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Battery Balancer

Initial Top Balancing Lifepo4 24v configuration

I have 4 SOK 12v 206ah batteries going into a 24v 412ah configuration to a Victron MP 3kw/24v

The SOKs have in-built BMS and have been sitting unused (in their shipping boxes) since late last year when I ordered them.

The voltage for each individual 12v battery is currently ~13.07 (two are at .07, one is .06 and one .08).

My question is what would be the best approach to do the initial load top balance? Should I use a bench charger device to bring each one up to proper voltage separately or will the Victron MP do the initial top balance correction even if they are in their ultimate 24v configuration? If the Victron MP will take care of it, are there settings I need to adjust from default for this to occur?


downgrader asked
downgrader commented ·

1 Answer

Cable or busbar for correct midpoint voltage?

In this section of the Wiring Unlimited book, the midpoint connections are illustrated as cables. Should the midpoints be connected to a busbar like the positive and negative cables in order to get the same midpoint voltage across each series?


[image]

damien-walker asked
johnsmith edited ·

3 Answers

Mobile + Stationary battery?

Background: I am converting my EV UTV to run on 48V lithium. I also have a 48V off grid solar system. All controlled by various Victron systems.


Question: Does Victron have a device or combination of devices that can detect when UTV is connected, and let it work as an extended battery without risk of a massive power balance war between the two battery banks?

drogos asked

0 Answers

How to keep 4S 2P 12V 220Ah Gel Victron batterybank balanced?

Hello Everybody,

As mentionned in §6.3 of this article

https://www.victronenergy.com/media/pg/Manual_SmartSolar_MPPT_100-30__100-50/en/operation.html#UUID-8215391b-0004-2e53-2eb5-521a9c260cf1

Gel batteries are not suitable for equalization charge.

How to keep balanced a 4S2P with 8 Victron Gel 12V 220Ah batteries without performing equalization regularly ?

How should be wired the battery bank? parallel wiring then serie

[image]

or

[image]

or Serie then parallel

[image]

In this second solution, wether batterie balancer should be used, each battery string will need battery balancer

What is your feedback about keeping balanced a serie string ?

Thanks for your replies.

cargol66 asked
kevgermany commented ·

2 Answers

Battery balancer

OK so I have 4 12v 100ah lifepo4. They are arranged 2s2p. I get the 24V goes to the positive (in my case a lynx distributor bus bar, similarly I will attach the common to the negative bus bar. I am assuming using the bus bars is OK?

What I am struggling with is the midpoint. I know one wire goes to the first series (either pos or neg). What I am struggling with is the daisy chain to the second series. What gauge wire is that meant to be? My bank uses 4AWG by the way. Is it like the first mid point? Also how don't the batteries get messed up? essentially you are adding an extra parallel connection to the two series banks, right?

That is what is confusing me.

Thanks in advance.

pittsburghred asked
kevgermany answered ·

1 Answer

Can I balance 4 strings of series 4x12(48V) SLA batteries with 3 Victron Balancers?

Can I balance 4 strings of series 4x12(48V) SLA batteries with 3 Victron Balancers?

johnsmith asked
johnsmith commented ·

6 Answers

Parent BMS for 4x 12v LiFePo4 bank

Hello folks,

In my battery bank setup, I have got four identical 12V LiFePo batteries (non-victron) connected in series into a 48V bank. Each battery here has got its own BMS i.e., the BMS's do not talk, each does it's own thing. As you might guess, the first battery to charge up goes open circuit and so the rest of the bank is not charged up properly. I also have imbalance issues during discharge, between the batteries and I suspect within each battery too.

I would like to have a "parent" BMS over all these four batteries. I suppose this would be a 4S 48V BMS if I am getting the type designation right. Is there such a victron product/solution (except the balancer that is) for this need? If anyone here has been in a similar sitiuation, how did you solve it?

J S asked
jjbond edited ·

2 Answers

Victron Battery balancer

Hello everybody,

I'm concerned with a 4S2P Victron Gel 12V 220Ah , so an 8 batteries 48V 440Ah bank in an unbalanced state.

How to recover the batteries with low voltage of 8V ?

could theses batteries be recovered ?

I wonder how the Victron battery balacer is able to manage balancing a 220Ah 48V 4 gel bat. bank with a soo smal current of 0.7A as explained in the datasheet.

What if i have two 220Ah 48V banks in parallel ?

I think battery balancer divert more or less current from the battery with the highest voltage to prevent from over charging. What is the capacity of this current diverting ?

Could you confirm that battery balancer is only acting during charge ?

What's the maximum battery capacity (Ah) the balancer can deal with ?

Thank everybody for your help.

cargol66 asked
kevgermany answered ·

1 Answer

Battery balancer needed?

