Modifying prebuilt junk, in stages, to be less junk like.

[SternWake]

I am not sure if my BMS is actually capable.of balancing. I can’t measure currents as low as 30mA with my clampmeter and A DMM inline would likely induce as much resistance as the BMS is supposed to use to bleed off the higher cells, and confuse me even more.

This AM my 10 P groups were reading 4.19v, with 2 groups toggling to 4.18v briefly, then back to 4.19. My DMM only reads two deckmals above 4v, and I crave 3.

The flatspotted kayak wheels had rebounded a tiny amount more towards round, and I placed them in the sun, and took Fiona out for a walk.
At the turnoff to goto the Kayak launch, she made a stand. I had no desire to walk the 2.5miles roundtrip, and had no ball in my pocket, and after a few minutes, she relented and we walked home.

I’d decided i was going to take her out on the kayak, flatspotted wheels or not, and came back to find them warm soft and fully round. I loaded everything, and started towing the FionaYak to the launch, and the soft but round kayak wheels kept gettjng softer and draggier and top speed was way down and was chewing through the battery.

There is 0.25 miles of crushed shell trail we have to walk to the launch, soft in parts, and these wheels rolled over the soft parts worse than the smaller wheels did.

Paddled 5 miles, threw the ball a hundred times so Fiona could romp and swim. We barked at cormorants, pelicans, ducks and gulls and turkey buzzards till we were exhausted.

The skate home was the slowest yet, and the soft wheel drag just kept getting worse and worse, but we made it back without battery dying. I likely have not drained it this low yet, ever.

Came back home to my dad pinching the bridge of his nose, shaking his head, and my Alzheimer’s infected mother having an anxiety episode, unable to form any words remotely relating to whatever she was trying to convey.

I picked a bad month to stop drinking beer, and run outta herb.

I had an idea that maybe the orange hubbed kayak wheels could be heated and compressed and squeezed within the vibrato wheels perimeter, if i can cut the spokes out cleanly, and thus give me low rolling resistance non vibrating kayak wheels.
Could be a giant waste of effort though.

[BillGordon]

Planning on cleaning up/rerouting balance wires? Having crossed balance wires without insulation is a bozo no-no.

[SternWake]

Yes, definitely.
I left the leads loose enough to get my my clampmeter around them. Hoping to be able to read balance current, even though I knew better.

I might still add JST connectors for checking Pgroup voltages, and manual balancing, as I am OCD like that

It’s still a ways away from powering my board, and my new enclosure might need modification to slide into Kayak well.

[ApproachCautiously]

@SternWake

I am not sure if my BMS is actually capable.of balancing. I can’t measure currents as low as 30mA with my clampmeter and A DMM inline would likely induce as much resistance as the BMS is supposed to use to bleed off the higher cells, and confuse me even more.

Is this the battery the pre-built came with? if it is then you could be wasting your time trying to get it fixed and working well. I only say that because I’ve done the same thing myself, and the time spent was not worth it for how low quality the cells were. I always say to try to fix things before replacing them, but for a prebuilt’s battery I think it is cheaper to replace after considering the time it take to work on them.

There are battery makers on here who can work with you to get a new battery that can fit into whatever enclosure you want to use. Many of said people have very reasonable prices too

[SternWake]

This questionably functional Daly 20 amp BMS is on the 10s2p battery I just built, but have not tidyied up, nor heatshrunk yet.
Pics a few posts above.

The 7s2p battery the prebuilt came with, is certainly suspicious, with balance.leads stuffed haphazardly under heatshrink, barely a MM away from to sharp nickel strip edges coming off Main +.
I’d cut the heatshrink over bms to inspect, out of curiosity, and just separated leads from each other and nickel with fishpaper dots and strips as best I could. and kapton taped the wound closed, and haphazard balance wires tight, and returned it to service, while I build larger enclosure for 10s batteries.

Ive no idea the P group voltages on the 7s2p, as the balance connector was glued, but did once notice (before opening heatshrink) the charger voltage at 29.4v was 0.4v higher than on the xt60 leading to the ESC so assume the BMS was bleeding voltage to balance, or there was just a shottkey diode in place of a BMS.

I have torn apart another inop 7s battery from a parts only board of same brand of premade junk. Cells were BFN, 2000mah and 2c rated from what little info i could find on them.

The 6 ‘good’ BFN cells from that pack now are comprising two 3s1p batteries with a non balancing bms on them. They do drift and I have JST plugs on them now, to monitor and manual balance them.

