diy solar

diy solar

SSR testing

When I eventually test the SSR dc-ac for running 120AC up to 25amps to see how hot it gets; and then use a Thermal Disc to trigger a 2nd parallel wired mechanical relay, I have this inexpensive $23 relay in mind. I have used these with different coil voltages for water pump applications, and viewed em as durable and dependable. They might be capable of being used solo, have low coil draw/ but not sure using coil to clamp contacts 24/7. I'd be more confident of durability using these for up to full 25 AMP, as a secondary kicked to ON or closed circuit when SRR get hot. I am considering the 60 amp rated dc-c SSR w Thermal Disc triggered Mechanical Relay setup as BMS control cut off of 120ac 25 amp out from my LV2424 to 120vac Circuit Breaker Box (as option to turn off inverter by turn of full all in one/ including the charger)

General Purpose Relay Rated for 25 Amps AC DPST
Normally Open Contacts, 158 mA Rated Load Current, 12 VDC Rated Load Voltage

Omron G7L-2A-BUBJ-CB DC12 General Purpose Relay With Test Button, Class B Insulation, Screw Terminal, Upper Bracket Mounting, Double Pole Single Throw Normally Open Contacts, 158 mA Rated Load Current, 12 VDC Rated Load Voltage: Electronic Relays: Am

Omron G7L-2A-BUBJ-CB DC12 General Purpose Relay With Test Button, Class B Insulation, Screw Terminal, Upper Bracket Mounting, Double Pole Single Throw Normally Open Contacts, 158 mA Rated Load Current, 12 VDC Rated Load Voltage: Electronic Relays: Amazon.com: Industrial & Scientific
www.amazon.com

I ordered from Allied to get faster delivery.

 
Last edited:
Cal said:
The turn-on inrush current for this relay is 3.8A for 130 ms. Can Chargery BMS handle this amount of current? Probably would be good to put an oscilloscope on relay coil during turn-on.
Click to expand...
No greater than the Electro-Mech Contactor's that Chargery has offered. The Chargery Spec says 15-30V @ 3A is what is needed to power the BMS.
 
upnorthandpersonal said:
That's what the capacitor I mentioned would be for.
Click to expand...

How big do you think that capacitor needs to be to supply 1.7 J?

Perhaps 23 mF?
That's a huge capacitor!

So much simpler to use a transistor to apply the necessary power. Apply a 20 mS pulse to the base of the transistor and there should be any issues.
 
Steve_S said:
No greater than the Electro-Mech Contactor's that Chargery has offered. The Chargery Spec says 15-30V @ 3A is what is needed to power the BMS.
Click to expand...
I went and looked this up in the Chargery BMS8T v4.0 manual (that mention you and this forum by name) , and found this in Frequent Questions section: " Confirm relay coil current requirement, it must not be over 1A for each relay or that the total
current with two relays won't be over 2.6A " ... earlier in manual, I see a small board that looks like option for in between BMS relay control out to big n small relay options. It was unclear to me, if that was separate card pictured was an option for bigger relay current, or internal part of BMS which I doubt. I did not see plug for external power on card picture/ but saw off on switch ? ... further into that manual, I got spec for the bigger Chargery supplied orange relay: 12V 600A relay, coil current is 1.3A at 12V drive voltage. ... just wondering out loud. ... and bet "turn-on inrush current for this relay is 3.8A for 130 ms" (not sure of accuracy) would work. / while just ... wondering out loud here.
 
  • Like
Reactions: Cal
Cal said:
How big do you think that capacitor needs to be to supply 1.7 J?

Perhaps 23 mF?
That's a huge capacitor!

So much simpler to use a transistor to apply the necessary power. Apply a 20 mS pulse to the base of the transistor and there should be any issues.
Click to expand...

A simple 1F 12V supercap. The reason to not rely on a transistor is so that in the case the 12V drops for whatever reason in a catastrophic event it will still have power to turn off the relay.
 
upnorthandpersonal said:
A simple 1F 12V supercap. The reason to not rely on a transistor is so that in the case the 12V drops for whatever reason in a catastrophic event it will still have power to turn off the relay.
Click to expand...

I wouldn't call that simple. You would need at least a 15V capacitor. You will see your catastrophic failure with your 12V cap. What happens when the cap isn't fully charged yet and the signal comes to switch relay states?

Use a $25 capacitor with iffy results when a 50 cents transistor will do the job?
 
No reason you can't do both, and add a monitoring circuit not to turn on the relay before the cap is charged. I just think it's a problem that the battery disconnect relay can keep the battery connected when the battery that it is supposed to protect is responsible to have the power available to turn it back off in order to disconnect.
 
upnorthandpersonal said:
No reason you can't do both, and add a monitoring circuit not to turn on the relay before the cap is charged. I just think it's a problem that the battery disconnect relay can keep the battery connected when the battery that it is supposed to protect is responsible to have the power available to turn it back off in order to disconnect.
Click to expand...
Sure, you can do both. But highly likely the super cap won't work alone, even with the now added complexity. BMS low voltage disconnect is at 10.0V. There won't be enough energy in the cap for a 8V signal to trip the relay when the cap is at 10V. Will you guarantee it will trigger the relay?

