Can I charge digital camera battery direct from 12v fuse block? - Page 1
Forum section: electronics / beginners

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: January 28, 2025, 09:30:58 am
content: I don't have the mains charger or indeed a mains supply in my van. Just the 12v.I brought the digital camera with me but forgot the transformer charger.I guess it is just a simple dc converter anyway? It does allow docking the battery though, which has to be taken out of the camera to charge - weird design but that is what it is.Anyway I don't have that with me either. So can I just get a positive and negative from the fuse block to touch the + and - on the battery? I says it is about 2.4ah battery. Will I have to do any step down? or will the ~13v work direct to the battery?Here are the battery details printed on it: Battery pack 3.6v, typ. 2.3wh, min 2.2wh, typ. 630mAh min. 600mAhAlso it is really fiddly because the battery is like phone batteries where there are just 3 flat pieces of metal where the pins of the camera make the connection when it is inserted.How can I get the wires to stay in place? I managed to solder them but I saw that was a bad idea to do regularly because I slipped a bit and melted some of the plastic of the battery! I guess just some simple electrical tape.If I can charge it in this manner how will I know when it is fully charged apart from plugging in to the camera? As in is there a fully charged voltage it will be at that I can check with multimeter?

author: Zero999
author_rank: Super Contributor
timestamp: January 28, 2025, 09:35:51 am
content: No, you'll blow up the battery. It needs a charger to limit the current and voltage.Can't you charge the battery in the camera with a USB cable? 12V to 5V USB converters are widely available.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: January 28, 2025, 09:47:07 am
content: Quote from: Zero999 on January 28, 2025, 09:35:51 amYea that is why I mentioned a step-down converter in the OP. I have a spare one which can regulate from 1-20 v or something. I think it is 2a current, or maybe 5 but that doesn't matter does it? I thought the current doesn't matter since people always say that it is the device that will request the power draw and not the current rating of the source?What volts should I put it at? Just a few above 3.6v since they say it has to be above the v rating due to resistance in order to charge?QuoteIf I could I wouldn't be making a post about some obscure way to charge it.I thought it idiosyncratic even when I bought it about 10+ years ago that I wasn't able to charge it in any way except the mains charger but it doesn't. The one I replaced, with this one at the time did charge by usb but this one doesn't. It only registers as a storage device but doesn't charge.No I don't wanna buy another one!

author: Zero999
author_rank: Super Contributor
timestamp: January 28, 2025, 09:57:19 am
content: Quote from: electroniclearner820327 on January 28, 2025, 09:47:07 amIt's not a battery charger. Batteries have to be subject to a specific charging regime. For example with a lithium battery, if the voltage is very low, the current needs to be limited more, then it can be increased, as it charges, then once the voltage reaches a certain point, the current needs to be reduced again.QuoteThen you're SOL I'm afraid. There isn't a way to do this safely, without reverse engineering the thing and building your own charger.

author: forrestc
author_rank: Unknown
timestamp: January 28, 2025, 10:04:07 am
content: If you want to buy something which is a lot more universally useful after you get home -There are lots of "universal digital camera battery chargers" which run $20ish and will charge pretty much any pack. They have adjustable pins to align with the pins on the battery. Some will automatically detect the battery voltage and do the correct thing and some you'll have to buy the one that matches the battery voltage. (I.E. 3.7 or 7.2V)In the US you can get them on Amazon, but also at various sources where "travel electronics" or "camera electronics" or "replacement batteries" are sold. If you want to see what I'm talking about just do a search for "camera battery universal charger". Some will run off of 12V as well...

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 28, 2025, 09:38:12 pm
content: It seems that you're in an emergency correct? If not an emergency then I would say forget it and get a correct charger. But if it's an emergency it helps to know where you are and what kind of things you can get.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: February 27, 2025, 08:49:02 am
content: Quote from: BeBuLamar on January 28, 2025, 09:38:12 pmIf it was an emergency I would be long dead by now.Not sure how using a digital camera could get you out of an emergency situation though? Perhaps take a picture of the surrounding area to send to emergency services but in this case you would have to send via internet so you could just send them your location without the camera eh?