That discrepency between charger input voltage and xt90s output voltage, is something I was unable to see on my 10s2p new baTtery last night, with 2 p groups 30mv below the other 8.
After an hour held at 42.00v and amperage tapering to below 100mA, there was no improvement in Vdelta, and the bms did not warm up at all, which makes me think it is not working at all in regards to balancing. More testing needed.

The plan is to remove 7s2p battery and Esc from service, replace with 10s2p and 10s ESC first, then make 10s 3p of higher quality cells and smart bms, then vesc at some later date, and then perhaps better hub motors.

This particular board needs to fit inside my Kayak hatch, but I might have to make a real board without such limitations, down the road some, as I miss surfing, and Esk8 is the only thing that comes close to that, in my experience/opinion, and one of my few joys available.
Paddling the kayak with my dog, are the other two, and the Esk8 tows us to the launch and back, so it’s a bit of a trifecta.

[Pecos]

Sparkey trick: If you can put multiple wraps around your amp clamp it will amplify the signal, probably good to test but not to leave too much extra length installed. Just divide the reading by the number of “turns” through the clamp.

Also, you could make a jst jumper with lots of extra length to extend the balance leads long enough to do your testing while also finishing off/cleaning up the packs permanent wiring.

[SternWake]

Thank you.
I can wrap the leads, as they are now, all loose, twice, through the Amp clamp, but I previously established it is blind to current below 60mA, and needs constant unclamping, rezeroing, and returning, just to read that much, briefly, so two wraps might or might not briefly show up at the 30mA the DaLy is supposedly capable of bleeding off.

No way three wraps work unless I desolder and extend the balance wires just for the testing.

I’ve again been shopping for an ampclamp which can read lower current, but my finances are struggling, and the more affordable ones are of questionable quality.

I discharged my 10s battery through the Daly BMS today. I was using a buck converter to charge my 7S batteries to 29.39v at upto 3.5 amps into the 7s2p battery.

Granted the amps were pretty low, but each time I checked all 10 P group voltages under load, the biggest voltage Delta was 4mv, and usually it was only 1 or 2mV.

I stopped discharging it at 35.79v and voltage Delta is 2mv, with 8 reading exactly the same, the two lower groups are only 1 and 2 mV off, and those lower cells were not the ones which were lagging by 30mV on initial charge before I manually top balanced them with a 4.2v source.

Unfortunately, the inline wattmeter i was using before buck converter is one that reads low, but it recorded 3.733ah taken from 5.4ah 10s battery discbarging from 41.85, to 35.79v.

I hate inaccurate data.
That wattmeter should get sledgehammered as it has other annoying issues, like not storing max watt or amp peak or minimum oltage for more than 5 seconds. I bought 2 and installed xt60 connectors on the one specifically to capture peak amps/watts and minimum voltage when accelerating, onky to find it didnt store anytbing. Made xt60 to anderson powerpole adapters to use a wattmeter I trust to capture a 538 watt peak figure from the supposedly 700 watts of hub motor.

I had to leave workshop just now, before I did break something else.

I spent considerable effort sawing off and sanding flush, the hub and spokes of the Vibrato Kayak wheels, hoping to compress the too soft and draggy , battery killing kayak wheels within the perimeter of the vibrato’s rims, for a nice low rolling resistance wheel for kayak scupper cart.

Due to not being able to find my ratchet straps and pressing on anyway, I broke the rim.

I just love wasting time, effort, and money.
I am so freaking good at it.
If only someone would paY me to do so…

Back to square one regarding the kayak wheels.

At least my 10s2p parallel groups seems really well balanced when discharging from 99.95%% to ~35% state of charge.

[SternWake]

Last time I was stuffing my front hanger freed board into the Kayak hatch, I realized my new maximum sized enclosure might prevent such stuffing.

Unfortunately, this is indeed occuring, but better to realize that now, and not at the kayak launch. Fiona would be so pissed off, as the sky turned black from vile curses.

Looks like I have a good excuse to modify the shape of the deck and make it look less recognizable as a premade that anyone with 280$ can purchase, even though i don’t find its shape displeasing as is.

I don’t need So much kicktail anyway, and a just tapering the nose a bit might be enough as well. The enclosure is getting a 3/16" gasket too.

It is hitting the front of the enclosure by the kayaks footwells, and i dont really want to modify enclosure, and lose interior volume if other options exist.

[SternWake]

I was not too thrilled to have to cut off the swallowtail tips, but am not displeased with how it looks with the minimum amount cut off to allow it to fit i to the Fionayak

As a bonus, I can more easily 2 finger carry it by the front truck hardware and it barely scrapes the ground. I figure once I own a pair of shoes again, the added height will prevent scraping at all.

