My JK and my meat

[BigBrosMo]

Which SSR are you using?
You had mentioned controlling the inverter directly from the battery protect, did that not work out?

No controlling it directly didn't work for the same reason. The BP doesn't "switch" the connection/load on and off. It just reduces the voltage, so there is a still a path... My remote switch for inverter is either on or off, so if that line doesn't go completely dead, it still registers as on.

The ssr I got (unfortunately not a top quality one, I am limited to what I can order here in the time I have) is rated from 3v to 32v. The BP reduces the voltage to 2 to 2.5/2.7. so at the high end of that (2.7) it seems to engage the ssr. I am going to get a 24v automotive relay tomorrow and use that for now... At least it will register "off" when the BP goes to the approx 2.5v.

I saw on another thread you were on that a poster saw the same residual voltage on the BP. And on the victron forum someone posted the same question with the same issue but it was never answered. Either these are all faulty units, or its the nature of the BP. Perhaps someone could test that?

 

[John Frum]

No controlling it directly didn't work for the same reason. The BP doesn't "switch" the connection/load on and off. It just reduces the voltage, so there is a still a path... My remote switch for inverter is either on or off, so if that line doesn't go completely dead, it still registers as on.

The ssr I got (unfortunately not a top quality one, I am limited to what I can order here in the time I have) is rated from 3v to 32v. The BP reduces the voltage to 2 to 2.5/2.7. so at the high end of that (2.7) it seems to engage the ssr. I am going to get a 24v automotive relay tomorrow and use that for now... At least it will register "off" when the BP goes to the approx 2.5v.

I saw on another thread you were on that a poster saw the same residual voltage on the BP. And on the victron forum someone posted the same question with the same issue but it was never answered. Either these are all faulty units, or its the nature of the BP. Perhaps someone could test that?

I have successfully controlled this

Opto 22 DC60S3 DC Control Solid State Relay, 60 VDC, 3 Amps, 4000 VRMS Isolation Voltage : Amazon.ca: Industrial & Scientific

Opto 22 DC60S3 DC Control Solid State Relay, 60 VDC, 3 Amps, 4000 VRMS Isolation Voltage : Amazon.ca: Industrial & Scientific

www.amazon.ca

via this

Victron Energy Smart Battery Protect 12/24-Volt 65 amp (Bluetooth) : Amazon.ca: Automotive

Victron Energy Smart Battery Protect 12/24-Volt 65 amp (Bluetooth) : Amazon.ca: Automotive

www.amazon.ca

My Opto_22 ssr has a control range of 3-32 volts.

 

[BigBrosMo]

I have successfully controlled this

Opto 22 DC60S3 DC Control Solid State Relay, 60 VDC, 3 Amps, 4000 VRMS Isolation Voltage : Amazon.ca: Industrial & Scientific

Opto 22 DC60S3 DC Control Solid State Relay, 60 VDC, 3 Amps, 4000 VRMS Isolation Voltage : Amazon.ca: Industrial & Scientific

www.amazon.ca

via this

Victron Energy Smart Battery Protect 12/24-Volt 65 amp (Bluetooth) : Amazon.ca: Automotive

Victron Energy Smart Battery Protect 12/24-Volt 65 amp (Bluetooth) : Amazon.ca: Automotive

www.amazon.ca

My Opto_22 ssr has a control range of 3-32 volts.

I wonder if the "dumb" BP works differently than the smart one. I would like to know if there's any measurable voltage on the Out when it's undervoltage. My friend here has another "dumb" BP I am going to connect to see if it's the unit that's faulty or not.

 

[John Frum]

I wonder if the "dumb" BP works differently than the smart one. I would like to know if there's any measurable voltage on the Out when it's undervoltage. My friend here has another "dumb" BP I am going to connect to see if it's the unit that's faulty or not.

I assume under-voltage is the same as when the remote jumper is open.
I expect there will be some voltage on the output but I can't verify it right now.

 

[DerpsyDoodler]

I wonder if the "dumb" BP works differently than the smart one. I would like to know if there's any measurable voltage on the Out when it's undervoltage. My friend here has another "dumb" BP I am going to connect to see if it's the unit that's faulty or not.

Have you reached out to victron tech support? The device sounds faulty.

 

[BigBrosMo]

Have you reached out to victron tech support? The device sounds faulty.