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: February 27, 2025, 08:53:10 am
content: Quote from: forrestc on January 28, 2025, 10:04:07 amWhat I am wondering is why is this situation different than charging my laptop direct from the 12v fuse block, which has worked fine for me?What is different about using barrel connector from fuse block to plug into laptop and charging the battery direct from the fuse block?Note I didn't use the mains transformer in the case of the laptop, I just got a barrel the correct size and made a wire to the fuse block.Apart from having to put a voltage regulator in between to charge at consistent 12v rather than the ~13 of the lifepo4 leisure battery, there was no extra setup required.I just had a quick look and most are mains again although I just found one that plugs into 12v cigarette port of vehicles. Could I instead just snip the cable and plug to the fuse block? I know I can buy those ports but it is an extra cost I would avoid if it would work wired direct.I have a cigarette port in the front of the van but that is not convenient so would prefer rig it in the back, living space.Here is the one I saw so far that looks most promising:https://www.ebay.co.uk/itm/256438117065?_skw=universal+digital+camera+battery+charger&itmmeta=01JN39S45ZRSJS4GQ5Q54QDJ7R&hash=item3bb4e722c9:g:8IwAAOSwPepl6dkl&itmprp=enc%3AAQAKAAABAFkggFvd1GGDu0w3yXCmi1dGjw0%2Bc6mjCTtsxLRpCRk5sZWDMlXLSUe%2FL0nmWHeBXFrfyhriBqwzR1vwOY72a%2F3d3FI4SzqvKEbJF6du6MFxL50FGGPmnK1wkdAxBSLvh9bbjGk1dwFYjGZB2o5Tbbg6hEC8%2BIJCiI2V3Sf33epCSzmHgeO0VixTi4K8vgdWtzzfXMhvx2ruRkAiFxYRAHYAcHjh5uchBe4P%2BylxsI7M8s0udDE1WqKw7OegeP2SWkB4muZ7Z%2BJYIFR6qhz5CSMLE351YCx2tCcpjdfntgmMfOE0cSDn%2FAcSx6PAIBfKENS7QG5cHqBU9BN6F6Yy%2F8k%3D%7Ctkp%3ABk9SR5LD5OmoZQOh that looks like it is only compatible with nikon, is that battery type or camera type? I don't think my camera is nikon. Forgot what it is and don't have it handy to look right now.The battery looks very similar to an older, circa 2014 or so, flat rectangular mobile phone battery.Ahthis onelooks like it has everything ready to go, using usb C connector.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: February 27, 2025, 11:18:33 am
content: Ok I have managed to find and order a usb one made specifically for my battery type.

author: Zero999
author_rank: Super Contributor
timestamp: February 27, 2025, 12:31:25 pm
content: A laptop has a built-in battery charger. It doesn't just directly connect the battery to the barrel connector.

author: BeBuLamar
author_rank: Super Contributor
timestamp: February 27, 2025, 12:47:09 pm
content: Quote from: electroniclearner820327 on February 27, 2025, 08:49:02 amWhen I said emergency I meant that perhaps you're traveling and in a place that you can't get to an electronic store that sells a charger.

author: CaptDon
author_rank: Super Contributor
timestamp: February 27, 2025, 01:25:09 pm
content: Do you even begin to understand that the laptop has a 'specific design' battery charging circuit built into the laptop? Why would you even begin to assume the 'barrel connector' goes straight to the laptop battery without intermediate circuitry? What do you 'think' will happen when you connect a 3.6 volt light bulb to 12 volts? I'll save you some time, it becomes a short lived flash bulb!! What do you assume will happen when you connect a 3.6 volt battery directly to 12 volts?I am thinking those little plastic 'charger' devices probably contain something more than just direct wires Wow.

author: Sassy Taste
author_rank: Contributor
timestamp: February 28, 2025, 03:37:30 am
content: How many watts to that digital camera? I'd say from wall outlet, USB-type c connector, about 5 watts charging that thing. The USB cable supplies 3 amps. Already you'll be over the limit if you do use a usb cable. Will not work from a fuse box. I bought a aiwa wireless speaker. Round. It is 5 watts, so that means it is 5 volts, 1 ampere, equaling to 5 watts. Connected to my pc with the USB-type c connector wire or cable, is 5 watts connected to 30 watts chrome, lab top. Which carries two ampere, 15 volts supply, and 30 watts to the chrome. Connected to the wireless speaker at 5 watts, this sounds fantastic. Loud speaker. Speaker for my Chrome. Watts in this case is not more, but less for a wireless Speaker. I would think that a digital camera also plays the same idea. Step down in watts.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: February 28, 2025, 10:26:09 am
content: Quote from: CaptDon on February 27, 2025, 01:25:09 pmWhy are you being rude and condescending when this is the BEGINNER's section?So we should not ask any questions here for self-important people like you to chastise us for our lack of understand; is that the message?How does learning happen? By asking questions. So your message is that asking questions should be punished and you should be made to feel small.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: February 28, 2025, 10:29:43 am
content: Quote from: Sassy Taste on February 28, 2025, 03:37:30 amDon't know about watts. I just know what information I posted earlier which was on the battery.What about the idea, which I have read is a common practice when using different charger, that the amps of the charger doesn't matter, and could be higher, because the device chooses how much to draw and will only draw how much it needs?

