There is another way to add hdd without replacing the battery with a smaler one
The express card can hold another m.2

Yes with the 4cell battery you can combine 2,5" HD/SSD with m.2 SSD with 6cell battery only m.2 SSD.

The 720p sucks majorly of course. Should have tested it with the 1080p screen. >:D
Dell WJ5R2 Laptop Battery 9Cell is the best replacement battery for Dell Precision 3510

@Juan Saez:
It depends on your battery configuration. The biggest battery can only accommodate M.2-2280 whereas the other smaller batteries will leave room for a 7mm 2.5" drive. Check the online PDF user manual.

Quote from: Robert on September 09, 2016, 11:33:12

Quote from: Richard on August 02, 2016, 17:18:15
Do you know if it's passible to combine an M.2 SSD and a HDD?

Yes with the 4cell battery you can combine 2,5" HD/SSD with m.2 SSD.

Hi,
Are you sure about this?
If I take a SSD 256 Go M2 2280 SATA3 from Dell, can I use the 2,5" bay to put a 2nd disk?

Quote from: rudepeople on September 24, 2016, 06:19:30
I couldn't help but notice this thing has an m.2 slot for a wwan card. In researching that slot it seems that an M.2 2242  PCIe SSD (not NVMe) could be used, like an ADATA Premier SP600NS34... Am I correct?

I've done some homework on the subject of m.2, but thus far it seems I am just generating more questions than answers... very confusing interface... even the wiki article has stumped me.

I can confirm that a SATA type ssd works and is bootable when used in the WWAN slot. slot size is about 46mm compared to the other slot's  80mm.

I don't believe it is possible to have both the m.2 SSD and the SATA HDD, regardless of the battery size. Similar to Latitude 5570, of which the Precision 3510 shares the same case design, the HDD covers the position where the m.2 card would go so user has to opt for only one of those.

Not sure if it's possible to use the WWAN slot for SDD instead, like it was possible on older Latitudes (7440). If so it will probably not be possible to boot from it.

I couldn't help but notice this thing has an m.2 slot for a wwan card. In researching that slot it seems that an M.2 2242  PCIe SSD (not NVMe) could be used, like an ADATA Premier SP600NS34... Am I correct?

I've done some homework on the subject of m.2, but thus far it seems I am just generating more questions than answers... very confusing interface... even the wiki article has stumped me.

Quote from: Richard on August 02, 2016, 17:18:15
Do you know if it's passible to combine an M.2 SSD and a HDD?

Yes with the 4cell battery you can combine 2,5" HD/SSD with m.2 SSD with 6cell battery only m.2 SSD.

The 720p sucks majorly of course. Should have tested it with the 1080p screen.

If only i5-6440HQ configuration featured a USB-C port...

Whoops. Misread. because limited on space.

Do you know if it's passible to combine an M.2 SSD and a HDD?