More fun with Renogy MPPT and LFP

[Almot]

Toying with a new to me 12V compressor car fridge. Cheap Chinese box, LG compressor, 50L volume split ~28L fridge, 22L freezer. The goal was to see whether my added insulation made any difference: Reflectix taped around the box, and an ugly cover made of an old bed spread - it had some "fur" inside.

Fridge draws >34AH per 24 hrs at 75F ambient, though in defence of a cheap box I should say that the freezer bin is huge and set to -2F. Fridge set to 39F.

Fridge connects to Load terminals of Renogy,
Renogy connects to 12.8V 120AH LFP,
LFP connects to nothing, partially charged.

Busy with other things, I suddenly noticed that don't hear quiet "purr" of the fridge. MPPT is blinking "battery problem", voltage 11.

Renogy Load terminals were supposed to cut the load off at 12.6V, - they didn't.
Renogy Low-voltage alarm was supposed to sound at 12.7V, - it didn't.

Independently, darn ice box didn't cut off at 12V either - downstream from MPPT on a thin #18 cable it reads lower voltage, so LVD 12 is a-okay, only it didn't cut off.

Yeah, I know, buy Victron, I've been warned. Still curious whether I did something wrong, other than buying Renogy.

[StirCrazy]

Almot wrote:

StirCrazy wrote:

where are you reading the voltage/amprage from?

Steve

Built-in display of Renogy controller.
Purists here could point out (rightly so) that voltage should be measured on the battery, but my cables to battery are short and currents are low so there is no issue with voltage drop.

There was also voltage measured on the load in this particular case - fridge display - it is of course lower than the one on the Renogy.

Note that while Renogy voltage settings are in the Battery Parameter tab of the app - not in the Load Parameter, some of them actually control the Load terminals, like Over Discharge and Discharge Limit. It disconnects the Load terminals. Other voltages and settings are related to charging process.

ok so your scorling through. mine never comes off the charging voltage (defaultscreen) as I use my battery monitor to look at everything else. but Im not running anything off the load termanals so that hasnt concerned me at all. I have to try remember the default admin password again so I can look at the other stuff on the app haha

Steve

[Almot]

StirCrazy wrote:

where are you reading the voltage/amprage from?

Steve

Built-in display of Renogy controller.
Purists here could point out (rightly so) that voltage should be measured on the battery, but my cables to battery are short and currents are low so there is no issue with voltage drop.

There was also voltage measured on the load in this particular case - fridge display - it is of course lower than the one on the Renogy.

Note that while Renogy voltage settings are in the Battery Parameter tab of the app - not in the Load Parameter, some of them actually control the Load terminals, like Over Discharge and Discharge Limit. It disconnects the Load terminals. Other voltages and settings are related to charging process.

[StirCrazy]

Almot wrote:
This controller has a mind of its own.

Turned the load off - enough pushing Chinese fridge, don't want it to die on me in the bush.

Charging battery via DC charger and Renogy. This time charging stopped at 14.3 - right at the Boost voltage. Forget those High Volt Disconnect and Charge Limit set to 14.8.

At least, it stopped after 14.3, didn't try to fry it up to 15.5. Don't know how long after 14.3 it stopped, Boost timer was set to 10 minutes but it looked longer.

Display reads Float 13.9, then 13.8, 13.7. My Float is set to 13.3, this is Lithium, don't need Float. Current was zero amps at this point. This isn't Flooded, with no load it will stay forever at 13.7, should read "Full", not "Float", but its firmware is not that good. This Renogy is a wet/gel/AGM controller that you "can" make work for Lithium, with some pains.

Boost Charge Return was set to 13.8V - nope, didn't return to Boost at 13.7 even.
Turned the Load on, fridge drawing 2A, now Renogy initiates Boost at 0.6A, rising immediately to 14.3 - the battery is apparently full, 2A load wasn't able to remove enough charge in those few seconds.

I wrote about this in the very 1st thread - this controller doesn't immediately feed the battery all the current that the load is drawing, even with a lot of "sun", i.e. DC charger. It did that with PV input, it did the same with DC charger. There was no need to feed the battery anything now that it's full, but Renogy played this trick earlier with PV when battery wasn't full, see my other thread https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/30245717.cfm.

where are you reading the voltage/amprage from?

