It shouldn't matter as it's a somewhat high impedance path (and when balancing you don't really care about voltage drop differences as the BMS can't measure the voltage because of said voltage drop).
New BMS from IC GOGOGO Store / E&J Technology Group
- Thread starter Frank in Thailand
- Start date
It shouldn't matter as it's a somewhat high impedance path (and when balancing you don't really care about voltage drop differences as the BMS can't measure the voltage because of said voltage drop).
Frank in Thailand
making mistakes so you don't have to...
Frank in Thailand
making mistakes so you don't have to...
Depending a bit on the length of the cables and the thickness.
For me I added 30cm on each cell, 2 wires.
My new setup will have 1mm2 wire from the terminal to the BMS / active balancer.
(Actually, I'm building the DIYBMS, that have different setup)
I don't know yet how much it will help the thicker cable and busbars, it should make measurements more accurate.
For the balancing it has almost no effect.
For BMS the same, as I like it to stop at 2.8-3.5
(MPPT inverter settings are set at 10-90%, maybe go in the future to 15-85%)
BMS is last resort, it normally should only be eating dust and never start working at all.
In case of emergency, like your seatbelt, it can safe your battery bank.
Giela
Newbie in Lifepo4 build for my RV
So If you work with that and with a Victron BMV712 with low and high voltage cutoff, it also works likes a BMS right?
Frank in Thailand
making mistakes so you don't have to...
No, sadly it does NOT!
I wish it did.
Lifepo4 (lithium general) doesn't self Balance like a 12v lead acid.
That have 6 cells, if there is voltage difference between them, it stabilise.
Lithium doesn't.
And it does get out of balance.
That's just how it works.
You can't stop this from happening.
With high charge and discharge like electric vehicle, this happens quite fast.
With low charge and discharge (like regular solar use) it goes a lot slower.
But it does get out of balance!!
At the top of the charge, between 3.5 and 3.65v there are just a few ah needed, like 1Ah for 100Ah cell.
When a cell goes too far out of balance, the other cells are still at the 3.49 bump, and a few already passed it, boosting to 3.65.
The BMS should be able to burn of the extra amps for the higher charged cells, giving the ones that are left behind time to keep up.
The cell should not be charged further than 3.65.
If it does damage can / will occur.
The BMS doesn't only slow down the charge of the highest cells, it also stops if one goes too far.
Sadly it can't stop 1 cell, only the whole battery.
One of the reasons for me to have the active balancer.
It helps reduce the (too) high charged cells, and boost the lower charged ones.
Still, depending on your charge speed (and that can be on a sunny day more Amps / watts then you first thought), one of the cells may get close to or pass that 3.65 volt mark
Then the BMS does need to do its job.
If it doesn't, you have one or more batteries in that parallel string damaged, and next day it gets more out of balance due this damage.
As result the next parallel string reached the 3.65 mark too fast, and your damaged string is still on 3.45 ...
(Or even lower, depending on damage)
Your settings on the inverter and charger don't help if the cells are too far out of balance.
As more cells get damaged, more imbalance occur.
Without BMS cell after cell is killed.
Manual monitoring works just as fine, if you stop the charge when it gets too high, and / or burn of the highest charge with resistor.
Most people don't like to watch their battery array so closely.
Bigger array is more stable.
I went from 32*152Ah to 48x, and that already helped.
Next step with 16*280Ah made it even more stable.
I'm still dubbing if I want to spend the money ($1400) to get +1000ah 50 kWh
It's now 736, 37.5 kWh
I'm a sucker for round numbers
BMS is a must, like your seatbelt.
You never need it.
Untill you do.
The damage without... You really don't want to know.
Safety first.
Giela
Newbie in Lifepo4 build for my RV
No, sadly it does NOT!
I wish it did.
Lifepo4 (lithium general) doesn't self Balance like a 12v lead acid.
That have 6 cells, if there is voltage difference between them, it stabilise.
Lithium doesn't.
And it does get out of balance.
That's just how it works.
You can't stop this from happening.
With high charge and discharge like electric vehicle, this happens quite fast.
With low charge and discharge (like regular solar use) it goes a lot slower.
