Building LiPo FF battery pack out of portable jump starting battery

I've always wanted to replace my 7Ahr lead acid battery with lipo but felt the costs (batteries, rigging, charger, etc...) never justified my infrequent outings of 3 to 5 times a year.

Saw this jump starting battery pack at a discount last week for $35. A few more $$$ than the lead acid battery but comes with everything needed, even a car charger! It may still on sale for $35 with code GZHPO9B5. Note not shown in pictures, it comes with a wall charger as well.
https://www.amazon.com/AUKEY-12000mAh-Portable-Motorcycles-Lawnmowers/dp/B01I55H3XI

Seeing various lipo battery posts inspired me to come up with this. I figured if it doesn't do it for FF, I'd keep it for its originally intended use. I haven't taken it out on the water yet but have been testing it on land, on two FFs. Run-times are as follow:

Humminbird 788CI, draws approx 0.8A, at 70% brightness, around 8.5 hours (previously 6.5 hours)
Garmin Striker 7DV, draws approx 0.7A, at 80% brightness, around 9.5 hours (previously 7 hours)

I have to say that I'm pretty satisfied with the runtime results so far. Plus everything else: the extra capacity, car charger, other usage options, 1/5 of the weight, etc... all made it well worth the effort and extra costs.

One thing though, with its 12000 mAh, I did expect much longer run times. Simple math result in approx 15 to 17 hrs but that was not the case. At this point, I'm not going to contemplate too much on this. There are other brands/models with higher capacity but at higher costs, which would defeat my purpose.

I hope this is useful to some of you. This post wasn't a how-to write up as it's pretty straight forward. It requires very minimal changes to your existing setup. Simply solder existing connections on your lead acid battery terminals to the jump starter output wires and rearrange it to fit it in your existing waterproof box. But feel free to ask any question and I'd be happy to reply to this post.

Interesting project, and Aukey could make a bundle with kayakers.  One question, though: where's the inline fuse?

Looks like a fuse holder near the terminals - yellow?

Very nice. But it would bother me that the runtime is nowhere near what it should be. It makes me wonder if other LiPo batteries have the same problem...

Yes, that yellow thing near the terminals is the inline fuse.