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Renogy Rover Lithium settings

I'm ok with my Lithium battery being constantly boosted at a lower voltage (14.0 max), because if you think about it, I believe that's how lithium batteries are charged in devices like your phone, computer etc. for example, it just hits 100% and stays there until you unplug it.
Checking with my consumer electronics engineer buddy. IIRC he said they terminate charging, not hold at a voltage. I'll edit this post when I hear back.

EDIT: His company does CC/CV until current tapers to a set value, then terminates charging altogether. Then periodically checking on state of charge and reactivating charging as needed.

He can’t speak for all companies but believes the vast majority follow the same procedures.

This makes sense to me as it’s exactly what I’d like the Rover to do and what all the research and guidance states for LFP.
 
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Checking with my consumer electronics engineer buddy. IIRC he said they terminate charging, not hold at a voltage. I'll edit this post when I hear back.
Interesting this is really good to know I'm learning something new everyday.

But if you think about it it's actually doing that already, I think.... let me try to explain. For example boost will provide a small charge to keep the voltage steady, but if the voltage is steady then it doesn't have to provide a charge, so it's basically floating until the voltage changes which it won't, because the self-discharge is very low on the battery.

For example, when my Rover is in boost my battery reports 0.00 amps (via the BMS). So it's kind of like it is floating until there's a change in voltage?? You know what I'm trying to say? I think this is the case were boost = float (and = equalize based on the defaw lithium charge profile).

Is renogy one of the few companies that builds charge controllers, batteries, solar panels, etc.?
 
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I saw this video and it explains quite a few things well about some of the settings we are talking about, above. Good 30 minutes:

 
Interesting this is really good to know I'm learning something new everyday.

But if you think about it it's actually doing that already, I think.... let me try to explain. For example boost will provide a small charge to keep the voltage steady, but if the voltage is steady then it doesn't have to provide a charge, so it's basically floating until the voltage changes which it won't, because the self-discharge is very low on the battery.

For example, when my Rover is in boost my battery reports 0.00 amps (via the BMS). So it's kind of like it is floating until there's a change in voltage?? You know what I'm trying to say? I think this is the case were boost = float (and = equalize based on the defaw lithium charge profile).

Is renogy one of the few companies that builds charge controllers, batteries, solar panels, etc.?
I’ve updated my prior post.

Float is a concept left over from lead acid. This is over simplified, but that chemistry works best and lasts longest when fully recharged as often as possible. Holding it at a 13.5-13.8V for float keeps them full and happy.

For LFP it’s best to fully charge and then terminate charging. No float necessary. Keeping them at a higher voltage (like Renogy does in their Lithium profile) has a detrimental effect on lifespan. The same is true for storing them at high states of charge. You can find excellent info in the Resources section that other generous members have posted.

Renogy is a budget player that rebrands products from other companies. There are many other higher tier companies. Poke around the forum and you’ll see there are a lot to choose from.
 
I’ve updated my prior post.

Float is a concept left over from lead acid. This is over simplified, but that chemistry works best and lasts longest when fully recharged as often as possible. Holding it at a 13.5-13.8V for float keeps them full and happy.

For LFP it’s best to fully charge and then terminate charging. No float necessary. Keeping them at a higher voltage (like Renogy does in their Lithium profile) has a detrimental effect on lifespan. The same is true for storing them at high states of charge. You can find excellent info in the Resources section that other generous members have posted.

Renogy is a budget player that rebrands products from other companies. There are many other higher tier companies. Poke around the forum and you’ll see there are a lot to choose from.
Thanks again, @Bob142 . So far, from a curiosity, this has turned into a mind opening thought process on this for me !

Could you please do me favor next time you have time, what is you AiLi current reading when you Renogy goes into boost? and then what is current after say 30 min or 60 mins?

If it reads 0 amps for the latter, then I believe it is doing exactly what your electrical engineering buddy is saying, "the CC/CV current tapers to a set value, then terminates charging altogether. Then periodically checking on state of charge and reactivating charging as needed." Except in the Rover case, it checks to see if the voltage dropped 0.1 V vs whatever the difference in float voltage is.

Assuming your voltage is stable, I would expect your answer to be 0 amps (which by definition, it cutting off the charge), like what happens to mine when it hits boost after a certain time. Despite the charger say its in boost, it could actually be in float, when float=boost.

However, there is a limitation to Rover that we've discovered (as others have reported also), that it cannot float at a lower voltage than the boost voltage, but if float=boost when the voltage is the same, unless the voltage changes than its boost.

I found a few other Charge controller companies, and they all seem to list float at a lower voltage than boost for lithium batteries. Renogy seems to be the only company that doesn't.
 
Thanks again, @Bob142 . So far, from a curiosity, this has turned into a mind opening thought process on this for me !

Could you please do me favor next time you have time, what is you AiLi current reading when you Renogy goes into boost? and then what is current after say 30 min or 60 mins?

If it reads 0 amps for the latter, then I believe it is doing exactly what your electrical engineering buddy is saying, "the CC/CV current tapers to a set value, then terminates charging altogether. Then periodically checking on state of charge and reactivating charging as needed." Except in the Rover case, it checks to see if the voltage dropped 0.1 V vs whatever the difference in float voltage is.