A sound design will use a capacitor to "program" the timing pulse, but not provide the energy to trigger the relay directly. That should be left for a transistor or mosfet.

Cal
 
Cal said:
Sure, you can do both. But highly likely the super cap won't work alone, even with the now added complexity. BMS low voltage disconnect is at 10.0V. There won't be enough energy in the cap for a 8V signal to trip the relay when the cap is at 10V. Will you guarantee it will trigger the relay?
Click to expand...

You would only use the cap to give the pulse to the relay to disconnect - it'll remain charged at 12V. A supercap self-discharge rate from 100% to 50% is 30 to 40 days. If your battery is at 10V and needs to be disconnected, will you guarantee it still has enough power to provide that to the relay (or that it indeed can still provide any power since it might have gone catastrophically wrong)?
 
Can we get this thread back to SSR testing and results. You guys have moved this way off topic. Even if it is useful info. Maybe you can start another thread.

Personally I don't want a complicated solution. The whole goal was one or 2 low draw SSR to use for HVD and LVD. This may not be possible but at least we will know what does or does not work.
 
Back on track. Here's the start of my DIY high side switch. Pictured are the sil pads for the TO220 mosfets (which will take a while to arrive). 6 mosfets will fit on the 2x2" heatsink. That should get the on resistance down to 3 mOhm. The switch should easily conduct 20A.

Power dissipated = I^2 * R = 20A^2 * 0.003 ohms = 1.2 W
The heatsink might be good for 5W (40A).

The fets will be secured with a M3 screw. Got a M3 tap on order to cut threads into the heatsink.

Heatsink.jpg
 
gpower07 said:
i bought this from amazon. it run warm without load. i didn't know what is the start current for that.

Amazon.com: Stinger SGP35 500-AMP Relay and Isolator: Car Electronics

Amazon.com: Stinger SGP35 500-AMP Relay and Isolator: Car Electronics
www.amazon.com
Click to expand...
Not quite an SSR, but option. If it warms up without a load, likely using some watts at trip coil. maybe you can find spec to know, or measure for amp draw. Re: Testing SSR ideas: I just found my Killawatt meter. Got too much stuff spread out here; and re-organizing my house and storage area, aiming to get to past old spring clean up project put off for too long/ to have an organized work area. My 8 x 280 Ah LifePO4s are due tomorrow. ... So SSR testing on my end will come soon, for an SSR dc-ac set up: I run 120 vac up to 20 amp. I want record rise of temps as I use more watts/ time, with and without heat sink; then record temp drops when I turn on a parallel mechanic relay to take current run too. We will see. I think that idea has greaer potential in for the higher DC amp zones (Like 500 - 1000 amps (maybe even for Electric Vehicle use, which is an arena I have not yet studied) :+)
 
Testing an inexpensive dc-ac SSR rated for 60 Amps, without and with heat sink / with switch wired to SSR load side to imitate a potential Relay wired in parallel that could be triggered by an $12 thermostat type heat sensing disc switch.

My Results: Without Heat Sink; running 20 amps @ 116 v ac load through SSR: Temperature climbed steadily over 6 minutes from about 80F to about 200F / then when I turned switch ON @200F / to imitate a mechanical Relay placed in a parallel circuit / the Temp then dropped from 200F to 140F over 6 minutes (might have dropped more with more time? The AC Volts Drop across the load side of SSR was one volt ac / 116.5 vac input / became 115.5 vac on load side of SSR

With Heat Sink attached to SSR / 20 amps @ 116 v ac ... got slower heat rise /Temp climbed from about 80F to 115F over 9 minutes /
Then when Switch turned ON to imitate parallel mechanical type relay /Temp Dropped, but was much slower. (and my notes could have been better

My Conclusions: My Without Sink Test shows potential benefit of using a Thermal Disc (like the NO - $12 Adjustable Snap Disc Fan Control (Adjustable to Close Circuit at 140F - 180F / releases to Open circuit w 20F differential; other ranges available/ links below). to reduce heat on a SSR running much larger DC currents that would be generating more heat, with a Relay wired in parallel to bring heat down.

This Test did Not impress me as a winner to copy (though anyone could) for a dc-ac SSR running only 20 - 25 Amps, when I see using the ac -dc SSR w Heat Sink by itself topped out at about 115F @ 20 amps over 9 mins; and just saw Craig's test on higher quality AC current load SSR that did better on max temp than the cheaper on I tested.

