My Lithium Upgrade

[rowiebowie]

UPDATE:

Day 9 & so far no glitches or problems with the lithium upgrade. Never below 63% and we like not having to worry about power so we use all we want with the microwave being the biggest draw. And love the super fast charging. Recharge by driving is a little slower than while plugged in, but even then, in 2-3 hours of driving we're at 100%.

[booster]

Originally Posted by rowiebowie

UPDATE:

Day 9 & so far no glitches or problems with the lithium upgrade. Never below 63% and we like not having to worry about power so we use all we want with the microwave being the biggest draw. And love the super fast charging. Recharge by driving is a little slower than while plugged in, but even then, in 2-3 hours of driving we're at 100%.

How much off grid, no charging time, did it take you to get to the 63% SOC.

[rowiebowie]

Originally Posted by booster

How much off grid, no charging time, did it take you to get to the 63% SOC.

That was only one time (most times we've stayed in the high 70% range) and it basically occurred during just a single overnight. We were boon-docking and using the microwave, tv, Tivo, and fans pretty heavy. Still figuring out all the drains, but the compressor fridge uses 45-50 watts and runs much more than 50% of the time even in cooler weather.

Sometimes the SOC drops more than others and I need to pay attention as to why. We're pretty consistent about shutting down the inverter and other peripherals. I just haven't bothered to track our consumption closer as we're trying to enjoy our travels.

[rowiebowie]

Another update after 2 weeks out:

Sometimes when plugged in to 30A and the lithiums are above 80% they won't charge until they sense a load (5 secs with the microwave on does the trick). Seems when below 80% charge they don't need the load to start charging but I'm still not sure of the exact % point. Not a problem, just a quirk, and maybe that is what they are designed to do.

Occasionally, my engine alternator is briefly not up to the 40A DC-DC charger requirements at idle and voltage drops as the charger begins to draw from the engine battery due to not enough output. Not good. But it is just momentary until the alternator catches up or RPM's go up above idle. Most times, however, it is fine.

I knew of this before my trip so I wired a switch between my ignition wire (that activates the DC-DC charger) so I can control when the engine charges. If I need it, I flip the switch "on" before we hit the highway. I keep the switch off whenever we are idling around sight-seeing in stop & go conditions.

[markopolo]

Originally Posted by rowiebowie

Another update after 2 weeks out:

Sometimes when plugged in to 30A and the lithiums are above 80% they won't charge until they sense a load (5 secs with the microwave on does the trick). Seems when below 80% charge they don't need the load to start charging but I'm still not sure of the exact % point. Not a problem, just a quirk, and maybe that is what they are designed to do ...........................................

Thanks for sharing the observation and the trick. That would explain why the 14.4V float that Booster mentioned in another post is permitted. It would appear that the BMS is preventing constant charging. In a back-up power situation there's a good chance that the battery bank capacity would be 20% less than expected when called upon. Probably a good idea to oversize the bank by 20% when calculating capacity requirements. Rowie's setup does seem to be adequately sized for his use

[rowiebowie]

One odd thing is the inverter/charger never had exceeded 13.7 volts even when charging. No where near 14.4v. Seems to be working fine, however.

The Renogy lithium batteries also like to rest at between 13.2 & 13.4V. Never seen them above 13.5v and that was only once.

Right now, after over night 30A plugin where they charged to 100% about 14 hours ago, they sit at 91% SOC and 13.2v with only my laptop charging.

Will have to satisfy my curisity when I get home and ask why I've never seen anything near 14.4v at any point. I have the 3000W inverter/charger on their "Lithium" setting which automatically sets charging parameters, so I really can't "see" what those are.

I haven't ridden in the back to see what the charging rate is from the engine alternator when allowing the DC-DC charger to be on.

[booster]

Originally Posted by rowiebowie

One odd thing is the inverter/charger never had exceeded 13.7 volts even when charging. No where near 14.4v. Seems to be working fine, however.

