Can a car battery be connected to a UPS?, Can a car battery be charged with a UPS?, Installing a car battery to a UPS. I was using a small 4Ah battery UPS uninterruptible power supply for my computer, a large 4-battery UPS power supply for cameras, TV and the lamp I use in a power outage. I also have a spare UPS inverter that I connect to the car battery to get electricity for a longer time.
A mixed, messy system that has formed over time since I got involved in battery desulfator work 🙂 I said it would be enough if I just used the uninterruptible power supply that I used the car battery for, I had to organize the installation accordingly and modify the UPS power supply. The spare device that I use the car battery for is more recently developed compared to the other 4Ah battery and 4 battery… but its case is plastic, especially in devices like UPS, I don’t like the use of plastic cases, it doesn’t seem safe. (I need to put the battery in a metal case later….)
What to do for UPS Modification;
- 1 I need a metal case.
- 2 I need to cool the mosfets better
- 3 I need to cool the transformer
I combined 2 PC power supply boxes for the metal case. The screwed parts to the PC case match each other when combined with a nut screw, it becomes a big box without any problems in terms of appearance and durability, you can make cuts from the joint section inside and use it as you want.
It will be very difficult to add to the cooler of the mosfets, there are 4 mosfets, 2 of them have isolators, the others do not, so the cooler I will add should not touch the case or I need to remove the mosfets and install an isolator, since I will use a fan in any case, I said I do not need an additional cooler, the fan will be enough. (test ok.)
The transformer was mounted to the plastic case of the device with sheet metal clamping screws, so they did two jobs at once, I removed these screws, added a mounting iron to the bottom and fixed it with a nut screw. I used a fan inside the transformer, but I had to mount the fan outside the case, the transformer did not save the size.
I used a 5V output SMPS adapter to operate the 12V fans, there is no noise since they work at low speed, they blow enough with 5V. In addition, I placed 4 aluminum coolers under the case, I had noticed before, the transformer was overheating, I added it just in case, this problem disappeared. Also, the value of the capacitor at the 12V battery input is 1000Uf, I changed it to 2200Uf.
Also, I made the UPS 220V input via surge protected socket and there was no protection at the input*
Why am I making these arrangements?
UPS uninterruptible power supplies are designed to work for certain periods of time according to their power. 650VA..850VA 12V single battery UPS devices can run the computer from the battery for around 10…20 minutes*.
The battery they use is 1 12V 7Ah or 9Ah. Since I will be using a 60Ah car battery, the working time will increase significantly, all calculations such as cooler, transformer etc. are made for short-term work, it is necessary to strengthen the cooling when extending the time by installing a more powerful battery.
Be careful, this process does not increase the power of the device, it only prevents it from causing problems in long-term work.
Using a UPS with a Car Battery?
Contents
Yes, the tricky part is connecting a car battery to the UPS uninterruptible power supply. First of all, my inverter has a single battery and a charging voltage of around 13.6v. This voltage is enough to keep the battery in floating charge. SLA lead acid batteries should be kept constantly charged anyway..
The problem will be the charging current. It gives a charging current between 700mA…1A. It will take a few days for the dead car battery to charge, but if it doesn’t, I can charge it with an external charger in a few hours. For this, I am thinking of modifying an SMPS adapter and adding a small voltmeter. (I added the voltmeter module, it was great…)
Finally, there is the issue of harmful gas discharge from the battery, @taydin teacher Using a car battery with UPS (https://mekatronik.org/forum/threads/ups-ile-araba-akusu-kullanmak.2107/) tested it in the project, made measurements, did not experience any problems, and this question was solved thanks to it. Thank you.
Yes, as you can see in these pictures, the system was as I wanted, including the metal case, fan, cooler, etc. I made a 15A dual switch connection to cut the battery’s attrition line when necessary, combined the two ends and increased the power of the switch, thickened the battery cables and kept them as short as possible.
Local Production UPS?
The rest of the article will be about the strange problems I experienced, reviews, etc. I said the UPS I connected to the car battery was new generation advanced because the other devices I used were 199x, 200x production and they were not suitable for the project, I didn’t examine it carefully at first, after all, it was a device that said domestic production from a company I knew was quality, it has very lively orange lines 🙂
When I started the modification work, I started to examine the device carefully, my eyes started looking for the charge regulator, it was not there.. There are 4 mosfets on the cooler, I say they are on the right and left, it is not there. There must be a 7812 or LM317, it is not there…
I said there must be something under the card, there is no TO-252, SOT-223 mosfets or anything… lots of SOT23 transistors etc. I started following it from the battery cable, what do I see? The TO92 case goes to the 2N2907A transistor, that’s not enough, it is being charged via the 600mA pnp transistor. I look at the 220V input, there is 1 filter capacitor, there is a varistor place for high voltage protection, but there is no varistor. The board and transformer originate from China.
I said no, this won’t work, they have seriously damaged the quality, I need to find a Chinese UPS that is not a domestic product… : D I looked at the yellow website and finally found a device from a different domestic company at a reasonable price.
I bought it and said it couldn’t be worse. The device arrived, I opened it up, a slightly different version of the same card 😀 Fortunately, UC3843 was used in the charging section, it’s better…
But this one doesn’t have a varistor on the 220V input, it’s still better quality than the other one, I checked it a little and said it would work, don’t mess with it too much, I said the project will take longer and I started modifying it. Here’s the situation… The marketing information, box design, etc. of the devices are very high quality… 🙂
A long time ago, I was in the technical service of Chinese made UPS devices. Their designs were full cmos, tll. I won’t lie, I would use one of those if I could find one. Actually, the best thing to do is to find a new generation APC 😀
UPDATE UPS Uninterruptible Power Supply Modification Working Time Limited?
It was necessary to make modifications within the possibilities and have the UPS uninterruptible power supply work for hours. However, the manufacturer prevented this in the processor software, even if there was no heating and the battery was full, the device shuts down. I am sure there is no fault in the device because there are 3 of the same model.
There is a PC program for these new generation UPS uninterruptible power supplies 🙂 It was mentioned that this period was extended through it. I found the program, made the settings, the device that worked for 1 hour now works for 5 minutes 😀 By the way, the microcontroller used in the device is MC9S08FL8C
I decided to use the 1999 4AH battery-powered uninterruptible power supply. Since I had used it on a computer before, I had renewed the electrolytic capacitors and re-soldered them.
In addition, I directly soldered the power cables, control, cleaning, etc. I finished with the UPS card. Then I cut the case and added a fan. I used a 5V adapter to run the fan. Since the case of this device is metal, it was much less hassle.
But there is a MC68HC705 microcontroller on the card 🙂 I don’t think they have a working time limit, I tested it for 2 hours. I think it will not cause any problems.