Assuming your voltage is stable, I would expect your answer to be 0 amps (which by definition, it cutting off the charge), like what happens to mine when it hits boost after a certain time. Despite the charger say its in boost, it could actually be in float, when float=boost.

However, there is a limitation to Rover that we've discovered (as others have reported also), that it cannot float at a lower voltage than the boost voltage, but if float=boost when the voltage is the same, unless the voltage changes than its boost.

I found a few other Charge controller companies, and they all seem to list float at a lower voltage than boost for lithium batteries. Renogy seems to be the only company that doesn't.
Zero current or not it is still holding the battery cells at a voltage that’s much higher than they want to naturally settle down to after being fully charged.

I now believe that the degree to which this is an issue depends on the use case. In mine, I’m usually close by while the crate is charging. So it won’t hold it at boost voltage for very long before I realize where it is in the charge cycle. Sometimes, however, it could be several hours. If most people deploy Rovers in vehicles or cabins, for example, then it’s likely there are some constant loads on the system and this issue is generally moot.

Since the revelation in this thread I have gone back and forth about whether I want to ditch the Rover. It does a good job harvesting the available power from my portable array and charging up the batteries fairly quickly. So from that perspective I have nothing to complain about. If the crate system is powering something like a TV or a crock pot while also charging, for example, there’s no issue there either.

I guess it comes down to people evaluating their use patterns and determining if they can live with the behavior. For those looking at buying their first solar charge controller I would suggest looking at something like Victron, Outback, MidNite, etc. (not intended to be a prioritized or exhaustive list - everyone should do their own research).
 
13.2-13.29v is what I thought the chart you sent me for lifepo4 voltages correlated to 70-80% capacity. Am I guesstimating wrong?

Edit: this is the chart I meant.
You’re never going to be able to accurately determine your state of charge using voltage with LFP batteries. As I suggested earlier, I recommend you get a shunt-based battery monitor. See below for some specific recommendations I made in another thread.

https://diysolarforum.com/threads/battery-charging-confusion.28667/post-344184

If you get a grid/mains charger like a Noco, make sure you get a substantial one and not something like the little 10A chargers. You’ve got 340Ah to fill. If your 300W of solar is struggling to charge up your bank I’d suggest a 30A charger minimum to supplement it.
 
13.2-13.29v is what I thought the chart you sent me for lifepo4 voltages correlated to 70-80% capacity. Am I guesstimating wrong?
Looks about right. I am not sure what your issue is with "topping out". Is that all your SCC will charge to?

Honestly, you're making this more difficult that it needs to be. My very conservative battery range is pretty much 13.0V-13.4.
They mostly sit in my driveway lounging at 13-13.2V. If they get down to 12.8V because the trickle charger is maintaining the engine battery, thats just fine. I'll turn on the solar for a day and hit 13.2-13.3V and its good for a few weeks.

Enjoy your batteries, don't fuss over micromanaging them. Even if you were riding them a lot harder like 12.0V to 14.0V they'd be just fine. Set your BMS to keep cells above 2.5V (to your comfort level, maybe 2.8V) and below 3.65V (to your comfort level, maybe 3.60V) and get on with more important things like using fun gadgets that use power.
 
Zero current or not it is still holding the battery cells at a voltage that’s much higher than they want to naturally settle down to after being fully charged.

I now believe that the degree to which this is an issue depends on the use case. In mine, I’m usually close by while the crate is charging. So it won’t hold it at boost voltage for very long before I realize where it is in the charge cycle. Sometimes, however, it could be several hours. If most people deploy Rovers in vehicles or cabins, for example, then it’s likely there are some constant loads on the system and this issue is generally moot.

Since the revelation in this thread I have gone back and forth about whether I want to ditch the Rover. It does a good job harvesting the available power from my portable array and charging up the batteries fairly quickly. So from that perspective I have nothing to complain about. If the crate system is powering something like a TV or a crock pot while also charging, for example, there’s no issue there either.

I guess it comes down to people evaluating their use patterns and determining if they can live with the behavior. For those looking at buying their first solar charge controller I would suggest looking at something like Victron, Outback, MidNite, etc. (not intended to be a prioritized or exhaustive list - everyone should do their own research).
This is so interesting actually, it just goes to show how lithium battery science, I believe is still evolving.

Part of me the thinks the whole float thing when using a lithium battery is because of lead acid batteries, and we're kind of hard wired to do that and it seems renogy is going rogue or they're ahead of their time.

Time will tell!
 
Looks about right. I am not sure what your issue is with "topping out". Is that all your SCC will charge to?

Honestly, you're making this more difficult that it needs to be. My very conservative battery range is pretty much 13.0V-13.4.
They mostly sit in my driveway lounging at 13-13.2V. If they get down to 12.8V because the trickle charger is maintaining the engine battery, thats just fine. I'll turn on the solar for a day and hit 13.2-13.3V and its good for a few weeks.