The Renogy lithium batteries also like to rest at between 13.2 & 13.4V. Never seen them above 13.5v and that was only once.

Right now, after over night 30A plugin where they charged to 100% about 14 hours ago, they sit at 91% SOC and 13.2v with only my laptop charging.

Will have to satisfy my curisity when I get home and ask why I've never seen anything near 14.4v at any point. I have the 3000W inverter/charger on their "Lithium" setting which automatically sets charging parameters, so I really can't "see" what those are.

I haven't ridden in the back to see what the charging rate is from the engine alternator when allowing the DC-DC charger to be on.

Very interesting information, to be sure. When I had looked at the specs for the Renolgy, it was a bit surprising to see the 14.4v charging as many many manufacturers have reduced that to get some "headspace" as they have been finding going to completely full isn't as good for battery life. 14.7 initially was the charge voltage for most. But now we seem to be seeing around high 13s volts more. Maybe they have changed the charge programming and not the literature or something like that. It would be interesting to hear what they say.


I don't recall right offhand what you are getting the SOC % off of for a meter, but the lower voltages you are seeing may be preventing a "full" reading calibration reset and not be totally accurate by now.


I just looked at the owner manual for the charger and the charge parameters show the charger going to 14.7v for charging then full cutout. Charging resuming at 12.5v. I would have to look at the battery curves again to see, but that seems like a very wide range for lithium. Doesn't seem to match what you are seeing.


I just looked at the curves. It looks like if they are restarting the charge at 12.5v like the manual shows, you would be at the end of the curve and nearly empty batteries. It is likely that they the have changed the charge profile parameters, and in this case for the better. You may just need to find out what they are so you know what to expect.

[rowiebowie]

Originally Posted by booster

Very interesting information, to be sure. When I had looked at the specs for the Renolgy, it was a bit surprising to see the 14.4v charging as many many manufacturers have reduced that to get some "headspace" as they have been finding going to completely full isn't as good for battery life. 14.7 initially was the charge voltage for most. But now we seem to be seeing around high 13s volts more. Maybe they have changed the charge programming and not the literature or something like that. It would be interesting to hear what they say.


I don't recall right offhand what you are getting the SOC % off of for a meter, but the lower voltages you are seeing may be preventing a "full" reading calibration reset and not be totally accurate by now.

The reading is off the Renogy 500A SOC monitor.

I just looked at the owner manual for the charger and the charge parameters show the charger going to 14.7v for charging then full cutout. Charging resuming at 12.5v. I would have to look at the battery curves again to see, but that seems like a very wide range for lithium. Doesn't seem to match what you are seeing.

Interesting indeed. Just before installing the Renogy 3000W inverter/charger I read under the manual what you quoted above (that it charges to 14.7v on their "Lithium" preset). Interesting because their battery's BMS claims to lock down if receiving more than 14.6v. So I called them and the person on the other end of the phone did not have an answer. They left the phone to speak to an engineer and came back on saying the 14.7v must be a misprint. He stated they would do some testing on this issue. Never got back to me as promised. It now seems the real charging rate max is probably 13.7v, but I don't like that they couldn't tell me.

I just looked at the curves. It looks like if they are restarting the charge at 12.5v like the manual shows, you would be at the end of the curve and nearly empty batteries. It is likely that they the have changed the charge profile parameters, and in this case for the better. You may just need to find out what they are so you know what to expect.

In my limited experience, I've never seen the voltage drop to less than 13.1v even when down in the high 60% state of charge range. Seems like 12.5v for lithiums would be dangerously low.

Had to resort to an unexpected Walmart boondock tonight. Batteries were 90% when I unplugged this morning and, anticipating a full hookup tonight, I never engaged the DC-DC charger. After 8 hours the batteries are showing 80% and will undoubtedly go into the low 60% or 50% range tonight given our typical use. I'll check in the morning and see what the % and voltage reading are.