I’ve managed to go a year with only flip flops, and hiking boots, and skate barefoot.

[SternWake]

I am not happy with the thickness, or width of the flanges on my enclosure, so will be adding more unidirectional tow/roving/fin rope to the areas lacking girth.
I could do it when not using the board as a mold, but temps are warm and i should be able to reassemble it tomorrow in order to be able to ride it, and it should equate to a better result and less dust/sanding.

My lesser 7s junk is just too slow to clear my head properly but far better than nothing.

I’m a bit bummed at the degradation of my fiberglassing skills, but not all the skills of laminating surfboards or foiling wood surfboard fins translate into making a positive mold for an Esk8, and there is are dozens of ways i would do it differently, if i were to do it again.

Well, when I do again.
The lesser 7s junk has 10 P42a’s waiting patiently.

Whatever finish that JKing’s factory used to seal the deck, is soft, porous, and stains easily and is nearly impossible to clean.

I sanded through it around where I filled in the hollow handles, so will later sand all their Shitty finish off, and use surfboard laminating Epoxy. Heck I might add a layer of cloth at that point.

My push longboard, I did not use grip tape, but brushed on some epoxy thickly, waited for it to thicken a bit then sprinkled the deck with raw sugar, added slight pressure to push it in and let it cure fully.

Fully, meaning a few days, as my epoxy will cloud if it gets wet if only 99% cured.

The sugar dissolves with a water rinse leaving behind a nice clear grip. Not as grippy as grip tape, but I’ve never slid off it, and it cleans up pretty easily with water and a brush.

[SternWake]

My kayak cart’s wheels were a serious issue.

The first set ejected a wheel, on the final turn, when the overheating hub was riding up against the push button wheel release.

Preventable, with a second washer, but dumbassery and complacency ruled the day.

The second wheels required a larger diameter axle that came with the wheels, I drilled out the original cart axle, JB welded new axle in, and the wheels vibrated horribly, the spokes and rim flexing , compressing and rebounding, causing bizarre harmonics.
The seat of the kayak was vibrating up and down about 3" at certain speeds, but they had low enough rolling resistance and allowed the Esk8 to reach its esc limited top speed.

The third set of wheels were included in another Kayak ‘scupper’ cart i reluctantky ordered. On arrival, they appeared hard as rocks. They fit my JB welded axles from vibrato wheels, better than the axle they came with, and I bolstered them with 3 washers on each side of hub, the center washer being a crinkle ‘spring’ washer.

First spin around the block, all was well.
Second spin it got draggier,
Third was downright bad and board was struggling to pull us.

When I stopped , I found the wheels had heated up and gotten soft.
When they cooled, with kayak weight still on them, they flatspotted.
They returned to round after sitting in the sun, and we went kayaking, the motors and battery struggling on the way there, struggling hard on the way back, and hot to the touch.

I modified a saw blade on oscillating tool, and cut out the hub and spokes off the vibrato wheels, then sanding the interior flush, hoping I could heat and compress and slide the soft wheels inside the LRR rims of the vibrato wheels.

Fail.
Waste of time, and effort, and sanity.

I asked here about pneumatics, bearing sizes, axles and such, and two awesome members here offered to send me hubs and tires.
Thanks again!

But I had already decided I would buy a 115$ passive mountainboard with 200x50mm pneumatics, cut one of the trucks, grind it down to fit inside my kayak carts crossbar, and JB weld them in place.

The ‘Vevor’ branded mountainboard was delivered by UPS this evening, the box in tatters, and turning box sideways, a wheel fell out of it.

It came with these little jokes of wrist, knee, and hand protectors, I thought the knee protectors had fallen out, but what I thought were the elbow protectors, were the knee protectors, the even tinier elbow protectors nestled within.

Awwwwww, How cute!

The deck itself felt alarmingly light. For grins, before I bust out the angle Grinder to a truck, I figure I’d assemble it. Push it around the driveway.
Holy horrible turning radius batman!

The washer cups impinge on the hanger, limiting travel.

I did not bother with attaching the footstraps, but do see potential in their future repurposing on something, somewhere, at some point.

The axles are 10mm, and the 2 piece plastic hubs have very little discernable to the eye, run out. One of the ‘C lever’ 200mm tires is also well formed, the other three are wobbly on the rims, but should be more than good enough for kayak scupper cart duty.

