Runaway Tractor
New Member
Lets say I have an APC Smart UPS SMX750 which is $310 with shipping and tax. It is designed for 48 volt battery packs (can you guess where I'm going with this). The APC battery packs are lead acid batteries, (2) parallel strings of (4) 12v 9a SLA batteries in series (48v 9a x2) per pack totaling ~90 amps or ~900wh per pack. I believe it can take maximum of 5 external packs, so a maximum of 4.5kwh of battery storage. Each external pack has a 1kohm resistor on a sense circuit to tell it how many packs are connected (pleasantly simple...). Each external pack refurbished costs $500 x 5 plug shipping and tax for $2,750 for the maximum APC packs.
What if instead I used a single EG4-LL 48v battery? At 100amps or 5.1kwh of battery storage, it is slightly more storage than the maximum quantity of APC packs and the same nominal voltage as the SLA (I think). The EG4 battery with shipping and tax is $1,623. The cost of 3 APC packs. So 5 for the price of 3 basically.
A grand total of $2,000 would give me 14-16hrs of UPS run time on my rack. What I do not know is if there is any reason to believe the APC SMX750 UPS couldn't recharge the EG4 battery?
Why do this instead of something like an EG4 3000? Communication. All of my computers, servers, home assistant, and other gadgets can communicate using APCUPSD for runtime and safe shutdown.
What if instead I used a single EG4-LL 48v battery? At 100amps or 5.1kwh of battery storage, it is slightly more storage than the maximum quantity of APC packs and the same nominal voltage as the SLA (I think). The EG4 battery with shipping and tax is $1,623. The cost of 3 APC packs. So 5 for the price of 3 basically.
A grand total of $2,000 would give me 14-16hrs of UPS run time on my rack. What I do not know is if there is any reason to believe the APC SMX750 UPS couldn't recharge the EG4 battery?
Why do this instead of something like an EG4 3000? Communication. All of my computers, servers, home assistant, and other gadgets can communicate using APCUPSD for runtime and safe shutdown.