It may be a few days before I post, depending upon wi-fi service.

[Boxster1971]

Originally Posted by rowiebowie

. . . I haven't ridden in the back to see what the charging rate is from the engine alternator when allowing the DC-DC charger to be on.

I also have a switch to control charging from engine alternator. It is very helpful to also have a meter in driver seat to monitor the rate of charging when connectiong the engine alternator to the house battery bank.

I used this device from DIYvan on eBay, run by forum member Hein.

https://www.ebay.com/itm/Mini-panel-...h/132286443113

It works great - here is a photo of my installation.

[booster]

Originally Posted by Boxster1971

I also have a switch to control charging from engine alternator. It is very helpful to also have a meter in driver seat to monitor the rate of charging when connectiong the engine alternator to the house battery bank.

I used this device from DIYvan on eBay, run by forum member Hein.

https://www.ebay.com/itm/Mini-panel-...h/132286443113

It works great - here is a photo of my installation.

Did that unit come with any accuracy specs? I ask because I also have an inductive on the dash for the same reason of seeing charge amps. I was looking for 300 amp capability and also low end accuracy to be able to see accurately the end of charge amps of only two amps. Many of the inductives were +/- 1% of scale, so that would totally blow my 2 amp accuracy with a 300 amp max. The one I got is rated in tech speak of numbers plus and minus some amount of significant digits, yadda, yadda. I contacted the manufacturer and they did the calc and said I would be well within +/- .4 amps which was good enough for me. I checked it against the two shunt meters and it is actually only about .1-.2 amps different than them.



Inductives are really useful as long as you can find the range and accuracy for what you need to do, without having to sell you house to pay for it.

[Boxster1971]

Originally Posted by booster

Did that unit come with any accuracy specs? I ask because I also have an inductive on the dash for the same reason of seeing charge amps. I was looking for 300 amp capability and also low end accuracy to be able to see accurately the end of charge amps of only two amps. Many of the inductives were +/- 1% of scale, so that would totally blow my 2 amp accuracy with a 300 amp max. The one I got is rated in tech speak of numbers plus and minus some amount of significant digits, yadda, yadda. I contacted the manufacturer and they did the calc and said I would be well within +/- .4 amps which was good enough for me. I checked it against the two shunt meters and it is actually only about .1-.2 amps different than them.

Inductives are really useful as long as you can find the range and accuracy for what you need to do, without having to sell you house to pay for it.

I should clarify that the item sold by DIYvan is only the 3D printed enclosure and switch. You need to buy the meter separately. I got mine from Amazon for $19. Here is link to the 100A version I used. It claims a +/- 1% accuracy. That was good enough for my use.

https://www.amazon.com/dp/B01DDQM6Z4

[rowiebowie]

Originally Posted by rowiebowie

Had to resort to an unexpected Walmart boondock tonight. Batteries were 90% when I unplugged this morning and, anticipating a full hookup tonight, I never engaged the DC-DC charger. After 8 hours the batteries are showing 80% and will undoubtedly go into the low 60% or 50% range tonight given our typical use. I'll check in the morning and see what the % and voltage reading are.

It may be a few days before I post, depending upon wi-fi service.

Ahhhhhhhhhhhhhh! Short story is I reset my SOC to 100% by accident this morning (for the second time this trip). The display has a feature to turn off the back-light which glows green and makes the display very easy to read. But I turn this feature off at night by pressing and holding the top button for 3 secs. just to avoid an additional light distraction.

In the still poorly lit morning light and without my glasses, I pressed and held the wrong button resetting the display to appear the batteries are full. So I never saw the actual overnight SOC %. This is just an annoyance, as the solution is just drive or plug in sufficient time to fully charge the batteries to 100%. The monitor doesn't affect the actual charging.

Sitting in a campsite with 30A plugged in, the charger ran about 45 mins. before fully charging the batteries and turning off. So now, I know my 100% charged batteries are actually 100% charged.

