OBDll adapter plug for solar panel charger

[Builder]

Quick question …. I’m looking at a 25w solar panel charger for my 12v AGM in my 2023 Hybrid Mav. I’m tired of leaving the hood open to charge the 12v with my Noco G5 and wanted a more mobile option when I’m not near a plug or I don’t have the Mav in the garage. I don’t want a permanent set up either. I need to use the OBD port since it is always on unlike the other interior ports. So …. Will the OBD connection work with the BMS to recognize the incoming charge via a solar panel? I know going around the BMS with a direct battery terminal connection is an issue since the BMS will not see the incoming charge and adjust accordingly.

Sponsored

 

[Escapologist]

Also curious about such matters. Probably some answers buried in upfitters guides and similar, but not up for digging into them tonight. Would also like to feed the battery to compensate for accessory and camping loads and longer sits and wanna stay right side of the BMS.

 

[CNJFF]

The BMS sensor is at the negative battery terminal with the chassis grounding point right next to the battery. So as long as you are grounding to the chassis you are good. There are a few smaller grounding points behind the rear seat not far from the battery.

You can tap off the battery positive without issue. Even the positive post under the hood is connected to the battery.

 

[JimKivi]

As a possibility, consider the 12v outlet in the passenger truck bed.

 

[Builder]

As a possibility, consider the 12v outlet in the passenger truck bed.

The 12v outlet in the truck bed is a timed off outlet after shutdown. OBDll is always on which would work much better to plug in the solar panel charger for longer term use. What I don’t know is if the OBDll plug bypasses the BMS if I plug the solar panel into it to charge the battery.

 

[Builder]

The BMS sensor is at the negative battery terminal with the chassis grounding point right next to the battery. So as long as you are grounding to the chassis you are good. There are a few smaller grounding points behind the rear seat not far from the battery.

You can tap off the battery positive without issue. Even the positive post under the hood is connected to the battery.

That’s always a good option but, I wanted to avoid playing around under the back seat for this and take an easier route by simply plugging into the OBDll port when Mav is parked in the driveway or parking lot. I just don’t know if plugging a solar panel charger into the OBDll port would bypass the BMS.

 

[JimKivi]

The 12v outlet in the truck bed is a timed off outlet after shutdown. OBDll is always on which would work much better to plug in the solar panel charger for longer term use. What I don’t know is if the OBDll plug bypasses the BMS if I plug the solar panel into it to charge the battery.

Good point - forgot about the shutoff.... but beware that most solar panels rated at 12 v actually have a 17 v max current, so going into the Mav computer might be potentially unwise. We have a solar panel on the camper shown on the left, and run our refrigerator with the bed outlet, switching to solar charged bats at night. On the wife's car, I just added a battery direct plug such as you see hanging out of front grills for engine heaters.

 

[gzmn5m]

OBD2 port works fine. Been using for 2 years. It's part of vehicle computer wiring so it's designed on correct side of BMS.

 

[gzmn5m]

OBD2 port works fine. Been using for 2 years. It's part of vehicle computer wiring so it's designed on correct side of BMS.

The only way to get around the BMS is to wire directly to the negative battery post. The BMS is part of the cable that connects the negative post to vehicle ground. So any vehicle ground is on the "good" side of the BMS.

 

[HeyBales]

I wouldn't worry about the BMS logging your charging - there is nothing to log it too.
So just use what's easy to do.

There are only 4 categories of tracking for the BMS - there is only one for charging.

Therefore external charging is never tracked to update any figures to do anything with.
The next BMS Relearn it does, will see the full battery. Hopefully.

I've tested this on 2 full recharges - the Ah's were never seen.
Below pic was 42 days after a BS Reset after a full charge, which did nothing but Zero out the figures related.
I did another full charge right before this screenshot, because the system log clicked over to slightly more discharge than charge, which would maybe explain the falling SOC and Voltage readings after a full recharge 42 days prior.

 

[Quest]

A few years ago I made 3 of them when I worked at a dealer, batteries were going dead when they installed tracking devices so I came up with this.
15W solar panel with an OBD2 connector connected with cheap cat5 cable.
Worked great but the dealer was too cheap to buy in bulk.
Each one was about $30 to put together but in their ultimate wisdom they thought buying batteries was cheaper than buying a few hundred panels

 

[Builder]

OBD2 port works fine. Been using for 2 years. It's part of vehicle computer wiring so it's designed on correct side of BMS.

Decided to go with a 25w, aluminum framed, solar panel so I can use it inside the cabin. The aluminum framed solar panel won’t deform in the cabin heat, on the dashboard, during hotter days; withstands 200F temps and -40F cold. I have to plug it into a Battery Tender adapter for the OBDll port; already anticipating the reverse polarity with an SAE reverse polarity adapter. The solar panel comes with a smart controller that works similar to my Noco G5; no battery drain at night. Thanks for all the good advice.

Sponsored