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LiFePO4 UPS

@smoothJoey I've been thinking along the same lines but going a bit simpler (no Pi req'd) with an all in one LiFePO4 battery with built in bms and charger.

Not as modular/flexible as your setup but should do the same thing. Would appreciate your thoughts.
A $649.00CAD 100ah lifepo4 battery with charger is scary.
Considering the name is "Scream Power", that's nightmare fuel.

UPDATE: Maybe I'm just out of touch. There are lots of batteries in that price range on amazon.ca.
 
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@smoothJoey I've been thinking along the same lines but going a bit simpler (no Pi req'd) with an all in one LiFePO4 battery with built in bms and charger.

Not as modular/flexible as your setup but should do the same thing. Would appreciate your thoughts.
Are you planning an online or offline ups?
Lifepo4 batteries do not like to be full so they should be cycled.
Have you characterized and/or quantified your loads yet?
 
A $649.00CAD 100ah lifepo4 battery with charger is scary.
Considering the name is "Scream Power", that's nightmare fuel.

UPDATE: Maybe I'm just out of touch. There are lots of batteries in that price range on amazon.ca.
ok scream power is just a hilarious name.

i can’t even begin to list the number of marketing jingles they must have available to them…


Yeah, I should have updated the thread. I adapted one of Will's milk crate builds, leaving out the solar charge controller, and using 4x 100Ah packs from batteryhookup.com. Way overkill for the power capacity, but it's working well so far.
awesome!! way to dodge the old chemistry!

feel free to update with details about your specific build :geek:(y) and good luck
 
Details? Well, this is what I used for battery:

Overkill to be sure, but it included the BMS, and I didn't need to mess with bus bars as the cell packs have flexible wires. The four cell packs fit very nicely into the milk crate. Otherwise, the build largely followed Will's video here:

...with the obvious exception of the solar charge controller. I used a 20A power supply instead of the 10A one he linked from his video, and a smaller fuse box. Also added a circuit breaker (in the red 3D-printed bracket at the bottom of the image above) to disconnect AC input power.
 
Yeah, I should have updated the thread. I adapted one of Will's milk crate builds, leaving out the solar charge controller, and using 4x 100Ah packs from batteryhookup.com. Way overkill for the power capacity, but it's working well so far.
@danb35 which charger did you use? how is it working for you? any reliability problems from Drok?
 
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I made my own double conversion ups.
Mine runs a base load of ~256 watts.
It can if needed deliver 1500 watts but in reality the load never exceeds ~512 watts.
At 512 watts my worst case scenario battery backup is 7 hours.
For the base load its 14 hours.

Mine charges off of mains power.
It discharges to ~50% DOD and then charges to full because lifepo4 batteries don't like to be kept full.
Even worse is to expose them to continual voltage stress above their full resting voltage.

Are you looking to build something?
Lifepo4 is not suited for the charge parameters most ups boxes use.
The issue is LFP needs to set at around 50% charge during storage. It doesn't like to rest full.
Most ups boxes float 14.8 for SLA.
A better plan would be a hybrid inverter configured for battery priority, where it runs off battery, switches to ac for charging then repeats.
@Supervstech Actually, Most UPS < 1000watts float at 13.6v which is perfect for LifePo4 . Check Will´s Video on Battleborn Factory Tour.
I have tested >20 UPS for Float Voltages.
 
Lifepo4 is not suited for the charge parameters most ups boxes use.
The issue is LFP needs to set at around 50% charge during storage. It doesn't like to rest full.
Most ups boxes float 14.8 for SLA.
A better plan would be a hybrid inverter configured for battery priority, where it runs off battery, switches to ac for charging then repeats.
Eaton makes 2 different versions of LiFePO4 rackmount UPS. Here is one version:
 
@Supervstech Actually, Most UPS < 1000watts float at 13.6v which is perfect for LifePo4 . Check Will´s Video on Battleborn Factory Tour.
I have tested >20 UPS for Float Voltages.
That is perfect for an in use lfp setup.
But if left plugged in, and only drawing from the bank when power is out, 13.6 will keep an LFP at 100% SOC and will degrade the cells in a short time.

For LFP to work in a UPS scenario, there would need to be a 3 fold charge profile, 14.4V then 13.2 float then 12.8 standby.
Otherwise the cells will be held at 100%SOC and fail.
 
