PLEASE HELP ME. Victron system, Amperetime batteries, nothing makes any sense

[Yurtdweller]

Quotd: After a day of 3A charging, it finally GRADUALLY came up to 14.4V, which I think is more honest, but it still drops way below 14v when disconnected.

How did you read this voltage reading? It is likely you were reading system voltage, rather than true battery voltage. I don't know why the batt is only accepting 3 amps, but it would take 66 hours to FULLY charge from dead this battery at 3 amps. After you disconnect, then you are reading Actual voltage of battery. Do you use a volt meter to verify?

 

[sunshine_eggo]

Anyway, here is a curve from today. You can see what I believe is the heater coming on in the morning, where the battery current goes up for a bit, then back down. I believe that is the heater heating up the batteries?

If the charge prevention is in place due to cold weather, then voltage should not rise if heater is engaged. If the unit can both charge and heat at the same time, then you would see both.

Additionally, the Victron MPPT can power loads directly without a battery attached, so even if the battery can't receive any current, the MPPT may still show amperage as it supplies the loads.

What I'm a little confused about tho, is the other photo, where it has the resting voltage shown in the morning, which is 13.2V. From what I understand, that means it isn't fully charged. Shouldn't resting voltage, after a night of no loads, be 13.5V? I am wondering if I have one bad battery.

It sounds to me as though one of the batteries can't take a full charge due to cell imbalance issues, and you may see unexpected resting voltage drops until the imbalance is corrected.

 

[Bluedog225]

Careful wrapping on Mylar. I suspect it’s conductive.

 

[Yurtdweller]

Careful wrapping on Mylar. I suspect it’s conductive.

My bad. Didn't consider. I was picturing mylar outside of a layer of foam, but this is a very good point. I edited my previous suggestion.

 

[ADDvanced]

I've been a part of the engineering team for a BMS that properly controls self heating, and to be frank, just stick a heating pad on the bottom of your battery and use a dedicated temperature control. There are far too many compromises and drawbacks to the internally self-heated designs.

This is what I got. If you're telling me to get something else, sorry, I spent the money already. If you're saying I should try to get amperetime to return these and give me regular ones, then fine.

 

[ADDvanced]

Show your connections of the the parallel connections of the battery, verify they are cross connected so the charge is evenly shared.

Do you have your smart shunt connected to the battery bank? This will allow the SCC to verify battery terminal voltages and avoid any voltage drop from SCC to battery.

Wait, you mean like put the pos from the charger one one battery, and the neg on the other battery? Why? It's all just big thick cables, and it's all the same circuit. That type of thinking seems like.... idk... not really grasping how electricity works. It shouldn't care if it's getting 12v on one battery terminal or the other, because there's a bigass cable going to the other battery.

Yes, I have a smart shunt installed, networked to the charge controller.

 

[Yurtdweller]

This is what I got. If you're telling me to get something else, sorry, I spent the money already. If you're saying I should try to get amperetime to return these and give me regular ones, then fine.

I think he's saying, get an external heater. They're cheap. Less than 30 bucks for a seedling heater on Amazon. Then the internal heater becomes a last resort. The seedling heater is programmable. You can set it to desired/required temp, and it will turn itself on and off. It also has a digital readout that will tell you the temp inside your battery box.

 

[ADDvanced]

This makes sense. It's an unfortunate fact that the battery is most likely to experience freezing conditions at night, when there's no incoming from PV. Therefore, the battery will experience a deep freeze condition. The battery cannot accept incoming power when it is deeply frozen, therefore, once the battery is deeply frozen, it will need to heat for several hours before it can accept charging.

My own self-built bank is over 200 lbs of thermal mass, and is sealed in a heavy wooden crate (inch thick plywood roadie crate with a foam liner). When freeze is predicted, I connect my heat pad(30 watts ac) to my inverter, and wrap the whole thing in thermal blankets. The thermal mass is sufficient to protect from freezing for some time. The power stored would run this heater for several days, depending on outside temps. If the bank never freezes, then the bank will charge whenever, and the heater will continue to function.

This is far superior to a situation where the battery freezes and then must be rewarmed before it can accept a charge.

