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Epoch 12V/460Ah IP67 after two months. Balancing: Oof!

Koyaanisqatsi

Electron addict
Joined
Sep 7, 2024
Messages
399
Location
San Luis Obispo county, CA
I've got one of these 12V/460Ah IP67 batteries from Epoch. Had it about two months or so. Here are my thoughts about these units...

TL;DR: I LIKE the battery. I don't LOVE it. It will work for my needs. But I have to put WAY too much time into getting it settled into the system and to stop throwing BMS alerts during normal charging. And there are a few too many things that I can't fix or even read myself (without the password to the app to change BMS settings).

1. BMS needs to be programmed differently.
1a. It shuts off the charging FETs at 14.0V if charge current is under 3-5A (not sure the exact value, but it's a lot higher than it should be), with a Full Charge alert, which is a big pain in the butt because it throws all my other devices into a tizzy fit and surges the DC bus voltage, which could legitimately kill some things in my trailer, not the least of which is my fridge that throws an over voltage alert at 15V. 14.0V is a terrible threshold value for anything that charges up to 14.6V. My solar charges at 10A MAX. Most of the time, I am charging below 3A.
1b. It really needs to sense current down to around 0.1-0.25A. The low limit for current sense is ~1.2, which is just too low for anything but a heavy load case! Big batteries are not always used for high-loads. Just like compact cars are not just for short people.
1c. SLOW BALANCING!! Holy crap, put something more than a 50-150mA balancer on 460Ah cells! What the heck were your engineers thinking!?! (or was this a financial decision) The balancer should be 1-5 AMPS on this thing. After 8 hours of floating at 13.9V, the cells get closer by MAYBE 5-10mV. It's taken more than 100 hours of holding the voltage at an unhealthy high level to get the balance closer, but it's still more than 50mV out of balance as I type this.
1d. Too wide of a voltage allowance in the balancer. It's 30mV. Should be more like 5 or 10mV.

2. For love of all that is good, START WITH BALANCED CELLS!! or at least cells that are not egregiously out of balance!
2a. I started off with more than 165mV difference between low and hi cells. This prevented me from fully charging the battery for a while. Could only charge to 13.8V without tripping on cell OVP for the first few charges. First screen cap is from after I had already cycled a couple times.

3. The app looks pretty and is good to view info. But what about actually accessing that info outside of the app, for use within monitoring and control systems? The only info I can get over MODBUS is min and max cell voltage and temp. But the app shows all voltages and more temperatures. Everything in the app should be available over MODBUS.
3a. Specifically missing are:
3a1. Voltages for all cells.
3a2. All temperature values.
3a3. Whether balancing is active.
3a4. Whether charge or discharge FETs are active or disabled.
3b. Labels and terminology: "VOL" is for VOLUME, not VOLTAGE. Labels should be "Vavg", Vdiff", "Vlo", and "Vhi", or if you want to be less technical: "Avg Cell V", "Avg Diff V", "Low Cell V", "High Cell V", not these meaningless VOLDIFF, VOLLOW, etc. Stop using ALL CAPS. And the shortened acronym, for MOSFET is FET, not MOS. They are Field Effect Transistors. And there are multiple types, most of which are MOS. You don't call orange juice "orange". You call it "juice".
3c. Measurements should be displayed at the same precision that they are used. The four icons and values should show three decimals, not one. Can you imagine charging a Li cell based on one decimal of precision? You'd have fire.
3d. Let me rename the battery, so that it's not lost in the sea of BT devices near me. AND FILTER OUT NON-EPOCH DEVICES FROM THE LIST.
3e. If it looks like a switch, and you can touch it to turn if off/on, then KEEP THE STATE. The little charge and discharge switches can be switched, but just return to their original state. If I can't change them, don't display them as changeable. OR honor my input and do what I am telling it to do. One or the other, please.

4. Last but not least: Included accessories. I did not get the set of DC cables nor the mounting brackets that are shown in the YT videos. Would have been really helpful to get at least the brackets. Now I have a 100lb battery sliding around in my trailer with no way to secure it. Yes, the site indicates these things are optional. But the mounting brackets?!? Come on.