author: BeBuLamar
author_rank: Super Contributor
timestamp: February 28, 2025, 11:24:58 am
content: If you want to make a charger to charge your battery it should be a constant current/constant voltage charger with the currenlt limit to about 300 to 600mA and the voltage is limit to 4.2V and stop charging when the current drops to about 18mA. That's for a 3.6V li-ion battery with 600mAh capacity.

author: xvr
author_rank: Frequent Contributor
timestamp: February 28, 2025, 12:04:49 pm
content: QuoteThis is true for a device that is powered by a constant voltage source (and this voltage must be the same for the device and the power supply). A battery is not such a device. The voltage and current on it change during the charging cycle. These changes must match the battery charging profile, so special chargers are used to implement this profile. Only a battery and/or a ordinary power supply alone will not be able to provide this profile.

author: CaptDon
author_rank: Super Contributor
timestamp: February 28, 2025, 06:31:02 pm
content: Sometimes it is the question or statement, "can I hook a 3.6v battery directly to the 12 volt fuse block", of course not and that would be apparent. Better question, "How can I safely charge a 3.6 volt battery from my 12 volt fuse block? I don't have any adapters with me." The answer would be "You need a way to safely limit the current and charge time". Possibly use a resistor, 12vdc minus 4vdc = 8vdc, then we could calculate a rough value for the resistor to limit the current to .1 amp. 8v divided by .1a = 80 ohms. 8v X .1a = .8 watts. If you could find locally an 82, 91 or 100 ohm resistor rated at 2 watts it would work and run cool enough to not melt anything. You would have to watch the charge time to keep the battery in the safety zone and not over charge. You could also stop by an auto parts store and purchase a #53 light bulb and socket with wires and simply use the lamp as your resistor. It is more likely you have access to an auto parts store as opposed to a resistor store.

author: tooki
author_rank: Super Contributor
timestamp: February 28, 2025, 07:02:09 pm
content: Quote from: CaptDon on February 28, 2025, 06:31:02 pmThat in no way meets the “safely” qualifier in the “better question” you suggest.

author: tooki
author_rank: Super Contributor
timestamp: February 28, 2025, 07:18:21 pm
content: Quote from: electroniclearner820327 on January 28, 2025, 09:30:58 amNo.The root issue here is that in colloquial language, we use the word “charger” in a very sloppy way to mean several distinct things.One meaning is a circuit that actually sets, monitors, and adjusts the charge current and voltage to a battery and decides when to terminate the charge. It knows how to properly charge that type of battery. A camera or power tool battery charger into which the battery is inserted to charge is a typical example of this as a dedicated unit.(Very rarely, an actual bona fide battery charging circuit will be provided in “wall wart” format. These are largely extinct, mercifully, because they cannot charge any of today’s popular battery technologies properly, meaning safely and gently.)Note that many types of devices, like phones and laptops,alwayshave the actual charging circuit integrated in the device itself.If a battery can charge inside the device, then the actual charger circuit is built into the device. This is the most common approach nowadays.Accordingly, the other major colloquial meaning of “charger” is actually just a power supply for a device that contains a built-in charger circuit. When you connect your phone’s or laptop’s “charger” to it, you are connecting a simple power supply. This power supply knows nothing of the battery inside the device.So the upshot is this: your camera battery charger is an actual battery charger, while your laptop and phone “chargers” are simple power supplies supplying power to the actual battery chargers inside the phone and laptop.

author: electroniclearner820327
author_rank: Regular Contributor
timestamp: March 01, 2025, 08:40:31 am
content: Quote from: tooki on February 28, 2025, 07:18:21 pmThanks for the explainer. It helps me understand that it was not worth pursuing and just buying a usb one was the better option.Is it the same idea as you wouldn't connect your solar panels directly to your leisure battery to charge it and rather use a pwm or mppt as the battery requires different charge levels at different stages of its charging cycle?