If my post isnt fit here, please move it to Serious Kopitiam, i hope this is the correct place to avoid spams, thanks.

Recently my expensive UPS died, cost like RM1k+ and just worked for like 4 years, i purchased that model mainly because i need to have the bigger battery capacity not the UPS able to supply more power, but still it unable to last for more than 30 mins. So i decided to read the net and DIY a new UPS with bigger batteries. I have some basic electronic skill, some soldering skill and smart enough not to kill myself in the process, but still can use some advises.

The main purpose of my UPS is because my house always have power interruption, right b4 a lightning strike, my house power have very high chance of trip, while my neighbor still have power, im not sure why, but ppl suggest me leave it alone. So i am getting UPS for this reason, to continue to use my pc during the thunder storm.

I am planning to get 2x NS60 car batteries instead of deep cycle, cause deep cycles are so much more expensive, and im not sure if the ups charger is suitable for deep cycle, will cost RM180 per unit(not maintenance free). So far i have install a rack outside my room, high up, planning to place the UPS and battery outside my room and pull cable into my room, due to i dont want any gas from the car battery released into my room which might be dangerous. Will consider deep cycle if nothing goes wrong and i didnt kill the car batteries easily.

The UPS im getting is "Cyberpower UT1500EI 1500VA" labelled 630 watt and im going to use less than 200 watt, so it supposed to be able to last more than 3 hours if my calculation is correct, even 2 hours would be enough 99% of the time.

Received the UPS today, and i have done remove batteries, extend cable, add fan (to cool down the inverter which should be getting hot running hours)

Anybody is welcome to give me advice, but those telling me not to do it, please leave. Thanks. And those who attempt what I am doing, i am not responsible for anything happen to you, UPS is dangerous, it store power, and it can still kill you even its not powered.

Work is not complete, will continue to update this thread.










This post has been edited by narf03: May 3 2018, 07:29 PM

most of your questions already answered, look at the image with a multi meter(should be the last unless i update the progress), can tell its 24V so its 2 piece of car batteries, its 1 of the reason im getting this, cause higher voltage reduce amp, means need not to have super fat cable, still im using the fattest cable i can find. and my home power trip too often, and i need to use the pc during a lightning storm, not going to shutdown and wait for it, and for most UPS, at beginning, it can last as per advertised, but very soon after, the duration drops very fast, much lesser than 50% of advertised, so im planning at least 3 hours, so worst case scenario, i can still get 1.5 hour of it, and im getting those non-maintenance free 1, so i can fill water, thus can last longer i guess.

dont think got such problem, i have read many posts and none of them state this.

i understood that, 1 of the reason the batteries wont be in my room and high up, its to avoid any sparks and not collecting any gas. And for capacity, i think i will use like 50% of the car battery only, its labelled 60AH, 2x = 120AH, and ill be using 200 watt per hour, thats like 20Amp per hour, 3hour = 60A. any idea what voltage of the battery will be if they are at 50% charge ? might consider adding a digital voltmeter

dont dare to simply change the type of battery, 2 reasons, not sure if the charger in the UPS suitable for other type of battery or not since certain battery need special charger and the voltage, UPS will stop charging when battery reach certain voltage, and if i change the battery type, either the charger wont stop cause the battery unable to reach certain voltage or the battery wont get full cause of the charger unable to provide enough voltage or current.

wah your work so cincai. i dont dare to do like that, fire hazard.

its not about ugly or not, its about potential dangerous doing that, if any metal touches those 2 terminals, its doing to be a very huge spark, and if nobody is there, it can heat up easily and start a fire. secondly if the battery overcharge, its going to release some hydrogen, and if your room is closed for few days while the overcharge happen, then you enter the room and turn on something that cause a spark, explosion might happen.

dont know why yours unable to work, lately i have done the same thing in my office, they works too

who cares, wet car batteries are cheap, and by 50% on 2x NS60, could means hours, even the battery degrade 70%, should still be able to last an hour, still better than the new original battery, unlike car batteries which need to be drain to push starters, need hundreds of amp, you might no longer able to use it after it degrade 30-40%, but for my case, i can use it as long as it can push out like 10 amp. i even can tell all ppl in my office to pass me their old car batteries, and i can put them all in parallel.