Max PSI is 35, and my gauge is missing, but it does not roll all that great, compared to 80mm urethanes.
They feel like they are in the 35psi range.

I’ll bust out the cut off and grinding wheel and JBweld tomorrow

My enclosure got a lot of sanding today, but I want to add more fiberglass in some areas, and am still deciding how i want to attach the heatsink without relying on a sealant after the fact, and without fasteners, if possible.

[SternWake]

Would have been nice to have a lathe.

After cutting the truck in half with a cut off wheel, and then cutting off the cast gussets and grinding them mostly flat, I put the taped 10mm axle in my drill chuck, and made cloud of aluminum dust with my angle grinder and a flap sander.

Since the previous round aluminum axles were JB welded inside the stainless square tubing, I saw no point in setting these new axles deeper into stainless square tubing than the Jb welded axles, as no way could i get It supported inside with JB weld any deeper.

I could have just cut the new axles shorter, saved myself some work, but decided the wider more stable track width was desirable.

There was that one time I hit the gap in the middle of the speed bump a little too fast, and felt some weirdness on kayak handle, turned around and saw the kayak on one wheel with Fiona leaning hard to level it out.

So the track width will now be at least 6" wider than before.

With all these improvements, Fiona is going to need some Doggles, and a scarf.

I should be mixing up JBweld instead of typing, but 24 hours of cure time maKes me miss the kayaking window tomorrow anyway.

[Arzamenable]

Subbed for cutting up axles and dogs.

[SternWake]

I aligned and JB welded the ground trucks to the best of my ability, into the kayak cart axle a few days ago, and had some time , and weather today, to go paddle.
So I put board on charger, cleaned up the excess JB weld, and blue tape, found a psi gauge, dialed in 35psi, loaded the kayak and hit the asphalt.
So quiet. so little drag, so.very much appreciated

Let off the throttle, and the Fiona laden kayak wants to roll faster than my dragging hub motors do.
Yeehaw.

Paddled 5.2 miles, according to Google earth
Barked at dozens of cormorants. and turkey buzzards.
Stupid turkey buzzards.

I dont know what she has against spoonbills, but those get no peace.

Threw the ball at least a hundred times, and watched Fiona throw off wake in chest deep(for her) water to retrieve it. Snort grunt snort.

Esk8’d back, faster than ever quieter than ever, with more battery left than ever.

Decided beer was in order.
Skated to liquor store.
Foster’s oil cans, green or blue buy 3, get 3 free!!!

Done and done.

3 left, and experiments to perform.

Gentlemen, man your multimeters.

[BillGordon]

Always cool to hear of DIY success. Excelsior and beyond!

[SternWake]

Such a slippery slope, this Esk8 thing.

And my cheap junk 7s fvcking board only allows 14mph, according to a radar sign yesterday alone, and today too, wben towing the Fionayak on pneumatics.

Fiona is snoring so hard right now.

Why can’t dogs live longer?
I miss her already

[SternWake]

Drilled some pilot holes through enclosure into deck, and then drilled deck for some threaded inserts, but have not yet epoxied them in place.

The cast inserts are disappointing. Blunt threads and the two halves of mold not well aligned, so the seam would gouge the hole wider than necessary, and lumpy dull threads cut more wood away than needed.

I’d not trust them to hold well if not epoxied in place.

I have 3/16" gasket material, but can still shorten 3/4" SS truss head screws, or thicken flange, if needed.

[BillGordon]

You don’t want to use philips heads here. Try to source some hex bolts. I use socket head for extra depth since I’ve had regular hex strip on me.

[SternWake]

10-32 threads, and Phillips head are nostalgic for me, and were a conscious decision.

Standard single fins box hardware on surfboards use 10-32 threads, but slotted/flathead usually.

I went Phillips head on them 35 years ago.

[SternWake]

Epoxied inserts in place.
Thirsty endgrain sucked up a lot of thin epoxy.

No issues with epoxy obstructing interior threads, but had to hover, and when epoxy was rubbery, ensure that no epoxy could.

Sanded flat, remove all original finish on hull.
Laminated one layer cheap folded bondo brand fiberglass onto hull.

I’ll estimate it is 7.5 oz per square yard weight. An hour later brushed on a thick weave filling topcoat, and hour later, another.

18650 fishpaper dots to cover inserts.
Smaller dots would have been better.
No dots, even better.
Oh well.

Let the wet laps hang, didnt try to wrap the rails.

4 hours later razor the edges of laps, a bit wide of perimeter

Razor and 1/8" Chisel off the oversized fishpaper dots.