To the OP, consider this in regards to insulating your batteries. Insulate the crap out of them. Wrap them tightly, without air gaps, and get them off that ice-cold cement. If you can prevent them freezing in the first place, that is more than half the battle. A couple layers of inch thick eps, spray foam, tyvek or (editing to say mylar is probably a bad idea!) mylar wraps, etc. Get a seedling heater. Install some extra thermal mass inside the insulation, like steel plates or bricks or something that can store warmth on those occasions when the room is above freezing. If the room is above the temp of the batteries, open up the insulation so that the batteries can warm up.

I did wrap them in the foam they came shipped in, it's a closed cell type of foam so it should be a decent insulator. I left the end exposed where the terminals are, because I couldn't figure out a clean way to deal with all the wiring.

Again, this is an off grid install where I am thousands of miles away most of the time. How are you controlling a heating pad remotely? If my VE Direct cables ever show up, maybe I could add one to the AC system and remotely turn on the inverter? I don't know yet, because none of these expensive ass components ship with 50 cents worth of cables, for some fucking reason.

 

[ADDvanced]

Quotd: After a day of 3A charging, it finally GRADUALLY came up to 14.4V, which I think is more honest, but it still drops way below 14v when disconnected.

How did you read this voltage reading? It is likely you were reading system voltage, rather than true battery voltage. I don't know why the batt is only accepting 3 amps, but it would take 33 hours to FULLY charge from dead this battery at 3 amps. After you disconnect, then you are reading Actual voltage of battery. Do you use a volt meter to verify?

Yes, system voltage. It will read 14.4 at the terminals too with a volt meter. However, once I turn off the PV, it dropped to 13.5 or whatever. Meanwhile the other battery would rest at 14v. The battery was not fully dead when I started this, it was reading 13.13V. What I meant by my comment was this if i gave it 45A it would just JUMP to 14.4V and I could not see much current going into the battery, if I turned off all loads it would be 0A going into the battery. If I lowered it to 3A, I could get a few A going into the battery.

 

[ADDvanced]

If the charge prevention is in place due to cold weather, then voltage should not rise if heater is engaged. If the unit can both charge and heat at the same time, then you would see both.

Additionally, the Victron MPPT can power loads directly without a battery attached, so even if the battery can't receive any current, the MPPT may still show amperage as it supplies the loads.



It sounds to me as though one of the batteries can't take a full charge due to cell imbalance issues, and you may see unexpected resting voltage drops until the imbalance is corrected.

So what is happening then?

How the fuck am I supposed to balance the cells if I don't have AC or a charger? jesus christ I regret getting these batteries.

 

[ADDvanced]

I think he's saying, get an external heater. They're cheap. Less than 30 bucks for a seedling heater on Amazon. Then the internal heater becomes a last resort. The seedling heater is programmable. You can set it to desired/required temp, and it will turn itself on and off. It also has a digital readout that will tell you the temp inside your battery box.

Link? Again, this is off grid, I don't have AC unless I turn on my inverter.

 

[sunshine_eggo]

Wait, you mean like put the pos from the charger one one battery, and the neg on the other battery? Why? It's all just big thick cables, and it's all the same circuit. That type of thinking seems like.... idk... not really grasping how electricity works. It shouldn't care if it's getting 12v on one battery terminal or the other, because there's a bigass cable going to the other battery.

Yes. You will over-work the battery to which both cables are connected. You have less wiring resistance to the two batteries, so the least resistance battery will bear the brunt of all charges/discharges.

So what is happening then?

I can't say for certain.

How the fuck am I supposed to balance the cells if I don't have AC or a charger? jesus christ I regret getting these batteries.

Regular use over time should correct it.

 

[ADDvanced]

Ok I'll go cross cables. Makes no sense to me but sure.

 

[Bluedog225]

An electrician once answered my electrical question with “the Lord works in mysterious ways.”

I don’t understand much of this stuff either. But it sounds like you are getting solid advice. Hope it works out.

 

[sunshine_eggo]

Ok I'll go cross cables. Makes no sense to me but sure.

try this:

 

[Rocketman]

ADDAdvanced - Remember you are the system engineer- it is your responsibility to keep the system up and to buy the best items for your situation, and to change paths when that becomes obvious. Yes sometimes companies marketing efforts can and will lead you astray, but the system engineer’s job is to adapt, take what you have, modify it, make it work better.

I believe you have made progress this last bit. We figured out the first big problem - the batteries were freezing - the heated battery feature was not adequate for your situation. You now have the information to address that.

Next issue is wiring needs adjusted a little - sunshine just posted a good visual diagram- use the 2nd one. It will help a little.

