Marc's Public Blog

Map: https://connect.garmin.com/modern/activity/5023804251

We've been going through bike/walks around the urban landscape next to our house. We found a hole in a fence at the end of our street, so we went to check it out, that took us to 280 and stevens creek. There was a big tunnel for the creek, but a second huge tunnel, for I don't know what, it's big enough for a road (advance planning, nice).

Many years back, when I jumped a fence to get there, I couldn't go down, but someone nicely installed a rope ladder recently, so we went down and into the tunnel. That took us to the railroad (mostly unused) on the other side and connected to a street, or to sommerset park after removing a few metal wires that tried to patch a hole in the fence (thank you swiss army knife).

The secret BMX park is inaccessible unless you get to it through the railroad tracks from another access point. No idea who built it, it doesn't look official but yet it was well built: https://www.google.com/maps/@37.3322805,-122.0624639,157m/data=!3m1!1e3

We found that the freeway had doors in the wall, some you could just open and someone put chairs on the other side, maybe to just relax and watch traffic go by? :)

On the way back, I noticed that you could drive from a hole between the freeway walls through a railroad crossing that had been built for car crossing, to nowhere, the road stops there, although it almost connects to the stevens creek tunnel.

There is probably some interesting history and roads that maybe used to connect and don't connect anymore, or were meant to connect, but never did in the end. Either way, it was fun, we felt like urban explorers :)

nice pink house on the way to Steven Creek Trail

lovely tree

Norcal radar site

babies are grown up already

so proud

Eventually we got to Alviso, the land that time forgot:

prime real estate in a flood zone, awaits for you

interesting house

it was a mixed neighborhood

From there, we got to the Alviso Don Edwards loop (we did the longer double loop):

for once, a train that almost looked fast

salt from evaporation

After the long loop, it was time to bike all the way home (almost 2H), back around great america, 49ers stadium, and greenbelt back to Stevens Creek Trail:

This was our longest bike ride ever, it went well considering. Maybe 50 miles next time? :)

So, I called it Skyline to the Castle Rock as we started with Skyline to the Sea backwards and finished at Castle Rock: Here is the garmin connect page:

Although here's a much nicer map, showing the previous Skyline to the Sea hike we did compared to this days's hike:

Planning the hike was a bit interesting because the CA Governor was nice enough to close all state parks, but in a way that someone could mistakenly enter them from another location and realize when exiting that the reason they didn't see anyone at all on the trail (and why it was actually so safe), was that other people were kept away.

nice parking spot next to the trail entrance

oh, not this way

this way ok?

I can see the tow truck saying 'fuck it, I'm not getting paid enough for this one'

castle rock trail camp now reservable, how nice!

beatles were out having orgy sex

we found out that the lizards get ticks and their blood kills the lyme bacteria in them

turkey vultures

Great that we got to see Castle Rock this time:

Then we got back to skyline. Ooops, you mean we weren't supposed to be here:

Across the street, Indian Rock and other trails not part of the CA park, were open:

The 3.3 mile hike back to the car looked ok, but was very close to skyline and car noise:

lookout tower, and old observation site, now overgrown

slight renovations required

Then, we have little lizards everywhere (well, big and small). The small ones are easy to catch :)

grippy claws :)

We've also heard racoons at night, and I was able to snap a couple of pictures. Thankfully they don't seem too bold and too much of a pest like we've heard they can be:

Howeer, what we have quite a bit is lovely possums, we mistakenly caught a few and of course released them:

such a cutie

it wasn't too scared to eat

we got another one the next day, or was it the same?

Ah, but the subject of pests brings us to gophers. Those fuckers have been making swiss cheese out of our lawn. Since repellents don't help, I've been using smokers in their tunnels, and poisnned worms they're supposed to eat. That seems to have helped with the problem, but I think we still have a couple left.

