12v DC battery questions - Page 1
Forum section: electronics / beginners

author: Mace_Hacker
author_rank: Contributor
timestamp: April 28, 2021, 11:25:33 pm
content: Hope everyone is doing well!My current project involves using several batteries I was given to make power supplies for my trail cams.My trail cams each use, 8 - AA batteries. ( So if I figured it right that's 12v at 50mah +/-)The batteries I was given are:1 - Tattu, 6S, 22.2v, 488.4wh, 22000, 25C/mah2 - HR 1234W, F2FR, 12v, 34WI "know" with the Tattu I will have to step down the voltage.....I just don't know exactly what circuit I need to construct to do this.With the 12v battery; My question is pretty much the same.....I don't know if I need to reduce the current/amperes ect to use it on my trail cam.Suggestion please.Thank you, again, in advance!Mace

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 28, 2021, 11:37:00 pm
content: You don't need to reduce the current. The camera will draw whatever it needs. Just the voltage to be 12V. So for the Tattu battery you can use something like the Riden DPS5003 module to reduce it down to 12V.

author: mariush
author_rank: Super Contributor
timestamp: April 29, 2021, 12:16:31 pm
content: You should first determine what's the almost lowest voltage the cameras will work with.The cameras will probably be designed to account for use of rechargeable AA batteries with 1v...1.35v range, or non-rechargeable batteries with 1.3v...1.65v range... so there's probably a high chance the camera will work with as little as 1.1v, which means you could probably power it with 9..10v instead of 12v.Also, it's quite likely the camera has a dc-dc converter inside to convert the battery voltage down to smaller voltages it needs like 3.3v or 2.5v so it may actually work with even lower voltages but it probably wants 12v for flash or infrared leds or something like that.. see what's the lowest voltage needed.If you don't have adjustable power supply try replacing one or two batteries with wires to have a lower overall voltage (ex. tape the ends of a aa battery, then a piece of wire across both ends to connect both terminals and see how the camera works.The 2nd battery seems to be 9Ah lead acid based on google results, and if so it will be charged up to around 13.5v and will provide useful energy down to around 10.2v ... if it discharges lower it can get damaged. At 50mA continuous discharge, the battery will probably discharge down to around 11v in around 30-40 hours.The first packs a lot of energy, but you're gonna need a dc-dc converter to reduce the voltage down to 12v-ish ...No need to worry about current, the camera will take as much as needed.All the talk about figuring out the minimum voltage is because you could make your own batteries from lithium cells or from other rechargeable alkaline batteries.You could get a laptop battery (16-20v ) and use a dc-dc converter to get 12vOr you could get a lithium battery (3.7v...4.2v) and boost the voltage to 12v using a step-up dc-dc converter

author: Mace_Hacker
author_rank: Contributor
timestamp: April 29, 2021, 02:05:00 pm
content: Ok, so the 12v battery I can use as is but, if I know what lowest voltage draw of my camera is I could limit the draw to that and extend the battery use time.As for reducing the 22v to 12v. I want to build my own module. If someone can possibly point me to a simple schematic for one that would work for me I would appreciate it!I have lots of parts laying around and I am certain I can cobble something together.

author: ledtester
author_rank: Super Contributor
timestamp: April 29, 2021, 11:42:45 pm
content: Quote from: Mace_Hacker on April 29, 2021, 02:05:00 pmAre you are thinking of stepping down the 12V battery to a lower voltage with the idea of having the camera using the battery more efficiently?QuoteIt's not worth it. You can get a simple buck regulator for about $1 a piece -- just search amazon/ebay/aliexpress for "LM2596 module".On the other hand, if the camera is worth anything I would put the money towards a battery I don't have to modify. Killing an expensive camera because a buck converter circuit failed doesn't seem to be a good risk to take.

author: Mace_Hacker
author_rank: Contributor
timestamp: April 30, 2021, 03:59:29 pm
content: No, not planning on reducing 12v battery voltage, I was just commenting on poster’s comments.As for buying an off the shelf converter..... no fun. LolPart of the fun for me is making something and learning as I go.

author: G7PSK
author_rank: Super Contributor
timestamp: May 03, 2021, 01:56:46 pm
content: The trail camera I have uses 8 AA batteries but the power socket says 6 volt DC next to it. Best check if you plan to use the auxiliary power input.