[larry barello]

I would think 5 Ahrs drain in 21 days on a 95Ahr starter battery should always crank over the engine ,,, no?

Sure, sounds good to me. Under all weather conditions (well, down to 11f) the Pentastar has always started with almost no cranking. I would expect you could start the car with a pretty depleted battery. Still, if storing for 6 months, maybe pull the ground clamp?

Keep in mind that at 10ma draw your 95 AH probably is more like 105-110, maybe more. LA chemistry capacity is pretty dependent upon the load. Also, I am inclined to believe the 3ma value. Dunno how much the B2B adds to the load. Best to measure directly with you multimeter:
Clip to negative post and clamp. Remove clamp, measure draw. (oh, yeah, wait for van to go to sleep first )

 

[Lolaeliz]

Ok, I read the manual. It looks like a good product.

RNG-220819-RBM500（EN） (mybigcommerce.com)

I think one needs to read the manual and understand all the user settings before it will accurately display values. There is no guidance, but the terminal voltages (full and empty) are going to be different for Lithium and various lead acid batteries. Determining full and empty will be essential for the unit to self-calibrate.

I installed it last summer and I did read the manual back then. I didn't understand a lot of it, and really still don't. I'm a learn as you go person with all this. I set it to100% and it has worked fine. I just trusted it self calibrated over time instead of knowing how it did that.

I set the capacity to 300ah and left everything else at the factory setting because I had no idea what to det it at.

 

[larry barello]

The manual is pretty sparse and doesn't really explain much. Probably calling technical support will get you more information - they have always been pretty helpful to me. However, just setting the capacity (like you did to 300AH) and a few charge/discharge cycles and the unit probably self discovers the other parameters. It is weird, though, that the default "full" and "empty" voltages are 0v and invalid, yet it seems to work.

I wonder if setting the V full to 13.5 and V empty to 11.0v would significantly improve the performance of the shunt. Gotta ask Renogy about that.

 

[proeddie]

When I got my Li batteries, I charged 'em until they were full... Then set the monitor for 400ah and 100 percent... The readings have appeared accurate since then, based on corresponding voltage readings (which is probably how the monitor displays percentage of charge)

 

[larry barello]

The readings have appeared accurate since then, based on corresponding voltage readings (which is probably how the monitor displays percentage of charge)

No lithium battery monitor shunt uses voltage to estimate SOC. They integrate current over time (the whole point of the "shunt"). The best you can do with voltage is "empty", "full" and somewhere in between. The following is one of many charts on the web that all have slightly different voltages. For measurement purposes the flat area is truly flat with variations of battery, load and age affecting the actual voltage.

 

[larry barello]

Ok, enough of this guessing: I called Renogy, just now, and talked with technical support on how to set up the 500A shunt monitor. You NEED TO SET VFULL AND VZERO for it to work properly. For Renogy Lithium batteries these are the recommended numbers:

• V Full 14.4v (I would use 14.3v to cover measurement errors since 13.5 and above is generally 100%)
• V zero 10.0v (or 12.0 if you want to be conservative and have ~10% reserve but this will affect the capacity #)
• V off 11.0v (this just turns the monitor off; button press wakes it up)
• Alarm 20Ah (low water mark for the alarm, 20% of capacity is typical)
• Attenuation: 0.000% (For Renogy. For other manufactures, call them and find out)

(IMO Capacity, V full and V zero are the only setting that are required. Alarm, Attenuation and Poff are optional)

With the batteries fully charged and the settings screen set appropriately, then:

• Press Ok
• Press << (to go back to main screen)
• Press ^ (to set 100% although this should be redundant if V-full has been set)

With V full and V zero the percentage value should be reset whenever the battery is fully charged or drained. The manual implies that a full discharge/charge cycle will reset/calibrate the capacity of the pack. The manual also implies that you can manually set 0% and 100% with the v & ^ buttons but is silent on whether it sets V zero and V full at the same time.

I am guessing that setting the capacity (e.g.300AH) and 100% is good enough for a general idea of battery status. Must be since that is what @Lolaeliz and @proeddie did and they seem satisfied with the results.

 

[free2roam]

Thank you Larry, you are a gentleman and a scholar!

 

[aaronmcd]

I also followed the instructions by setting capacity and 100%. Never set 0%, since my manual only says to do that to recalibrate. I've never recalibrated and it has been working fine for the past year. The lowest it's shown was 6% a few mornings ago.

 

[Lolaeliz]

When I got my Li batteries, I charged 'em until they were full... Then set the monitor for 400ah and 100 percent... The readings have appeared accurate since then, based on corresponding voltage readings (which is probably how the monitor displays percentage of charge)

Nice! You have 400ah!

@larry barello Thanks for calling to find out. I manually set mine to 100%. I don't think the batteries were full because I took them off shelf mode, and one was new. But the monitor only monitors, so the solar probably kept charging and once that hit 100%, the monitor was accurate. That was my logic.

Here are readings from my van. It's off a little because it's charging still even though the monitor says 100%, but it's close enough.
Mine has High V instead of Vfull. I wad gonna set that to 100, but then wondered if I might throw something off, since it seems to be working fine.

 

[larry barello]

Yeah, HIGH == full, LOW == empty. I would set both. HIGH = 14.3 and LOW = 10.5. Then set 100% on the main screen ('^' arrow) when the reported voltage is in the 14v range.

 

[didz1982]

Hi, I have an issue I can’t work out. My report 500a battery monitor is installed but not reading ah and constantly alarming. batt is a 200ah lithium lifePO4. where am I going wrong? I used Larry’s settings above. Please helo, many thanks in advance.

 

[larry barello]

Any chance you installed it backwards?

Picture of the installation? The main screen, the programming screens?

 

[didz1982]

Any chance you installed it backwards?

Picture of the installation? The main screen, the programming screens?

I took this pic. But to best of my knowledge it was correctly installed. I read somewhere in to fully charge the battery and then hold the up arrow for 3 seconds to calibrate it. Will try that next.