Victron says to contact my distributor. They don't offer tech support. My friend bought it on Amazon so I don't have the distributor info. I'll try the other one my friend has and see if it does the same and I'll ask him for the Amazon seller info

 

[DerpsyDoodler]

Victron says to contact my distributor. They don't offer tech support. My friend bought it on Amazon so I don't have the distributor info. I'll try the other one my friend has and see if it does the same and I'll ask him for the Amazon seller info

Yeah, the device should have no voltage on the ouput side when off, otherwise it's not protecting the source battery. When reaching out to either amazon or the distributor, they will walk through testing steps to verify it is faulty. Distributor handles warranty for the products (unless youre within a certain window of time in which amazon will still handle it).

 

[John Frum]

Yeah, the device should have no voltage on the ouput side when off, otherwise it's not protecting the source battery. When reaching out to either amazon or the distributor, they will walk through testing steps to verify it is faulty. Distributor handles warranty for the products (unless youre within a certain window of time in which amazon will still handle it).

Setting up to test now.

 

[John Frum]

I just tested my old battery protect.
I get 28.4 volts between the converter bp.in and converter.negative.
With remote.positive and remote.negative shorted I get 28.4 volts between bp.out and converter.negative.
With no continuity between remote.positive and remote.negative the voltage slowly drops away.

Side note: There is 27.95 volts between remote.positive and remote.negative.

 

[John Frum]

@BigBrosMo do you have any pure dc loads?
If you add a tiny load to the the bp_out the the voltage should drop to near zero quicker.
You mentioned going with a relay which would achieve the same end.
I only mention it in case you are buying the relay and wan't to prove the concept before you order something.

 

[BigBrosMo]

@BigBrosMo do you have any pure dc loads?
If you add a tiny load to the the bp_out the the voltage should drop to near zero quicker.
You mentioned going with a relay which would achieve the same end.
I only mention it in case you are buying the relay and wan't to prove the concept before you order something.

Thanks @smoothJoey I have hooked up my friends other Victron and see the same results. ie. When undervoltage is detected and it "disconnects", the voltage hovers between 1.5v and 2.8v. Whenever it hits the higher end the SSR engages since it's rated input is between 3v-32v. So this is useless to me as-is. I went to the mainland yesterday and got a Bosch 24v automotive relay. It was less than $5 CAD. I was surprised at it's numbers too actually - relay engages at only 11.5v and disengages at 9.5v, though its a 24v relay. Nonetheless, this will work in conjunction with the BP.

I am not sure I understand your request for the DC load. Like put a 24v light bulb on the bp.out in parallel with the SSR for example?

 

[BigBrosMo]

Ok actually, I put a small 24v load on it... here's what happened:
1. I had my bench power set at 26v. I turned it down to 22v which initiates undervoltage at the BP.
2. bp.out dropped to 22v until the undervoltage kicked in, at which point it dropped to a voltage rapidly fluctuating between ~1.5v and ~2.8v.
3. the SSR, which is enabled between 3v-32v, turned off but would cycle on every time the fluctuating voltage hit ~2.8v.
4. I turned on a small 24v load (small inverter with no AC connected)
5. bp.out immediately stabilized to 1.5v and SSR stayed off, but then bp.out slowly increased upwards. The higher it got, the slower the voltage would increase. it leveled off somewhere around 2.4v I think.
6. I then adjusted bench power up to 23v. bp.out suddenly began to increase and then slowly leveled off around 2.6v
7. Again I adjusted bench power to 25v. Again bp.out began to increase quickly and then slowed as it approached 2.7v
8. My BP is set to re-engage at 26.5v. I increased bench to 26.2v and watched as bp.out began to increase again. This time when it got to 2.85v the SSR turned on.
9. bp.out immediately dropped to 1.5v, the SSR turned off, and bp.out once again began to slow climb back up to 2.85v.
10. I increased bench to 26.5, bp.out re-engaged as designed and SSR turned on as expected.

We are now into the realm of understanding the BP itself as the automotive relay solution is the one I will employ. The behavior of the BP is not faulty - it's by design for some reason. I can only imagine that it works with your SSR because your SSR engages more closer to its rated 3v rather than 2.85v where mine kicks in?

 

[John Frum]

We are now into the realm of understanding the BP itself as the automotive relay solution is the one I will employ.

Glad you are understanding.
I will re-read this again later after a strong cup of coffee.

What is the exact make and model of your SSR?

 

[BigBrosMo]

Glad you are understanding.
I will re-read this again later after a strong cup of coffee.

What is the exact make and model of your SSR?