Next issue is one battery seems to have some cell imbalances. That can be fixed, the bms should fix it naturally, but you may want to contact the battery manufacturer for the best way/voltages to fix it. (For example- this is just a guess - charge to 14.4 v - but length the absorption time until the cell imbalances are corrected- may take a few weeks. Then reduce the absorption time back to normal).


Good Luck with your project

 

[Yurtdweller]

Ok. I've rewatched the video, and read the entire thread.

I have to ask some questions that may seem insulting, but please don't take offense.

When you had voltages spiking really high, did you have your batteries in series or in parallel? You don't say, but it seems that you are running a 12v system. If you connected your batteries in series, it might explain those voltage readings.

Do you have your panels in series or in parallel?

Your panels seem capable of producing over 50 amps at 12v, whereas your charge controller can only produce 45 amps. I don't know if this can cause issues. Probably not, because you are not over the CC's voltage limit.

The charge controller is recommended a max of 650 watts@12v. In winter, your array is probably capable of producing 700 watts or 750 or more. Panels produce more power when very cold. This could be an issue. You may want to test this by disconnecting one panel.

What gauge are the wires from the circuit breaker to the cc? Do they get warm? They seem small.

Apologies about the heater pad. I did not realize that you are not on site for long periods. The heater pad would be recommended for when you are in residence. You would want to run the heater when you are onsite, primarily, because prolonged bad weather could cause the heater to drain the batteries. However, if the cc can power the inverter without draining the batteries, like if you had a battery protection circuit, then you could leave the inverter and the heater turned on at all times, and the batteries would be warmed up any time the weather was good. Once warmed, they could charge.

As to parts of the battery being exposed to the cold, wrap an old sleeping bag around them, if you must. It's really important to keep them warm, as if us saying that over and over hasn't gotten that point across.

Please take pictures of your batteries when they are both connected to the system so that we can observe your wiring.

When commenters here ask for your specs, trust that we are asking for a reason. We simply cannot advise on certain details without information. Every single part of a system must be considered. A member will not ask for non-relevant information. If someone asks for information, and you refuse to render that information, then a member will probably write you off, and will cease offering their help. If you want us to help you, then you must help us understand your whole system.

It would be helpful if you could tell us what kind of panels you are using, beyond simply their wattage. If you have a picture of the spec sheet from the back of the panel, that would be helpful, too.

Good luck. We want to help.

 

[ADDvanced]

try this:


View attachment 139883

I mean yeah, but w big ass cables I just didn't think the resistance of the 6" ones would matter. Regardless I hooked it up the second way for now.

 

[ADDvanced]

ADDAdvanced - Remember you are the system engineer- it is your responsibility to keep the system up and to buy the best items for your situation, and to change paths when that becomes obvious. Yes sometimes companies marketing efforts can and will lead you astray, but the system engineer’s job is to adapt, take what you have, modify it, make it work better.

I believe you have made progress this last bit. We figured out the first big problem - the batteries were freezing - the heated battery feature was not adequate for your situation. You now have the information to address that.

Next issue is wiring needs adjusted a little - sunshine just posted a good visual diagram- use the 2nd one. It will help a little.

Next issue is one battery seems to have some cell imbalances. That can be fixed, the bms should fix it naturally, but you may want to contact the battery manufacturer for the best way/voltages to fix it. (For example- this is just a guess - charge to 14.4 v - but length the absorption time until the cell imbalances are corrected- may take a few weeks. Then reduce the absorption time back to normal).


Good Luck with your project

What's frustrating is that I am only here in short spurts, a few weeks at a time, and then I'm back home 1000s of miles away. And right now? Snow, winter storms, and clouds for the next 8 days. I leave in 7.

 

[ADDvanced]

Ok. I've rewatched the video, and read the entire thread.

I have to ask some questions that may seem insulting, but please don't take offense.

Lets do it.

When you had voltages spiking really high, did you have your batteries in series or in parallel? You don't say, but it seems that you are running a 12v system. If you connected your batteries in series, it might explain those voltage readings.

12v system, parallel. I believe the spike is the SCC attempting to charge the battery but the BMS providing an abrupt halt, and the SCC realizing it stopped and cutting power.

Do you have your panels in series or in parallel?

Your panels seem capable of producing over 50 amps at 12v, whereas your charge controller can only produce 45 amps. I don't know if this can cause issues. Probably not, because you are not over the CC's voltage limit.

