SSR testing

[Capt Bill]

Yes

Thread got kind of long to review: Do you know if anyone consider testing this 200A rated beefy looking SSR ($30 on eBay) https://www.ebay.com/itm/Durable-SS...-4-32VDC-480VAC-200A-DC-to-AC-SL/124114069380

 

[Craig]

Not sure about that particular one but I have one that looks just like that that I've been using for weeks now with no problems

 

[Capt Bill]

Just tested the 200 amp AC SSR ran 2500 watts through it for 30 minutes the most it heated up to was 101 degrees if that according to my heat gun. By touch it didn't even feel that warm. My shop was about 75 degrees when i started the test.

I just saw this by going backward for review here/ and this looks like a great choice for my Chargery BMS charge side control at my Solar Input to All In One ... when I configure them for Solar Charging Only (& and keep auto battery charging from grid options configured to OFF). I think I will order a couple of em. Thanks for posting those test results

 

[gpower07]

I guess I could cobble together a schematic. Here's the stepdown that I use.

https://www.amazon.com/gp/product/B...]https://www.amazon.com/gp/product/B00LW15F42

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I followed the diagram and seting the relay...it overcharged the batteries to 3.9v and it still not trip. here is the program settings. please help.

 

[onemorebattery]

I followed the diagram and seting the relay...it overcharged the batteries to 3.9v and it still not trip. here is the program settings. please help.

I'm going to give some general info first before addressing your situation. Whenever you put together a control circuit test it before leaving it unattended. For BMS systems set the max/min charge voltages down above/below the current voltage and verify that circuit is operating. Use a heat source and an ice cube to test min/max temperature cutoffs. Once your setup is verified working restore your settings and start normal operation.

Now for your specific case I would do the above testing and using a multimeter test that the Chargery relays outputs drop for the cutoff conditions. If that is working then review your wiring carefully. If the wiring is correct then you may have gotten a bad module. If you bought the two-pack it is unlikely that you received two bad modules. Try the other module and repeat the tests. If the circuit still fails looks again at your circuit wiring until you find the problem.

Also you could upload pictures of your circuit showing all the wiring and we can take a look at that.

 

[gpower07]

I'm going to give some general info first before addressing your situation. Whenever you put together a control circuit test it before leaving it unattended. For BMS systems set the max/min charge voltages down above/below the current voltage and verify that circuit is operating. Use a heat source and an ice cube to test min/max temperature cutoffs. Once your setup is verified working restore your settings and start normal operation.

Now for your specific case I would do the above testing and using a multimeter test that the Chargery relays outputs drop for the cutoff conditions. If that is working then review your wiring carefully. If the wiring is correct then you may have gotten a bad module. If you bought the two-pack it is unlikely that you received two bad modules. Try the other module and repeat the tests. If the circuit still fails looks again at your circuit wiring until you find the problem.

Also you could upload pictures of your circuit showing all the wiring and we can take a look at that.

same as this. i just need the battery reach 3.65 and disconnect. i tried at home and it works when charge over 3.65v. after install i changed some setting like diff of cell voltage.

 

[Allgood-Energy]

The thought of $55 for a Victrorn 100 Amp battery protect makes me Shudder. So I am going to try to make my own $10 design.
Use a 375 Amp HexFET $5.68 for the solid state switch. Here is the design and I have not tested it yet and it will need refinement.
The Driver should use a opto-coupler and FET driver. This will drive up the cost. But I still think I could make it for under $20 including the Heat Sink.
Here is the simple design. The voltage drop across the FET at 100 Amp is only .185 Volts dissipating 18.5 Watts. this is why you Need a Heat-sink.
Tell me what you think. if you need to use the device on the plus side you will need the FET driver and the opto. The RDS on for the FET is what is important for this device. see the Spec. sheet. The FET is good for 70 Volts and 195 Amps. Also you should Also use some decoupling filter caps on the regulator.

 

[BiduleOhm]

Nice project

What I'd recommend:

- a diode in series with the input to prevent destroying things if connected in reverse.
- a resistor and a zener instead of the regulator (you can't use decoupling caps as it would slow down the turn on/off times too much and regulators can oscillate without them, so not a recommended configuration)
- a 12-15 V small TVS between the gate and source to protect the gate oxide layer against overvoltages if you don't chose the zener solution
- a resistor between the gate and source to force the mosfet off
- 330 Ohm seems low for the LED, especially as you don't need to drive it hard, 10 mA is plenty good enough for an indicator LED
- the 1N4007 will never handle the flyback current spike with a 100 A load. You need some big TVS and you can put it/them between the drain and source in the same direction than the mosfet body diode, no need to put it/them at the load.