165mV!?! This should be considered a defective battery on that stat alone. The low cell is so low that it's near the bottom of the neck voltage range and needs a LOT of charge to catch up.
Total battery voltage: 13.97V.
Screenshot_20241006_210040.jpg

After well over 100 continuous hours of floating at 13.9V, in order to force balancing, I'm still almost 60mV off balance. (note the red highlight on the high cell. That indicates the balancing circuit is active on that cell. It runs for a few minutes at a time, and shuts off for a moment, and starts again).
Total battery voltage: 13.952V
Screenshot_20241118_152354.jpg

EDIT: MODBUS, not CANbus.
EDIT 2: Battery voltage, not total cell voltage.
 
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Hey, what charge controller are you using?
I have two chargers:
1. Victron 100|30 solar charge controller
2. Victron 12|25 AC charger.

Both are now set to 13.96V to keep pushing that balancing circuit until I'm fully balanced.

Once I've done what I can below 14.0V and 3-5A, I'm going to set my AC charger to 14.2V with a 5A tail current and see how it behaves. If that's all good, I'll step up again to 14.4V. I'm hoping it will charge over 14.0V and cut off, but keep running the balancing. Ultimately, I want to charge at 14.4-14.5V whcih is still below the voltage indicated in the instruction manual. I can't charge to 14.6V unless the cells are PERFECTLY balanced, because 14.6V / 4 cells is 3.65V/cell. I don't want over voltage on any cell. And I want to be sure I will get proper balancing once I'm charging properly. And for these batts, "proper" is 14.6V and 5A minimum tail current, per the instructions, though I'll stay at maybe 14.4V.
 
From what I hear, the solution is to open the lid using a heat gun/paint scraper and balance cells manually with something like an balancer like a heltec or neey and then close the lid and using duct tape to keep the lid closed.
 
I think EPOCH are using JBD BMSs for most of thier Bluetooth enabled batteries.

So if you need/want to change parameters, try using the Overkill solar app.
 
I have two chargers:
1. Victron 100|30 solar charge controller
2. Victron 12|25 AC charger.

Both are now set to 13.96V to keep pushing that balancing circuit until I'm fully balanced.

Once I've done what I can below 14.0V and 3-5A, I'm going to set my AC charger to 14.2V with a 5A tail current and see how it behaves. If that's all good, I'll step up again to 14.4V. I'm hoping it will charge over 14.0V and cut off, but keep running the balancing. Ultimately, I want to charge at 14.4-14.5V whcih is still below the voltage indicated in the instruction manual. I can't charge to 14.6V unless the cells are PERFECTLY balanced, because 14.6V / 4 cells is 3.65V/cell. I don't want over voltage on any cell. And I want to be sure I will get proper balancing once I'm charging properly. And for these batts, "proper" is 14.6V and 5A minimum tail current, per the instructions, though I'll stay at maybe 14.4V.
Are you still working on getting the battery balanced? I have been playing with a powerurus battery that is also made by Roypow who also makes the epoch batteries, they also make the bms and I have some insight into at least how the powerurus one works and might be similar for the epoch but wasn't sure where you stood with your battery.
 
Are you still working on getting the battery balanced? I have been playing with a powerurus battery that is also made by Roypow who also makes the epoch batteries, they also make the bms and I have some insight into at least how the powerurus one works and might be similar for the epoch but wasn't sure where you stood with your battery.
I got them balanced to within 30mV (apparently the balance circuit threshold) at 13.97V after about 125 hours of holding at that voltage. After that, I charged and held at 14.2V without any cell going over-voltage, and that caused some more balancing to occur. Then tried a couple more times and got to 14.45V safely, each time the increased charge voltage causing more balancing. Over the last couple weeks, I left the solar charger on at 13.97V with about 1.25A idle load and full charge from solar each day. I hadn't looked at the cell info since my 14+V charge tests a couple weeks ago. I'll need to check them again at the next full charge.

