Can I use my BYD modules and chevy volt modules in my power wall together

[hotrod]

I'm needing so advice from you guys or gals on my power wall set up. I bought a set of the used LiFePo4 BYD 24v 5.63 kwh 220 ah battery modules from tech direct. I'm connecting them for a 48v system I have not capacity tested them yet. The specs on them are

BYD module LiFePo4 cells
Cell over Discharge = 2.50v x 16 cells = 40.0v
Cell over charge = 3.65v x 16 cells = 58.4v

I just came across a super deal on a complete low mile (63,000) 2012 Chevy Volt battery module for 400.00 So I had to purchase it for the price. I know I can break it down to make 8- 48v modules but the problem I see with using them with my BYD modules is the voltage difference's the byd battery will be set up for 48v with 16 cells the chevy volt will be set up for 48v but only 12 cells. I do not want to break the volt modules apart to reconfigure.

Chevy Volt module Lithium Ion LG Chem cells
Cell over Discharge = 3.00v x 12 cells = 36.0v
Cell over Charge = 4.15v x 12 cells = 49.8v
So if I connect these to my system together in a 48v configuration I want have a very wide usable voltage range. 1 can't go below 40.0 volts and the other can't go above 49.8 so that will only give me 9.8 volts to work with and that is at the low limit on 1 battery and the high limit on the other battery which I would not want to do.
How can I make this work using both sets of batteries. Please let me know what would be the best way to set these up to be able to use together.

 

[hotrod]

If I purchase 1 Nissan Leaf module Lithium Ion for each 48v Chevy Volt module could I wire it in series with the volt module to bring the voltage up on each pack.

Chevy Volt low v 36.0v + Nissan leaf low v 5.0v = 41.0v
Chevy Volt high v 49.8v + Nissan leaf high v 8.3v = 58.1v
So this would widen my range to 41.0v to 58.1v
This would give me a 17.1v volt range instead of the 9.8v
Would this work ok together or what do you suggest I do to make these work together. Thanks for any help you can give me on this setup.

 

[jwu_cc]

You would need to consider cell capacity as well and since they are all used batteries the capacity would be all over the place and you'll likely get the overall capacity based on the weakest cell. Plus, Li-Ion and LiFePO4 have different charge and discharge curves they will be on different voltages even at the same SOC, so you may have a difficult time getting balanced charge from the two packs.
I think the best option here would be to put two parallelable inverters if you want to combine the output, one on each pack, so you can adjust discharging parameters separately. Same on the charging side.

 

[hotrod]

You would need to consider cell capacity as well and since they are all used batteries the capacity would be all over the place and you'll likely get the overall capacity based on the weakest cell. Plus, Li-Ion and LiFePO4 have different charge and discharge curves they will be on different voltages even at the same SOC, so you may have a difficult time getting balanced charge from the two packs.
I think the best option here would be to put two parallelable inverters if you want to combine the output, one on each pack, so you can adjust discharging parameters separately. Same on the charging side.

Thanks jwu_cc for your reply
I'm gonna be using a 12kw off grid all in one Growatt split phase inverter so I want be able to split them up without taking part of my 6.25 kw solar array and sending that to a separate charge controller and a separate inverter then tie that into my ac load panel. I may just start out with the chevy volt batteries and see how well they do I'm hoping for about 10 to 12 kw of usable power from those by there self. I just hate not to be able to use the BYD batteries that I payed over a thousand bucks for without spending a lot more money on more equipment.

 

[stargazer]

I'm needing so advice from you guys or gals on my power wall set up. I bought a set of the used LiFePo4 BYD 24v 5.63 kwh 220 ah battery modules from tech direct. I'm connecting them for a 48v system I have not capacity tested them yet. The specs on them are

BYD module LiFePo4 cells
Cell over Discharge = 2.50v x 16 cells = 40.0v
Cell over charge = 3.65v x 16 cells = 58.4v

I just came across a super deal on a complete low mile (63,000) 2012 Chevy Volt battery module for 400.00 So I had to purchase it for the price. I know I can break it down to make 8- 48v modules but the problem I see with using them with my BYD modules is the voltage difference's the byd battery will be set up for 48v with 16 cells the chevy volt will be set up for 48v but only 12 cells. I do not want to break the volt modules apart to reconfigure.

Chevy Volt module Lithium Ion LG Chem cells
Cell over Discharge = 3.00v x 12 cells = 36.0v
Cell over Charge = 4.15v x 12 cells = 49.8v
So if I connect these to my system together in a 48v configuration I want have a very wide usable voltage range. 1 can't go below 40.0 volts and the other can't go above 49.8 so that will only give me 9.8 volts to work with and that is at the low limit on 1 battery and the high limit on the other battery which I would not want to do.
How can I make this work using both sets of batteries. Please let me know what would be the best way to set these up to be able to use together.

 

[TKB4]

In my opinion the best way would be to have a switch to swap the inverter from one bank to the other you could use a voltage sensitive switch to do this, But you would also need to change charge settings etc or maybe just use lifepo at night on a timed switch . Its not going to be easy you would be better off selling one or the other etc. You could do it in parallel if you kept highest charge in safe levels for both chemistries by adjusting number of cells of each etc but definitely not great for the batteries ,
David Poz was considering trying something like this . You might check in on his discussion group to see if he ever did.

 

[TKB4]

BTW many inverters when placed in parallel still need to be attached to the same battery bank. I wanted to do this too but opted not to because of this. Of course you could use the switch like I mentioned above and get desired voltages in similar range without reprogramming each time but you will be wasting ta lot of potential battery capacity. You could also use smaller one for Backup and then use a higher percentage of the main pack since you have a backup.