The charge controller is recommended a max of 650 watts@12v. In winter, your array is probably capable of producing 700 watts or 750 or more. Panels produce more power when very cold. This could be an issue. You may want to test this by disconnecting one panel.

Series, so 690 watts at 89.8V, and yeah, I have observed 104-105volts in the early morning if sunny. This is why I upgraded to the Victron 150/45, and as far as I know you can overpanel as long as you don't exceed the max input voltage. It's competely overkill in summer, I designed this for worst case winter scenarios, it needs to run 3 security cameras, a DVR, and a 4g router for 4-5 days. According to my estimations, it should be able to stay online for over a week with zero sun, so it should be running awesome but so far I've had no luck, which is why I'm switching to Victron components in an attempt to figure out WTF is going on (renogy sucks!)

What gauge are the wires from the circuit breaker to the cc? Do they get warm? They seem small.

10 awg. No, they stay cool.

Apologies about the heater pad. I did not realize that you are not on site for long periods. The heater pad would be recommended for when you are in residence. You would want to run the heater when you are onsite, primarily, because prolonged bad weather could cause the heater to drain the batteries. However, if the cc can power the inverter without draining the batteries, like if you had a battery protection circuit, then you could leave the inverter and the heater turned on at all times, and the batteries would be warmed up any time the weather was good. Once warmed, they could charge.

As to parts of the battery being exposed to the cold, wrap an old sleeping bag around them, if you must. It's really important to keep them warm, as if us saying that over and over hasn't gotten that point across.

I really thought self heating batteries meant I didn't need to do any of this stuff, but okay, I'll add more insulation and post pics later tonight.

Please take pictures of your batteries when they are both connected to the system so that we can observe your wiring.

When commenters here ask for your specs, trust that we are asking for a reason. We simply cannot advise on certain details without information. Every single part of a system must be considered. A member will not ask for non-relevant information. If someone asks for information, and you refuse to render that information, then a member will probably write you off, and will cease offering their help. If you want us to help you, then you must help us understand your whole system.

It would be helpful if you could tell us what kind of panels you are using, beyond simply their wattage. If you have a picture of the spec sheet from the back of the panel, that would be helpful, too.

Specifications:​

• Peak Power: 230W
• PTC Rating: 208.9W
• Power Output Tolerance: 0/+3%
• Maximum Power Voltage:29.8 V
• Maximum Power Current:7.78 A
• Open Circuit Voltage: 37.0 V
• Short Circuit Current: 8.26
• Module Efficiency: 14.1%

 

[HighTechLab]

This is what I got. If you're telling me to get something else, sorry, I spent the money already. If you're saying I should try to get amperetime to return these and give me regular ones, then fine.

Honestly, yes, that would be better...but is this is really all you got from my post?

Your lack of planning and testing in advance doesn't constitute an emergency on our part. Your attitude and demeanor is not appreciated. We are all volunteers on this forum and not your servants to treat like garbage. We have not treated you poorly. You need to do some of the work and thinking here too. If you want to treat the free help as your servant then you'll find yourself with a broken system and without help before you know it.

 

[ADDvanced]

You're reading way into that, man. I've never made any of those claims.

I am 1800 miles from my house though. I come here for a week or two then need to get back home. It is literally not an option to order different batteries at this point, they would not get here in time and I would be out a ton of money, and on top of that AmpereTime is sponsoring this project as well. You're basically telling me they're garbage, and I have no other options so I'm not sure what you expect me to do with your response, other than maybe have a different strategy months from now.

 

[MisterSandals]

I believe the spike is the SCC attempting to charge the battery but the BMS providing an abrupt halt, and the SCC realizing it stopped and cutting power.

This caught my eye. Have you figured out why the BMS is cutting out?
If this is expected to be a regular occurrence, i think you need a system that disconnects the solar when the battery is disconnected by the BMS or other method.

Please take pictures of your batteries when they are both connected to the system so that we can observe your wiring.

This would be very helpful to identify or rule out quite a few aspects of your system.

 

[dmsims]

@ADDvanced why do you keep dropping the F bomb ? Do you think it makes people want to help ?

 

[ADDvanced]

I'm really, really, really frustrated. "Self heating" are advertised as ... idk... SELF HEATING. If none of them work, why are they being produced by more and more companies?