But it does get out of balance!!
At the top of the charge, between 3.5 and 3.65v there are just a few ah needed, like 1Ah for 100Ah cell.
When a cell goes too far out of balance, the other cells are still at the 3.49 bump, and a few already passed it, boosting to 3.65.
The BMS should be able to burn of the extra amps for the higher charged cells, giving the ones that are left behind time to keep up.
The cell should not be charged further than 3.65.
If it does damage can / will occur.
The BMS doesn't only slow down the charge of the highest cells, it also stops if one goes too far.
Sadly it can't stop 1 cell, only the whole battery.
One of the reasons for me to have the active balancer.
It helps reduce the (too) high charged cells, and boost the lower charged ones.
Still, depending on your charge speed (and that can be on a sunny day more Amps / watts then you first thought), one of the cells may get close to or pass that 3.65 volt mark
Then the BMS does need to do its job.
If it doesn't, you have one or more batteries in that parallel string damaged, and next day it gets more out of balance due this damage.
As result the next parallel string reached the 3.65 mark too fast, and your damaged string is still on 3.45 ...
(Or even lower, depending on damage)
Your settings on the inverter and charger don't help if the cells are too far out of balance.
As more cells get damaged, more imbalance occur.
Without BMS cell after cell is killed.
Manual monitoring works just as fine, if you stop the charge when it gets too high, and / or burn of the highest charge with resistor.
Most people don't like to watch their battery array so closely.
Bigger array is more stable.
I went from 32*152Ah to 48x, and that already helped.
Next step with 16*280Ah made it even more stable.
I'm still dubbing if I want to spend the money ($1400) to get +1000ah 50 kWh
It's now 736, 37.5 kWh
I'm a sucker for round numbers
BMS is a must, like your seatbelt.
You never need it.
Untill you do.
The damage without... You really don't want to know.
Safety first.
Great, thanks for you explanation!
I think I'm gonna use a Daly BMS then, a 4S 12volt BMS for my 8S (4x2S) 12v battery and will monitor it with a BattGO BG-8S to watch all individual cells. Just to be sure then. I think that would be a good enough system
I know you can use a separate port BMS for charging, but what does the seperate port do? Balance charge it?
Frank in Thailand
making mistakes so you don't have to...
The separate port have one port for charge, the other for discharge.
For balancing, the (reliable) Daly (not smart edition) is one of the worse BMS.
With its 0.35ma it's about nothing.
The BattGO BG-8S have good Balance function, and if you use it for solar, check and if needed Balance every 3 months normally is enough.
Several other BMS have more power for balancing (burn off excessive watts)
Daly is one of the more reliable brands.
The new type "Smart" is really not ready for launch.
For balancing, the (reliable) Daly (not smart edition) is one of the worse BMS.
With its 0.35ma it's about nothing.
The BattGO BG-8S have good Balance function, and if you use it for solar, check and if needed Balance every 3 months normally is enough.
Several other BMS have more power for balancing (burn off excessive watts)
Daly is one of the more reliable brands.
The new type "Smart" is really not ready for launch.
Giela
Newbie in Lifepo4 build for my RV
0,35ma? That is really bad indeed. I think I will do that then. Use a Daly BMS for protection and the BG-8S for monitoring if it need balancing. Can't find a reliable BMS which have it all. A Daly with better balance function and bluetooth would be the way to go. The Daly is really good build quality but if it ain't working good enough...
Frank in Thailand
making mistakes so you don't have to...
Sadly the Daly with Bluetooth (smart) isn't ready yet.
The ones who did buy are sorry they did (me included)
You have 2*12 Volt?
2 different chargers and inverters?
Otherwise you can put them together, 2 cells in parallel, 4 in series.
On 12 Volt, the Amperage goes high fast, with imbalance as result.
I don't know your charge and discharge.
Higher amperage is faster imbalance.
Probably start with Balance charge first.
If they are new cells, they probably are already a good match.
Many people don't charge 100% full but try to stay in the range of 15-85% or 7-93% to increase cycle life.
(Can give 50% boost) only once and a while they go closer to Full, to balance.
Depending on your cells and usage, you need to balance every day/week/month/ quarter or half year.
