I love this project. I wish you would do a simpler version though. Like with just a few smaller sealed lead-acid batteries and without the extra electronics upgrades - you know, for the less technically inclined of us.
Thanks for your kind words! Unfortunately as seen in the main build video, the UPS is designed to have the internal battery discharge before the inverter overheats. Without that fan, I'd have a magic smoke generator instead of a power supply! A bigger, higher quality unit has better chances of surviving expanded battery capacity. Time will tell what a future version 2 of this project will be. Extra bits like the voltmeter and USB ports on the battery box of course were entirely optional. Fuses however were mandatory given the extreme fault current available from large batteries.
Lesson learned! My parents did that too with one of their backup batteries. They since upgraded to sealed AGM and LiFePo4 so no watering needed. Thanks for watching!
you could have bought one lifepo4 for cheaper and had better results. , i made my own from raw cells for 50$ 12ah 25.6v and get an equivalent run time of 24v 28ah leadacid on my ups . 6 of the 9ah leadacid that my ups use would cost me 120$ even if i buy the cheapest of cheap Vietnamese cell. and they don't last more than 5yrs,
That's really cool you built a pack! How did you go about the BMS for cell balancing? Certainly can't get new raw cells that cheap where I'm at unfortunately :( Any off the shelf LiFePo4 that I trust costs way more than lead acid for equivalent capacity, and would need a separate charger for best performance and reliability. With raw cells like you used I'd need 3 times as many to equal the lead acid here. I agree the performance per size and mass are far superior, and a second version of the project will likely use lithium instead. Lead acid: 75ah @ 25A draw x 12V = 900 watt-hours under load Lithium: 12ah x 25.6V = 307 watt-hours
@@MetaphysicalEngineer They are also not compatible with the charging circuit for Lead Acid batteries. AGM like to be floated for standby (UPS) applications at about 13.8V. 13.8/4 = 3.45 - above the recommended float voltage for LFP.
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I love this project. I wish you would do a simpler version though. Like with just a few smaller sealed lead-acid batteries and without the extra electronics upgrades - you know, for the less technically inclined of us.
Thanks for your kind words!
Unfortunately as seen in the main build video, the UPS is designed to have the internal battery discharge before the inverter overheats. Without that fan, I'd have a magic smoke generator instead of a power supply! A bigger, higher quality unit has better chances of surviving expanded battery capacity. Time will tell what a future version 2 of this project will be.
Extra bits like the voltmeter and USB ports on the battery box of course were entirely optional. Fuses however were mandatory given the extreme fault current available from large batteries.
Yes, that was the mistake I made, not checking electrolyte levels. Now I realize that. TY for the great content!
Lesson learned! My parents did that too with one of their backup batteries. They since upgraded to sealed AGM and LiFePo4 so no watering needed. Thanks for watching!
@@MetaphysicalEngineer Yup, won't make that mistake agian. Ty!
I bought 2 of these, ready to replicate what you have here, thanks for sharing :)
Follow the notes and supplemental material. Can always drop a comment if you have further questions! Good luck!
@@MetaphysicalEngineer will do, thanks :)
you could have bought one lifepo4 for cheaper and had better results. , i made my own from raw cells for 50$ 12ah 25.6v and get an equivalent run time of 24v 28ah leadacid on my ups . 6 of the 9ah leadacid that my ups use would cost me 120$ even if i buy the cheapest of cheap Vietnamese cell. and they don't last more than 5yrs,
That's really cool you built a pack! How did you go about the BMS for cell balancing? Certainly can't get new raw cells that cheap where I'm at unfortunately :(
Any off the shelf LiFePo4 that I trust costs way more than lead acid for equivalent capacity, and would need a separate charger for best performance and reliability. With raw cells like you used I'd need 3 times as many to equal the lead acid here. I agree the performance per size and mass are far superior, and a second version of the project will likely use lithium instead.
Lead acid: 75ah @ 25A draw x 12V = 900 watt-hours under load
Lithium: 12ah x 25.6V = 307 watt-hours
@@MetaphysicalEngineer They are also not compatible with the charging circuit for Lead Acid batteries. AGM like to be floated for standby (UPS) applications at about 13.8V. 13.8/4 = 3.45 - above the recommended float voltage for LFP.
Go LiFePo4.