[rowiebowie]

Here's an update on my Renogy 200ah lithium battery/charger/3000W inverter install after being home from our trip for a week.

First let me say, still no problems or glitches to report. But I have a few observations that I haven't yet devoted sufficient time to explain.

In order to verify some of these with any certainty will require me to ride in the back while my Wife drives so I can observe the SOC monitor while underway. Two big problems with this are my Wife doesn't like to drive it (she's done fine in the few occasions I've coaxed her into it) and I get car sick really, really fast (I mean in a few blocks) on the few occasions I've ridden in the back.

1) When the 3000W inverter/charger was charging the batteries on 30A shore power, I never saw more than 13.6V of input on the Renogy SOC monitor. No where near the 14.4v I expected see. Input amps were spot on at 45A (programmable in 5A increments from 5A to 65A). It always cut off charging shortly after the SOC monitor showed 100%.

2) Regarding the 40A DC to DC charger. I did go back while parked and idling to see the DC to DC charger was delivering 40 amps as advertised. Forgot to check charging voltage at idle or while driving, however, and never observed how long it continued charging after reaching 100%.

3) The 40A DC to DC charger activates by an ignition wire, not by voltage input and there is no delay to allow for the alternator to warm up. On a few occasions, I noticed when at idle in traffic the dash voltage meter would show the engine battery voltage drop momentarily (lowest was 11.92 volts) as if the charger was pulling more power than the alternator could deliver. This seemed to happen when the engine was cold, and I rarely noticed the drop after everything was warmed up. The DC to DC also seems to want to charge the batteries even when they've just been charged to 100% by shore power. I never let it charge this way for very long to see when it would turn off on it's own.

4) Because of the above, I installed a switch on the ignition wire. When we needed to charge using the engine alternator, I would wait until we had pulled out of camp, everything was warmed up, and were getting ready to drive at speed. Then I'd pull over and have the Wife go back and flip the switch on the DC to DC ignition wire. After an hour or two of driving (depending on the amount of charge needed) we would turn off the ignition switch once the SOC got between 90 - 100%.

5) A final fact regarding the resting drain. Monitor only shows a drain of 1W (.12A). The SOC has stayed at 83% (166ah) for the entire past week while sitting in the driveway. That is great.

As I stated in a previous post, the 3000W inverter/charger will not automatically charge on shore power unless the SOC is below 80%. But I was always able to force charging by introducing a load, which in our case was the microwave. One final observation, the inverter charger uses about 4 watts extra when plugged into shore power, even though it's turned off. I guess this is to pass through shore power. Drain drops back to 1 watt when unplugged.

[@Michael]

Originally Posted by rowiebowie

In order to verify some of these with any certainty will require me to ride in the back while my Wife drives so I can observe the SOC monitor while underway. Two big problems with this are my Wife doesn't like to drive it (she's done fine in the few occasions I've coaxed her into it) and I get car sick really, really fast (I mean in a few blocks) on the few occasions I've ridden in the back.

I bought a Thornwave Bluetooth battery monitor. It's Bluetooth-only - no display or buttons - so you need to use your phone to check it. But that means you can monitor your voltage and current from your phone while driving - hands free of course .

Also - It's cheaper than the big names by about $100, can be hidden in your electrical cabinet, has all the data gathering that the expensive monitors have, and can control a solid state relay to turn stuff off and on based on various measurements and parameters.

Today I have a Xantrex for my lead-acids, and Thornwave for my Lithium. I'm going to dump my Xantrex and get another Thornwave.

[I have no connection to them].

[rowiebowie]

Originally Posted by @Michael

I bought a Thornwave Bluetooth battery monitor. It's Bluetooth-only - no display or buttons - so you need to use your phone to check it. But that means you can monitor your voltage and current from your phone while driving - hands free of course .

Also - It's cheaper than the big names by about $100, can be hidden in your electrical cabinet, has all the data gathering that the expensive monitors have, and can control a solid state relay to turn stuff off and on based on various measurements and parameters.

