I am not understanding why it doesn't work.

I was unable to successfully upload the image here for some reason but here is the permalink from solar forum where I have the image showing the adapter used to charge at the mains. I don't want to use that, it is only to illustrate the power requirements. I want to charge direct from the battery fuse block with just wires and connector to the device.

You can also see the rest of the discussion for background what I have tried in that whole thread and everyone else coming up short for solutions so far.

If you have not read the linked thread with all the details, I have tried to connect direct to leisure battery fuse block and it shows charging but even after an overnight charge it does not show any progress.

Any more detail wanted please read that other thread I linked rather than repeat myself.

Ideally I want to be able to connect direct to the leisure battery and not buy additional converters but I am not able to fathom what is wrong since it is 12v. So don't know what is missing to make it work.

Post the specifications of the adapter. We can not read it directly from the picture. It becomes somewhat fuzzy reading the other posts.

Dell and Apple power adapters are actually "smart", they have a memory chip where the device knows the current capabilities. If Dell can not read the adapter it will not charge, Apples I believe will charge at a min rate. Your tablet probably does not but just throwing that in.

What is a 12v leisure battery? As posted on the other website typically power adapter maintains voltage <= +/- 5% of the rated voltage. What is the size of the wiring and how long is it to the fuse block. The smaller or longer the wiring the more the resistance, the more the voltage drop. Did you measure the voltage when the table is connected?

Here is a link to the device advert on amazon.

Leisure battery means 12v battery for leisure purposes as opposed to starter battery. Used for campervans and such to power all the leisure items.

I have measured the voltage of the wires but not the device itself. How do I measure voltage when connected? I only know how to measure bare wires. The voltmeter I have is really only and only a needle so doesn't give precise number. I checked just positive and negative and the dial goes up to around the same point I noticed all other readings have from device which are working fine. Or do you mean with software in the tablet?

The wire is not an issue. It is less than 1 meter.

It would be difficult to measure the voltage under load unless you built a special adapter. With the wire being only one meter lets ignore. The current draw from the laptop depends the charge of if its own battery.

So the range of the battery is something on the line of 11.8 to 12.6 or 12.8. If we go with 5% tolerance for the power adapter that would be 12.4 to 12.6 VDC. What is the actual leisure battery voltage at full charge? Does the laptop battery charge when the leisure battery is at full charge?

It goes up to 14.4 volts at full charge. I don't think the variation accounts for the problems or else why would everything else work fine? Around 12 volts marks means it is almost empty. Most times it will be at 13 something. I think it works rather different in terms of voltage to normal lead acid batteries since it is a lithium battery. I don't know much about either since I only just bought and started using a couple months ago but that is what I have read, that lifepo4 batteries have irregular voltage patterns so do not charge and discharge linearly, as I understand it.

I linked the amazon advert of the exact tablet. I think it runs at 7v. Doesn't seem to say there but I think I read it on another advert for version or model that looked very similar.

The laptop does not charge even if the battery is at full charge?