****************
Adjustable Thermal Disc options:

Emerson 3F05-2 Adjustable Snap Disc Fan Control - Hvac Controls - Amazon.com

Emerson 3F05-2 Adjustable Snap Disc Fan Control - Hvac Controls - Amazon.com
www.amazon.com

The Inexpensive $18 w heat sink dc-ac SSR Relay I Tested was

Baomain SSR-60DA 60A Solid State Relay Module 4-32VDC / 24-480VAC + Heat Sink: Amazon.com: Industrial & Scientific

Baomain SSR-60DA 60A Solid State Relay Module 4-32VDC / 24-480VAC + Heat Sink: Amazon.com: Industrial & Scientific
www.amazon.com

Might be worth Testing this Idea out on a 200 to 500 amp DC load.
Attached picture shows one test cycle with switch imitating a relay wired in parallel.

************
Side Lesson: While using a heat gun, plus an electric induction cook top plate to produce a 20 amp load: In running 20 - 21 Amps AC through my Kill A Watt meter that is rated for 15 amps, I got a flashing display I could have paid attention to, then I burned out my Kill A Watt Meter (no big deal, already ordered another one). In the future, I will measure only up to 15 amps with those meters, and add loads I measure separately together, to get higher than 15 amp loads.
 

Attachments

  • wo.HeatSink [800x600].jpg
    wo.HeatSink [800x600].jpg
    59.5 KB · Views: 20
Last edited:
Craig said:
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.
Click to expand...
WOW, Low temp for AC current of about 20 amps. ... Seem Like Winner SSRs. Wonder How much in $ arena?
...Also wondering what the Testing large load DC current SSRs will reveal.
 
Craig said:
I think you missed that part the 500 amp SSR tested at 150 amps went to 170 degrees in 30 minutes
Click to expand...
I remember that (not exact temp numbers), and think you said you thought that it got too hot ??? ... This thread is getting long enough to be a challenge to go back for easy review. Maybe at some later date, I suggest summary post most relevant test results ... info together (Later / for easy reference. I still Wonder: What kind of heat will produce on 500 amp dc-dc SSR at a 500 amp load; and if a Relay wired in parallel could bring the heat back down. and What the voltage drop will be on lad running through the SSR. ;+)
 
Capt Bill said:
I remember that (not exact temp numbers), and think you said you thought that it got too hot ??? ... This thread is getting long enough to be a challenge to go back for easy review. Maybe at some later date, I suggest summary post most relevant test results ... info together (Later / for easy reference. I still Wonder: What kind of heat will produce on 500 amp dc-dc SSR at a 500 amp load; and if a Relay wired in parallel could bring the heat back down. and What the voltage drop will be on lad running through the SSR. ;+)
Click to expand...
I think your solution has serious merritt. I think the heat dropped slowley because the heat sink was actually holding some heat so it took a bit longer to cook off. Honestly a 500 amp SSR would probably be fine 99% of the time. Especially in a 24v it 48v system
 
onemorebattery said:
I guess I could cobble together a schematic. Here's the stepdown that I use.


Edit: Diagram for common port single relay

View attachment 12677

For two contactors run 12v+ through NO1/COM1 and NO2/COM2 separately to each coil+.

The parts:

Amazon.com: HiLetgo 2pcs DC 12V 2 Channel Relay Module with Isolated Optocoupler High and Low Level H/L Level Trigger Module Triggered by DC 12V: Office Products

Buy HiLetgo 2pcs DC 12V 2 Channel Relay Module with Isolated Optocoupler High and Low Level H/L Level Trigger Module Triggered by DC 12V: Relays - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com

www.ebay.com

TE Connectivity Kilovac EV200AAANA Contactor 500A 12~24VDC Coil USA Shipper. | eBay

Find many great new & used options and get the best deals for TE Connectivity Kilovac EV200AAANA Contactor 500A 12~24VDC Coil USA Shipper. at the best online prices at eBay! Free shipping for many products!
www.ebay.com
Click to expand...
This looks like my best way to wire my 5 amp SSR 3-32vdc control as OFF switch of my MPP All In One, for BMS ... low cell volt trigger or high cell volt trigger, for connection to my Chargery BMS8T. I was wondering how to use both low and high / charge and discharge control at same time on one SSR. I was considering just my BMS to discharge side to switch of All In one at low volt trigger. >>> Looks like you gave me great inexpensive relay module idea to wire one SRR to both low and high volt triggers. I will study more before wiring this up. My current understanding is the Chargery BMS8T powers the charge and discharge side to relay(s) / and release volt power at triggers. Thanks for sharing :+)
 
You must log in or register to reply here.

Similar threads

Mattb4
Proper load testing method for LiFePO4 batteries.
Replies
3
Views
384
wattmatters
wattmatters
frankz66
SSR for AGM battery
2
Replies
39
Views
636
frankz66
frankz66
pollenface
What's everyone using for battery capacity testing?
Replies
17
Views
391
pollenface
pollenface
M
Low voltage cutoff?
Replies
1
Views
352
sunshine_eggo
sunshine_eggo
areoseek
Newtipower 700$ amazon 48v server rack Lifepo4 teardown (with pictures)
Replies
3
Views
392
Zivva
Z

diy solar

diy solar
Back
Top