To make an UPS requires little more than a decently configurable inverter/charger and a battery.
LFP batteries like to be cycled but many inverter/chargers can be configured to do manage this.
 
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To make an ups requires little more than a decently configurable inverter/charger and a battery.
LFP batteries like to be cycled but many inverter/chargers can be configured to do manage this.
Yes, inverter chargers, or all in ones can be. So it’s best to get one of these to draw from the battery daily… not use a UPS designed for SLA and putting LFP instead.
 
Yes, inverter chargers, or all in ones can be. So it’s best to get one of these to draw from the battery daily… not use a UPS designed for SLA and putting LFP instead.
Actually, Lifepo4 are drop in replacements for SLA.
That is perfect for an in use lfp setup.
But if left plugged in, and only drawing from the bank when power is out, 13.6 will keep an LFP at 100% SOC and will degrade the cells in a short time.

For LFP to work in a UPS scenario, there would need to be a 3 fold charge profile, 14.4V then 13.2 float then 12.8 standby.
Otherwise the cells will be held at 100%SOC and fail.
So you´r saying that if you follow Battleborn´s recomendation to float their LFP batteries at 13.6V. The batteries will FAIL?
 
Actually, Lifepo4 are drop in replacements for SLA.

So you´r saying that if you follow Battleborn´s recomendation to float their LFP batteries at 13.6V. The batteries will FAIL?
Check any battery source… LFP is not designed to be stored at 100%
It is designed to be cycled.
Fully charging LFP and NOT draining it is bad for the battery.
LFP would work perfectly in the ups, the problem comes when you use it AS a UPS, keeping it plugged in always floating fully charged, and never draining it.
 
Check any battery source… LFP is not designed to be stored at 100%
It is designed to be cycled.
Fully charging LFP and NOT draining it is bad for the battery.
LFP would work perfectly in the ups, the problem comes when you use it AS a UPS, keeping it plugged in always floating fully charged, and never draining it.
Well, that is a pretty awfull blanket statement right there.
there is no Good or Bad. there are cycle charts that each cell manufacturer provides that gives you the results of their tests based on multiple changing variables. 1c, 3c, 5c, 10 c and 20c discharge. same for Charging. there are so many variables and types of LFP cells and each come with its own values. I could fill this post with datasheets.

LFP currently are being Floated by multiple legacy RV chargers around the country. to just say that they will fail if implemented that way is just WRONG.
Specially when you have major manufacturer giving 10 year warranty on their LFP batteries even if you float your LFP batteries at 13.6V.

as a Staff member, you should not be generalizing .
 
On a side note,
My point is that, as a forum, we should be encouraging people to use our latest Lithium technologies and spreading best knowledge on how newbies can benefit from them.
Most people first encounter with LFP Will be their upgrade form SLA to LFP, and probably their existing equipment will not be upgraded.
We should organize ourselves as a group to spread this knowledge and make LFP accessible to the masses.
Not promoting obsesions with obtaining every little squeeze form the batteries no matter how impractical that makes it.


Whitepaper:

LFP have such high cycle life, even if you dont follow manufacturers instructions to the letter, still outlives SLA X3 times. in the worst of conditions.
LFP is the only Lithium Technology that has all the attributes to replace SLA. (drop in replacement)
LFP Price have decreased such in the past 2 years, that today you can build them for the same cost than SLA ( Ah to Ah).
LFP Will dominate the SLA Market in the near future, from Golf Cars, Forklifts, Engine Cranking, telecom Backup, to mini EV from China.
LFP should be regulated as SLA by the Department of Transportation. Not NMC. (thermally unstable)
We should work together to differentiate LFP from other Earlier Lithium Chemestries that are a Fire Hazard. NMC, NCA, LCO, LMO.
 
I do not see LFP replacing lead for cranking engines anytime soon since they don't work in sub freezing temperatures. That would be a no go.
 
No Charging, but you can Discharge, Start the car, and then the internal heater can warm it up.
 
13.6 will keep an LFP at 100% SOC and will degrade the cells in a short time.
"Float Voltage

"LFP batteries do not need to be floated. Charge controllers have this because lead-acid batteries have such a high rate of self-discharge that it makes sense to keep trickling in more charge to keep them happy. For lithium-ion batteries it is not great if the battery constantly sits at a high State-Of-Charge, so if your charge controller cannot disable float, just set it to a low enough Voltage that no actual charging will happen. Any Voltage of 13.6 Volt or less will do."

 
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