Today I have a Xantrex for my lead-acids, and Thornwave for my Lithium. I'm going to dump my Xantrex and get another Thornwave.

[I have no connection to them].

Thanks. I do have the Victron solar controller with bluetooth. I like the detailed information it provides. However, for battery SOC, I like having a monitor I can read "at a glance" when camped. Plus, I'm pretty old-school.

[markopolo]

Originally Posted by rowiebowie

.................................................. .......................

1) When the 3000W inverter/charger was charging the batteries on 30A shore power, I never saw more than 13.6V of input on the Renogy SOC monitor. No where near the 14.4v I expected see. Input amps were spot on at 45A (programmable in 5A increments from 5A to 65A). It always cut off charging shortly after the SOC monitor showed 100%.


.................................................. .....................


As I stated in a previous post, the 3000W inverter/charger will not automatically charge on shore power unless the SOC is below 80%. But I was always able to force charging by introducing a load, which in our case was the microwave. One final observation, the inverter charger uses about 4 watts extra when plugged into shore power, even though it's turned off. I guess this is to pass through shore power. Drain drops back to 1 watt when unplugged.

On the Renogy Inverter/Charger is Program Setting 05 Battery Type set to b-L or b-0?

If 05 is set to b-0 is Program Setting 94 set to ALb?

If so, what voltage did you choose for Program Setting 26 t0C and
what voltage did you choose for Program Setting 27 |-C ?

I have been considering those and other batteries. Note that there's 120 or 124 small batteries in each of those 100Ah cases depending on which PDF from Renogy you look at. It's unlikely that there is individual cell balancing IMO. My guess is that the 4 parallel strings of 30 or 31 cells are voltage balanced. With the Renogy inverter/charger, t0C at 14.6V and |-C at 13.4V is probably what I'd use. I'd likely try t0C at 14.4V, 14.5V and 14.6V to see if any differences are noticeable. I have read that some balancers require more than 14.4V to trigger balancing.

Looks like Renogy defines full for that battery as 14.6V and amps in at 2% of capacity. That would be 4A for a 200Ah battery bank.

You'd need to see 14.6V & 4A (plus any other loads) in and then set the Battery Monitor to Full.


Edit to add: After 100% capacity is established then it would be easy to figure out what 99% or 95% is. For the long term one, might choose to make the actual 95% full as the 100% full Monitor indicator for example. The absorption charging voltage might be able to be lowered and still get to say 95% actual (100% Monitor) in a reasonable amount of time.

[rowiebowie]

Originally Posted by markopolo

On the Renogy Inverter/Charger is Program Setting 05 Battery Type set to b-L or b-0?

If 05 is set to b-0 is Program Setting 94 set to ALb?

If so, what voltage did you choose for Program Setting 26 t0C and
what voltage did you choose for Program Setting 27 |-C ?

I have been considering those and other batteries. Note that there's 120 or 124 small batteries in each of those 100Ah cases depending on which PDF from Renogy you look at. It's unlikely that there is individual cell balancing IMO. My guess is that the 4 parallel strings of 30 or 31 cells are voltage balanced. With the Renogy inverter/charger, t0C at 14.6V and |-C at 13.4V is probably what I'd use. I'd likely try t0C at 14.4V, 14.5V and 14.6V to see if any differences are noticeable. I have read that some balancers require more than 14.4V to trigger balancing.

Looks like Renogy defines full for that battery as 14.6V and amps in at 2% of capacity. That would be 4A for a 200Ah battery bank.

You'd need to see 14.6V & 4A (plus any other loads) in and then set the Battery Monitor to Full.


Edit to add: After 100% capacity is established then it would be easy to figure out what 99% or 95% is. For the long term one, might choose to make the actual 95% full as the 100% full Monitor indicator for example. The absorption charging voltage might be able to be lowered and still get to say 95% actual (100% Monitor) in a reasonable amount of time.

