Planned Mods

[krbjmpr]

Victim is 2012 Yukon SLT...

-Going to be adding a pwm box to alternator to better support LFP battery(s). Saw 15.2vdc on torque pro, last night. Had for a while, too busy to fuss with and is my Daily Abuser.

-Add a pair of EcoFlow 12v 100Ah LFP batteries. Will be shoe horned for sure. Batteries state not for vehicle starting, but TM version rated at 300A/30seconds. Gotta knock down that 15v+ alternator output.

-Whilst doing battery upgrades, gonna redo my Big3+ cables. 4awg isn't adequate, have several feet of 2/0 and a bunch of 2 to play with. As well as 4 and 7 (yes, 7). Smoked a 4awg cable going to battery2 (driver side) due to abrasions and current. Alternator survived. Cable didn't. Using factory cable left in place.

-Inverter in DS rear jack storage area towards rear. Have to figure out ducted cooling. Which got me to thinking about...

-Converting rear AC to Electric but standalone. Condenser on roof, compressor under & inside frame. Anybody else contemplated / accomplished?

-Add exhaust fans to rear vents on either side of lift gate top trim pieces. Be nice to keep air circulating when truck parked in TX summer sun.

-Make / Buy sliding adapters to 'close mount' cargo carrier on top of roof and support other project (incl AC condenser), and might include solar power.

Saw a Dodge hybrid mini pickup last year. Had electric assist via motor/generator. Doubtful can get a strong enough belt on aftermarket crank pulley, but will do due diligence. Be nice to add 50 ft# torque if needed.

What is on your list?

 

[justchecking]

“-Add exhaust fans to rear vents on either side of lift gate top trim pieces. Be nice to keep air circulating when truck parked in TX summer sun.”

You might find the little rubber flappers are already dried up and broken off. If you buy new replacement assemblies you could mount quieter computer fans to blow out from the inside and power them with solar. Then when ever the sun is beating down the fans will power on and exhaust hot air.
On my old old dodge truck I had something similar set up. I had bought some small fans and solar panels to help exhaust hot air from bee hives. One I never got installed so instead put it in back window of my truck. Worked great.

 

[krbjmpr]

Computer fans are what I had in mind. Would prefer to fit inside cavity, will just have to see what I can work with.

Surprisingly, the flaps are still in good shape. Every 1 or 2 quarters, I pull off the fascia / trim pieces to replace the pieces of EPDM foam Imused to eliminate squeaks. What started out as quick fix couple years ago (until can shim screws) will continue. Maybe once fans are in will do something longer term.

Eventually. Though not at current rate, will have a LFP battery 'somewhere' in back. That will be primary power, with solar charging whenever I get around to cargo rack / sled.

Anybody happen to know default position for fresh air blend motor? If is closed, fans will help minimally.

 

[justchecking]

“default position for fresh air blend motor?“ i believe it stays in the last commanded position. Unless you remote start the vehicle and the defrost comes on, then it may go to recirc.

 

[mikez71]

My impression is it defaults to open, as I'm always having to hit the recirculate button..
Just did a test, had recirc on. Shut truck off, key on, recirc was off.

As others have mentioned, GM seems to have an aversion to recirc for some reason..
No recirc on defrost allowed. Or feet only. Needs face vents to allow recirculation.
Recirc seems to cycle off periodically as well. I'll be going down the highway, smell outside truck exhaust and notice the flipping recirc went off again.
Will have to see if it happens with the manual hvac controls, but I remember it did that with the auto controls.

 

[krbjmpr]

Yeah, I have noticed recirc locked out as well. Figure is function of temperature and humidity.

You are right about turning off while driving. I have been idling at lights and heard mechanism change over. First time, didn't know what it was until felt air blowing get few degrees warmer. This was at 95°F, in South Texas. Was nice and cool inside, then it switched and became nice and less-cool.

I think fan idea will work as long as can draw fresh air through air conditioner.

 

[j91z28d1]

curious what all the battery power is for?


if you don't already have the lpf batteries, try to find or wait till the sodium cells hit the market and make your 12v pack out of them. from my testing so far, voltage and temp range is much much wider. 15v won't hurt them and they handle charge and discharge at high and low Temps much better. I don't have 12v packs made up, doing testing on the 300v hybrid replacement cells. but the lithium testing didn't go great in high tx Temps. under hood in winter without a bms to run them wouldn't last thru one winter. but if you have a bms, 15v isn't a issue then either.


I use this pwm controller for my alt. on another car. it's the pretty standard one used with the pwm alt.

US Signal Generator Module Adjustable PWM Pulse Frequency Duty Cycle Square Wave | eBay

PWM signal generator is a device that provides electrical signals at a variety of frequencies, square wave, and output levels. 8>.1-Channel PWM output. Display ‘***’. No decimal point, The minimum frequency is 1Hz.

www.ebay.com

works well, but I'd install it inside the cabin long term. it's not sealed at all. mine is under the passengers dash.

 

[krbjmpr]

Extra battery power is for additional lighting, inverter, and electric rear hvac compressor, onboard air compressor (not suspension). I already have the LFPs, though considering increasing to 3 x 100Ah. -Starting (charge occasionally) Cab / Vehicle, and Toys / rear hvac compressor & fan.

 

[krbjmpr]

During the terrible freezing temps, I still had to drive. Let me tell you, driving in 27F is no fun

Seriously, I was surprised that could switch from fresh to recirc while was waiting at a stoplight (with only me present). On a whim, reached over, pushed button, and surprised when got steady light instead of flashing.

Exterior temp 25-27F, Interior temp around 34F (pocket thermometer) and Auto wants to circulate fresh air?!? Great heat output once recirc turned on, stayed in Auto. Rear AC eventually started blowing hot as well.

Did appreciate the remote start turning on seat warmers ( driver & pass) but would have preferred seat & back vs seat only but I understand why (current).. Maybe should add slight wiring change to seat warmer relay block. 3 heat settings, 2 heaters with 2 elements each (hi / lo). Haven't seen diagram yet, but suspect 3 relays per seat, 1 to choose seat / back, 1 for low element (low heat), 1 for high element (medium heat), both on for high heat.

 

[j91z28d1]

gm has always been against recirculate with their hvac all the way back to days of fully manual controls in cars. they would only do it in max ac. in my yukon you can do it with floor only heat, gotta atleast be bi level.

27deg is cold to me to be outside but around here, these guys go fishing colder than that haha. - 27 would be more like it lol.


my seat warmer does back and bottom when prestarted in the morning. maybe make sure last use was with both turned on?

there's a heated steering wheel mod you can do too.