ones that you are not sure of.

1) I would take all of the ones that I was the most confident about and bring them to roughly the same voltage.

2) Then I would connect these all together in parallel and apply a solar charge for a few days. After this time, you can be pretty sure that they are fully charged to effectively 100% SOC and are balanced with each other. Perhaps limit it to not more than 5 - 10 amps per battery in the pack.

3) Go ahead and use these in 24 volt packs in the other off grid home, ideally with the breakers in place for each parallel pack. This might require some rationing on the part of your guests for a bit.

_________________

4) Inspect / review the ones that you are unsure about. Do what you can to gain some confidence or move to the "I don't trust them pile"

5) Repeat (2) above and perhaps test a bit to see if they get hot or not from reasonably healthy charge / discharge cycles with some testing that is fully under your control.

6) Once you have these working, then I would take them over to the other site and try to get both their pack and these at roughly the same voltage. Then hook them up.

 

[JunglePower]

To some extent, yes you are a bit spooked.

I would not be too worried about the individual capacity of each battery having shifted.

If it were my setup, what I would do:
- sort out the batteries into 3 piles
- ones that you have no faith in at all
- ones that you have confidence in based on their physical attributes. (terminals are solid )
- ones that you are not sure of.

1) I would take all of the ones that I was the most confident about and bring them to roughly the same voltage.

2) Then I would connect these all together in parallel and apply a solar charge for a few days. After this time, you can be pretty sure that they are fully charged to effectively 100% SOC and are balanced with each other. Perhaps limit it to not more than 5 - 10 amps per battery in the pack.

3) Go ahead and use these in 24 volt packs in the other off grid home, ideally with the breakers in place for each parallel pack. This might require some rationing on the part of your guests for a bit.

_________________

4) Inspect / review the ones that you are unsure about. Do what you can to gain some confidence or move to the "I don't trust them pile"

5) Repeat (2) above and perhaps test a bit to see if they get hot or not from reasonably healthy charge / discharge cycles with some testing that is fully under your control.

6) Once you have these working, then I would take them over to the other site and try to get both their pack and these at roughly the same voltage. Then hook them up.

Great information and suggestions. I'm on that road as I write. Two are holding steady at 13.6 after their 48dc charge/balance.
Two are still in resuscitation but looking good.
I have a month during which the house will be unoccupied so I have them all on the bench. An endurance test (just leaving them alone) is next.
I will be using breakers in the string from now on!

 

[JunglePower]

That is interesting. Note that the max rated charge current is 50 amps for the BBs and they have one of the higher charge rates of batteries on the market for size 27s commercial batteries. Many LiFe batteries on the market have max charge rates of 1/2 of that. For the stuff that I build, I really need the high charge rate and that is exactly why I use Lifeline AGM and BB LiFe batteries in my builds.

Li batteries are a little bit like a black hole. They will try to suck dry the universe if you let them - even if they destroy themselves in the process. It is up to you to regulate how fast they are allowed to absorb that energy. If your charger has too much power capability, then you will need to spread it out over more batteries in parallel.

I use a charger from dual pro to balance charge batteries to make a sort of "matched set" prior to using them in 24 and 48 volt banks.

Another method that works is to wire them all together in parallel / 12 volt, and put them on a small solar charger ( like 100 - 200 watts ) and just let it run for a while. In a pinch you can even just hook it up with a nominal 12 volt panel and no charger if you keep an eye on it with a volt meter.

After a while they will all be pretty balanced with each other. At that point, usually they stay balanced for years.

Don't beat yourself up for going through a learning process. Experience doesn't come for free and without some pain - We just don't always talk about that part.....

________--

I still remember being in a physics class ~ 1979 and the professor was up front. He needed something for a demonstration and ended up using a fairly expensive book as a prop - more or less destroyed it in the process. We were all poor students and one of my buddies asked - "why did you destroy that expensive book? His broken english response "knowledge costs money".

I think a follow-up is helpful. I put four of the healthiest batteries in parallel (after individual balancing) for a few days. No change, they held 13.5vdc. So yesterday I connected them in series with brand new cables and got 26.97vdc.

This morning they read 26.94vdc. I'm gonna leave them and continue to monitor them before hauling them back over to the other house.

Just an update.

 

[HarryN]

I think a follow-up is helpful. I put four of the healthiest batteries in parallel (after individual balancing) for a few days. No change, they held 13.5vdc. So yesterday I connected them in series with brand new cables and got 26.97vdc.

This morning they read 26.94vdc. I'm gonna leave them and continue to monitor them before hauling them back over to the other house.

Just an update.

Good news.

It takes a few charge / discharge cycles where the charge voltage hits ( I think ) > 14.1 volts for the BMS to do the internal balancing between cells.

So perhaps put a load on them to bring the SOC down enough to trigger a solar charge cycle.

 

[JunglePower]

Good news.

It takes a few charge / discharge cycles where the charge voltage hits ( I think ) > 14.1 volts for the BMS to do the internal balancing between cells.

So perhaps put a load on them to bring the SOC down enough to trigger a solar charge cycle.

Thanks. I did this prior to connecting them together. The average for each individual battery was as low as 12.8vdc when I began gradual charging to each (almost a full day per battery). Once the charger draw was below a full amp at 13.6, I set it to 47.8 for each one until the charger amps were nil. I then set them aside for a couple days as they settled to 13.5 on the average.

 

[JunglePower]

Good news.

It takes a few charge / discharge cycles where the charge voltage hits ( I think ) > 14.1 volts for the BMS to do the internal balancing between cells.

So perhaps put a load on them to bring the SOC down enough to trigger a solar charge cycle.

It's fascinating to watch the BB BMS do their job. I have three "resting" after disconnecting them from a parallel charge. They remained around 13.98, 13.97vdc for two days, now one has jumped to 14.14vdc overnight.
I really need to get them all balanced before the new warranty-replacement batteries arrive from BB. Seems it takes almost three days of careful charging and monitoring to insure they are stable and balanced.

 

[HarryN]

It's fascinating to watch the BB BMS do their job. I have three "resting" after disconnecting them from a parallel charge. They remained around 13.98, 13.97vdc for two days, now one has jumped to 14.14vdc overnight.
I really need to get them all balanced before the new warranty-replacement batteries arrive from BB. Seems it takes almost three days of careful charging and monitoring to insure they are stable and balanced.

Looks like real progress on the balancing. Interestingly the full balancing does not happen until the pack hits at least 14.1 IIRC. You have a few more days to go.

 

[JunglePower]

Looks like real progress on the balancing. Interestingly the full balancing does not happen until the pack hits at least 14.1 IIRC. You have a few more days to go.

 

[JunglePower]

Yes, thanks. Seems they are settling at 13.46 across the first three for a couple days. This was their voltage when I first pulled them out of the box when new.
I have until the 25th to insure they are ready for service. My wife calls them "my babies."

 

[HarryN]

On some chargers, they go into a sort of standby mode after xx hrs to prevent issues in case something goes wrong.

I am not sure if it is the right thing to do or not, every few days on a charger, I will unplug the charger, let things setting for a few hours - and plug it back in. Seems to help on my charger.

This is not in the manual and you have to really watch it, but if you have a small panel nominal Vmp ~ 18 volts, you can just hook it up to some in parallel and let it run for a while. It will just trickle in.

You have to really keep an eye on things though so it does not go out of control and go to like 15 volts or more.