Author Topic: Best DIY 48V Lithium setups and sources right now?  (Read 280 times)

davidshelton

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Best DIY 48V Lithium setups and sources right now?
« on: September 24, 2018, 07:41:45 PM »
So my AGM's are a couple of years old now and I want to donate them to a community project in the area so I am thinking about taking the leap with Lithium so I can learn about the tech before selling systems for my customers. I would like to get about 6-8kWh useable out of them and we'll be giving offgrid living a shot. I have just started researching options. Our energy needs average 4-6kWh daily so pretty small system. I will use the grid as a backup and I also have my trusty Honda gennie just in case. I mostly install Midnite Solar and Outback product and don't plan on changing my system much except for adding some PV.
I would love your thoughts and advice for sourcing a DIY setup from the US.
cheers!
Installer in Central America based out of Nicaragua
FX3048T w/ Epanel and Classic 200SL w/Whizzbang jr, AXS port, 100Ah Outback 106NC,  4 x Topoint 190W 24V 72 cell modules. Grid tied currently.

mike90045

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Re: Best DIY 48V Lithium setups and sources right now?
« Reply #1 on: September 26, 2018, 11:44:44 PM »
>   I would love your thoughts and advice for sourcing a DIY setup from the US.

I would not do DIY Li battery setup.  I don't have the patience to babysit them, and the few DIY BMS systems that exist, don't inspire me.
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV

davidshelton

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Re: Best DIY 48V Lithium setups and sources right now?
« Reply #2 on: September 27, 2018, 12:43:25 PM »
Doing some more research, it seems CALB cells are a fairly low cost way to go. I am not about to be making up hundreds of 186500 batteries even with a kit nor even striping down old laptop batteries and then building packs from the good cells and adding balancers and BMS etc etc. So I am already not DIY but don't want to pay the premium for a pretty box aka integrated solution.
So far Electriccarpartscompany.com seems to have good pricing on the cells. Not sure about the balancers or BMS. I am definitely looking for something reliable as I have to wait for weeks if not months to ship replacement parts down so I need a reliable BMS and a spare on hand.
Installer in Central America based out of Nicaragua
FX3048T w/ Epanel and Classic 200SL w/Whizzbang jr, AXS port, 100Ah Outback 106NC,  4 x Topoint 190W 24V 72 cell modules. Grid tied currently.

ClassicCrazy

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Re: Best DIY 48V Lithium setups and sources right now?
« Reply #3 on: September 27, 2018, 06:42:59 PM »
Doing some more research, it seems CALB cells are a fairly low cost way to go. I am not about to be making up hundreds of 186500 batteries even with a kit nor even striping down old laptop batteries and then building packs from the good cells and adding balancers and BMS etc etc. So I am already not DIY but don't want to pay the premium for a pretty box aka integrated solution.
So far Electriccarpartscompany.com seems to have good pricing on the cells. Not sure about the balancers or BMS. I am definitely looking for something reliable as I have to wait for weeks if not months to ship replacement parts down so I need a reliable BMS and a spare on hand.

Go to main page and do a search for lithium and or Calb batteries.  There have been some detailed discussions in the past on using those and various charging schemes. I tried bottom balancing with no other protection and don't recommend that . It might work with some other safety measures. Seems like there have been various BMS solutions over the years so you will have to do some careful study to figure out what is available.  Read up on the discussions and that will give you a lot of information . 

There are ready made lithium packs with all the BMS built in available now too .

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

RossW

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Re: Best DIY 48V Lithium setups and sources right now?
« Reply #4 on: September 27, 2018, 09:28:35 PM »
Seems like there have been various BMS solutions over the years so you will have to do some careful study

I've been using LFP for 4.5 years now and really happy with the entire setup.
Well before I even got the lithium, I built cell monitors that show me exactly what each cell in my battery is doing.
I consider "monitoring" perhaps the single most important thing you can do to any battery bank, not just lithium. Spot a developing problem early and fix it rather than have to deal with the consequences of a failure later.

With whatever form of cell balancing you choose to use (including none!), cell monitoring gives you the continuous confidence everything is ok.

I run all my loads through an inverter, so the LVD in the inverter is my "failsafe" against over-discharge.
Automatic generator start by the inverter, if battery volts or SoC ever get low (but still well before the LVD) means I've never got close to disconnect, and as such I consider a battery management system with LVD more of a liability than a benefit.

My charge sources all have a capped high voltage that is below the safe limit of the pack.
I have an alarm should voltages get close to that. It's only gone off once, and that was due to a deliberate act to test it.