So, what I think I'm going to do for the long-term is (this is in my RV):

In storage:
Solar charger off until 20% SoC, then on until voltage reaches 13.97V (3.47V/cell) for 4 hours, and then off again. This cycle takes 3-4 weeks to repeat @ 1.25A idle load and 300W PV panel on 460Ah battery. And I'm hoping 4h is long enough to keep the cells well-balanced.
AC charger mostly stays off, but scheduled once every three months to charge and hold at 14.45V (3.61V/cell) for 5 hours, then shut off. I'm hoping the balance doesn't drift enough to cause a cell over-voltage at 14.45V. This is just to trim the balance a bit more than what I'm getting at 13.97V. It will also turn on if the battery drops below 10% SoC.

In use:
Solar charger always on at 13.97V
AC charger may or not be used, depending on where we are staying and if I feel like tinkering with it, but is still set to 14.45V for 5h.
 
I got them balanced to within 30mV (apparently the balance circuit threshold) at 13.97V after about 125 hours of holding at that voltage. After that, I charged and held at 14.2V without any cell going over-voltage, and that caused some more balancing to occur. Then tried a couple more times and got to 14.45V safely, each time the increased charge voltage causing more balancing. Over the last couple weeks, I left the solar charger on at 13.97V with about 1.25A idle load and full charge from solar each day. I hadn't looked at the cell info since my 14+V charge tests a couple weeks ago. I'll need to check them again at the next full charge.

So, what I think I'm going to do for the long-term is (this is in my RV):

In storage:
Solar charger off until 20% SoC, then on until voltage reaches 13.97V (3.47V/cell) for 4 hours, and then off again. This cycle takes 3-4 weeks to repeat @ 1.25A idle load and 300W PV panel on 460Ah battery. And I'm hoping 4h is long enough to keep the cells well-balanced.
AC charger mostly stays off, but scheduled once every three months to charge and hold at 14.45V (3.61V/cell) for 5 hours, then shut off. I'm hoping the balance doesn't drift enough to cause a cell over-voltage at 14.45V. This is just to trim the balance a bit more than what I'm getting at 13.97V. It will also turn on if the battery drops below 10% SoC.

In use:
Solar charger always on at 13.97V
AC charger may or not be used, depending on where we are staying and if I feel like tinkering with it, but is still set to 14.45V for 5h.
Sorry for the late reply, having to dig out from the snow storm, ugh. I am about to post my findings when trying to balance out some powerurus batteries (100ah variety). I know you have epoch battery and the BMS may be different but both batteries and BMS are made by Roypow. The epoch app or RoyPow app will connect to the BMS. Here is what I have found in my loooong ordeal trying to get a new battery to balance out - https://diysolarforum.com/threads/charging-question-new-battery.94653/

Here is what we found after the long process as to how the bms behaves some of which you also have discovered:
bms cut off charging - One cell hits 3.6x volts (I believe it is 3.65v but I know its over 3.6v) OR average voltage hits 3.5v
Balance discharge only starts with a delta voltage of .030v
Balancing will only work when current is higher than .3a, at .3a the balancing comes on and off, at .4a it stays on as long as the voltage difference is greater than .030 ( I used .4a to balance the cells out)
Balancing appears to start in the 3.36v range and maybe sooner as long as the delta voltage is met, I saw it kick in at 3.36v and upwards

This is what we found, again this is for a Powerurus 100ah battery but my guess the bms are probably pretty similar but I have never tested an epoch but thought this may help. What @sunshine_eggo came up with was to charge at .4a up to 13.98 or as high as you can without triggering the bms cutoff and then apply a load to bring it down to just below where the bms would kick on to start balancing, rinse and repeat once it hits it target keep doing this and the cells will slowly balance out. For my 100ah hour took me about a a day of repeating to get things in line. The initial times the balancing kicks in quickly and you can pull your battery down further, once things get closer it becomes a shorter duration, once you get close to your .030v delta voltage you are done since it will not balance below that. The other thing to note is if you do not have a bench power supply or something that allows you to set the amps and voltage it will be near impossible to get one of the batteries to balance out.

