Goto not working properly with 12v battery

[msacco]

Hello, I got recently my 12v deep cycle battery(75 AH), I made a battery box out of it and yesterday I went out using it, unfortunately I encountered a problem. It basically works fine, but whenever I try to use both RA and DEC at the same time, the DEC simply stops and only the RA keeps moving. At first I thought its because I modded something in my motors, but today I tested with a wall plug and it worked just fine on both RA and DEC, meaning the problem is with the battery/cable I used somehow. I plugged a car 12v socket to the battery box, and then used the following cable to the mount:

https://www.aliexpress.com/item/12V-24V-DC-2-1x5-5mm-Plug-Car-Cigarette-Lighter-Charger-Power-Cable-Cord-Lead-For/32790479617.html?spm=a2g0s.9042311.0.0.27424c4dVBPu4G

I tested the voltage going from the cable to the mount, and its on 12.63v, which is great, and my battery is charged obviously, on the wall plug the voltage is 12.41v, so I don't think thats the problem. It might be an amperage problem, but I don't really know how to test it, I can plug it through my car 12v socket to check if it works, but that probably won't happen very soon. Any suggestions on what I can do or try? Thanks

[Thalestris24]

Hi

It may be that the cable you have somehow limits the current that can be supplied - it's described as a charger/monitor cable. If that's the case, you need a cable that will supply 12V without current limiting (or can supply 5A).

Louise

[msacco]

13 minutes ago, Thalestris24 said:

Hi

It may be that the cable you have somehow limits the current that can be supplied - it's described as a charger/monitor cable. If that's the case, you need a cable that will supply 12V without current limiting (or can supply 5A).

Louise

Actually, I just managed to check the cable and the motors with a car before my family is going for a while, and it worked just fine, but when I checked it just now with the 12v deep cycle battery it had the same problem, which I believe means its not the cable after all, but then again, I have no idea why it doesn't work. The voltage going from the battery to the cable is really good, so its not voltage, and I don't see a reason for the battery to somehow block the current, even tho I use 5A fuse, but that should be way more than enough...Any ideas?

[Thalestris24]

10 minutes ago, msacco said:

Actually, I just managed to check the cable and the motors with a car before my family is going for a while, and it worked just fine, but when I checked it just now with the 12v deep cycle battery it had the same problem, which I believe means its not the cable after all, but then again, I have no idea why it doesn't work. The voltage going from the battery to the cable is really good, so its not voltage, and I don't see a reason for the battery to somehow block the current, even tho I use 5A fuse, but that should be way more than enough...Any ideas?

Dunno - maybe a contact problem with the socket. Maybe you could try powering something else (that draws 3-5A) from the battery. What mount do you have? What voltage do you have at the 2.1mm plug?

Louise

[Alien 13]

The problem still sounds like a voltage drop when under load which still suggests that the cable or its connector is not mating fully with your batteries connector. Its worth checking the voltage at the mount when its running this will require breaking into the plug insulation at the mount end with a pair of sharp probes or similar.

Alan

[Dr_Ju_ju]

It's not the voltage per se, but the current that is supplied to the mount. 9 volts with 5 amp is no good, neither is 13v with 1 amp... 

You need to have 12 to 13.8 volts with 5+ amps at the mount, don't measure @ the battery.

[msacco]

54 minutes ago, Alien 13 said:

The problem still sounds like a voltage drop when under load which still suggests that the cable or its connector is not mating fully with your batteries connector. Its worth checking the voltage at the mount when its running this will require breaking into the plug insulation at the mount end with a pair of sharp probes or similar.

Alan

That is correct, luckily I have a voltmeter in my battery box(it wasn't wired before when testing for a specific reason), and I see that my voltage is dropping really hard when slweing, like from 12.5v to around 12.0-12.2v, I have no idea why the voltage is dropping so hard, doesn't feel like it should be that way, I don't think its the battery as its brand new, I don't think its the cable as well as it worked when tested in the car perfectly, I'll try figuring what the problem is, maybe something with the wiring even tho I did it very well in my opinion.

11 minutes ago, Dr_Ju_ju said:

It's not the voltage per se, but the current that is supplied to the mount. 9 volts with 5 amp is no good, neither is 13v with 1 amp... 

You need to have 12 to 13.8 volts with 5+ amps at the mount, don't measure @ the battery.

As far as I know mount slewing takes around 3A max(thats what google searches gave me before), even then, the cable should deliever up to 5A which I think is enough, and again, the cable itself worked when I tested in a car, so that doesn't seem like the problem.

[Alien 13]

I would check the fuse and holder for poor contact, you would be surprised how much voltage they can drop.

Alan

[Gilez]

Is the voltage dropping that much at the battery too or just at the load end? If the voltage at the battery end is fine, it will most likely be the cable.  If it does it at the battery too, then that's your problem.

[Merlin66]

A 5A 12v supply is more than sufficient for the HEQ5 or NEQ6 SW mounts. Pulls just less than 3A with full slewing both axis.

 

I've been using a 12v to 15v 120W car converter with my mounts for the past ten years. Works for me - never a voltage drop "flashing red led" problem.