Basically this thing by "Fotek":
https://tinyurl.com/yc9fxhr6

But I bought it on the local Amazon equivalent called Lazada. Same part number SSR-40DD but the output is 5-220v not 110, otherwise it looks exactly like this. same markings etc

 

[John Frum]

Basically this thing by "Fotek":
https://tinyurl.com/yc9fxhr6

But I bought it on the local Amazon equivalent called Lazada. Same part number SSR-40DD but the output is 5-220v not 110, otherwise it looks exactly like this. same markings etc

This datasheet says https://datasheetspdf.com/pdf-file/1329618/EKT/SSR-40DD/1
"On Voltage: ≤1V"
I think that is the problem.

 

[John Frum]

@BigBrosMo did you get things working?

 

[BigBrosMo]

@BigBrosMo did you get things working?

Hey there! Sorry for not updating. Yes... And no. I ended up just adding a 24v automotive relay instead of the solid state one and was able to turn the inverter on and off with the Victron.

I was packing up my house to leave for the rainy season and come back to Canada. Unfortunately, something happened at the very last moment when I switched my system from generator to solar and the inverter I had died. So all of that was for naught. I didn't have time to get a new inverter so will have to try again when I return in November.

Thanks again for all your assistance during that time! Much appreciated.

 

[BigBrosMo]

Add lead in parallel.

I know this is an unpopular idea, but the lead will keep the SCC alive overnight until solar comes back. Your lead will need to be enough for one night.

Also @timselectric because you chimed in at the time

Going back a bit here but I am preparing for my winter away back in Thailand. I have no need to replace my inverter as it works fine, and the relay system I hooked up in a rush is hokey. To recap - I want to keep my SCC alive if the BMS shuts off in LV protection.

You suggest running a parallel lead from battery to the SCC to keep it alive. I understand this needs to be a minimal wire. My SCC specs "<12mA" used for consumption and I don't run any loads off it directly. So to me all that's required is just any basic jumper wire.

Is the overall risk here that my battery cells drain to <2.5v without the BMS hard cutoff at some point? Because to me that is minimal, for example:

UVP is 2.8v/cell (~5% capacity)
Shutdown is 2.5v (0% capacity)

If I have 280Ah batts, 5% is 14Ah.

Standby "Loads" would be:
12mA for SCC
33mA for the BMS (spec'd 8mA@100v = 33mA at 24v I assume?)
12mA for the Battery Monitor
= 57mA

14Ah/0.057Ah = ~245 hours or more than 10 days without any charge power BEFORE it starts to harm the cells (ie below 2.5v)

ie. as long as I realize that something is wrong within a week, there's little risk to my setup. And if I increase my UVP to 3v, it would be substantially longer (~2 weeks)

Is my math right, and/or am I missing something else to consider? I would simply disconnect that jumper lead if I knew I was going to be away for awhile.

 

[gelmjw]

Also @timselectric because you chimed in at the time

Going back a bit here but I am preparing for my winter away back in Thailand. I have no need to replace my inverter as it works fine, and the relay system I hooked up in a rush is hokey. To recap - I want to keep my SCC alive if the BMS shuts off in LV protection.

You suggest running a parallel lead from battery to the SCC to keep it alive. I understand this needs to be a minimal wire. My SCC specs "<12mA" used for consumption and I don't run any loads off it directly. So to me all that's required is just any basic jumper wire.

Is the overall risk here that my battery cells drain to <2.5v without the BMS hard cutoff at some point? Because to me that is minimal, for example:

UVP is 2.8v/cell (~5% capacity)
Shutdown is 2.5v (0% capacity)

If I have 280Ah batts, 5% is 14Ah.

Standby "Loads" would be:
12mA for SCC
33mA for the BMS (spec'd 8mA@100v = 33mA at 24v I assume?)
12mA for the Battery Monitor
= 57mA

14Ah/0.057Ah = ~245 hours or more than 10 days without any charge power BEFORE it starts to harm the cells (ie below 2.5v)

ie. as long as I realize that something is wrong within a week, there's little risk to my setup. And if I increase my UVP to 3v, it would be substantially longer (~2 weeks)

Is my math right, and/or am I missing something else to consider? I would simply disconnect that jumper lead if I knew I was going to be away for awhile.

I don't have an answer for low voltage cutoff. I thought we were discussing what to do if your SCC stops running after a low temp cutoff by the BMS.

 

[timselectric]

Bypassing the protection and hoping that nothing goes wrong is a gamble, that I wouldn't be willing to take with my expensive battery. If you want longer run time, the answer is to increase capacity.