Best is to monitor closely the first period, and slowly loosen.
There is a videos of Will about top Balance.
Be careful, babysit.
If you let it charge like I did, you might end up with bloated cells.
They aren't useless (depending on your overcharge) no longer nice to look at.
Most people continue to use, without noticing any difference.
Some choose to buy new cells.
My vision is that slightly bloated lifepo4 cells aren't dangerous.
Bloated Lithium polymer is.
Some people say all bloated are as dangerous as lithium polymer..
Up to you to decide.
If you no longer want to use then, please send to me. I'll pay for the postage cost
Top Balance can be needed and can be dangerous for your cells if you just let them be.
Charging takes for ever to pass the 3.49 volt per cell.
The step from 3.49 to 3.65 (and over) is just a few minutes !!!!
(As @Jeremiah found our recently)
I like the active balancer who does all the time something and prevent to go too much out of balance (in theory)
High C rate charge or discharge, that's something it can't handle.
The BMS or BattGO BG-8S need to do that
The ones who did buy are sorry they did (me included)
You have 2*12 Volt?
2 different chargers and inverters?
Otherwise you can put them together, 2 cells in parallel, 4 in series.
On 12 Volt, the Amperage goes high fast, with imbalance as result.
I don't know your charge and discharge.
Higher amperage is faster imbalance.
Probably start with Balance charge first.
If they are new cells, they probably are already a good match.
Many people don't charge 100% full but try to stay in the range of 15-85% or 7-93% to increase cycle life.
(Can give 50% boost) only once and a while they go closer to Full, to balance.
Depending on your cells and usage, you need to balance every day/week/month/ quarter or half year.
Best is to monitor closely the first period, and slowly loosen.
There is a videos of Will about top Balance.
Be careful, babysit.
If you let it charge like I did, you might end up with bloated cells.
They aren't useless (depending on your overcharge) no longer nice to look at.
Most people continue to use, without noticing any difference.
Some choose to buy new cells.
My vision is that slightly bloated lifepo4 cells aren't dangerous.
Bloated Lithium polymer is.
Some people say all bloated are as dangerous as lithium polymer..
Up to you to decide.
If you no longer want to use then, please send to me. I'll pay for the postage cost
Top Balance can be needed and can be dangerous for your cells if you just let them be.
Charging takes for ever to pass the 3.49 volt per cell.
The step from 3.49 to 3.65 (and over) is just a few minutes !!!!
(As @Jeremiah found our recently)
I like the active balancer who does all the time something and prevent to go too much out of balance (in theory)
High C rate charge or discharge, that's something it can't handle.
The BMS or BattGO BG-8S need to do that
Giela
Newbie in Lifepo4 build for my RV
Sadly the Daly with Bluetooth (smart) isn't ready yet.
The ones who did buy are sorry they did (me included)
You have 2*12 Volt?
2 different chargers and inverters?
Otherwise you can put them together, 2 cells in parallel, 4 in series.
On 12 Volt, the Amperage goes high fast, with imbalance as result.
I don't know your charge and discharge.
Higher amperage is faster imbalance.
Probably start with Balance charge first.
If they are new cells, they probably are already a good match.
Many people don't charge 100% full but try to stay in the range of 15-85% or 7-93% to increase cycle life.
(Can give 50% boost) only once and a while they go closer to Full, to balance.
Depending on your cells and usage, you need to balance every day/week/month/ quarter or half year.
Best is to monitor closely the first period, and slowly loosen.
There is a videos of Will about top Balance.
Be careful, babysit.
If you let it charge like I did, you might end up with bloated cells.
They aren't useless (depending on your overcharge) no longer nice to look at.
Most people continue to use, without noticing any difference.
Some choose to buy new cells.
My vision is that slightly bloated lifepo4 cells aren't dangerous.
Bloated Lithium polymer is.
Some people say all bloated are as dangerous as lithium polymer..
Up to you to decide.
If you no longer want to use then, please send to me. I'll pay for the postage cost
Top Balance can be needed and can be dangerous for your cells if you just let them be.
Charging takes for ever to pass the 3.49 volt per cell.
