Help with Victron Lithium Install

[Troutboy]

Quick question for Victron battery owners: what is the voltage when your batteries are fully charged? I remember mine being 13.9V. After this episode I am only getting 13.54V.

I wonder if this equates to lost capacity.

[pdavitt]

Originally Posted by Troutboy

Quick question for Victron battery owners: what is the voltage when your batteries are fully charged? I remember mine being 13.9V. After this episode I am only getting 13.54V.

I wonder if this equates to lost capacity.

I would track 5-10 more charge/discharge cycles. It may take them awhile to recover from a traumatic experience. Or not.


Pat

[wulfraat]

Originally Posted by Troutboy

Quick question for Victron battery owners: what is the voltage when your batteries are fully charged? I remember mine being 13.9V. After this episode I am only getting 13.54V.

I wonder if this equates to lost capacity.

I just checked on some data on VRM portal for my 300ah batts - 13.54v per battery (3.385v/cell) is spot on for 100% SOC with no load! That is a good voltage!

You should be floating at 13.5v / charge at 14.2v.

Do you have the smart batteries with bluetooth built-in? If so you can connect via the victron connect app and see individual cell voltages. Would be good to verify that your cells are balanced.

Those victron Prismatic cells are rugged SOBs!

[gypsydad]

Keep us posted...glad things looking up...Hope you get a mechanical disconnect switch going forward..those are pretty expensive Li's; no??

[lsbrodsky]

Yes, 13.54
Larry

[wulfraat]

Originally Posted by gypsydad

Keep us posted...glad things looking up...Hope you get a mechanical disconnect switch going forward..those are pretty expensive Li's; no??

Troutboy has got all the correct disconnects in place - well thought out install. This was a situation where batts where connected to the system and floating/charging while on shore power, but shore power failed while the unit was unattended, causing batts to supply load until they ran down, and were then automatically disconnected by the BMS based on low voltage to protect from damage.

The victron multiplus does not act like an old school converter, so you need batts connected to the system for 12v gear even when on shore power

[uncle_bob]

Originally Posted by wulfraat

Troutboy has got all the correct disconnects in place - well thought out install. This was a situation where batts where connected to the system and floating/charging while on shore power, but shore power failed while the unit was unattended, causing batts to supply load until they ran down, and were then automatically disconnected by the BMS based on low voltage to protect from damage.

The victron multiplus does not act like an old school converter, so you need batts connected to the system for 12v gear even when on shore power

Hi

Victron really does not have a good way to fully auto disconnect the multi from their batteries .....

Bob

[wulfraat]

Originally Posted by uncle_bob

Hi



Victron really does not have a good way to fully auto disconnect the multi from their batteries .....



Bob

Not sure I follow. In a victron system you install victron battery protect cutoffs for your various charging sources / load draws and they are triggered to disconnect the designated circuit by the BMS / AMS 4.2 for over/under voltage and temperature conditions. This includes disconnect of the multi if you wire it as such.

https://www.victronenergy.com/batter...attery-protect

[Troutboy]

Here is a final description of my issue and the solution in case anyone has the same issue. Thanks to all of you that replied and tried to offer help or advice. Happy to answer any other questions….

Issue:

Battery cutoff was on, as batteries were charging
Inverter was on and cutoff was on
Was in maintenance mode, floating charge to maintain.
Color Control CGX and Propane Monitor are on the battery and will drain when battery cutoff is on position.

I lost power to the garage outlet and did not know it.
I was not paying attention to the unit for a VERY long time (over a month), working on other stuff and it was winter (I was not checking on it like i did when it was stored elsewhere)

With the power failing and off, the battery drained down from inverter being on as well as parasitic loads. When I found it it had a voltage of 5.4V.

When I contacted AM Solar they were AWESOME in supporting and helping me, I highly recommend them. Their service was great and my purchase was over 2 years ago and they still were offering support. I asked about the protection of the BMS and what happens, and this was their response:

“The Batteries ability to protect itself only has a couple day's of reserve once the system has been cut out from low SOC. The intention is that if the battery hits its low voltage cutout value then it gets connected to a charging source asap. With the CCGX connected to the battery and no charger, the CCGX drained the battery down to the cutout point within a few weeks most likely. At that point if the system doesn't get charged up then the battery will drop below the safe voltage/functional voltage. This is the state you found it in where you couldn't get it reactivated.”