We even ended up with a skunk, oopos:

it was tricky to get out without being sprayed

We also have the occasional rabbit:

And rats:

I have many pictures of those birds, but these are hopefully the best:

a junko was feeding the wrong bird, oops

that was a lot of doves

After a while, built aa new mostly squirrel proof bird feeder:

We also got beautiful woodpeckers: [rigimg:1024:501*|]

We also got a few wounded birds:

And we also got a few hummingbirds. Those are cool:

Squirrels started by being cute before the bird feeder:

The only problem were the squirrels that started by eating fallen seeds, but eventually went to the source:

they look good when they start

clean the seeds by your doorstep

then they climb

and climb

and jump

and climb

and jump

The squirrels really became a problem, so I had to trap them and get rid of them:

I tried to build a defense, but it was pointless

on the plus side, I could capture all the grain the birds were dropping

so I had to bait them with peanut butter

Thinkpad P73 vs P70, not a win all around: only one 2.5" drive instead of 2, and a badly designed power system

P70 vs P73, they look pretty similar

*Update*: it seems if that if you get a cheaper nvidia chip with the P73, it is then configured to accept 135W power supplies as the minimum required. That said, it will still refuse to work with any regular 90W power supply or external battery back, unless you force it with the center pin resistor swap.

While I have no plans to use windows on that machine, I thought I'd just try it out to see how it does on power. This is where I was impressed, windows can idle at less than 10W for more than 11H runtime, while I'm lucky if I can get linux at 15W. This is definitely a place where linux should do better, of course, it's not as if Lenovo put any work into making linux more efficient on their hardware either:

*Update* : with tlp and using the nouveau driver just enough to turn off the nvidia chip, I'm now able to tune the laptop down to 10W, almost matching windows.
See tlp issue 494 for details on how to setup tlp to run in low power mode when power is plugged in.

Another disappointment is that the P73 is mostly the same size and weight than the P70, but it has less room for storage. It has a bunch of empty spaces that aren't used for anything, and it can't use two 2.5" SATA drives anymore, like the P70 could. Worse, the now single 2.5" slot uses a lenovo only ribbon cable that does not ship with the laptop and basically means you cannot even add a 2.5" drive without that special ribbon cable, which isn't in stock yet. Well done... Ah yes, the battery is also not hot swappable, even if it is replaceable (unlike a Mac laptop where everything is sealed shut).

this shows the unobtanium lenovo cable for the now only single drive that fits, along the unused space

Ok, stop complaining, just buy a bunch of 170w or 230W power supplies and move on with your life

Tricking the P70 and P73 into accepting a power supply it wouldn't otherwise use

For the P70, I built this power supply adapter with a resistor bridge to tell the laptop how big it should think the power supply, is:

It's basically a configurable version of this. Yes, lenovo, I thank you for the hours I wasted opening up power supply plugs and replacing the center pin resistors:

Here's how the P73 responds:

- 230W works fine   4.6k => I have seen power supplies work with 170W but fail at 230W, so the laptop does draw more
- 170W works ok     1.9k (1.8k also ok)
- 130W rejected     1k
- 90W  rejected     550 

The rejected power supplies will be used to charge the laptop if it is shutdown, but they will not be used in any way otherwise. On the P70 the laptop would at least use the power supply to keep the laptop alive, and use half battery half external power supply. Not so with the P73, it just ignores it entirely.
This is utter bullshit as I have plenty of 90W power supplies, including 12V car converters, or a 90W external 20V battery pack I can't use anymore.

You can go read my Hacking a thinkpad slim tip adapter to output more than 90W (required to charge a Thinkpad P70) page for details, including this nice battery pack I couldn't use anymore:

*Update* : so, actually with some serious tlp hacking (basically I told it to force battery mode even if a power supply is plugged in), I've managed to throttle the laptop enough, even when plugged in, so that it only uses 20W. At that point, I'm actually able to use my old external battery pack, as well as a 90W power supply, as long as I lie to the laptop and pretend they are 230W power supplies with the resistor trick. In my tests with windows, it was not possible to throttle the laptop enough when plugged in, not to have it overwhelm a smaller power supply (not that 90W is small for a laptop that normally uses 20-30W when it's not charging batteries).
If you scroll to the bottom of the page, you'll also see a terrible buffer lipo hardware hack I did that allows to use the battery pack with higher amp draws, but it's a bit ridiculous (and bulky).
See tlp issue 494 for details on how to setup tlp to run in low power mode when power is plugged in.

