4x 24V EG4 200Ah vs 4x 48v EG4 100Ah….

[NC_hydro]

So help me understand why anyone would do 24V 200Ah EG4 Lifepower, two each in parallel and then each in series, to power a 48V Sol-Ark 12k…. Have seen two setups now where I think the same person has advised this and the first they are always having issues with two batteries getting out of balance and shutting off. The second person hasn’t even opened their batteries yet and is thinking of sending them back (they’ve had them unopened a year). When I asked they said oh they said because the 24v batteries were 200Ah vs 100Ah of the 48V. But they’re both 5kWh each….I don’t think they are getting the benefit they think they are..

 

[FilterGuy]

So help me understand why anyone would do 24V 200Ah EG4 Lifepower, two each in parallel and then each in series, to power a 48V Sol-Ark 12k

I don't think there is one.

.I don’t think they are getting the benefit they think they are..

Yup.... confusing Amp-hour as an energy rating without considering the voltage is a mistake we have seen a few times.

 

[NC_hydro]

I don't think there is one.


Yup.... confusing Amp-hour as an energy rating without considering the voltage is a mistake we have seen a few times.

Thanks, that was my understand but wanted to make sure I wasn't misunderstanding. Much appreciated.

 

[underdog5004]

I have four 24 volt 200 amp hour life Power Batteries two each and series to reach 48 volts. The reason for this is because I started off on a 24 volt system and recently upgraded to a 48 volt system. I recently got a couple more easy for Life Powers this time 48 volt 100 amp hours and they all seem to play nice together. The monitoring is a little wonky because of the additional cells that are shown in the BMS monitoring compared to the 24 volt batteries 16 versus 8 but otherwise seems to do well. I have noticed that one of my series pairs of 24 volt batteries is showing a pretty serious imbalance where one is at 3.3 volts per cell average while the other one is at 3.56 volts per cell and is showing an over volt alarm this just happened this morning my plan is to disconnect these two batteries connect to 24 volt inverter to the higher One and drain it down to average 3.3 Volts for sale then reconnect and see if that manual balancing had the intended effect. The 24 volt batteries were about a year and a half old before I connected them in series to reach 48 volts.

 

[FilterGuy]

I have four 24 volt 200 amp hour life Power Batteries two each and series to reach 48 volts.

Please check with Sig Solar or EG4 to find out if this is supported.

 

[underdog5004]

Please check with Sig Solar or EG4 to find out if this is supported.

I did, it is, but I've also got a letter i to them today about this unbalanced pair situation. I don't feel great about it...

 

[underdog5004]

Please check with Sig Solar or EG4 to find out if this is supported.

Can I wire 2 EG4-LifePower4 24v 200Ah to create a 48v?

I was in the process of building a 24v system, but decided to reconsider and go for 48v. So the simple question is: can i take 2 EG4-LifePower4 24v/200AH and put them in series to make a 48v battery system. I've read through the manual and I don't see anything that says "Don't do this" and...

diysolarforum.com

Also

https://diysolarforum.com/threads/would-these-work-together.31214/post-377966

 

[timselectric]

I did, it is, but I've also got a letter i to them today about this unbalanced pair situation. I don't feel great about it...

This is normal when putting BMS controlled batteries in series. They will drift away from each other. And need periodic balance maintenance. Either manually (separate and fully charge individually) or with extra equipment to automatically balance series connected batteries.

 

[underdog5004]

This is normal when putting BMS controlled batteries in series. They will drift away from each other. And need periodic balance maintenance. Either manually (separate and fully charge individually) or with extra equipment to automatically balance series connected batteries.

I'd like to get ahead of this "balancing act" if possible. Can you recommend an external battery balancer for 24v batteries?

Edit: looks like victron has a 24v balancer for around 70$...

 

[timselectric]

I'd like to get ahead of this "balancing act" if possible. Can you recommend an external battery balancer for 24v batteries?

Edit: looks like victron has a 24v balancer for around 70$...

Yup

 

[underdog5004]

Yup

Looks like I was mistaken. The victron balancer is made for balancing 12v segments of a 24v or 48v nominal bank. I need something that will balance 24v segments of a 48v nominal bank. Any suggestions?

 

[timselectric]

Looks like I was mistaken. The victron balancer is made for balancing 12v segments of a 24v or 48v nominal bank. I need something that will balance 24v segments of a 48v nominal bank. Any suggestions?

Oh, right.
I don't know of any, personally. But, they probably exist.

 

[hwy17]

Use 4 12v for 4x the amp hours.

 

[underdog5004]

OK, I fixed the pack imbalance issue by taking these 2 batteries off line, disconnecting, then wiring in parallel with #2 cables. Turned on the first (low) one, connected to bms to monitor, then turned on the second (higher) battery. There was immediate high current flow, up to around 99a, for a couple moments, with exponential decay. Within 5 minutes, both packs showed the same internal voltage and no current flow. I turned off the packs disconnected them then rewired them in series for 48 volt nominal then reconnected them to the rest of my power bank and no worries they seem to be in line with everything else now. Unfortunately this looks like something I will have to do on a weekly or monthly basis and I will now always be worried about a cell over voltage or pack imbalance condition. I do plan to get 48 volt batteries in the future but for now I think I'll live with the eccentricities of running two 24 volt batteries in series for 48 volt nominal.

 

[K2mannn]

Good to know underdog. Thanks for sharing. I've told friends who were buying new systems that 24V is really obsolete.