Other advice/info they gave me that might be helpful to others on the Victron systems:

“When put in storage you need to ensure the master switch is turned off. This will prevent the batteries from draining. It's ideal for the battery to be stored at 80%”

I asked how the BMS works and if it protects the batteries:

“The BMS shuts off the batteries based on the lowest voltage cell in the pack. Once any one cell drops below the cutoff voltage the whole system shuts down. This typically happens around or just below 0%. The 20% value you are referring to might be the low SOC relay which is set to 20% for the Time To Go function of the BMV-712. This feature tells you how long you can run your system at a continuous averaged current over the last 3 minutes. We recommend you avoid discharging the battery below 20% but the BMS is only there to protect the batteries if needed not to act as a shut off switch. If the BMS has shut down due to low voltage then it must be reactivated asap.”

The fix:

When I found it in the deactivated state, I could not get the inverter or solar charger to fire up and charge the battery. So I shut off battery cutoff and the inverter cutoff, so both were now in the off position. The battery voltage slowly rose (recovered a bit), once all of the loads where removed back up to around 6.5V (took 1.5 days). This must have been enough to reactivate the BMS, because I then turned on the inverter switch, and then the battery switch to on, and the system fired up and recharged the battery.

Had that not worked they told me to get a trickle charger and slowly charge the battery up using super low AMPS. They said It’s ideal if the charging current is 2 amps per 100 Ah of battery. No more and to take it to 12V, then turn on the system and charge as normal. I was waiting for the trickle charger to arrive today, and just happened to check the volts and tried to fire it up…., and it worked, otherwise I would have used the rifle charger…

They also said with some of the new systems there are other ways to reactivate the system through the BMS, but I didn’t ask since I didn’t have it.

Hope this helps others.

Thanks for everyones suggestions and help…… If you have questions or want more clarification, let me know.

[wulfraat]

Thanks for the details Rich. Super glad the cells all recovered. I think it sais a lot about Victron lithium prismatic cells, where they source them and “you get what you pay for”.

PS on AM solar - they are no doubt the experts in North America and have a customer service philosophy that’s impressive. I posted an odd engineering question on the victron forum a while back... within a day or so my mobile phone rang for OR and it was AM Solar’s head lithium engineer - and we had a great technical dialog around my question on the victron forum. Good people up there in the PNW.

PPS - are you going to adjust your wiring topology as a result?

[lsbrodsky]

Thanks Rich! I hoped the Victron system was durable and your situation demonstrated that. I store outside so my solar keeps everything charged, but I did wonder whether I should open the switches when I left it with the dealer for a water tank replacement last winter. I concluded that they would not take up valuable indoors space long enough to cause trouble as my only drain is the propane detector, I never went for the color display. Glad it worked out!
Larry

[uncle_bob]

Originally Posted by wulfraat

Not sure I follow. In a victron system you install victron battery protect cutoffs for your various charging sources / load draws and they are triggered to disconnect the designated circuit by the BMS / AMS 4.2 for over/under voltage and temperature conditions. This includes disconnect of the multi if you wire it as such.

https://www.victronenergy.com/batter...attery-protect

Hi

Yup, that's pretty much what *everybody* though you should do with the setup. I include myself in the "everybody". There also are a bunch of dealers and installers in various countries in the group.

Well, Victron Engineering came out with a pronouncement that "if you do this you will create a fire hazard. DO NOT DO THIS." (that's as close as I can get to a direct quote from memory). Needless to say, there has been a bit of pushback. They have stood firm.

The BP is a "single direction" device. You can only have current sourced from one side of the device. Run current both ways (as you do with a multi) and somehow someway the world will end.

So it's *not* really a battery protect (like the name says). It's a *load* protect. That's as close as I can get to figuring it out.

I now have a couple of BP-220's sitting on the shelf back at home and the Blue Sea 7700's in their place. Fortunately PKYS had the 7700's in stock when I came across the "information".

https://community.victronenergy.com/...#comment-15343

Bob

[wulfraat]

Bob - as always you bring great insights. I do now remember that the BP is uni-directional and I do not have one on my Multiplus, just a mechanical switch. I had no idea that if you apply reverse flow at higher currents it will heat up and could cause problems like, um, fire.

So thanks for correcting my statement above that you can place a BP on your multi-plus 12v circuit (aside from the fact that they don't even produce one with a high amperage rating required for the multiplus).

What you've brought to light for me is that the BP and VE.Bus BMS disconnect "non essential loads"... not "all loads".