 

[Cal]

How much current will you be conducting? A single fet may not be adequate. I did a similar project this spring.
High side switch

I used 6 P-channel mosfets (STP80PF55). 16 mOhms on resistance each. 10 ohm gate resistor. A BSX46 transistor turns the 6 fets on/off.

The high side switch works well. It's installed in my VW Westfalia, as a low voltage load disconnect.

 

[Craig]

The thought of $55 for a Victrorn 100 Amp battery protect makes me Shudder. So I am going to try to make my own $10 design.
Use a 375 Amp HexFET $5.68 for the solid state switch. Here is the design and I have not tested it yet and it will need refinement.
The Driver should use a opto-coupler and FET driver. This will drive up the cost. But I still think I could make it for under $20 including the Heat Sink.
Here is the simple design. The voltage drop across the FET at 100 Amp is only .185 Volts dissipating 18.5 Watts. this is why you Need a Heat-sink.
Tell me what you think. if you need to use the device on the plus side you will need the FET driver and the opto. The RDS on for the FET is what is important for this device. see the Spec. sheet. The FET is good for 70 Volts and 195 Amps. Also you should Also use some decoupling filter caps on the regulator.

I'm sure this may work but honestly you are way over my head.

Nice project

What I'd recommend:

- a diode in series with the input to prevent destroying things if connected in reverse.
- a resistor and a zener instead of the regulator (you can't use decoupling caps as it would slow down the turn on/off times too much and regulators can oscillate without them, so not a recommended configuration)
- a 12-15 V small TVS between the gate and source to protect the gate oxide layer against overvoltages if you don't chose the zener solution
- a resistor between the gate and source to force the mosfet off
- 330 Ohm seems low for the LED, especially as you don't need to drive it hard, 10 mA is plenty good enough for an indicator LED
- the 1N4007 will never handle the flyback current spike with a 100 A load. You need some big TVS and you can put it/them between the drain and source in the same direction than the mosfet body diode, no need to put it/them at the load.

How large of a diode would be necessary and how much would that choke the current. I researched this with my own diode and found that t the hit to performance was just too much But I fully admit I am not an EE so there could be Diodes that work better

 

[BiduleOhm]

How much current will you be conducting? A single fet may not be adequate. I did a similar project this spring.
High side switch

I used 6 P-channel mosfets (STP80PF55). 16 mOhms on resistance each. 10 ohm gate resistor. A BSX46 transistor turns the 6 fets on/off.

The high side switch works well. It's installed in my VW Westfalia, as a low voltage load disconnect.

I checked and at 100 A it would dissipate around 20 W worst case so that's ok given the big size package

How large of a diode would be necessary and how much would that choke the current. I researched this with my own diode and found that t the hit to performance was just too much But I fully admit I am not an EE so there could be Diodes that work better

Not in series but in anti parallel, like a flyback diode on a relay coil

If you talk about the diode in series with the input it's on the gate side of the circuit and just need to charge the gate capacitance, so no big deal.

 

[Cal]

I checked and at 100 A it would dissipate around 20 W worst case so that's ok given the big size package

I don't like putting 100A through those small leads. 20W isn't the driving parameter. It's junction temperature. I believe max junction temp is 150C. What's max ambient temperature. My vehicle can get quite hot. 50C (122F) is not unusual.

Given:
Tj - Ta = P * theta_ja

solving for theta_ja:

theta_ja = Tj - Ta / P

Usually derate Tj to 125C

Theta_ja = 125C - 50C / 20 W = 3.75 C/W

A 3 C/W heat sink will increase junction temperature to 125C when dissipating 20W. I would choose a heat sink that will keep junction temps below 100C. Probably <= 2 C/W heat sink.

 

[BiduleOhm]

Tj max is 175 °C on this one but I wouldn't go past 150 °C worst case.

With watercooling it would handle twice that but, yea, it's just a bit borderline here and it's always a good idea to reduce current per device if possible. Two mosfets would be ideal here (only 10 W total worst case so only 5 W per mosfet, 1/4 the original power so much better) and not super expensive to do

I always design for 50 °C ambient or even more if possible to be safe.

 

[Marinepower]

I am in the process of designing a LVC circuit for an Electrodacus BMS. This has been a great thread to research cost effective options.

I am settling towards the TE Connectivity Kilovac EV200 because they are fairly priced and I have some large inductive motor loads in my build (windlass and electric winches) and a solid state solution may not be best for my application.

In my internet rabbit hole research, I discovered a few items which maybe (?) relevant to this thread I thought I would mention. I am not an expert so pls don't flame me if I have this wrong.

