I have a 12kva (10kw) ups and I want to power it from a 24v battery bank. The dc input is 192dc input from the battery side. I was thinking off getting a 24 to 220 Inverter and rectifing it to output 200v dc if possible. I know a little about electronics so not to much off a noob. Thank you for your time

This is the ups that I have 8 to 18kw https://www.jsfleming.com/wp-content/uploads/2016/07/sl-24870.pdf

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    \$\begingroup\$ How many batteries do you have in your 24v battery bank and what capacity are they? \$\endgroup\$
    – brhans
    Dec 27, 2018 at 20:27
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    \$\begingroup\$ 220 AC rectified is 311V... So not a good plan. Given the voltages and powers, this seems like a dangerous project given your experience level. \$\endgroup\$
    – MadHatter
    Dec 28, 2018 at 0:19
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    \$\begingroup\$ So to recap, you need to provide information on the UPS and the batteries you intend to use. The UPS likely includes a charger. All cabling you use should be properly rated for the maximum current of the UPS, regardless of what you intend to plug in. The UPS won't limit it's output until 10Kw(Which really isn't that much as domecile power consumption goes) so you must be sure the input is rated to sustain that full 10kw. If rated current is 490A, you must use 490A or better wire and batteries that can sustain that draw. Use a suitable battery bank jfor the UPS and contain it properly. \$\endgroup\$
    – K H
    Dec 28, 2018 at 0:31
  • \$\begingroup\$ I don't have any batteries but I can get them, my plan was to build a power supply with a low voltage between 24 to 48 volts and output the required dc voltage to run the ups system. \$\endgroup\$ Dec 29, 2018 at 2:06
  • \$\begingroup\$ About the 220 to 200 dc power supply, yes it's 311v but I was going to use a step down transformer to 120 or so then rectify it, caps and filter etc. and it should be in the ball park off the voltage that I'm looking for.(yes, no)???? \$\endgroup\$ Dec 29, 2018 at 2:20

1 Answer 1


To get 10 kW out of an inverter with 85% efficiency your input current at 24 V would be \$ I = \frac {P}{V \times e} = \frac {10000}{24 \times 0.85} = 490 \ \text A\$.

If, instead, you arrange your batteries in series connection of eight you get 192 V nominal and the current from the batteries would be \$ I = \frac {P}{V} = \frac {10000}{192} = 52 \ \text A \$ with no inverter losses.

Most of us, given the option, would opt for the 192 V setup to avoid the very high currents and inverter losses. Either option requires a high level of understanding of the risks to personnel and equipment involved.

  • \$\begingroup\$ Okay you lost me at the 8 batteries, thats only 96v? Are you telling me to just go with the dc voltage input on the Inverter. Also the other reason why I want to use smaller input dc voltage, because off the charging back of the batteries. \$\endgroup\$ Dec 27, 2018 at 21:57
  • \$\begingroup\$ 8 x 24 V = 192 V. \$\endgroup\$
    – Transistor
    Dec 27, 2018 at 21:59
  • \$\begingroup\$ Okay what about charging setup? Im trying to get the longest runtime. Im not using total 10kw, thats max output kw that the UPS produces. \$\endgroup\$ Dec 27, 2018 at 22:14
  • \$\begingroup\$ There isn't enough information in your question to comment on charging setup or what your question is regarding charging. \$\endgroup\$
    – Transistor
    Dec 27, 2018 at 22:49
  • \$\begingroup\$ okay let me start from the beginning. I have a libertarian "UPStation S" 12kva 10.1kw. I want to run my house with this unit. 1. it's 3 phase(split) 2. Its normal DC input is 192vdc 52amps full load 3.I want to build a power supply using 24v/48vdc input and supplying the ups with the required voltage to run my house. 4. I'm not unsing `10kw so I will not be running at full load. 5.if I use the batteries with the required dc input(192vdc) I need to build a charger to charge the batteries back to full, with a good charge amp rating. \$\endgroup\$ Dec 27, 2018 at 23:42

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