Steve

[Almot]

This controller has a mind of its own.

Turned the load off - enough pushing Chinese fridge, don't want it to die on me in the bush.

Charging battery via DC charger and Renogy. This time charging stopped at 14.3 - right at the Boost voltage. Forget those High Volt Disconnect and Charge Limit set to 14.8.

At least, it stopped after 14.3, didn't try to fry it up to 15.5. Don't know how long after 14.3 it stopped, Boost timer was set to 10 minutes but it looked longer.

Display reads Float 13.9, then 13.8, 13.7. My Float is set to 13.3, this is Lithium, don't need Float. Current was zero amps at this point. This isn't Flooded, with no load it will stay forever at 13.7, should read "Full", not "Float", but its firmware is not that good. This Renogy is a wet/gel/AGM controller that you "can" make work for Lithium, with some pains.

Boost Charge Return was set to 13.8V - nope, didn't return to Boost at 13.7 even.
Turned the Load on, fridge drawing 2A, now Renogy initiates Boost at 0.6A, rising immediately to 14.3 - the battery is apparently full, 2A load wasn't able to remove enough charge in those few seconds.

I wrote about this in the very 1st thread - this controller doesn't immediately feed the battery all the current that the load is drawing, even with a lot of "sun", i.e. DC charger. It did that with PV input, it did the same with DC charger. There was no need to feed the battery anything now that it's full, but Renogy played this trick earlier with PV when battery wasn't full, see my other thread https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/30245717.cfm.

[StirCrazy]

Almot wrote:
Follow-up. Can live with Renogy controller and the app but it sucks.

Steve, there are 2 tabs in the app Settings screen: Battery Parameter and Load Parameter. Tap the Battery Parameter. My Renogy is Rover 30, maybe yours doesn't have these settings?

On to testing the controller.

There is an LV disconnect and an LV "alarm" - a single beep.
High Voltage protection doesn't seem to work.
Boost timer (set to 10 minutes for LFP battery) doesn't seem to work either.

1) Over-discharging.
Set Low Volt Warning to 12.7, Discharge Limit to 12.6, Over Discharge to 12.6. Probably "Over Discharge" is LVD.

Tapped Read on the app - it doesn't tell the truth until it talks to controller first, double-checked that the settings on the actual controller are same as in app - some were not, had to set them on the controller.

After getting down to 12.7-12.6 and sitting there for an hour it beeped once - wouldn't have heard it if TV was on - and disconnected.

2) Over-charging
Hooked up 15A DC charger to where PV should be connected.
Boost set to 14.6, High Volt Disconnect to 14.8, Charge Limit to 14.8 (don't ask me how HVD is different from Charge Limit).

Voltage climbed to 14.6, then I left it unattended, the Load got disconnected and Renogy kind of "locked" - blinking "high voltage" with display reading 13.3, charging current less than 0.5A.

Unplugged DC charger, Renogy display immediately reads 14.8, then goes down to 14.4. App reports that the highest voltage was 15.5.

Battery survived - yay!

I think that DC fridge did the disconnect - there is no real manual for the fridge but DC devices often have 15.5V protection.

ok I thought you were talking about a voltage disconect in the load settings. well its a good thing your on it, you'll have a new manual writen by the time I get my LFP batteri for the camper haha

[pianotuna]

Almot,

Great news on the battery!

[Almot]

Follow-up. Can live with Renogy controller and the app but it sucks.

Steve, there are 2 tabs in the app Settings screen: Battery Parameter and Load Parameter. Tap the Battery Parameter. My Renogy is Rover 30, maybe yours doesn't have these settings?

On to testing the controller.

There is an LV disconnect and an LV "alarm" - a single beep.
High Voltage protection doesn't seem to work.
Boost timer (set to 10 minutes for LFP battery) doesn't seem to work either.

1) Over-discharging.
Set Low Volt Warning to 12.7, Discharge Limit to 12.6, Over Discharge to 12.6. Probably "Over Discharge" is LVD.