Without the tlp hack or the buffer lipo hack, when I lie to the laptop and tell it is connected to a a bigger power supply, manage power draw with what I run, and disable battery charging in software, but the laptop will still draw the power supply for over 100W when you plug it in for a fraction of a second, and refuse it if the voltage drops.
Obviously this would not be a problem if the laptop simply had a 90W power supply mode where it throttle things down and turned off battery charging. This is mostly what the P70 does.

In the meantme, on top of hacking my power supplies, I also made this for my laptop, it looks silly and makes the thinkpad not look like a professional laptop, but well, that's lenovo's fault:

this takes any power supply and replaces the center tip resistor with a 1.9k one to emulate a 170W power supply

From talking to Lenovo, they don't think that this is really a problem, so since I'm an engineer, I made my own external battery pack, but I otherwise recommend to road warriors to avoid thinkpads from now on, given the backward power design in this one.

Making a Thinkpad P73 compatible external battery pack

Prototype with 150W step up converter which takes my 16V lipo to 20V while delivering enough amps to make the laptop happy:

it works, and the laptop thinks it's connected to a 230W power supply thanks to the center pin resistor.

Here's a quick demo:

Version 2 was to have a way to recharge the battery pack while it's being used. I've used this to use the battery pack as a buffer to absorb peaks from the laptop without tripping an external power supply, including in a car limited to 100W or a plane power supply limited to even less:

this works in theory, but the lipo charger is quite slow and wouldn't keep up for long, but I made a better version shown lower down

Lenovo's P73 airplane mode simply stops using the external power supply and reverts to batteries. Sigh...

Making a battery pack to act both as buffer for a smaller power supply, and as emergency external power (even power the laptop from 12v)

version 1 was a bit bigger than I wanted, 90W power supply shown for scale

here, the 90W power supply is recharging the battery at 2.5A while it's being discharged at 3A on the output side, using the battery as buffer

I made version 3 a bit smaller, with a built in 12V lipo to act as buffer for a smaller power supply. Yes, it's a beautiful piece of art, I know :)

Pushed to the extreme, I can now use my original external battery pack again by having it recharge my lipo+150W step up that can output more amps than the ravpower pack can. Of couse, it's inefficient, the ravpower pack outputs 20V that gets down converted to 12V by the H605 Air lipo charger, which charges the built in 3S lipo in the box, and then gets up converted back to 20V without the amp limitation (the phone used to control the lipo charger also inside the box):

The really cool thing is that by using tlp, it's actually possible to tune the laptop down to very low power use, even when plugged in, something that windows probably can't do:

7.3W with the screen off (and around 10W with wifi off and the screen on low dim) is not bad for a laptop that big

4S Lipo vs 4x 18650 or 26650 batteries

That said, as I recently found out that 16650 (or better 26650) batteries are both lighter and smaller. The only thing the lipos do, is offer a better discharge rate, but while that's useful for a high power RC plane motor that can empty the batteries in 10mn, it's not needed for a laptop:

26650s are 195 Wh/kg while the lipo I gave was 184Wh/kg. The 3rd battery listed is supposed to be 260Wh/kg which is much nicer, that said, it looks like those samsung batteries are actually smaller than 26650s, lighter, and yet offer the same 5Ah at 3.6V. If so, that's very impressive.

As of this writing, I have however not found 26650 battery holders that hold 26650 protected cells that are a bit longer. This seems to the be only one available, and it's too short to hold the batteries: https://www.amazon.com/gp/product/B074GVPWSH

A few months later, I ended up cutting them and taping them to make them longer. It doesn't work great, but it was enough for a few tests. In the end, I found that somehow I wasn't getting enough amps out of them, which surprised me, so they didn't work that well compared to a lipo:

Conclusion

Here is the navigation track on google maps

Took about 25mn and 4 miles to get to the bottom of montebello (600ft altitude), and then we biked up. Jennifer did better on the way up than I did (last time, many years back, it was the other way around):

then up

more up

took about 1h from the bottom to get to ridge (4 miles, 1600ft climb)

welcome to the top before entering the preserve

not a terrible time for a 2000ft climb

new gogle campus

top of black mountain

2h, 2500ft up to the top

the hiking path was nicer

we got to pagemill in no time

nice views from pagemill

I know this turn from driving up, can't clip the apex on this one :)

We then got back to foothill and biked home:

Very nice loop, glad that we did it.