The step from 3.49 to 3.65 (and over) is just a few minutes !!!!
(As @Jeremiah found our recently)
I like the active balancer who does all the time something and prevent to go too much out of balance (in theory)
High C rate charge or discharge, that's something it can't handle.
The BMS or BattGO BG-8S need to do that
I have 8 new CalB 100ah cells which I made a 12V battery pack from. So a 200ah 12V (4x2S) battery which I use it in my RV. I have a solar charger with 100watt solarpanel and a Victron Multiplus for charging and inverting. I use very little AH, maximum 14ah with the fridge and heating on. The charger I can setup the AH as high (or low) as I want. So I set it to 20ah right now with a 14.0V absorption voltage. That 20ah is the maximum of the Victron Multiplus.
But how can I balance charge the battery? Via the Separate port on the Daly BMS?
Frank in Thailand
making mistakes so you don't have to...
The balancing goes "automatically" when you reach the region above 3.5v
Daly just can do little.
If it's not mission critical, and you can do a few hours without power, you also can wait till the Daly protect a cell, disconnect the charge if it's 3.65 range or discharge if it's 2.5v range.
Your BattGO BG-8S can level out the difference between the cells at high or low charge state.
It's not a big deal, you'll find out soon enough how it works with hands-on.
Electrodamus is reliable BMS.
I never heard one failed.
Costs a some more then Daly, probably have it faster
(Restock in August)
(Daly overseas transport +8 weeks)
And it comes with all the bells and whistles!! (BT)
Google it
Canadian product!
Daly just can do little.
If it's not mission critical, and you can do a few hours without power, you also can wait till the Daly protect a cell, disconnect the charge if it's 3.65 range or discharge if it's 2.5v range.
Your BattGO BG-8S can level out the difference between the cells at high or low charge state.
It's not a big deal, you'll find out soon enough how it works with hands-on.
Electrodamus is reliable BMS.
I never heard one failed.
Costs a some more then Daly, probably have it faster
(Restock in August)
(Daly overseas transport +8 weeks)
And it comes with all the bells and whistles!! (BT)
Google it
Canadian product!
Frank in Thailand
making mistakes so you don't have to...
I've done some additional reading on the BattGO BG-8S, it is not for Lifepo4!!
(Only 3.7v and higher voltage lithium batteries)
The active balancer, while higher in price probably will suit you better.
(Only 3.7v and higher voltage lithium batteries)
The active balancer, while higher in price probably will suit you better.
Giela
Newbie in Lifepo4 build for my RV
Where did you found that? What I read about the BattGO BG-8S is that it is working with Lifepo4. In fact it is balancing the cells right now. It takes a huge amount of time but still. The Active Balancer you pointed out does need an external supply which I don't have in the RV.
Talked to the guy from ElectroDacus and his system looks like something I need but back in stock end of august. In the meantime I think I'll be working with a Daly BMS and with the BattGo to watch them the first few weeks...
How many MV from each other do we called it balanced?
Attachments
Frank in Thailand
making mistakes so you don't have to...
Battgo website doesn't mention lifepo4 at all.
www.isdt.co
(English website)
Screenshot from the specifications:
For the balancing, I wish it was that easy.
Between 20 and 80% it's almost impossible to say "it is balanced".
The voltages can be almost identical yet have 5 to 10% imbalance.
This is why "we" do top Balance or bottom balance.
At low or high SOC the voltage difference between the cells are getting more obvious.
Between 3.49 and 3.65 is just a few watts, yet "high" voltage difference.
Below 2.6 and -2.5 again bigger difference, jet a few watts.
My Daly stopped at 2.25v, starts again at 2.6v, difference roughly 7-8 watts.
How do I know?
It took my active balancer (1A) 3 hours to get from 2.25 to 2.6 volts
It never hurts to start with fully charged (almost, like 95-98%) lifepo4 cells.
In this region, the Balancer will do its job.
BG-8S - ISDT
ISDT-艾斯特专注于无人机航模领域的电源系统的创新和变革，这只是开始，请尽情期待我们更多创新和变革性的新产品：无人机智能停机坪、无人机户外供电系统、多轴VR穿越机、智能ESC、智能舵机。
www.isdt.co
(English website)
Screenshot from the specifications:
For the balancing, I wish it was that easy.