Tapped Read on the app - it doesn't tell the truth until it talks to controller first, double-checked that the settings on the actual controller are same as in app - some were not, had to set them on the controller.

After getting down to 12.7-12.6 and sitting there for an hour it beeped once - wouldn't have heard it if TV was on - and disconnected.

2) Over-charging
Hooked up 15A DC charger to where PV should be connected.
Boost set to 14.6, High Volt Disconnect to 14.8, Charge Limit to 14.8 (don't ask me how HVD is different from Charge Limit).

Voltage climbed to 14.6, then I left it unattended, the Load got disconnected and Renogy kind of "locked" - blinking "high voltage" with display reading 13.3, charging current less than 0.5A.

Unplugged DC charger, Renogy display immediately reads 14.8, then goes down to 14.4. App reports that the highest voltage was 15.5.

Battery survived - yay!

I think that DC fridge did the disconnect - there is no real manual for the fridge but DC devices often have 15.5V protection.

[StirCrazy]

Almot wrote:

JimK-NY wrote:
I have never seen a controller which actually shut down the draw on the batteries and certainly doing so at 12.6 would make absolutely no sense. Even fully charged batteries could easily drop down to that level with just a compressor fridge and another load such as a furnace blower.

Instead it is highly likely that the compressor refrigerator/freezer has a shut down when voltage drops to somewhere around 11.0 - 11.5 volts. If that happened right away then your initial battery charge was low and/or the wiring to the refrigerator was insufficient.

The load was connected to Load terminals. This is what they do, disconnect (or not) load from the controller.

The battery is LFP, it has 20% SOC at 12.5V. I set LVD slightly higher to 12.6 - or I thought that I did, see the explanations about the app, LVD and Discharge Limit.

Thin wire to the fridge and controller cutting off at 11V means that the fridge was at 10.5V at that moment. Should've cut off at 12V measured at the fridge - which would've been ~12.5 measured at the controller.

There was supposed to be 2 levels of protection - fridge and Load terminals, but none worked. Actually, 3 levels if you count the "low voltage alarm" that apparently is not an alarm but a "warning" in the way of a blinking LED.

I dont see any adjustments using the load for voltage cutoff or on, the only thing I see to control the load is time based, am I missing a section in the app?

Steve

[StirCrazy]

Almot wrote:

StirCrazy wrote:

so did you change battery types and go back and not realize that things had reverted? all the numbers you gave above looks like this happened. I wonder if it resets when you take the power off also? Ill have to play with mine and see.

Steve

Settings change only in User battery type. In Flooded, Sealed etc they are fixed, you can't change those. I didn't change battery type during the initial test.

Regardless, the app is confusing and has glitches. What you enter in the app, isn't always what is set on the controller. You can change settings directly on the controller by holding the right arrow until it starts blinking. Then you scroll through the screens by pressing the same right arrow once, and change the values by pressing the Up or Down arrow. It doesn't show all the settings - the app has more - and some values that you see on the controller can only be changed in 0.2V increments, not 0.1, and some are unnamed - say, it shows 12.0 and 12.6 (obviously some low-voltage point) but it doesn't tell whether this is LVD or what. App requires manually "finding" the correct Bluetooth every time you turn the phone On, and entering password every time you want to change settings. Same password for all the thousands of users.

It's easy to incidentally change the battery type while doing programming - but this wasn't the case with my 11 V puzzle. Most likely it was a confusion btw the (not clearly named) LVD in the app and the other "Discharge Limit", and also the fridge cutting off way lower than it was supposed to. After you've done and saved the settings by holding the right arrow, they are stable.

ya I will agree the app needs some sort of file to explain stuff better. have you tried to email them and ask them about it? they have been pretty good when I had questions when I ordered mine. Maybe you could be the one to get a new instruction set written for it.

Steve

[Almot]

JimK-NY wrote:
I have never seen a controller which actually shut down the draw on the batteries and certainly doing so at 12.6 would make absolutely no sense. Even fully charged batteries could easily drop down to that level with just a compressor fridge and another load such as a furnace blower.

