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6ixgun avatar image
6ixgun asked

IP22 / LifePo4 Compatibility question

I am using a IP22 Smart charger and so far, it does a great job of charging LifePO4 batteries after getting all the settings right. Here is what is happening when I don't want it to charge :

1>. Battery is stored @ 65% SOC , no charging during storage (RV storage facility)

2>. Nominal House Current is 1A, due to security cameras, BMS & LTE modem

3>. If I leave battery connected and charger not on the battery drains as expected

4>. If I leave the battery connected and charger on power supply mode, with voltage @ 12.8V, battery seems to be fighting the charger (i.e. battery BMS shows battery is absorbing current).

5>. If I disconnect the battery and leave power supply mode on , all is good but then prior to charging I have to manually switch the battery back in. This also throws off my PICO SOC.

6>. If I leave the battery in the circuit with the charger enabled the charger charges the battery to 100% and maintains it - DONT want that !

So the question is this - is there a way to leave the charger engaged WITHOUT the charger topping off the battery -OR- leaving the power supply mode on without the battery fighting it ? I want to leave the base van systems on AND the battery in the circuit WITHOUT damaging either the battery / BMS or the charger !


If I leave the battery in the circuit and the charger in power supply mode - will the battery voltage eventually equalize with the charger or will it just continue to fight with it ? If they equalize - should I set the output voltage of the IP22 to closer match the current state voltage of the LifePo4 ? (i.e. 13.2 instead of 12.8) ? I believe what is happening is the higher voltage (battery) is trying to "charge" the lower voltage (power supply). I did play with the outputs - when I bumped the voltage up it started charging the battery by a couple of Amps.


Bottom line - I want to be able to fully remote manage these setups - as of now I have to be present to manually flip the battery switch and change from power supply more to charger mode to charge before trips - its a waste of time - I would rather just go into the victron settings and turn the charger on remotely via my phone app and a remote control app.

Ideas ?


ip22
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4 Answers
Alexandra avatar image
Alexandra answered ·

@6ixgun

Your RV is in storage, but your battery is providing for loads - so technically not in storage. Storage suggests it is being placed a cupboard with nothing connected.

You can alter the charge profile to include a storage mode. Or bring the charge voltages down, but the battery will not balance and you will end up with issues.

So you either need to store the battery (out of circuit) or have it go up and down through different SOCs. It is easy enough by setting the DC off set (where it triggers another charge cycle) much lower so it does not keep the battery charge but rather cycles it then charges it back up again.)

So create a different charge profile for your storage setup.

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6ixgun avatar image
6ixgun answered ·

Currently there is nothing connected , however yes, I want to be able to leave the supply connected and not have to manually disconnect every time I store the vehicle. I know all those settings can be played with - I just don't have a clue how and don't want to start without knowledge of how they work. Is there *any* detailed documentation anywhere on those functions ? The manual is more or less not of any help.... thanks for the reply !


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Alexandra avatar image Alexandra ♦ commented ·

There are a couple of resources.

How to create a custom profile.

You can even do it in demo mode on your phone so you can experiment without making changes to the device.

It is pretty much the same as on an mppt or any other victron device.

Or you can just check the storage setting and ket the algorithm sort it out.

Storage on the IP22 allows the battery go down to a lower voltage and does not charge it up all the time.

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6ixgun avatar image 6ixgun Alexandra ♦ commented ·

@Alexandra - not trying to bash the products , we use a lot of them, but I am absolutely amazed at how fragmented and inconsistent the settings are across individual products. It truly makes setting these systems up to play together a total nightmare. I also cannot figure out why does Victron insist on carrying over all the lead acid settings to LifePo4 ? At the very least every one of these products should be able to disable / hide those options - period. Anyway, some major firmware work needed on that end, for sure. Until then, even for us engineers, getting this stuff straight is a constant battle. I cannot imagine anyone who is not an experienced installer being able to get any of this straight, it is VERY confusing due to this inconsistency.


The above aside - taking into account your information and that supplied by my battery manufacturer AND the differences between the various victron products does this look reasonable ?


None of these chargers have the ability to disable float - some have a storage voltage option some don't, (again - super wonky) so I set them up as follows and hope for the best ....

1> Absorption Voltage 14.6 (recommended by mfr,I will prob reduce this to 14.4 after a few cycles.
2> Storage Voltage (IP22) & Float 13.2 (all) - basically disabled

3> Absorption time limit - 30 min / 100 AH (1 hr for my 200AH batt) for cell balance only. I will probably set this to zero after a few cycles and run this only on occasion to rebalance.

4> Rebulk voltage offset .5 (do not really know what a good setting is here) I would rather this be based on SOC via input from Smart Shunt.

5> Tail Current - disabled

6> Equalization - disabled

7> Temp Comp- disabled


ALL other settings I left as is or ignored.

LifePo4 charging should do nothing more than charge to desired SOC, then do nothing until we want it charged again. We do not want the bank maintained at 100% SOC full time, in fact, that is a bad practice even on the road. That said, we DO want the chargers kicking in when the SOC drops below a set point.

Figuring out how to do that has been a major challenge and it should not be. Unfortunately, the chargers more or less still act like lead acid chargers.


What <should> happen in LifePo4 mode is this :

1> Charge to set absorption voltage, in this case, 14.6V

2> Hold @ X minutes or hours based on setting for cell balance

3> Shut charger off and maintain a nominal bus voltage to prevent discharge (i.e. switch to power supply mode ) ( I believe this already happens)

4> Charger remains off until battery drops below specified SOC (i.e. using inputs from Victron Smart Shunt) - user defined. The Rebulk setting may be able to acommodate this as well, but not sure what value to use as stated above and I am sure it varies by battery / BMS / etc.


THAT would be golden and make setup of these systems SO much easier and LifePO4 batteries would last a lot longer.


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6ixgun avatar image 6ixgun Alexandra ♦ commented ·
Awesome, thank you !!
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6ixgun avatar image
6ixgun answered ·

Thanks.. Yes I agree they are very flexible - part of the main reason we use them - just wish they were consistent across models (like Orion having V.E. Network, or all chargers having the same options like the IP chargers do, etc.). I can wish I guess... I did not realize you had a site for us - I now found the videos you were referring to - awesome. I did not know these existed, I am sure they will be a big help.

Again - thank you for the replies, they have been a BIG help ! Cheers !

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6ixgun avatar image
6ixgun answered ·

@Alexandra One last question - sorry this is "kind of" a newbie question , but I am still learning these systems. When the LifePo4 battery has achieved full charge (or whatever charge state we define) what happens then ? In the case of an IP22, MPPT or Orion charger - do these chargers continue to supply current to the bus to power the system as long as their input has power (i.e. plugged into the mains, sun is out , engine running, etc) or does the charger shut off completely and now the battery supplies all the power until the SOC drops to the point where Bulk Charge kicks in again ?

I would "assume" whatever we are setting the float voltage or storage voltage to IS what is applied to the system bus and that is what is maintaining the power - and as soon as those sources disappear (i.e. sun goes down, engine stops running, or IP22 is unplugged) the battery takes over.

Its important to understand these cycles as they have a direct effect on battery life. Ideally, the chargers continue to provide power and the battery is not engaged as long as the source is available, and when the source is removed the battery takes over. If you can confirm that would be very helpful !

I have not been able to find any description or video on this..


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