The Kilovac EV200 uses PWM circuits in its external 'economizer' so RF could be an issue if you are installing it close to sensitive electronics (like a BMS?). Gigavac makes non PWM 500 amp model which uses a bit more power (2.4w vs 1.7w). Not sure how reliable TE's PWM circuit is?

The Blue Sea latching relay mentioned (at around page 10 of this thread) are expensive as Will points out. There was some discussion on how to control it from a constant voltage BMS relay output (like the Chargery) as most of the Blue Sea latching relays need a voltage pulse. I understand there is a Blue Sea latching model (#7713) which has onboard logic that allows for opening / closing a contact for latch switching (ie, no pulse needed). http://assets.bluesea.com/files/resources/instructions/980018140-002.pdf.

I am still leaning towards the TE Connectivity Kilovac EV200 because they fail in the 'off' position, which seems a safer design.

MP

 

[grizzzman]

I run the EV200 kilavac's. They have a large inrush "peak"(no more than 3.8 amps each.) They pull .13 amps each during "hold" If the inrush is to high a micro mini relay (or an SSR) can be used to trigger the relay.

 

[RCinFLA]

See this is old thread. Did not read all pages so sorry if some my comments are redundant.

50amp with 0.1v drop is 5 watts of heating. That heatsink should be good for 15-20 watts of heat dissipation before it gets too hot to touch.

0.1v/50 amps is 2 milliohms Rs. Some of the 2 milliohm is internal connections resistance added to MOSFET Rds_ON. As mosfet gets hotter its Rs goes up 50% at about 100 degs C.

sqrt (18 watts of heating heat sink limited / 2.5 milliohms @hot temp) = 85 amps max continuous capability with a little over 0.2v of drop.

With a 75vdc rating, and from picture, probably a single HY5608W or IRFP4368PBF MOSFET which at room temp has Rds_ON of about 1.5 milliohms.

With single MOSFET this is not a bi-directional switch. If you attempt to charge battery at high current when device is OFF the reverse current will be going through MOSFET body diode and with about 1 volt reverse voltage drop could get extremely hot to point of destruction.

Not a replacement for a BMS cutout switch.

 

[Craig]

See this is old thread. Did not read all pages so sorry if some my comments are redundant.

50amp with 0.1v drop is 5 watts of heating. That heatsink should be good for 15-20 watts of heat dissipation before it gets too hot to touch.

0.1v/50 amps is 2 milliohms Rs. Some of the 2 milliohm is internal connections resistance added to MOSFET Rds_ON. As mosfet gets hotter its Rs goes up 50% at about 100 degs C.

sqrt (18 watts of heating heat sink limited / 2.5 milliohms @hot temp) = 85 amps max continuous capability with a little over 0.2v of drop.

With a 75vdc rating, and from picture, probably a single HY5608W or IRFP4368PBF MOSFET which at room temp has Rds_ON of about 1.5 milliohms.

With single MOSFET this is not a bi-directional switch. If you attempt to charge battery at high current when device is OFF the reverse current will be going through MOSFET body diode and with about 1 volt reverse voltage drop could get extremely hot to point of destruction.

Not a replacement for a BMS cutout switch.

Yes these are not Bi directional. I have devised a system where I use a DC-AC SSR after my inverter and a DC-DC SSR between panels and SCC. This has advantages and drawbacks. The advantage is the SCC always stays on and the relays are placed in the areas that flows the least amps in all cases. The disadvantage is the inverter will stay on in a lvd situation. which has never been a problem for me but could be to some. This method works exceptionally well with an all in one unit. Just add one more relay to the AC in if you are using grid power or generator for charging.

 

[Capt Bill]

I am coming back to this thread wondering: Has anyone successfully tested a BiDirectional SSR on PV Solar Array IN to a MPPT Charge Controller, like for an easy cut off relay when BMS indicates an over charge fault: ???

Here's a dialog from another thread on this subject:

************
Hi Capt Bill. I’m very interested in your experience on this, as I seem to be trying to accomplish the same thing (controlling a ~30A/~100v Input side of my MPPT with a SSR. I was planning to use a Crydom DC200D60 for the job. Could you provide the specifics of the 120A/220vdc SSR that didn’t work for you? I’m interested in the comparing the specs to the Crydom unit I’m considering.

I should add that I’m not using a chargery BMS (I have a TinyBMS 150A), so I’m not sure if the Charger DCCs are comparable with my setup. They probably are, but I’m not crazy about employing a ‘black box’ solution that I don’t understand.

Thanks in advance.