 

[hotrod]

BTW many inverters when placed in parallel still need to be attached to the same battery bank. I wanted to do this too but opted not to because of this. Of course you could use the switch like I mentioned above and get desired voltages in similar range without reprogramming each time but you will be wasting ta lot of potential battery capacity. You could also use smaller one for Backup and then use a higher percentage of the main pack since you have a backup.

Thanks for your reply TK84, I was thinking the bms's would take care of the charge voltage and wouldn't let the voltage get too high on the (volt) battery modules and the bms would take care of the discharge voltage on the BYD batteries. But that is taking a chance of relying on the BMS's to do there work correctly. If they failed to stop the charge or discharge I could ruin a good set of batteries. I've about decided to remove the BYD's and sell them and install the volt modules the volt modules should over double the amp hour capacity over the BYD's and that should be more than enough for what I'm needing right now. The BYD modules run out of juice about half way through charging my Chevy Volt car when using just battery for charging my car which is what I have to do because the sun is already down when I get home from work. My solar panels and inverter charge the car and charge my BYD modules just fine during the day when the sun is shining and not cloudy.

 

[TKB4]

Thanks for your reply TK84, I was thinking the bms's would take care of the charge voltage and wouldn't let the voltage get too high on the (volt) battery modules and the bms would take care of the discharge voltage on the BYD batteries. But that is taking a chance of relying on the BMS's to do there work correctly. If they failed to stop the charge or discharge I could ruin a good set of batteries. I've about decided to remove the BYD's and sell them and install the volt modules the volt modules should over double the amp hour capacity over the BYD's and that should be more than enough for what I'm needing right now. The BYD modules run out of juice about half way through charging my Chevy Volt car when using just battery for charging my car which is what I have to do because the sun is already down when I get home from work. My solar panels and inverter charge the car and charge my BYD modules just fine during the day when the sun is shining and not cloudy.

yes I understand better now . You still might be able to use a voltage sensitive relay set up to Charge the Volt Pack first then when it reaches the desired voltage switch to the BYD pack. You might be able to get a little more out of the BYD pack by rewiring the weaker cells in parallel together. (see David Poz you tube video on getting more capacity out of his.) I guess you could also use a timed switch to swap the battery pack about when the first should be full on a sunny day but on a less than full sun day neither pack would be full or just physically disconnect BYD before leaving for work if not predicted sun. Of course a remote switch would also be possible. Just a lot of trouble to set up and more expense . I agree i think you would be better off selling the BYD and using that money to buy more Volt batteries or similar chemistry cells to connect in their own parallel packs.

 

[hotrod]

yes I understand better now . You still might be able to use a voltage sensitive relay set up to Charge the Volt Pack first then when it reaches the desired voltage switch to the BYD pack. You might be able to get a little more out of the BYD pack by rewiring the weaker cells in parallel together. (see David Poz you tube video on getting more capacity out of his.) I guess you could also use a timed switch to swap the battery pack about when the first should be full on a sunny day but on a less than full sun day neither pack would be full or just physically disconnect BYD before leaving for work if not predicted sun. Of course a remote switch would also be possible. Just a lot of trouble to set up and more expense . I agree i think you would be better off selling the BYD and using that money to buy more Volt batteries or similar chemistry cells to connect in their own parallel packs.

Do you have a picture or a part number for a remote switch or a voltage sensitive switch I don't have a clue as to what to look for

 

[TKB4]

Here is a link to a remote operated breaker says its wifi operated probably has an app for phone etc. Even my garage door opener has an app to operate it from my phone now. Any of the home automation remote systems can use your phone to remotely turn on a switch or relay just like they do a light etc.

WIFI 230V Circuit Breaker Smart Switch Remote Phone Control Home Appliance OnOff | eBay

1x Wi-Fi Smart Circuit Breaker. It's better to check than to discover a problem after the item have arrived! Before You Order.

www.ebay.com

You could even have a remote camera to view a voltage meter etc but getting a little carried away there.

Here is a voltage sensor switch

Voltage Switch

electronics educational software; graphical assembler program for development of PIC microcontroller systems including robots. Educational software for microchips and electronics, Frame Page

www.elabtronics.com

In general you may want to learn about arduino microprocessors . here is something to use in connection with them.

Max471 Voltage Current Sensor Votage Sensor Current Sensor For Arduino | eBay

Find many great new & used options and get the best deals for Max471 Voltage Current Sensor Votage Sensor Current Sensor For Arduino at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Personally I haven't used any of them just know they exist. It would be nice if these type things were readily available as a solar accessory at AltE and other similar stores and maybe they are . You might call them and see if they have anything available or recommendations.

i think there are large discussions in forums about the arduinos.

 

[steviep19]

I charge an 18650 bank using two of these below.

https://www.amazon.com/dp/B07N6BJWXH/ref=cm_sw_r_cp_api_glt_fabc_7DRM7AEYK852V6WZGGNB?_encoding=UTF8&psc=1

You can set a constant voltage /current. I use a pair of them. One for charging. Another for discharging.

These boost buck converters are great. For battery charging you could set the optimal setting. Then for discharge boost it up to your byd pack voltage. I’m assuming you have a BMS for the volt pack as those cells have the potential to be a flame thrower when over charged.

This has the added Benefit of not disconnecting and reconnecting the volt pack and causing current surges