battery drain

[jaygpoo]

Hi out there, I have made up a battery power supply box that has a brand new 100ah leaisure battery. I have 4 car type cigar sockets and a double usb charging unit with an LED voltage display. Its wired in paralell. This should power my setup for a weekend with I thought no trouble. I am running a NEQ6 mount. QHY8L ccd. 2 dew heater wraps. and possibly a Skyfi unit. I thought the worst thing I coulkd use would be a power supply for my laptop from the 12v if needed. Well thats the max I am talking about. So the other night I set up using just the mount and CCD. I have by the way installed a voltage regulated power supply unit for the NEQ6 that gives it 14volts all the time. After about 2hrs of running I noticed the mount led flashing, a sure sign the voltage has dropped below 12v an sure enough the dispay showed just 8.5volts. I jumped and switched it off before damaged occured and slowly the voltage returned to 11 an then 12v. How can the mount just moving here and there and a ccd drain the battery which was charged. I am going to Kelling Heath in April an do not want trouble after all I have done to give myself outside power. Any ideas on what could be the cause ? I was under the impression these batteries where the gods of weekend power!!!!!!!! an I have not even connected the dew heaters yet.

[Daz69]

Have I read this correctly? You're trying to give a constant 14v from a 12v battery Fully charged and rested off charger will only give around 13.6v. You might be lucky and get your battery back up to accepting a charge if it hasn't been damaged by running it that low. Leisure batteries are deep cycle batteries, and in my experience as a caravanner, they charge best on a computer controlled "stage charger". Are you using a step up boost converter? Where did you buy it (post a link if you can) or did you build the board yourself? Have you set the output voltage correctly?

In regards to the battery rising back up, it will do when it is at rest and off load. It sounds as if you are just pulling far too much from the battery rather than having a short somewhere, but to pull 50 amps every hour, 100/2, that is going some! Personally, I'd de-solder each circuit and test them separately, concentrating on your step up converter and leaving it powered for another couple of hours just to see if it is that that is causing the issues.

1. Are all of your circuits, that's every USB port and other sockets independently fused? That would show if any circuit has a short as it would blow that fuse, rather than just using one master fuse for the whole box (if you have one).

2. If you have a circuit tester, check every possible circuit for current drain when it has power but nothing is plugged in, including any switches, sockets or shop bought electronic circuit boards to try and find a drain. An LED voltage meter will only take a few milliamps if it is on constantly, but I doubt very much that is your problem, as they are very fragile and will just give up if there was any short on the board.

3. Can you post a link to the USB charging device?

4. Personally I would not have every socket wired in parallel, i.e. just simply jumping live and negative from each one to the next, because if you have an issue with anything plugged into one of the sockets, it could damage anything else that's plugged into the other sockets. Look up "Wago" connectors here http://global.wago.com/en/products/product-catalog/terminal-blocks-connectors/installation-connectors/compact-splicing-connectors-all-conductor-types-222-series/index.jsp I have used the 5 port ones, and have the master fused supply live wire from the battery input go into one hole, and then you use the remaining 4 like a CANBUS to power other circuits via their own independent fuses suitably rated. Same with the negative wires for each circuit. 

[Daz69]

This my power distribution box 

Each circuit is fused and there is a master fuse rated at 5 amps. The circuits are fused depending on the expected pull. That way any issues with any circuit will not damge anything else. 

[jaygpoo]

Wo thats some box, Yes I do have a brought voltage regulator that I have adjusted to give 14v  and have used it foe a few years before trying to build this box and it works fine. Any chance of a wiring diagram and parts list for your unit ?  Jay

 

[abhoriel]

Well something clearly isn't right here.

Do you have a multimeter? You really want to be testing the current thats being drawn. With that equipment, it should probably be less than 1-2amps, although it will rise higher when the mount is slewing. 

Any short circuit which would drain that battery in 2 hours would get very hot.

Is the battery dead?

[jaygpoo]

Battery not hot but just puzzled as to why its run down so quick when it shou;d last ages. Got an electrician looking at it tomorrow and will report back.

[Daz69]

43 minutes ago, jaygpoo said:

Battery not hot but just puzzled as to why its run down so quick when it shou;d last ages. Got an electrician looking at it tomorrow and will report back.

Was the battery fully charged before you used it? You're right, it should last a long time. My 9ah deep cycle batteriy box lasts several days when I use them for when i go away fishing for a couple days, running an LED strip light when needed, and charging my phone and my tablet. I can also connect another battery box in parallel to give me 18ah if needed. This would be plenty for my astronomy needs at the mo, and save lugging my caravan battery out every time. 

If you haven't got a multimeter get one because they are a real godsend for things like this. If you've got plenty of cash get a FLUKE one, or just a simple digital one from ebay. They start around £3.99 and last a few years. 

I'll sit down over the weekend and draw a simple diagram with a parts list for you, no probs. My box only cost around £25 but I did have a few bits already including the box, but they are only around £5 each, again on ebay, but much cheaper than Maplins boxes for that size. Don't forget though, they are no longer weather proof when you start adding sockets etc. It took me a couple of days to build but I work slow due to being on some heavy meds. 

Good luck with the electrician. 

[jaygpoo]

Thanks for all your thoughts on my so called problem. An elec confirmed that my wiring was ok. He suggested that I couple the led display to the plug feeding 14.5 v to my mount. That way I could see if the main battery was too low as the regulator would struggle to maintain 14.5v. This done I turned to the battery and connected it to my NEW 12amp fully auto charger. This indicated that the battery was very low and proceeded to charge it in a controlled way back up to full. I have now had it runnning almost everything including my laptop for hours and it has not failed. Conclusion is that my 2amp battery charger was incapable of doing the job properly. Roll on clear skies. Jay