******** my response:

I tried a couple of kind of inexpensive SSR from CoG CE company (blue lable) dc-ac rated for 220vdc./ two rated for 150Amp / and one rated for 400 amp. I tested this for my MPPT PV IN to my LV2424(s) All In Ones. / obtained these via eBay, and via Alibabaexpress. The two 150A SSRs got wasted to trash, the 400 Amp one had such I voltage drop, I took it off. for that 400 A rated one, Solar Watts Input showing on my LV2424 LCD went noticeably UP when I shorted across the SRR main current side, as briefly tested. My conclusions: First: The high Amp ratings of these small ac-dc SSR seem ridiculous to me/ Second, I kind of believe the way SSRs work, I think they do not handle the MPPT protocols going back and forth through them (but do not have specific proof other than my testing of some economical priced SSRs). Note: There may be some better quality of SSR that might work, ??? but I currently have big doubts. Let us know how you testing of that Crydom DC200D60 goes. I'll be interested.

I will add: I am successfully using some dc-ac SSRs mounted on heat sinks , on my AC circuits IN to my LV2424s that seem to work great; running 120vac up to 20 - 30 amp through dc-ac SSR rated @ 24-480vac /60 amp (obtained via Amazon; with my Alibabaexpress backups rated dc-ac SSR rated 24-480vac 120Amp. ... Hope that helps as frame of references :+)

Added Note: I have a 100 amp rated Chargery DDC Contactor on way; & think it will be a good working relay choice in that MPPT inbetween position; and I will be testing it out soon. :+)

 

[Cal]

Why would you want a bi-directional SSR? Current flows in one direction only: from solar panel to charge controller.

 

[Craig]

I am coming back to this thread wondering: Has anyone successfully tested a BiDirectional SSR on PV Solar Array IN to a MPPT Charge Controller, like for an easy cut off relay when BMS indicates an over charge fault: ???

Here's a dialog from another thread on this subject:

************
Hi Capt Bill. I’m very interested in your experience on this, as I seem to be trying to accomplish the same thing (controlling a ~30A/~100v Input side of my MPPT with a SSR. I was planning to use a Crydom DC200D60 for the job. Could you provide the specifics of the 120A/220vdc SSR that didn’t work for you? I’m interested in the comparing the specs to the Crydom unit I’m considering.

I should add that I’m not using a chargery BMS (I have a TinyBMS 150A), so I’m not sure if the Charger DCCs are comparable with my setup. They probably are, but I’m not crazy about employing a ‘black box’ solution that I don’t understand.

Thanks in advance.

******** my response:

I tried a couple of kind of inexpensive SSR from CoG CE company (blue lable) dc-ac rated for 220vdc./ two rated for 150Amp / and one rated for 400 amp. I tested this for my MPPT PV IN to my LV2424(s) All In Ones. / obtained these via eBay, and via Alibabaexpress. The two 150A SSRs got wasted to trash, the 400 Amp one had such I voltage drop, I took it off. for that 400 A rated one, Solar Watts Input showing on my LV2424 LCD went noticeably UP when I shorted across the SRR main current side, as briefly tested. My conclusions: First: The high Amp ratings of these small ac-dc SSR seem ridiculous to me/ Second, I kind of believe the way SSRs work, I think they do not handle the MPPT protocols going back and forth through them (but do not have specific proof other than my testing of some economical priced SSRs). Note: There may be some better quality of SSR that might work, ??? but I currently have big doubts. Let us know how you testing of that Crydom DC200D60 goes. I'll be interested.

I will add: I am successfully using some dc-ac SSRs mounted on heat sinks , on my AC circuits IN to my LV2424s that seem to work great; running 120vac up to 20 - 30 amp through dc-ac SSR rated @ 24-480vac /60 amp (obtained via Amazon; with my Alibabaexpress backups rated dc-ac SSR rated 24-480vac 120Amp. ... Hope that helps as frame of references :+)

Added Note: I have a 100 amp rated Chargery DDC Contactor on way; & think it will be a good working relay choice in that MPPT inbetween position; and I will be testing it out soon. :+)

Are you using DC-AC ssr on panels or DC-DC you are posting DC-AC. I have used DC-DC ones without issue between panels and SCC 100 AMP SSR with only about 20 max amps produced by the panels.

 

[Capt Bill]

Are you using DC-AC ssr on panels or DC-DC you are posting DC-AC. I have used DC-DC ones without issue between panels and SCC 100 AMP SSR with only about 20 max amps produced by the panels.