Setting 05 Battery Type is set to b-L. Which in their manual says: "When battery voltage reaches 14.7V charging will stop. When battery voltage drops below 12.5 volts, charging will resume." In reality, it seems to charge around 13.5 13.6V and resumes when SOC shows less than 80% (probably 13.2 volts). The batteries "rest" at 13.3. A very narrow range.

The manuals charge parameters seem odd in two ways. First, the battery BMS says it will shut down above 14.6V, and second, 12.5V for a lithium battery is very low. I noticed this wording before installing and called Renogy. The tech wasn't sure and left the phone to speak to an engineer. When he came back, he said it was probably a printing error, but they would do further testing. I asked him let me know what they found, but never got a reply. I need to follow up with them.

You may be right that individual cell balancing is not a feature of this battery. My main reason for using it was size, which was only 6.22 inches wide which allowed me to install in the box inside next to the inverter. A normal group 24 or 27 size would not have fit due to their being 1/2 inches wider. A total of 1" wider for the pair.

Do I understand from your post you believe the lower charge rate will acutally give me a 95% charge, yet the SOC monitor will show 100%.

[Winston]

Originally Posted by rowiebowie

1) When the 3000W inverter/charger was charging the batteries on 30A shore power, I never saw more than 13.6V of input on the Renogy SOC monitor. No where near the 14.4v I expected see.

We're not chemists, so can't be sure that all LiFePO2 cells are created equal. But we'll assume that the basic cells in our Starlight/Elite lithium pack (20 x 100ah cells) are similar to those in your 'drop-in' 100ah battery modules.

Each Elite cell is fitted with a PC Board the measure cell voltage and temperature and a 1/2 ampere load which is placed across the cell when the cell reaches 3.55 volts. Why 3.55 volts?

Our measurements have established that 3.55 volts closely approximates the high voltage knee of our LiFePO2 cells. "Knee" being the point where, apparently, the cell is fully, or close to fully, charged and further attempts to charge the cell cause the cell voltage to increase very dramatically. One can 'pump' large amounts of charge (current) into the cell with the cell voltage rising very, very slowly until this 'knee' is reached, thereafter, comparatively smaller charge (currents) send this voltage higher very rapidly.

Elite, therefore, sets the maximum charge voltage to 4 times 3.55 or 14.2 volts. As the cells are never identically charged, one cell will reach 3.55 volts first - - at which point charging of this cell all but stops due to the 1/2 ampere (resistor) now shunting the cell. (Interestingly, if one were to raise the charging voltage above 14.2 volts, then the overall charging current correspondingly rises which, in turn, would cause that first cell to continue to charge - - as the 1/2 ampere load/shunt across the cell would no longer be enough to stop cell charge.) What eventually occurs with the Elite system is 'balance' . . . as the voltage of the less charged cells gradually approaches 3.55, the overall charge current continues to drop until the shunts across the now slightly overcharged cells actually cause a slow discharge of those cells. In the end, the cells below 3.55 volts continue to get charged, those above 3.55 volts get discharged until they all happily meet at the same fully charged "knee" voltage.

Much of the above is specific to the Elite PC Board system and its method of 'balancing' cell charge levels. But we suspect that the 3.55 "knee" is probably applicable to most LiFePO2 cells. Possibly other manufacturers, in order to achieve 'balance' and full charge, suggest applying 14.4 volts - - maybe, to force laggard cells to reach full charge, i.e. the 3.55 volt 'knee', they will somewhat overcharge the already fully charged cells.

In any event, you'll not see these high (>14 volt) numbers except when charging. Look at the following graph of pack voltage vs time. This pack was fully charged using Elite's 14.2 volt recommendation:



This curve was taken with no charging or loads on the battery pack (except for some trifling 'milliamperes' necessary to power the Battery Management System PC sensing boards). Note that a fully charged LiFePO2 battery approaches a resting voltage of approximately 13.75 volts. Remove the charger and your fully charged lithium pack drops - - still at full charge - - nearly 1/2 volt over time.

We offer another set of measurements to more fully set forth expected lithium pack voltages. Over a period of three years we've run very careful and controlled lithium voltage vs Percentage of Charge curves. Our technique is to place a 10 ampere load across our 500ah pack for 5 hours (thereby discharging the pack by 10%), then, wait a minimum of 10 hours before taking a measurement so that the measured voltage closely represents the 'resting voltage' (defined as the voltage of the cell that has not been recently charged or discharged) at each interval. This test generally takes over a week to perform and close adherence to an alarm clock.



Notice that a 90% PoC/SoC represents a pack voltage of less than 13.4 volts. (And if you've recently been popping corn in your microwave - - expect even lower voltages). Thus, in summary, we don't think the voltages that you've been seeing are unusual or unexpected.

As an aside, we've discarded all those pesky lead-acid terms such as Bulk, Absorption and Float - - terms which we contend have little to do with lithium.

Instead, we fixate on Constant Voltage charging. We have three charging sources, two of which (our solar controller and our shore power charger) are very easily (on the fly) reset. But, normally, both these charging sources are set to either 13.3 or 13.4 volts - - a level we can leave 'connected' to the batteries forever . . . to hold the batteries at 80% SoC. If we have been dry-camping for a period that leaves our overall SoC lower than desired, we may reset these chargers to higher voltages in order to more quickly restore our overall SoC - - but, again, normally, we just leave these charge sources programmed for the 80% SoC level.

Our third charging source, a 2nd Nations Alternator with Balmar regulator, we program for a higher Constant Voltage . . . maybe even 14.2 volts . . . This is our way of quickly charging the pack. As the Balmar regulator is difficult to program, we currently have it programmed for a Constant Voltage of 13.8 volts which produces a compromise charge rate in the order of 100 amperes . . . a charge rate that generally doesn't overheat the alternator, yet gets the job done. (More to follow in the future on the "Balmar" in a new thread.)

[markopolo]

Originally Posted by rowiebowie

................Do I understand from your post you believe the lower charge rate will actually give me a 95% charge, yet the SOC monitor will show 100%.

Something like that. I added that bit to show that you can define the 100% for the purposes of the monitor. The batteries don't have to actually be at 100%. To me, it seems very unlikely that they're getting to 100%. That is due in part to the data in this paragraph:

Originally Posted by rowiebowie

............1) When the 3000W inverter/charger was charging the batteries on 30A shore power, I never saw more than 13.6V of input on the Renogy SOC monitor. No where near the 14.4v I expected see. Input amps were spot on at 45A (programmable in 5A increments from 5A to 65A). It always cut off charging shortly after the SOC monitor showed 100%...........

It's unlikely that ending the absorption (constant voltage stage) with 45A in at 13.6V results in an actual 100% SOC.

I agree with you about the b-L profile (14.7V down to 12.5V) being odd and that's why I detailed an alternative.

05 set to b-0
94 set to ALb
26 t0C set to 14.4V+*
27 |-C set to 13.4V

* You might end up choosing to set t0C set to 14V or 14.2V if no benefit of going to 14.4V+ is observable. By benefit I mean a capacity gain due to balancing having occurred.

[rowiebowie]

Winston & Marcopolo, thanks for the informative posts.

At this point, I'm not disappointed in my battery performance. But unlike the voltage in lead-acid batteries, relying on the SOC monitor makes me a little nervous if it's not reporting accurate numbers.

While my impression of Renogy tech support is not the highest (maybe a C+), I'm sure at least some of their difficulty has been due to how I phrased my questions to them.

In trying to get the best (not perfect) charging pattern for my batteries using their lithium default setting, how you put the question to them about their default b_L setting if you had them on the phone?

Same for using their b_0 programable setting?


Below is their battery spec sheet for the ones I purchased.