Keeping batteries in series in balance

[jflorey2]

Wow I did not know that. So how about these new Outback carbon batteries do they have a higher carbon content or something? What is it that they have to brag about?

It's marketing. It sounds really cool.

[travissand]

I found this HC02 Equalizer. Looks like a good thing to have ?

https://www.amazon.com/Battery-Equal.../dp/B01JJ4X8CO

I was looking at this balancer myself. The balancer is inexpensive enough and I like the idea of resting assured that they'll stay in balance but can this balancer create problems? I have 32 six volt batteries on my first solar set up. It's only 24 volt system . Unfortunately they sat dead for 2 years and got sulfated. They vary in age by one year. I'm not positive how many kilowatt-hours they hold but somewhere between 5 and 10 instead of 30.

They seem to be having trouble staying balanced. I think I need to identify the weakest view batteries and kick them out of the system. It doesn't help that a lot of my wires are different lengths but are hugely oversized which helps counter the different voltage drops under load. This is not my design but it's enough storage for me so I'll continue using it for now. Anyway my point is I'm wondering if a balancer could help. I'm worried with a balancer installed if a battery starts to short out it will drain all of the others further down then it would have if the balancer wasn't in place. Obviously my batteries are not balanced very well especially now so would this help my situation or hurt? I'd rather not bring every single battery down to the point of the lowest battery instead of the lowest string. Or would it bring the lowest up to the highest or somewhere in the middle? The balancer itself is very inexpensive and I think it would be nice to install with a new set of batteries. I'd like to be able to pull small 12 volt loads for some equipment without throwing things out of balance.

I don't like this guy's comparisons in his sales pitch about a car battery lasting longer. It's not a fair comparison but here's his Pro balancing lead acid sales pitch. https://youtu.be/d7bIwEB3iWk

[travissand]

Every deep cycle battery made today has a bit of carbon and antimony added to the lead.

Wow I did not know that. So how about these new Outback carbon batteries do they have a higher carbon content or something? What is it that they have to brag about?

[jflorey2]

When you say lead acid I assume lead carbon respond the same ?

Lead "carbon" is still lead acid, yes.

[Sunking]

When you say lead acid I assume lead carbon respond the same ?

Same battery no difference. Lead carbon = lead acid. Every deep cycle battery manufacture today adds a bit of carbon to the lead alloy to slow down sulfation. Nothing new, been around 10 or more years.

Deep cycle batteries add carbon, SLI batteries are now adding silver. Every Ford vehicle today uses silver calcium lead acid batteries. Every deep cycle battery made today has a bit of carbon and antimony added to the lead.

[Mike90250]

Hello from Croatia. I am new here and dont want to add new topic so i will ask here... just want to ask you guys one question. I have 24v system. 6 bateries. 2 in a row. What is the critical moment to bateries get charged on generator. They are at morning before sun mostly at 23.4-23.7. In rare cases they fall to 22.9. Any sugesetions?
Ty

Welcome. If you have solar, running the generator in the morning, so that you are shutting it off by 10 am, allows the generator to quickly boost the battery, and then the solar can slowly complete the charging.

If you don't have solar, you have to balance the cost of generator fuel & maintenance against the cost of batteries, save fuel, run generator less = ruins batteries by letting them sit in a low state of charge for long times.

[Adailton11]

Hello from Croatia. I am new here and dont want to add new topic so i will ask here... just want to ask you guys one question. I have 24v system. 6 bateries. 2 in a row. What is the critical moment to bateries get charged on generator. They are at morning before sun mostly at 23.4-23.7. In rare cases they fall to 22.9. Any sugesetions?
Ty

[Helimadness]

Ironically the opposite is true with lead acid.

At first, yes. The 2 that are higher voltage will start to outgas. They will not charge any further, and will convert that extra energy to chemical energy (i.e. will split water into hydrogen and oxygen) and heat. The 2 that are lower will continue to charge until they are back in balance.

This means that lead acids have a mechanism that allows them to come back into balance, at the cost of some lost electrolyte. A well balanced pack (i.e. all purchased at the same time) will need to self-balance very rarely so you won't lose a lot of electrolyte.

However, if you put batteries in parallel, then the "stronger" (lower ESR) strings will take most of the current, leaving little for the "weaker" strings. There may not be enough current to completely charge the lower cells in the weaker strings. This is one of the reasons why multiple parallel strings are a bad idea.

When you say lead acid I assume lead carbon respond the same ?

[jflorey2]

I totally get how batteries in parallel will stay in balance but dont understand how batteries in series can.

Ironically the opposite is true with lead acid.