I just assumed the multi-plus would completely shut down under instruction from the BMS in a low voltage situation, but after reviewing the VE.Bus BMS and multi documentation, this is not the case. The VE.Bus BMS will shut down the inverter function of the Multiplus so it does not put a large load on the batteries, but if it is connected to the system (not mechanically disconnected) it will still will draw ~9 watts to "stay alive" and kick in the charger if shore power returns. This is in addition to tiny milliamp draw from the BMV (1mA) and BMS itself (2mA).

So battery discharge will continue if everything is connected to the system, albeit at a greatly reduced rate. IE - if low voltage protection kicks in, get a charge on the system ASAP.

Somewhere between 6-9.5v certain components will theoretically loose life... the VE.Bus BMS requires 9v to operate and the multi requires 9.5v, smart BMV requires 6.5v..... but clearly in Troutboy's situation, something took the batts down even further to 5v....

So... great callout Bob, appreciate the additional insights you bring.

[Troutboy]

Thanks Bob, where do you place theBlue Sea 7700, in place of the normal cutoffs? I have the standard Blue Sea on/off switches for my batteries and for the inverter.

WHat is the advantage of these, do they shut off automatically at low Voltage?

[Troutboy]

Peter, the CGX is what took the batteries lower, its connected to the battery directly....

[lsbrodsky]

I also do not see how the Bluesea 7700 is an improvement. It appears to be a solenoid operated battery switch. Maybe today's BMS can trigger the solenoid but my BMS is 2 years old and not that smart, unless I am missing something here. It seems that the manual switches Rich has are just as good, if he had opened them instead of trusting shorepower.
Larry

[wulfraat]

Originally Posted by Troutboy

Peter, the CGX is what took the batteries lower, its connected to the battery directly....

Good to know. I will verify if mine is setup the same, or if it is on the other side of the BP that disconnects house loads.

[57Vintage]

My question parallels Isbrodsky's comments. I looked at the detail at Blue Sea on the 7700's. I can't see how you would control this relay from a separate component to open the circuit if battery level reaches a low level. I fully admit to being weak with understanding some electronics.

I posed the question to Lewster if a 7700 could be controlled either through a Smart BMS 12/200 (which I have) or a Victron Bus BMS for this purpose. He forwarded the question to AM Solar. I'll pass on whatever I get back.

I'm glad Uncle Bob passed on the issue with the Victron Battery Protect. I was considering adding them.

[uncle_bob]

Hi

Ok, so a few more details. The multi has a CPU in it. That CPU runs off of 12V. The only way to stay in control of the device is *if* the CPU is powered up. There's about 100 to 150 ma of drain all the time from a "connected" Multi as a result. Some have indeed put BP-220's in series with Multi 2000's and ... gee ... it works. The 2000 pulls < 150A in normal operation.

Solar chargers (at least the MPPT's) have a similar issue. They pull 30 or 40 ma off the battery when nothing is going on. The basic issue is the same. They have a CPU and it keeps running all the time.

Those following along in the Victron data sheets might note that the currents mentioned above are a bit higher than what the spec sheet says they should be. How about that ... Indeed this seems to be the case for a lot of outfits making this stuff. Measure the device you have

You need an easy way to do a disconnect, even with big batteries and "week or two" indoor storage. Running around pulling cables off of batteries each time you get home ... not so much. The long promised power at the storage place *may* get there some day ... it's been two years so far.

So, right now I'm running the 7700's manually. It's what I used the BP-220's for before. They are simply easy to use disconnect switches at this point. The control circuit is low current. You give it a short contact closure and it flips the 7700. They give you a fancy looking button to do this. Yes it pulls an alarming 7A off the battery to do the switch. That's for 20 ms or so. ... not many AH to do that ...

The relay / alarm output from the BMV712 should be fine for operating them automatically ( = it will give you a signal). That closure would need to be converted to a pulse. There are devices that do this. I have not *yet* hooked it all up. I only at the "90% sure" point about what needs to be done.

As long as we're digging into the details. The main reason I put two of them them in is to disconnect the batteries in the outside battery box. If it's getting really cold overnight, I punch the button to isolate those two batteries. We run overnight on the two that are indoors. In the morning when it's warm, punch the button to reconnect them.

The whole "isolation" thing is what got me back to looking at all this again. That's when I bumped into the random post about the BP-220's.

Bob

[swilly43]

Excellent discussion, wonderful group.