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Battery Monitor

LabRat

Grenadier Owner
Forum Supporter
Local time
5:36 AM
Joined
Feb 13, 2025
Messages
182
Location
Pennsylvania USA
After my first camping adventure running my fridge and got tired of needing to start my truck to get a voltage reading. Seemed like a waste so searched and found The Doc's Battery Monitor Review and picked up one BLE to put on my auxiliary battery. The app worked well, but really wanted to monitor both batteries. Went to the online FAQ and they recommended this software. While not free - was $9.99 from the iStore here in the US and works like a charm. Can monitor up to 4 devices, thus overcoming one of the limitations Doc cited in his blog.

Both the free app and this one ask to share your location. They claim it is to allow the app to automatically connect when in range. Figure what the hell, give it a try. Nope, you still have to open the app to get it to connect, so turned it back off.

Well worth the 10 bucks to monitor both batteries and not needing to start the engine.


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After my first camping adventure running my fridge and got tired of needing to start my truck to get a voltage reading. Seemed like a waste so searched and found The Doc's Battery Monitor Review and picked up one BLE to put on my auxiliary battery. The app worked well, but really wanted to monitor both batteries. Went to the online FAQ and they recommended this software. While not free - was $9.99 from the iStore here in the US and works like a charm. Can monitor up to 4 devices, thus overcoming one of the limitations Doc cited in his blog.

Both the free app and this one ask to share your location. They claim it is to allow the app to automatically connect when in range. Figure what the hell, give it a try. Nope, you still have to open the app to get it to connect, so turned it back off.

Well worth the 10 bucks to monitor both batteries and not needing to start the engine.


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Did you purchase two of the BLE monitors; one for Aux and one for the starter? Or does it have positive leads for 4 batteries and I imagine all 4 batteries need to share a common ground.

I use the a 500A Victron Smart Shunt on my Aux battery and it has a lead to connect to the starter battery to monitor the starter battery voltage. Both batteries can then be monitored via the Victron Connect App. I believe with the VE Direct port you can hook to a physical display or into a CerbGX -> GX Touch50. The 500A smart shunt bluetooth version is about $100 USD.

Victron Energy SmartShunt Battery Monitor (Bluetooth) - Victron Smart Shunt - 6.5V-70V, 500 amp

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Did you purchase two of the BLE monitors; one for Aux and one for the starter? Or does it have positive leads for 4 batteries and I imagine all 4 batteries need to share a common ground.
Purchased 2 BLE monitors for about $20 USD each and $10 for the app, so $50 total to monitor both batteries while at camp.

While I was in there, I installed a Victron IP65 charger on my starter battery. That way if I'm at a site with power, I can just plug in while camped.

Picked up a CTEK 250SE and GP-Factor bracket as well for solar, but was getting late and needed to get the truck back in driving shape for work in the morning.
 
I just ordered a few of the BLM monitors as my battery ran down over a week of no use. They should arrive in the next few days. Mostly just to gather some data before I take it back to the dealer and suggest the batteries are toast on a new car. Guessing it sat round too long on a flat battery?
I do like the Victron shunt however as that would give you an idea of what’s gone in vs what’s gone out. You could get a better idea of if it’s a battery self discharge or a current drain.
I take it the Victron just goes in series with the earth lead from the battery?
 
I just ordered a few of the BLM monitors as my battery ran down over a week of no use. They should arrive in the next few days. Mostly just to gather some data before I take it back to the dealer and suggest the batteries are toast on a new car. Guessing it sat round too long on a flat battery?
I do like the Victron shunt however as that would give you an idea of what’s gone in vs what’s gone out. You could get a better idea of if it’s a battery self discharge or a current drain.
I take it the Victron just goes in series with the earth lead from the battery?
Correct. The Victron shunt has a negative lead that does to the negative on the aux battery and then all other negatives (Earth) go to the shunt, so the only negative on the battery is the lead from the shunt. I have a CTEK 250SE and that is connected to the negative on the shunt. There is a power lead connected to the positive side of the aux battery. For the starter battery there is a positive and earth and just need to make sure you earth and aux share the same ground for accurate voltage reads. After a few YT videos it makes sense.

I would have gone @LabRat s BLE route if I knew about it as the info there is what I wanted.
 
After my first camping adventure running my fridge and got tired of needing to start my truck to get a voltage reading. Seemed like a waste so searched and found The Doc's Battery Monitor Review and picked up one BLE to put on my auxiliary battery. The app worked well, but really wanted to monitor both batteries. Went to the online FAQ and they recommended this software. While not free - was $9.99 from the iStore here in the US and works like a charm. Can monitor up to 4 devices, thus overcoming one of the limitations Doc cited in his blog.

Both the free app and this one ask to share your location. They claim it is to allow the app to automatically connect when in range. Figure what the hell, give it a try. Nope, you still have to open the app to get it to connect, so turned it back off.

Well worth the 10 bucks to monitor both batteries and not needing to start the engine.


View attachment 7899116

View attachment 7899117
The Ancel battery monitor can also monitor up to 4 devices, at once. The BLE is just more accurate for my purposes.
 
Did you purchase two of the BLE monitors; one for Aux and one for the starter? Or does it have positive leads for 4 batteries and I imagine all 4 batteries need to share a common ground.
I have one on the aux and one on the main battery. I used two on the Nissan Patrol for many years, before the Grenadier.

The BLE is a simple low cost monitor, no where near as fancy as the Victron which uses a shunt (as you note). The Victron would be more accurate.
 
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After my first camping adventure running my fridge and got tired of needing to start my truck to get a voltage reading. Seemed like a waste so searched and found The Doc's Battery Monitor Review and picked up one BLE to put on my auxiliary battery. The app worked well, but really wanted to monitor both batteries. Went to the online FAQ and they recommended this software. While not free - was $9.99 from the iStore here in the US and works like a charm. Can monitor up to 4 devices, thus overcoming one of the limitations Doc cited in his blog.

Both the free app and this one ask to share your location. They claim it is to allow the app to automatically connect when in range. Figure what the hell, give it a try. Nope, you still have to open the app to get it to connect, so turned it back off.

Well worth the 10 bucks to monitor both batteries and not needing to start the engine.


View attachment 7899116

View attachment 7899117
Thanks, I will probably take a look at that app. That would make life easier for the two batteries on the car.
 
The Ancel battery monitor can also monitor up to 4 devices, at once. The BLE is just more accurate for my purposes.
I gathered that from your blog, which is why I initially only purchased one unit to go onto my auxiliary battery. I figured I was good with just monitoring the one, but then unfortunately the more I read the more I got confused and read some more. I figured might as well get a second one after I learned about this different software to be able to monitor both batteries.
 
Oh, you can rearrange what position each battery is in. Just click on the spot you want the battery in and bind the device to that position, it will move the historical data with it when you move it. I'd love to get rid of the unused slots, but haven't figured that out yet.

Also, if you started with the original free app, this new app will pull the historical data from the old app and move it to the new app.


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Thanks for posting! I just ordered two BLE monitors as I have the factory dual battery system. I've also got the magnetic battery tender hookup installed on the front of the vehicle... next step is to research hooking up solar there as well. Keep my vehicles in at a car club storage facility when not in use so the easy on/off for the trickle charger was highest priority for me.
 
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