I consider a battery management system with HVD more of a liability than a benefit too! (in my installation anyway)

I have 900AH @ 52V (around 40kWh of usable capacity) in my bank and am super happy with every aspect of them.
(I do have suitable HRC DC fuses in each bank as the ultimate disaster protection)
3600W on 6 tracking arrays.
7200W on 2 fixed array.
Midnite Classic 150
Outback Flexmax FM80
16 x LiFePO4 600AH cells
16 x LiFePO4 300AH cells
Selectronics SP-PRO 481 5kW inverter
Fronius 6kW AC coupled inverter
Home-brew 4-cyl propane powered 14kVa genset
2kW wind turbine

Matrix

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Re: Best DIY 48V Lithium setups and sources right now?
« Reply #5 on: September 28, 2018, 08:21:31 AM »
Check with mcgivor  and Raj174 over at Northern Arizona Wind & Sun Solar Forum.  I believe they are both doing something similar to what you are wanting.

http://forum.solar-electric.com/discussion/353773/instalation-up-and-running#latest
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

davidshelton

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Re: Best DIY 48V Lithium setups and sources right now?
« Reply #6 on: October 05, 2018, 11:30:05 PM »
Seems like there have been various BMS solutions over the years so you will have to do some careful study

I've been using LFP for 4.5 years now and really happy with the entire setup.
Well before I even got the lithium, I built cell monitors that show me exactly what each cell in my battery is doing.
I consider "monitoring" perhaps the single most important thing you can do to any battery bank, not just lithium. Spot a developing problem early and fix it rather than have to deal with the consequences of a failure later.

With whatever form of cell balancing you choose to use (including none!), cell monitoring gives you the continuous confidence everything is ok.

I run all my loads through an inverter, so the LVD in the inverter is my "failsafe" against over-discharge.
Automatic generator start by the inverter, if battery volts or SoC ever get low (but still well before the LVD) means I've never got close to disconnect, and as such I consider a battery management system with LVD more of a liability than a benefit.

My charge sources all have a capped high voltage that is below the safe limit of the pack.
I have an alarm should voltages get close to that. It's only gone off once, and that was due to a deliberate act to test it.

I consider a battery management system with HVD more of a liability than a benefit too! (in my installation anyway)

I have 900AH @ 52V (around 40kWh of usable capacity) in my bank and am super happy with every aspect of them.
(I do have suitable HRC DC fuses in each bank as the ultimate disaster protection)

Thanks for the detailed response! What was the SOC range you could play in without any individual cell reaching a critical low or high voltage? Did just using balancers keep the pack working together in harmony? Setting the LVD of the inverter within the bottom end of the operating voltage range good enough?
Installer in Central America based out of Nicaragua
FX3048T w/ Epanel and Classic 200SL w/Whizzbang jr, AXS port, 100Ah Outback 106NC,  4 x Topoint 190W 24V 72 cell modules. Grid tied currently.

RossW

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Re: Best DIY 48V Lithium setups and sources right now?
« Reply #7 on: October 06, 2018, 02:33:37 AM »
Depending on the day - we're a month into spring now, and if we've had a decent day previously, my banks are down to about 80% SoC at sunrise and back in float by around 10am. As the days get longer and the nights get shorter that gets even better.

A couple of overcast days sees the batteries getting down a bit. I had to start the generator the other day because I was going interstate for the day, batteries were down to 40% at 6am and I had doubts we'd get any useful sun - and I'd just made modifications to the generator on the weekend so wanted to be here when (if) it had to run. Ran the genset for an hour, brought the bank back up to 53% before I left. Of course we had enough sun then to have reached full charge during the day and I need not have bothered.

The inverter will autostart the genset at 30% SoC or 48V (3.0V per cell), both well within what I'd call "safe" limits. It's only done that a few times in the last 18 months, and has worked flawlessly.

I have simple balancers that maintain equal cell voltages all the time (not just "top-of-charge balancing"), and monitor their state to remain confident everything is doing as it should.
3600W on 6 tracking arrays.
7200W on 2 fixed array.
Midnite Classic 150
Outback Flexmax FM80
16 x LiFePO4 600AH cells
16 x LiFePO4 300AH cells
Selectronics SP-PRO 481 5kW inverter
Fronius 6kW AC coupled inverter
Home-brew 4-cyl propane powered 14kVa genset
2kW wind turbine

mike90045

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Re: Best DIY 48V Lithium setups and sources right now?
« Reply #8 on: October 06, 2018, 02:33:16 PM »
....Ran the genset for an hour, brought the bank back up to 53% before I left. Of course we had enough sun then to have reached full charge during the day and I need not have bothered......

Wife calls the generator "Cloud Repeller"  If not raining, clouds usually clear 20 minuets after starting it up !
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV

ClassicCrazy

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Re: Best DIY 48V Lithium setups and sources right now?
« Reply #9 on: October 06, 2018, 07:14:07 PM »
....Ran the genset for an hour, brought the bank back up to 53% before I left. Of course we had enough sun then to have reached full charge during the day and I need not have bothered......

Wife calls the generator "Cloud Repeller"  If not raining, clouds usually clear 20 minuets after starting it up !

Ha ha - yeah  - often works that way doesn't it !

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie