Renogy 12V 200Ah drop-in LiFePO4 battery

[MtB]

Ok the xiaoxiang app looks very similar to the Overkill app. Clearly related if not identical.

 

The xiaoxiang app also fails to detect the BMS in the Renogy battery however. 

 

Given the lengths Renogy have gone to dumb down their proprietary app though, I would not be surprised to find they have disabled the BMS from connecting to any app not their own.

 

[MtB]

2 hours ago, nicknorman said:

Firmware version V0100. Otherwise known as V1. Is there a firmware update available?

 

I'm never quite sure what firmware is! 

 

I'll have a poke about on the Renogy support pages but given the sketchiness and dumbed-down nature of most of their documentation, I'm doubtful I'll find anything. 

 

 

[cheesegas]

Just now, MtB said:

Ok the xiaoxiang app looks very similar to the Overkill app. Clearly related if not identical.

 

The xiaoxiang app also fails to detect the BMS in the Renogy battery however. 

 

Given the lengths Renogy have gone to dumb down their proprietary app though, I would not be surprised to find they have disabled the BMS from connecting to any app not their own.

 

Thanks for checking. Yep, the Overkill app is a recent addition as of November this year, it's simply a rebranded version of the xiaoxang app but it's also not as stable for some reason, stick with xiaoxang. Before November, Overkill BMSs would ship with a link pointing you to the xiaoxang version. Are you on Android or iOS? The app for iOS is much better and easier to use, but the Android version does still allow you to change all of the charge/discharge cutoff parameters, and view cell voltages to 3 decimal places along with balancer status.

 

As for connecting to your Renogy, also try the Daly app, called either SMART BMS or DalyBMS. There is of course a chance that the board is now proprietary to Renogy, or locked down as you say. As far as I know, there's no way to update the firmware on the JBD or Renogy BMS boards.

 

I have a JBD BMS on a DIY pack and the cell voltages are to within 2-3mv of my calibrated Fluke meter, which I'm happy with. 

[nicknorman]

4 minutes ago, MtB said:

 

I'm never quite sure what firmware is! 

 

I'll have a poke about on the Renogy support pages but given the sketchiness and dumbed-down nature of most of their documentation, I'm doubtful I'll find anything. 

 

 

Firmware is like software, only firmer.

 

Software typically runs in memory that is lost when power is removed - eg when you start you PC, programmes are loaded into memory from hard disk, and the they run from that memory. If power is turned off, the memory is wiped and you have to load it all again.

 

With firmware the programme typically runs directly from flash memory (EEPROM) and thus it is retained in the place it runs, even if the power is removed. Hence it is less soft and more firm! 

[MtB]

2 minutes ago, cheesegas said:

Thanks for checking. Yep, the Overkill app is a recent addition as of November this year, it's simply a rebranded version of the xiaoxang app but it's also not as stable for some reason, stick with xiaoxang. Before November, Overkill BMSs would ship with a link pointing you to the xiaoxang version. Are you on Android or iOS? The app for iOS is much better and easier to use, but the Android version does still allow you to change all of the charge/discharge cutoff parameters, and view cell voltages to 3 decimal places along with balancer status.

 

As for connecting to your Renogy, also try the Daly app, called either SMART BMS or DalyBMS. There is of course a chance that the board is now proprietary to Renogy, or locked down as you say. As far as I know, there's no way to update the firmware on the JBD or Renogy BMS boards.

 

I have a JBD BMS on a DIY pack and the cell voltages are to within 2-3mv of my calibrated Fluke meter, which I'm happy with. 

 

 

Thanks for all that. 

 

There is however, on searching the Renogy site, mention of firmware for two of their batteries, neither of them mine. No clue or guidance as to what to do with the 200kB download though! 

[MtB]

3 minutes ago, nicknorman said:

Firmware is like software, only firmer.

 

I get you. 

 

And going in the other direction, we end up with vapourware, yes? 

 

As in, "We are still developing the first release of our super-dooper new program".

 

Translation: "We've specced it but no-one will accept the job of writing it". 

 

Yes?

[nicknorman]

Just now, MtB said:

 

I get you. 

 

And going in the other direction, we end up with vapourware, yes? 

 

As in, "We are still developing the first release of our super-dooper new program".

 

Translation: "We've specced it but no-one will accept the job of writing it". 

 

Yes?

 

Yes. Or “we had this great idea but when we tried to make it work, it didn’t.”

[MtB]

3 minutes ago, nicknorman said:

 

Yes. Or “we had this great idea but when we tried to make it work, it didn’t.”

 

But the MD refuses to admit it...

 

 

[PeterF]

55 minutes ago, MtB said:

An intriguing assertion.

 

How can the total battery voltage ever be anything other than the sum of the individual cell voltages? 

 

55 minutes ago, MtB said:

 

1 hour ago, PeterF said:

The individual cell voltages and total cell voltage may be being measured by different sensors which have their own inaccuracies and may therefore read slightly different. The total voltage is not necessarily the mathematical sum of the 4 cell voltages.

For the avoidance of doubt I meant

 

The measured total voltage is not necessarily the mathematical sum of the 4 measured voltages because the BMS may use a different sensor for the total voltage and not just add up the 4 individual voltages. I thought this would be understood from the context.

[ditchcrawler]

5 hours ago, MtB said:

Ok the xiaoxiang app looks very similar to the Overkill app. Clearly related if not identical.

 

 

 

Mine doesn't

[MtB]

18 minutes ago, ditchcrawler said:

Mine doesn't

 

Mine does.

[Tony1]

Twere best you speak no ill of lithium batteries here, good sir.....

Bit of a long shot, but I wonder if there might a compatible windows based program for managing the cells etc? 

There might even be a Renogy or other lithium user forum where they've discussed this issue...

So am I right in thinking you're going to be experimenting with varying lengths of wire as a way of limiting the current draw from the alternator? 

It all sounds like great fun. 

[MtB]

2 hours ago, Tony1 said:

Twere best you speak no ill of lithium batteries here, good sir.....

 

It's remarkable how quickly I've got to the stage of considering sawing the top off this battery and installing an Overkill BMS.

 

 

2 hours ago, Tony1 said:

Bit of a long shot, but I wonder if there might a compatible windows based program for managing the cells etc? 

There might even be a Renogy or other lithium user forum where they've discussed this issue...

 

So you've found it too then, eh? Its a bit like facebook, but without the intellectual rigour....

 

 

 

2 hours ago, Tony1 said:

So am I right in thinking you're going to be experimenting with varying lengths of wire as a way of limiting the current draw from the alternator? 

It all sounds like great fun. 

 

 

Dunnit already. about 7m of 25mm CSA plus a cheap-as-chips isolator switch loses about half a volt and limits the charge current to about 40A. 

 

Well put it this way, it might also be the slightly slipping vee belt but one way or another, it charges at 50A-ish then subsides to about 40A-ish and the alternator is perfectly happy with that, from a not overheating perspective. 

 

So there we are, another quick and dirty was of saving the alternator delivering too much current and overheating itself. Slacken orf ya fan belt a bit!

 

All greenies gratefully accepted. 

 

Nice wine, this....

 

 

[Tony1]

4 minutes ago, MtB said:

 

It's remarkable how quickly I've got to the stage of considering sawing the top off this battery and installing an Overkill BMS.

 

 

 

I must be honest, I was thinking I would probably do this if it was the only way to get more than 1 decimal place for the voltage reading. 

Although I think a BMV 700/712 will give you a voltage to 2 DPs, for the overall battery anyway. 

 

For top balancing and all that malarkey it appears you need about 200 decimal places for each cell, but for day-to-day checking on the overall state of the battery, you only need say two DPs. 

My batteries are at 70% Soc at about 13.20 volts (resting), and at 13.10volts they are at 40%. So a lot of the real world day-to-day action happens within a single decimal place, in terms of the voltage. 

I reckon two DPs gives an acceptable view of what's happening for the day to day management. And you can check that voltage against the calculated SoC reading, and if they both agree, you can sit back with a cuppa and contemplate the joys of life after lithium. 

As you well know, these things could easily last 10 years and more, so they are worth a bit of extra investment in managing them (and not just because one might form a romantic relationship with them, as I have). For many of us they are a lifetime decision, in the sense that they will outlast us on the boat, and many of us will never again need to buy batteries.

 

 

4 minutes ago, MtB said:

Dunnit already. about 7m of 25mm CSA plus a cheap-as-chips isolator switch loses about half a volt and limits the charge current to about 40A. 

 

Well put it this way, it might also be the slightly slipping vee belt but one way or another, it charges at 50A-ish then subsides to about 40A-ish and the alternator is perfectly happy with that, from a not overheating perspective. 

 

So there we are, another quick and dirty was of saving the alternator delivering too much current and overheating itself. Slacken orf ya fan belt a bit!

 

 

Yes, it does seem a bit odd that the charging current drops. In my case the current stays the same throughout the charge, unless I'm doing a 100% charge to synchronise them (every couple of weeks), in which case it does the expected thing of the current reducing as you get over 90%, and then tailing down to maybe 10% or so when they are almost full.

 

But for me, what is more of a snag is only being able to charge at 40amps. To be fair, that is a liveaboard perspective, but I want to get a days charging done in an hour or so. 

But at 40 amps it used to take  3 hours engine running to replace my 120Ah on a winter day, and I got fed up doing that. 

 

 

[TheBiscuits]

9 hours ago, nicknorman said:

Firmware is like software, only firmer.

 

Nonsense, it's like hardware but softer!

 

 

[MtB]

7 minutes ago, TheBiscuits said:

 

Nonsense, it's like hardware but softer!

 

 

Sloppy comparison!

[Richard10002]

Will Prowse was quite impressed by Renogy a couple of years ago:

 

 

They seem to be made from proper cells now, rather than pouches?

 

4th Picture shows the internals:

 

https://uk.renogy.com/12v-200ah-lithium-iron-phosphate-battery-w-bluetooth/

 

 

[MtB]

21 minutes ago, Richard10002 said:

Will Prowse was quite impressed by Renogy a couple of years ago:

 

Interesting. 

 

Not the same battery I have though. Mine has no comms port, but Bluetooth instead. Also has that puzzling thing they call "shelf mode".

 

Shelf mode as far as I can determine, turns the BMS off when there has been no load on the battery for 24 hrs, in order to reduce the self discharge in transit and/or storage. In my hybrid system it never seems to enter shelf mode, as it is constantly delivering a tiny trickle charge into the LAs in parallel. 

 

 

Edited January 2, 2023 by MtB
Bloody spell checker interfering

[ditchcrawler]

10 minutes ago, MtB said:

Shelf mode as far as I can determine, turns the BMS off when there has been no load on the battery for 24 hrs, in order to reduce the self discharge in transit and/or storage. In my hybrid system it never seems to enter shelf mode, as it is constantly delivering a tiny trickle charge into the LAs in parallel. 

 

 

I switch mine off when I go home leaving the battery about 60% charged

 

[MtB]

Now here's a thing. A curiosity I hadn't expected and haven't thought through yet. 

 

I fitted my Renogy 200AH battery with about ten metres of cable to get the charge current down to a value that avoids the alternator overheating. It charges steadily at a comfortable 40A without overheating. All ok, yes? 

 

So with some time to spare and my other LiFePO4 battery lying about in the van (the Lifebattery 100AH drop in), I decided to disconnect the Renogy and test-run the Lifebattery 100AH. 

 

I expected the charge current to be the same 40A I was getting with the Renogy 200AH but no, the Lifebattery 100AH charges at only 28A installed on the exact same system. Is that what the team would expect? 

 

I'm not particularly concerned, just curious that my expectations were not met! I guess the smaller battery must have a higher internal resistance. The values are tiny but I'm imagining if I could measure the internal resistances of the batteries, they would have a ratio of 28:40. Or something along those lines...

 

 

 

 

 

 

[nicknorman]

1 hour ago, MtB said:

Now here's a thing. A curiosity I hadn't expected and haven't thought through yet. 

 

I fitted my Renogy 200AH battery with about ten metres of cable to get the charge current down to a value that avoids the alternator overheating. It charges steadily at a comfortable 40A without overheating. All ok, yes? 