Instead it is highly likely that the compressor refrigerator/freezer has a shut down when voltage drops to somewhere around 11.0 - 11.5 volts. If that happened right away then your initial battery charge was low and/or the wiring to the refrigerator was insufficient.

The load was connected to Load terminals. This is what they do, disconnect (or not) load from the controller.

The battery is LFP, it has 20% SOC at 12.5V. I set LVD slightly higher to 12.6 - or I thought that I did, see the explanations about the app, LVD and Discharge Limit.

Thin wire to the fridge and controller cutting off at 11V means that the fridge was at 10.5V at that moment. Should've cut off at 12V measured at the fridge - which would've been ~12.5 measured at the controller.

There was supposed to be 2 levels of protection - fridge and Load terminals, but none worked. Actually, 3 levels if you count the "low voltage alarm" that apparently is not an alarm but a "warning" in the way of a blinking LED.

[Almot]

StirCrazy wrote:

so did you change battery types and go back and not realize that things had reverted? all the numbers you gave above looks like this happened. I wonder if it resets when you take the power off also? Ill have to play with mine and see.

Steve

Settings change only in User battery type. In Flooded, Sealed etc they are fixed, you can't change those. I didn't change battery type during the initial test.

Regardless, the app is confusing and has glitches. What you enter in the app, isn't always what is set on the controller. You can change settings directly on the controller by holding the right arrow until it starts blinking. Then you scroll through the screens by pressing the same right arrow once, and change the values by pressing the Up or Down arrow. It doesn't show all the settings - the app has more - and some values that you see on the controller can only be changed in 0.2V increments, not 0.1, and some are unnamed - say, it shows 12.0 and 12.6 (obviously some low-voltage point) but it doesn't tell whether this is LVD or what. App requires manually "finding" the correct Bluetooth every time you turn the phone On, and entering password every time you want to change settings. Same password for all the thousands of users.

It's easy to incidentally change the battery type while doing programming - but this wasn't the case with my 11 V puzzle. Most likely it was a confusion btw the (not clearly named) LVD in the app and the other "Discharge Limit", and also the fridge cutting off way lower than it was supposed to. After you've done and saved the settings by holding the right arrow, they are stable.

[StirCrazy]

Almot wrote:


Possible reason: confusing Chinglish of the app with no LVD but with "Discharge Limit" and "Over Discharge" instead, the former being a mystery and the latter (probably) an inept name for LVD. I thought that LVD was a "Discharge Limit" and set it at 12.6, but the LVD apparently was an "Over Discharge" (set below 12, don't remember now).

Also, settings in User-defined mode would revert back to defaults if I dial in a different battery type, ex. Gel or Flooded and then return it back to User-defined mode. If you do this, all User settings are lost - LVD would change to 11V, Boost time to 120 minutes and Temp Comp to 3C. Very dangerous. But, hey - who would ever change their battery, right?

so did you change battery types and go back and not realize that things had reverted? all the numbers you gave above looks like this happened. I wonder if it resets when you take the power off also? Ill have to play with mine and see.

Steve

[StirCrazy]

pianotuna wrote:
The load terminals on my Blue Sky are used as a "sun sensor" switch. Perhaps yours are too?

they can be set by time. so you can set it to be active all the time, or spicific hours on the renogy. I played with mine for my porch light fron say 9pm to 11pm for a bit, now I dont use it at all. would rather my fridge stay on propane anyways, as the load current is subtracted from the available charing curent.

Steve

[JimK-NY]

There seems to be a lot of confusion here.

First start with the Reflectix. What do you really expect this to do? The insulation value is very minimal. You will likely need an inch or two of good quality insulation foamboard to see any effect.

Next I am totally confused on the complaint. If the output of the panels drops below 12.6, I can understand the solar charger shutting down. I have never seen a controller which actually shut down the draw on the batteries and certainly doing so at 12.6 would make absolutely no sense. Even fully charged batteries could easily drop down to that level with just a compressor fridge and another load such as a furnace blower.

Instead it is highly likely that the compressor refrigerator/freezer has a shut down when voltage drops to somewhere around 11.0 - 11.5 volts. If that happened right away then your initial battery charge was low and/or the wiring to the refrigerator was insufficient.