3-12v in series to an Ecoflow. Help me not die.

[steppinout]

I want to connect three Siekon 12v 100ah batteries in series to a Ecoflow Delta 2 (with the extra battery). I believe this 36v system will maximize the 'siekon to Ecoflow' charging via a xt60i.

1. All three Siekons were bought at different times, will this be okay (they all have different amount of use)?

2. As I understand, before connect them in series I need to charge and balance them. I was going to put each one on the charger to top them off, then connect in parallel to balance. Is this correct? How long will they need to balance?

3. I saw a video where they connected the two batteries they were using into a balancing module (I think that's what they called it). Is that required?

4. Will my Delta 2 be okay with the extra battery and this 36v setup connected at the same time?

5. How do I charge my 36v system when it is empty? In series or in parallel? (My current charger only does 12v&24v so I'd need to buy a new charger... So is it better to keep them in series or will charging them in parallel work just as good?

6. I bought a 20amp circuit breaker. Can I install this in front of the xt60i?

Sorry for the 20 questions, any help is appreciated!!!

 

[j3rk]

1. They should be fine as long as ...
2. You charge them all up to the same voltage. Top each one off, let them rest for a few hours, then check their voltages. If it's within a few hundredths of a volt, you should be good to go. If you connect them in parallel at fully charged, it shouldn't take long for them to balance.
3. I don't know enough about balancing modules to answer this directly. I know I have never used one with my 12v and 24v batteries and don't have any issues.
4. I don't know anything about Delta products specifically, but if the max DC voltage input is higher than 43v, you should be good to go with three 12 volt LiFePO4 batteries in series (max voltage is 14.2v * 3 = 42.6V).
5. You're going to need a 36v charger unless you're crazy enough to disconnect and reconnect the system every time the batteries get low. From a balancing perspective, you don't want to charge each one up individually while it's still in series with the others.
6. Usually circuit breakers are rated for amperage, not voltage. But if you have a breaker that says max 20V, you may want to consider buying something that can handle higher voltages. They're not that expensive.

 

[steppinout]

1. They should be fine as long as ...
2. You charge them all up to the same voltage. Top each one off, let them rest for a few hours, then check their voltages. If it's within a few hundredths of a volt, you should be good to go. If you connect them in parallel at fully charged, it shouldn't take long for them to balance.
3. I don't know enough about balancing modules to answer this directly. I know I have never used one with my 12v and 24v batteries and don't have any issues.
4. I don't know anything about Delta products specifically, but if the max DC voltage input is higher than 43v, you should be good to go with three 12 volt LiFePO4 batteries in series (max voltage is 14.2v * 3 = 42.6V).
5. You're going to need a 36v charger unless you're crazy enough to disconnect and reconnect the system every time the batteries get low. From a balancing perspective, you don't want to charge each one up individually while it's still in series with the others.
6. Usually circuit breakers are rated for amperage, not voltage. But if you have a breaker that says max 20V, you may want to consider buying something that can handle higher voltages. They're not that expensive.

Thank you!
Luckily this is a off grid cabin I use every few weekends. I take the batteries home to charge, so they will be getting disconnect anyway. So I'll just repeat #2.

I edited the post a second after to fix the circuit breaker from volts to amps. Did it not change?

 

[j3rk]

I see the change now. The forum must have cached the original post when I saw and responded to it. A 20A breaker will limit you to ~720W of power at 36 volts before it pops. It shouldn't be a problem to put it between the batteries and the Delta 2; it looks like the Ecoflow site says the maximum solar input is 500W, so you should be fine. It will only try to draw 500W of power from the battery bank, even though that bank could potentially put out much more.