Just thought I would pass along...:)
 
That's all pretty much in line with what I experienced as well. There are only a few minor diffs:
1. My BMS reports full charge instead of cell OV if the voltage is above 14.0V and a cell goes too high. It cuts off the charge FETs. But I still hold the charge voltage that high, to prevent any discharge current. As soon as it discharges even a tiny amount, balancing stops. I've had many times when the charge voltage is say 14.4V, but the FETs are off and the battery voltage slowly fades to about 13.6-13.8V as it balances cells and the cell voltages settle.
2. Full charge cutoff (FETs off) is also at anything above 14.0V and less than 3.5A (I originally was guessing between 3 and 5A). But I can charge to 13.97V at any current and float there indefinitely.
3. I'll have to look again, but I think our balancing circuit thresholds are the same +/- accuracy. But what I didn't see is whether all cells had to be above 3.4V or just the cells that are high. I want to say that any cell above 3.4V and higher than 30mV above the lowest cell will start to balance, even if other cells are not above 3.4V. But I need to confirm that.
4. The advice from @sunshine_eggo is basically what I have been doing, except I hold the voltage high and I don't let the battery discharge at all, if I can help it. The Epoch BMS stops balancing as soon as any discharge current is detected.

My Victron 12|25 AC charger is great for balancing. I have all output voltages set to the same value. I also control the AC charger with a smart outlet and control that in Home Assistant. So I can charge and hold at a voltage for some time for balancing, then just shut off the charger. I don't like shifting from absorption to a lower float voltage, because that causes the charger to discharge the battery down to the float voltage, which kills balancing activity.
 
4. The advice from @sunshine_eggo is basically what I have been doing, except I hold the voltage high and I don't let the battery discharge at all, if I can help it. The Epoch BMS stops balancing as soon as any discharge current is detected.

This was the first thing attempted - hold at 13.8V for 24 hours on the charger. This battery would NOT balance at all unless at least 0.4A of charging current was into the battery. It clearly has the "only balance while charging" option active.
 
This was the first thing attempted - hold at 13.8V for 24 hours on the charger. This battery would NOT balance at all unless at least 0.4A of charging current was into the battery. It clearly has the "only balance while charging" option active.

And it took like 7-8 pages to figure this out... :(

Shout out ot @bishoptf for his intestinal fortitude and willingness to flog something until the bitter end.
 
And it took like 7-8 pages to figure this out... :(

Shout out ot @bishoptf for his intestinal fortitude and willingness to flog something until the bitter end.
Eh I'm an old engineer and like to try to figure things out. This probably is not an issue with the bigger 460ah battery but for the 100ah battery you really have to slow the charge rate down or it will just never balance out. The key was being able to slow it down, most lifepo4 chargers are at much higher rates. At least for the 100ah powerurus batteries they will never balance at those higher rates, well I guess it might but it would take a LOT of cycles.
 
Eh I'm an old engineer and like to try to figure things out.

We have this in common. Thank goodness. One of us would have pissed the other off at some point :)

This probably is not an issue with the bigger 460ah battery but for the 100ah battery you really have to slow the charge rate down or it will just never balance out. The key was being able to slow it down, most lifepo4 chargers are at much higher rates. At least for the 100ah powerurus batteries they will never balance at those higher rates, well I guess it might but it would take a LOT of cycles.

Yep. Normal use cycling would probably get it there... in like a year or two, and I do recall seeing balancing happening at lower than 3.40V. Not necessarily good, but might take a small portion of the sting out of "balancing only when charging" by allowing more balancing time per cycle.
 
That's all pretty much in line with what I experienced as well. There are only a few minor diffs:
1. My BMS reports full charge instead of cell OV if the voltage is above 14.0V and a cell goes too high. It cuts off the charge FETs. But I still hold the charge voltage that high, to prevent any discharge current. As soon as it discharges even a tiny amount, balancing stops. I've had many times when the charge voltage is say 14.4V, but the FETs are off and the battery voltage slowly fades to about 13.6-13.8V as it balances cells and the cell voltages settle.
2. Full charge cutoff (FETs off) is also at anything above 14.0V and less than 3.5A (I originally was guessing between 3 and 5A). But I can charge to 13.97V at any current and float there indefinitely.
3. I'll have to look again, but I think our balancing circuit thresholds are the same +/- accuracy. But what I didn't see is whether all cells had to be above 3.4V or just the cells that are high. I want to say that any cell above 3.4V and higher than 30mV above the lowest cell will start to balance, even if other cells are not above 3.4V. But I need to confirm that.
4. The advice from @sunshine_eggo is basically what I have been doing, except I hold the voltage high and I don't let the battery discharge at all, if I can help it. The Epoch BMS stops balancing as soon as any discharge current is detected.

