Using solar controller as charge controller - Page 1
Forum section: electronics / general

author: System Error Message
author_rank: Frequent Contributor
timestamp: March 24, 2021, 01:50:15 pm
content: Hi im trying to set up a more efficient CCTV and alarm setup for someone and have ran into a snag which i hope its not because of a defective battery. I quickly set up all the parts to test before they will be set up, and while everything works, i noticed the battery doesnt charge.The input is a 12V PSU while the battery is a sealed lead acid (with possibility of maintaining). First battery i tested drained itself in the controller powering everything all the way down to 10V despite the input shown to be 11.8V however i found the lid of the first battery to be a little open. I put a second battery in and it still shows no signs of charging so i've left it in overnight not powering anything to see if it will have charged or not.The solar controller is rated for 30A, 12V or 24V lead acid battery setup but also rates for 12V for the input to be from 8V to 23V, however i suspect that it is not charging the battery because the input voltage isnt something like 14V or higher. Im using sealed lead acid batteries and right now have the dead one attached to the direct output of the PSU in hopes it should at least gain some charge.If i have to increase the voltage that goes into the controller, is there any way to stack voltage regulators for increased amp output? One thing the guy insists on is to only buy from local sellers and many things are not available under budget locally, but if i could stack say 10 regulators to increase the voltage from 12-15V at 3A each, i should be able to get 30A but my question is on how well it would work because finding one that can be paired or with the capacity im looking for is impossible. The setup is powering will use around 10A in total at the moment, but if it works well more might be added to it and more batteries as well since each battery isnt rated in output as high as the total either.A UPS would be easier but costs more and will have a lot less efficiency/ run time. Since everything in the system uses 12V it just seemed like the best choice.

author: nuclearcat
author_rank: Unknown
timestamp: March 26, 2021, 04:00:27 pm
content: If solar charger is not buck-boost and just buck - it wont charge unless voltage is higher than ~13-14V.Try to put on input higher voltage, for test.

author: System Error Message
author_rank: Frequent Contributor
timestamp: March 27, 2021, 04:53:55 pm
content: thanks, the controller says it accepts up to 23V for a 12V battery. IT turns out i do have to program it because it ruined the first battery i tested on its default dry battery setting.I found a voltage booster that is capable of handling the amps needed, So is it better to have it output 15V or 23V? The output is adjustable. What does suck is that my bench PSU is too far away to bring to check. Since this will be in an enclosed space, need to make sure it does not overheat and i was reading that they use some kind of switching transistor to lower the voltage.

author: nuclearcat
author_rank: Unknown
timestamp: March 27, 2021, 06:09:49 pm
content: Quote from: System Error Message on March 27, 2021, 04:53:55 pm15VFor many (if not most) buck or boost - smaller difference between Vout and Vin - higher the efficiency.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 28, 2021, 01:34:52 pm
content: Have you considered using a PSU with current limiting that can be adjusted to output 13.8V or whatever the battery datasheet suggests for a float voltage? Then it can just directly connect, very simple.You can also consider using a 3S lithium pack, it so happens that 12V is 4V/cell which is great as a float charge. Especially for small sizes, lithium is cheaper than sealed lead acid nowadays.