Dont really have any experience with larger banks in series. The battery voltage read is only the total voltage yeah. So 4x12v = 48v. So the charger can only see the 48v. What happens if 2 batteries are at 11v and 2 at 13v Its still 48v total which is what the charger will see but 2 will get over charged and 2 over discharged yeah ?

At first, yes. The 2 that are higher voltage will start to outgas. They will not charge any further, and will convert that extra energy to chemical energy (i.e. will split water into hydrogen and oxygen) and heat. The 2 that are lower will continue to charge until they are back in balance.

This means that lead acids have a mechanism that allows them to come back into balance, at the cost of some lost electrolyte. A well balanced pack (i.e. all purchased at the same time) will need to self-balance very rarely so you won't lose a lot of electrolyte.

However, if you put batteries in parallel, then the "stronger" (lower ESR) strings will take most of the current, leaving little for the "weaker" strings. There may not be enough current to completely charge the lower cells in the weaker strings. This is one of the reasons why multiple parallel strings are a bad idea.

[Sunking]

My concerns were because it might be left for 6+ months at a time unattended I wanted to make sure it was safe over time.

Well then you do not have much to worry about. Batteries become unblalanced from being used. Batteries on a Float Charger never become unbalanced. Telephone companies have batteries in service up to 40 years, and never ever have an EQ charge except for one time when they were installed.

As for monitoring battery voltage. A waste of time and money with any lead acid battery.

[Helimadness]

For extended absence the most critical thing is preventing the batteries from going dry and exposing plates.
Set your Absorb times to something low, 10 min, and locate what the FLOAT SERVICE voltage settings are, since you won't be cycling these. There are NO loads while you are absent, correct?
Inverter powered off ?

The Lead carbon batteries I was looking at are so called "Maintenance free" So I assume no need or option to top up liquids.
I was thinking of leaving the system live. Maybe just having a outside light on a timer so the place doesn't look totally abandoned. Also will give power to things like cameras I can connect to remotely and will look at setting up remote monitoring for the solar and batteries. So will have very minimal current draw. There is a neighbour I can call on if things start to go pear shaped.

I also love the tech side so the remote monitoring thing is the nerd coming out in me

Cheers

[Mike90250]

For extended absence the most critical thing is preventing the batteries from going dry and exposing plates.
Set your Absorb times to something low, 10 min, and locate what the FLOAT SERVICE voltage settings are, since you won't be cycling these. There are NO loads while you are absent, correct?
Inverter powered off ?

[Helimadness]

No you do not understand anything abou thow batteries charge them from this statement. All batteries except Lithium are self balancing. When one cell becomes charged up, the curent is still passed along to lower cells to charge up. Simple Series Law. !1 = I2 = I3...... The cells that are fully charged stop charging and start heating up, but they still pass current. Try that with Lithium and you will have an explosion.. Last thing you want is Lithium Ion Batteries on a solar system. Buying any battery Balancer is like buying Lithium Ion Batteries for Solar. You just throw away good money.

Ok so the high batteries naturally slow down due to getting inefficient and let the low ones catch up. My concerns were because it might be left for 6+ months at a time unattended I wanted to make sure it was safe over time. Planning on setting up a security system I can monitor remotely and will try and work out a what to get the solar and battery info remotely as well so I can at least monitor.
Cheers

[Sunking]

I totally get how batteries in parallel will stay in balance but dont understand how batteries in series can.

No you do not understand anything abou thow batteries charge them from this statement. All batteries except Lithium are self balancing. When one cell becomes charged up, the curent is still passed along to lower cells to charge up. Simple Series Law. !1 = I2 = I3...... The cells that are fully charged stop charging and start heating up, but they still pass current. Try that with Lithium and you will have an explosion.. Last thing you want is Lithium Ion Batteries on a solar system. Buying any battery Balancer is like buying Lithium Ion Batteries for Solar. You just throw away good money.

[Helimadness]

Charge using the voltages and times recommended by the battery manufacturer. They will stay in balance. Lead acid batteries in series "self balance" during charging.

I totally get how batteries in parallel will stay in balance but dont understand how batteries in series can. Dont really have any experience with larger banks in series. The battery voltage read is only the total voltage yeah. So 4x12v = 48v. So the charger can only see the 48v. What happens if 2 batteries are at 11v and 2 at 13v Its still 48v total which is what the charger will see but 2 will get over charged and 2 over discharged yeah ?

I found this HC02 Equalizer. Looks like a good thing to have ?

https://www.amazon.com/Battery-Equal.../dp/B01JJ4X8CO

Cheers