[Project] Extending EV range by offsetting auxiliary 12v loads using solar

meetyg

Solar Enthusiast
Joined
Jun 4, 2021
Messages
253
Another update:
Finally got around to mounting the battery and solar components in a plastic ammo box.

I mounted the SCC, fuse/distribution box and breaker on a melamine coated piece of plywood.
I found that piece in the trash, which was used as a shelf for a bathroom cabinet. The fun part is that I didn't need to cut it at all. It fit perfectly in the ammo box.
20211207_160005.jpg20211207_160412.jpg

I decided to use XT60 connectors between the SCC, MC4 connectors and fusebox, and between fusebox and loads, so that it would be easier to dismantle should I need to do some changes or maintenance.

I do regret not mounting the breaker (connected to the battery positive) in a more accessible location, like maybe on the lid if the ammo box, so that power could be disconnected without opening the box.
I might do that change in the future.

Here is are pictures of the box with the battery and shunt too.
I still have to add some double sided tape to hold the battery in place, and maybe add some foam between the SCC and the battery to prevent movement.
20211207_162429.jpg

I have MC4 connectors on the back of the ammo box, connected to the SCC.
On the front, I have an XT60 for loads. This will be connected to the DC-DC boost converter box as posted previously. The problem is that I have run out of XT60 connectors, and I need one with a long cable to connect the two.

Anyways, I like how it turned out, because I can also use this as a portable solar generator, currently supplying only 12v DC loads up to 20A but in the future I would be able to add a small DC-AC inverter if I want to.

As you can see, I have a 30A mini-ANL fuse on the battery (in addition to a 30A breaker) and all connections are also fused accordingly, as they are connected to the fuse box (including the shunt's VIN line).

I powered the box just to see if all is connected well and surely enough the Juntek shunt displays voltage. I still need to test with loads/charging, to see that I can view proper current draw with the shunt.
20211207_162755.jpg20211207_162800.jpg
20211207_162731.jpg

That's it for now...
I have ordered some more XT60 connectors, but until they arrive I still can't install in my car.
But I will be doing some more testing with both "solar box" and with DC-DC converter box.
I still need to figure out how I can view both shunts from one display screen. The Juntek supports thus using addresses, but I need to learn how to set it up.
 

meetyg

Solar Enthusiast
Joined
Jun 4, 2021
Messages
253
@meetyg, you have proven that the upgrade from PbA to LiFePO4 has improved system voltage stability! wow! thank you for proving out this concept thus far. the documentation in this thread intensely motivates me to continue with my self chosen research path as well. big up.

thank you for these updates. your methodology is commendable, and i think your sensitivity to safety while still making progress is also incredible.


as it happens, the 12V PbA battery in my car died recently, and sourced a 12V LiFePO4 equivalent capacity pack to replace it. still doing due diligence on the self install. your graph of voltage vs time has massively reinforced the decision to include continuous voltage and shunt ampere logging at some timescale like 1 per minute at least.

thank you, and i know you’re not done yet ;)

☀️🔋🖖
I have done manual amperage measurements using a clamp meter, but connecting a shunt with logging would be cool :cool:

For now I just have a (hardwired and fused) simple BM2 battery monitor that logs for up to 31 days, and has a Bluetooth app.

Which LiFePO4 did you get? I'm curious...
Also, please remind me what car you have?

Are you getting along with your VIPV setup?
 
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meetyg

Solar Enthusiast
Joined
Jun 4, 2021
Messages
253
Yay, I got the Juntek display to work with both shunts!
For some reason, one if them wasn't connecting wirelessly at all, it took me some time to figure it out.
I initially thought that maybe because the two shunts are different models of the VAT series (one is VAT-1100 the other VAT-1050) that they can't use the same display.
But after doing a factory reset, it started to communicate! So I set up each one with a different address (A01 and A02), and now I can see both with one display (but only one at a time of course).
I also connected the DC-DC box to the solar box, and did some more testing. I simulated the car's load using the DL24 battery capacity meter. All is working well. As mentioned, in order to connect them in the car I would need a longer cable and I'm all out of XT60 connectors for now.

Here are some pics. A01 is the shunt in the solar box connectedto the battery. A02 is the one in the DC-DC box, connected to the output of the DC-DC boost converter.
(Ignore the battery capacity on A01, it wasn't calibrated at the time I took the pictures).SmartSelect_20211208-215422_Gallery.jpg20211208_134132.jpg20211208_134137.jpg

I powered the display with a separate USB cable coming from a portable power bank. As you can see the wireless icon at the top left, the display is connected wirelessly to both shunts. Pretty cool little gadget!
It also has some neat features like relay control, but I don't have usage for it currently.

That's all folks... stay tuned :)
 

curiouscarbon

Science Penguin
Joined
Jun 29, 2020
Messages
1,795
Which LiFePO4 did you get? I'm curious...
Also, please remind me what car you have?
ohmmu, model 3
Are you getting along with your VIPV setup?
Still planning phase :) replacing the PbA with LiFePO4 is strongly motivating to get acting soon 🔧 maybe after checking airbag locations the dash might be an ok spot for placing some PV like in this project.

Cheers!
 

curiouscarbon

Science Penguin
Joined
Jun 29, 2020
Messages
1,795
Yay, I got the Juntek display to work with both shunts!
For some reason, one if them wasn't connecting wirelessly at all, it took me some time to figure it out.
I initially thought that maybe because the two shunts are different models of the VAT series (one is VAT-1100 the other VAT-1050) that they can't use the same display.
But after doing a factory reset, it started to communicate! So I set up each one with a different address (A01 and A02), and now I can see both with one display (but only one at a time of course).
I also connected the DC-DC box to the solar box, and did some more testing. I simulated the car's load using the DL24 battery capacity meter. All is working well. As mentioned, in order to connect them in the car I would need a longer cable and I'm all out of XT60 connectors for now.

Here are some pics. A01 is the shunt in the solar box connectedto the battery. A02 is the one in the DC-DC box, connected to the output of the DC-DC boost converter.
(Ignore the battery capacity on A01, it wasn't calibrated at the time I took the pictures).View attachment 75032View attachment 75033View attachment 75034

I powered the display with a separate USB cable coming from a portable power bank. As you can see the wireless icon at the top left, the display is connected wirelessly to both shunts. Pretty cool little gadget!
It also has some neat features like relay control, but I don't have usage for it currently.

That's all folks... stay tuned :)
nice enclosures!
 

meetyg

Solar Enthusiast
Joined
Jun 4, 2021
Messages
253
Just an update on both my disputes:
One for the 20Ah Lifepo4 (buffer battery) and another for the 45Ah Lifepo4 starter battery.

I won them both!
I ask for a $20 refund on the 20Ah because it gave only 17.5Ah, and $100 for the 45Ah which gave only 20Ah.

For these prices after refunds, it was totally worth it!
 

curiouscarbon

Science Penguin
Joined
Jun 29, 2020
Messages
1,795
Just an update on both my disputes:
One for the 20Ah Lifepo4 (buffer battery) and another for the 45Ah Lifepo4 starter battery.

I won them both!
I ask for a $20 refund on the 20Ah because it gave only 17.5Ah, and $100 for the 45Ah which gave only 20Ah.

For these prices after refunds, it was totally worth it!
good going navigating the disputes👍
 
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