Between 20 and 80% it's almost impossible to say "it is balanced".
The voltages can be almost identical yet have 5 to 10% imbalance.
This is why "we" do top Balance or bottom balance.
At low or high SOC the voltage difference between the cells are getting more obvious.
Between 3.49 and 3.65 is just a few watts, yet "high" voltage difference.
Below 2.6 and -2.5 again bigger difference, jet a few watts.
My Daly stopped at 2.25v, starts again at 2.6v, difference roughly 7-8 watts.
How do I know?
It took my active balancer (1A) 3 hours to get from 2.25 to 2.6 volts
It never hurts to start with fully charged (almost, like 95-98%) lifepo4 cells.
In this region, the Balancer will do its job.
Last edited:
Giela
Newbie in Lifepo4 build for my RV
Battgo website doesn't mention lifepo4 at all.
BG-8S - ISDT
ISDT-艾斯特专注于无人机航模领域的电源系统的创新和变革，这只是开始，请尽情期待我们更多创新和变革性的新产品：无人机智能停机坪、无人机户外供电系统、多轴VR穿越机、智能ESC、智能舵机。
(English website)
Screenshot from the specifications:
View attachment 17016
For the balancing, I wish it was that easy.
Between 20 and 80% it's almost impossible to say "it is balanced".
The voltages can be almost identical yet have 5 to 10% imbalance.
This is why "we" do top Balance or bottom balance.
At low or high SOC the voltage difference between the cells are getting more obvious.
Between 3.49 and 3.65 is just a few watts, yet "high" voltage difference.
Below 2.6 and -2.5 again bigger difference, jet a few watts.
My Daly stopped at 2.25v, starts again at 2.6v, difference roughly 7-8 watts.
How do I know?
It took my active balancer (1A) 3 hours to get from 2.25 to 2.6 volts
It never hurts to start with fully charged (almost, like 95-98%) lifepo4 cells.
In this region, the Balancer will do its job.
I see in the screenshot that it supports lifepo4 (life) batteries. I will check it out when I get charging and discharging via the Daly the couple of weeks. But what's the difference between seperate port charging en common port?
Great, I will try it out.
Frank in Thailand
making mistakes so you don't have to...
It supports LiFe lithium battery, something different then Lifepo4.
Lithium Iron Phosphate Vs. Lithium-Ion: Differences and Advantages
Advances in battery technologies has placed lithium chemistry at the fore front for being the best power source for high energy use in portable devices.
blog.epectec.com
Difference between common port and separate??
Separate port have one cable for charging and one different for the discharge.
Common port use the cable for charging or discharge.
Frank in Thailand
making mistakes so you don't have to...
Yes, so many different types and naming confusion.
When people talk about lithium or lithium ion, 95% of the time they talk about lithium polymer.
If we assume the manufacturer knows the correct abbreviation, they mention only the higher voltage type of cells (where the Life with 3.6 the lowest one is)
lifepo4 are 3.2 volt.
it doesn't mean it won't work!
its not in the specification. That's all.
I can see from the pictures it's connected and shows the correct Voltage.
I hope it can do the balancing as @Giela likes to use.
@Giela , can you please make new post about the BattGO BG-8S??
I'm really interested to hear about your experience with it.
Can you advise people to buy?
and what can they expect?
MisterSandals
Participation Medalist
Chortle... since you're correcting...
Po4 is polonium IV which should be a quadruple ionized polonium (Po) atom. Highly radioactive and deadly in tiny amounts.
PO4 is phosphate which is a phosphorus (P) atom and 4 oxygen (O) atoms. Commonly found in lithium iron PHOSPHATE batteries.
Frank in Thailand
making mistakes so you don't have to...
? ??
Po4 is polonium IV which should be a quadruple ionized polonium (Po) atom. Highly radioactive and deadly in tiny amounts......
Good we have LiFePO4
??Po4 is polonium IV which should be a quadruple ionized polonium (Po) atom. Highly radioactive and deadly in tiny amounts......
Good we have LiFePO4
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