Just purchased BMV712 Smart - 3 12v batteries in parallel - is a balancer needed? - or could I just rely on a mid-point reading?

kirk4life asked
kevgermany answered ·

2 Answers

Viewing Lithium Smart Balance status without Bluetooth App

so i guess the question is somewhat self explanatory?


Is it possible to view the balance status of the Lithium Smart batteries without using the bluetooth app? for instance, via the colour control GX or something similar?


i agree the app is nice, but just wondering if it can be done? it would be nice for someone to view this status on the screen, rather than needing to connect to it every time to check.

william-brack asked
Stefanie answered ·

1 Answer

Battery Balancer not working?

Hi, I installed a few days ago a Battery Balancer Unit as per the diagram below however instead of 6 Series-Parallel 12v (AGM) Batteries (24v system) I only have 4, when I first installed it the green standby led was on, after a couple of days it has gone out, it's in the engine room so I have been down there to check it in closer detail, I notice on the BMV-712 the Mid-point voltage deviation is showing 0.00% so it appears to be fully in balance. Any clues why the led is not showing, it is still working?


[image]

jcottis asked
kevgermany commented ·

1 Answer

Intermittent use of battery balancer?

I just purchased a Victron battery balancer to correct a voltage imbalance issue I'm having. I have 3 parallel strings of 2x12v batteries. I do not have the midpoints connected, and I don't really want to have to do that.

Only one string has more than an .1v imbalance - 0.4v or so - I suspect I didn't get them fully equalized when installed. My question is, can I use this on an intermittent basis only to correct rather than maintain? I'd like to be able to correct this situation (verify it's not an ongoing battery issue) and remove the balancer, or apply to any string that develops a problem.

Since this balancer is a low current - is there anything stopping me from attaching these with a fused set of jumper clips for a few days as needed? I'd rather not rely on these long term, or have the potential for more issues with an additional installed component.

dtcassist asked
kevgermany answered ·

2 Answers

Checking diagram of an 24V 1000Ah Lead-Gel configured as 5x (2x12V 200Ah)

[image]

Hi all,

We have the challenge that we need to provide a batterie for a Off Grid open environment (construction site).

We have only control of the battery box (All in the Diagram) the rest like charger & solar panels we have no access and no control of it. So therefore, we would like to protect the Battery at least from deep discharge <= 22V

Details:

  • Power Consumption of the Load Mid is 75W/h => Peak 150W/h
  • Power Input from Solar Power is Max 450W for a Very short time.
  • The Capacity is 24V 1000Ah Lead-Gel configured 5x (2x12V 200Ah)

Victron equipment:

  • 1x BMV-712 Smart
  • 1x Smart Battery Protect => I believe this would generate a Problem when Charging::?
  • 1x Battery Balancer

The large size of the battery is because the place (construction site) is in a valley between mountains and therefore the Sun is only a vew hours or sometimes now in the winter no sun for several Days and it is coold +8° to - 20°(extrem at some nights)

Could you check the diagram and guide me to a proper wiring, that would be great

Any help appreciated, thx in advance

lotus111 asked
lotus111 answered ·

2 Answers

Battery Balancer Design - Conflicting Product Manuals

Hi everyone,

Trying to plan a new battery deployment for my off-grid cabin.

I'm planning on installing 4x Victron Smart Lithium Batteries - 12V/200Ah - in a 24V system (2p2s)

I'd also like to include a battery balancer to keep the two sets of series batteries balanced. As per the Battery Balancer manual, bridging the middle connections should allow a single Battery Balancer to manage all 4 batteries.

Picture from the manual for reference:

[image]

This design makes sense to me, I understand that the midpoint connections must be sized appropriately to handle load should a battery fail. However, the manual for the Victron Smart Lithium batteries mentions that midpoints should not be connected together:

[image]

Can someone provide some insight here? I don't understand why the batteries shouldn't be connected like this. Thanks for any help you can give!

cdav3435 asked
cdav3435 commented ·

1 Answer

Another Battery Balancer Query

I've searched, can't find a clear answer.


System is 4*106Ah lead carbon Wired in 2 pairs for 24V. Victron balancer, BMV712 monitor. Pretty new, kit is roughly 12 months old, batteries have never been discharged below 90%. Permanent charge ftom Easy solar.

One bank is always lower than the other, but doesn't alarm. Difference usually about 0.1-0.2 V. Have measured this on the batteries, at the balancer and with the monitor. All agree. Measured the current at the balancer with a clamp meter. It's draining the bank with the lower voltage.

I'm about to start using it more heavily, down to about 20%DOD.


So

Is this normal?

Is it going to lead to battery damage?

What to do?




kevgermany asked
kevgermany commented ·

3 Answers

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