 

So with some time to spare and my other LiFePO4 battery lying about in the van (the Lifebattery 100AH drop in), I decided to disconnect the Renogy and test-run the Lifebattery 100AH. 

 

I expected the charge current to be the same 40A I was getting with the Renogy 200AH but no, the Lifebattery 100AH charges at only 28A installed on the exact same system. Is that what the team would expect? 

 

I'm not particularly concerned, just curious that my expectations were not met! I guess the smaller battery must have a higher internal resistance. The values are tiny but I'm imagining if I could measure the internal resistances of the batteries, they would have a ratio of 28:40. Or something along those lines...

 

Yes I think that is to be expected. Higher internal resistance and slower reaction rate for the smaller battery. Bear in mind that a slight difference in voltage make a big difference to current because current only flows due to a somewhat higher charge voltage than battery resting voltage. 0.5v excess voltage pumps a big current into the batteries. So a doubling of internal resistance (even though it is very small) is bound to make a significant difference to that 0.5v.

[Tony1]

1 hour ago, MtB said:

Now here's a thing. A curiosity I hadn't expected and haven't thought through yet. 

 

I fitted my Renogy 200AH battery with about ten metres of cable to get the charge current down to a value that avoids the alternator overheating. It charges steadily at a comfortable 40A without overheating. All ok, yes? 

 

So with some time to spare and my other LiFePO4 battery lying about in the van (the Lifebattery 100AH drop in), I decided to disconnect the Renogy and test-run the Lifebattery 100AH. 

 

I expected the charge current to be the same 40A I was getting with the Renogy 200AH but no, the Lifebattery 100AH charges at only 28A installed on the exact same system. Is that what the team would expect? 

 

I'm not particularly concerned, just curious that my expectations were not met! I guess the smaller battery must have a higher internal resistance. The values are tiny but I'm imagining if I could measure the internal resistances of the batteries, they would have a ratio of 28:40. Or something along those lines...

 

 

The next bit of research is to see what length of cable will result in a charge rate of 40 amps for the 100Ah battery, maybe?

(And there is the question of how fast can the 100Ah battery be safely charged)

 

 

[MtB]

17 minutes ago, nicknorman said:

Yes I think that is to be expected. Higher internal resistance and slower reaction rate for the smaller battery. Bear in mind that a slight difference in voltage make a big difference to current because current only flows due to a somewhat higher charge voltage than battery resting voltage. 0.5v excess voltage pumps a big current into the batteries. So a doubling of internal resistance (even though it is very small) is bound to make a significant difference to that 0.5v.

 

Pretty much what I decided too after thinking about it for a bit. People often make (what I see as) the mistake of thinking their batts charge at 14.4V, 14.8V or whatever when the potential driving the charge current is 14.4V minus the battery resting terminal voltage. I think this is another reason the charge current on a LA batt subsides substantially in the first five or ten mins of charging. DMR reckons its the winding getting hot in the alternator and increasing in resistance, but I reckon part of the reason is the rising terminal voltage of the batt as it takes up some charge, thus reducing the effective charge voltage. 

[rusty69]

11 minutes ago, MtB said:

 

Pretty much what I decided too after thinking about it for a bit. People often make (what I see as) the mistake of thinking their batts charge at 14.4V, 14.8V or whatever when the potential driving the charge current is 14.4V minus the battery resting terminal voltage. I think this is another reason the charge current on a LA batt subsides substantially in the first five or ten mins of charging. DMR reckons its the winding getting hot in the alternator and increasing in resistance, but I reckon part of the reason is the rising terminal voltage of the batt as it takes up some charge, thus reducing the effective charge voltage. 

Stupid question alert....... Why not charge at the maximum voltage Lithiums will accept then?

 

ETA. I can partially answer my own question in terms of the voltage applied to the boat services.

Edited January 9, 2023 by rusty69

[MtB]

5 minutes ago, rusty69 said:

Stupid question alert....... Why not charge at the maximum voltage Lithiums will accept then?

 

Because automotive alternators are not rated to run continuously at full rated output. They overheat....