I was using dc-dc SSR rated for up to 400 Amps at up 220vdc, and another same COGce brand 150amp rated for up to 220vdc .. Putting that in postion as a relay control switch for about 80vdc , up to 30 amps IN to my LV2424 All In One(s), just destroyed the smaller SSR, and showed a significant wattage drop at the 400 amp version. Have you ever successfully used a dc-dc SSR at that Solar IN location, maybe for BMS charge side cut off??? I was thinking/& this is just a theory with no definite proof of / that the MPPT protocal of my Solar In is in some ways bi directional. ??? I have thoughts a bi-directional SSR would do better on a DC current line with a MPPT protocols on the other side. That is why I am wondering about trying on a bi-directional SSR. I also think the SSR I tried could have just been poor quality, and I need to try one that you have tested and recommend. I know you have gotten good SSR results on main battery line; as high dc amp disconnect relay. Have you ever successful use a SSR on the Solar IN to MPPT protocol converting that dc current into both battery charging current and supply to an inverter for 120vac out ??? If so, please share that info. , including which SSR (that maybe I can get from you, Craig) for my ongoing testing ... Still fine tuning, and update tweaking for better results over here. Plus have a 2nd set of 8 280Ah cells due here soon, to up my battery bank to 560 Ah :+)

 

[rhino]

Was trying to figure out why you were trying to do what you want when I realized it must be because the all-in-one has no way to have separate connections for the charging of batteries and withdraw/inverting from batteries.

 

[Capt Bill]

Was trying to figure out why you were trying to do what you want when I realized it must be because the all-in-one has no way to have separate connections for the charging of batteries and withdraw/inverting from batteries

My Fuller Set Up Picture: Plus Food for Thoughts on BMS control options.

My MPP brand LV2424s All In Ones DO HAVE SEPARATE INPUT CONNECTIONs for my 24v battery bank; as in biggest cables to batteries, plus my separate Solar PV arrays IN, my separate Grid Out, and my separate Grid IN (which can function as a backup to loads beyond Solar In, or back up loads above the 2400 watt rating of each unit; and/or be the line that feeds current back to the grid (just one of my over 28 plus config options). ... I have 3 LV2424 units networked together for a combined 60 amp ability 240ac split phase output.

... For my controls via my Chargery BMS8T, to protect my LiFePO4 batteries; instead of using the simple one battery disconnect relay for charge side and discharge side BMS protection triggers; I have one SSR connect to BMS discharge trigger that turns off my three inverter draws on battery (except for about 6 watts of idle draw from my 3 All In Ones); ... and for my BMS charge side triggers, I have a way to turn off my 3 Solar PV INs, plus my 240vac IN (and my 3 x up to 60 amp grid powered battery chargers) via 2 ac-ac SSRs for my Grid IN to All In Ones; ... & to cut my Solar IN, I am using one SSR that energizes 3 used overkill (500 amp rated) Kilovac mechanical relays. ... That is my current set up. I rather use 3 SSRs directly at my Solar In cut, but I have had no success at the particular junction with the SSRs I tested for that.

I have one 100 amp rated Chargery DDC Contactor on way here to test out, that I think will function great at my Solar PV In location (will see). If Craig has an SSR he thinks would work there, I will test it. ... I have major questions about one way dc-dc SSRs handling MPPT controlled dc current that seems only going one way, but have thoughts MPPT protocols from the Solar Controllers make using a SSR at that location a challenge ??? ). Also : I am going to update my BMS discharge side protection to disconnect my full battery bank. I currently have my BMS discharge circuit connected to one SSR that when released, puts all three of my all in ones into standby mode, which allow Solar PV IN to still work while turning off my 3 Inverters / preventing them from drawing down my battery. I got that idea from Will P's Occicoupler video lesson for that cool easy option. The aspect I do not like is: because if you are down near the bottom voltage on a cell, one's idle draw (which for me, is about 2 watts for each all in one, x 3, plus some minor kilovac relay draws) ... could still draw down battery into the really hurt your battery zone/ which I think is the more dangerous could still kill a LiFePO4 zone; especially if no one is there when that happens !!! ... So that particular BMS discharge trigger is going to be switched to Disconnection my Battery on my set up for fuller protection. ... I still like the idea of connecting my Solar IN, and Grid In to my BMS charge side triggers; and exploring to find my best reasonable priced relay choice for my 3x Solar IN locations.

... I think that is likely some Food for Thoughts on BMS control options. ... Happy Trails :+) Bill

 

[peter_nominal]

View attachment 9360

View attachment 9361

lol these transitor typically does 80A tops, manufacturer has their legs rated at ~120A or so.

 

[BradCagle]

You can use these contactors https://batteryhookup.com/collections/accessories/products/te-connectivity-ev200aaana-500a-0-900vdc

And don't let the thought of high hold current sway you, these have economizers attached only uses 1.7w to hold.