My Victron 12|25 AC charger is great for balancing. I have all output voltages set to the same value. I also control the AC charger with a smart outlet and control that in Home Assistant. So I can charge and hold at a voltage for some time for balancing, then just shut off the charger. I don't like shifting from absorption to a lower float voltage, because that causes the charger to discharge the battery down to the float voltage, which kills balancing activity.
Just got the new 460ah last week, there's a firmware update from epoch. Been charging to 14.2v without any issues. Might contact them to see if you can update yours?
 
You used the password method?
Yes. But in all transparency, the first thing I did was open the app and try to update the BMS firmware, which SHOULD BE THE RIGHT process. But no. They made it so that it can be done incorrectly and you wouldn't have any idea until you go looking for help.

So, I'm stuck until I have the patience to go ask Epoch for assistance.

I hate systems that allow the user to screw up something as important as a firmware update. The app should have been set up to do the whole process completely without the user having to know anything.

At least my battery still works, as far as I can tell.

EDIT: I need to mellow out...
 
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Yes. But in all transparency, the first thing I did was open the app and try to update the BMS firmware, which SHOULD BE THE RIGHT process. But no. They made it so that it can be done incorrectly and you wouldn't have any idea until you go looking for help.

So, I'm stuck until I have the patience to go ask Epoch for assistance.

I HATE SYSTEMS THAT ALLOW THE USER TO SCREW IT UP, when it's just something so simple as a firmware update. The app should have been set up to do the whole process completely without the user having to know anything.

At least my battery still works, as far as I can tell.
I initially did it without the password method and it failed, found the password method afterwards and I think it worked. I asked epoch if there's a way to check your firmware version to confirm it updated and no response 😔

@Epoch Support
 
I'm going to have to contact Epoch support. I tried again last night and the app just freezes and doesn't ever progress to installing the new firmware. Whether I choose the EMS or BMS it does the same thing.
If you get ahold of them ask if there's a way to check which fw version is currently installed?
Do you have the meter hooked up?
 
If you get ahold of them ask if there's a way to check which fw version is currently installed?
Do you have the meter hooked up?
I hooked up the meter last night and tried again without success. But since it was dark, I couldn't drop the 12 volt power system to properly restart my battery. Once the sun is high enough in the sky today I'm going to disconnect everything and let the battery reboot. And then follow the instructions a lot more carefully than I have so far.
 
I hooked up the meter last night and tried again without success. But since it was dark, I couldn't drop the 12 volt power system to properly restart my battery. Once the sun is high enough in the sky today I'm going to disconnect everything and let the battery reboot. And then follow the instructions a lot more carefully than I have so far.
Ah OK, yeah the steps are overly complex.
 
I'm going to have to contact Epoch support. I tried again last night and the app just freezes and doesn't ever progress to installing the new firmware. Whether I choose the EMS or BMS it does the same thing.

Do you have the new V2 Elite or V1 Epoch 460's? The new V2's just started shipping last week and have over the air firmware updates for the BMS. The V1's don't have this capability.





Screenshot 2025-01-24 at 8.43.47 PM.png
 
Well, looks like I'm one of the lucky contestants who gets a Windows tablet with special software shipped to me in order to clean up my battery firmware.

I conveyed to him that this should have been a button in the app that just does everything for us and does not allow any kind of room for user error. He agreed, and informed me that is what he told his superiors as well. I told him to forward my comments and contact info, and I'll happily explain the situation to them. I also complained about the balancing circuit only balancing to within 30mV instead of 5 or 10mV, and that the cells were more than 160mV out of balance new, and I had to spend more than 100 hours balancing it initially.

I'm hoping to gain some back-end knowledge about this battery, so I can adjust it to my needs. But if the stupid issue with the battery cutting off at 14.0V is resolved, as I understand it to be in this firmware update, I'll be pretty happy with Epoch and this battery, finally.
 

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