Enjoy your batteries, don't fuss over micromanaging them. Even if you were riding them a lot harder like 12.0V to 14.0V they'd be just fine. Set your BMS to keep cells above 2.5V (to your comfort level, maybe 2.8V) and below 3.65V (to your comfort level, maybe 3.60V) and get on with more important things like using fun gadgets that use power.
Fair enough. Thanks for the reassurance.
 
After our discussion above and watching this video:


I have changed my charge profile to this:

High Voltage Disconnect: 14.2 V
Charge Limit Voltage: 14.0 V
Equalize Charge Volt: 13.8 V
Boost Charge Volt: 13.8 V
Float Charge Volt: 13.8 V
Boost Charge Return Volt: 13.2 V
Over Disc Return Volt: 12.6 V
Low Voltage Alarm: 12.1 V
Over Discharge Volt: 11.1V
Discharge Limit Volt: 10.6 V
Over Disc Delay Time (S): 5
Equalize Charge Time (min): 0
Boost Charge Time (min): 60
Equalize Charge Interval: 0
Temp Comp: 0

You'll see that I set the boost for 60 min, but as we've discovered, it will just stay in boost.

As long as there is a value there, I think the Rover will like it because Renogy's recommend charge profile for lithium batteries is set to 10 minutes when boost=float=equalize.

In the event it actually is boosting for 60 minutes, I increased it from 10 only because its at a lower voltage of 13.8 compared to 14.4 by default.

Any thoughts on this charge profile?

For the record, my battery is basically running some landscape and security lights at night time, which uses around 6 or 8 amp h all night, essentially my battery is running from 92 to 100% everyday. I have a 1000W inverter which runs some loads but the charge controller seems to just use power from the panels as opposed to the battery during the day (as my battery voltage stays the same)
 
After our discussion above and watching this video:


I have changed my charge profile to this:

High Voltage Disconnect: 14.2 V
Charge Limit Voltage: 14.0 V
Equalize Charge Volt: 13.8 V
Boost Charge Volt: 13.8 V
Float Charge Volt: 13.8 V
Boost Charge Return Volt: 13.2 V
Over Disc Return Volt: 12.6 V
Low Voltage Alarm: 12.1 V
Over Discharge Volt: 11.1V
Discharge Limit Volt: 10.6 V
Over Disc Delay Time (S): 5
Equalize Charge Time (min): 0
Boost Charge Time (min): 60
Equalize Charge Interval: 0
Temp Comp: 0

You'll see that I set the boost for 60 min, but as we've discovered, it will just stay in boost.

As long as there is a value there, I think the Rover will like it because Renogy's recommend charge profile for lithium batteries is set to 10 minutes when boost=float=equalize.

In the event it actually is boosting for 60 minutes, I increased it from 10 only because its at a lower voltage of 13.8 compared to 14.4 by default.

Any thoughts on this charge profile?

For the record, my battery is basically running some landscape and security lights at night time, which uses around 6 or 8 amp h all night, essentially my battery is running from 92 to 100% everyday. I have a 1000W inverter which runs some loads but the charge controller seems to just use power from the panels as opposed to the battery during the day (as my battery voltage stays the same)
That will probably work well for you. I can't find the reference material at the moment, but I believe I've read a research paper that indicates you'll get to full charge at as low as 13.8V on a 12V LFP battery as long as you let it stay in absorption (boost) long enough. Your use case is so gentle on the battery if you're only using 8% of the capacity each day. At this point I'd just set it and forget it.
 
I've read that too, somewhere about 13.8V

So far, during the day with good sun the battery hits 13.8 (according to the Rover) and 13.9 (according to the battery BMS) and capacity stops at 98.0 %(ah) for my 100 ah battery and it doesn't actually hit 100% charge like it did when I had it at the 14.0V (or above) setting.

According to Will Prowse's video about making you battery last 20 years, ideally you want to charge/discharge around 50% ( i.e. 25 to 75%) which is not practical for some since you capacity will diminish), but being at 0% or 100% seem to be the most damaging for the battery so if my charge cycle is 90 to 98%, its better than it was by default. Who, knows, maybe I can experiment with bringing the charge cycle lower to that 50% mark (40 to 60% charge-discharge), for as long I only need 8 ah a day.

Unrelated- Any of you know how I can tell if my battery has an active or passive balancer?
 
Unrelated- Any of you know how I can tell if my battery has an active or passive balancer?
I’m not sure what Renogy has for a BMS in their batteries but I strongly suspect it incorporates passive balancing. Either way that’s not something you should need to be concerned with. The beauty of buying a complete battery as opposed to building one from cells is that you should be able to just drop it in and use it.
 
After reading this thread, I feel less confident about the default settings on my Rover 40A MPPT.
I have now changed to user settings and put in the numbers that SolarShed suggested.
 
After reading this thread, I feel less confident about the default settings on my Rover 40A MPPT.
I have now changed to user settings and put in the numbers that SolarShed suggested.
Is that the charge profile with a float at the lower voltage than boost?

If you can get your Rover to float your lithium battery please post a picture here thank you!
 
The only thing I've seen on my Rover is MPPT charge mode. It's never ever gone to Boost or Float. I'll keep an eye on it if it ever changes.
 
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