Charger tripping breaker

Luke B

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May 31, 2021, 2:19:30 PM5/31/21

to electrodacus

I am using a meanwell rsp 50a 12v charger for my 200ah lifepo4 battery and my 70 amp breaker is tripping after about 10 minutes or so of charging. The charger is also only putting out about 22 amps according to the sbms0. I have the output voltage set to 14.4 should I increase it? This is the breaker im using. It got to just over 100* on the outside, so Im wondering if its overheating and I need a better or a bigger one.

https://www.amazon.com/gp/product/B08D3L9498/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Any help would be great, this is my first build and first time im charging it more than a few percent. Not to sure where to go from here. Thanks

Dacian Todea

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May 31, 2021, 2:49:38 PM5/31/21

to electrodacus

It seems you have multiple problems.

If the charger is 50A then you will get around 50A meaning you did not setup your current shunt resistance value correctly in to SBMS0 so go to ADC menu and set the correct shunt or shunt resistance then go to Device Settings menu as push the save device settings button so the shunt resistance value is permanently saved even if you power cycle the SBMS0.

Then that is clearly not a 70A breaker. Those are cheap thermal only breakers and they just have exaggerated ratings on them.

Get something that is build by a known brand like maybe this 80A one https://www.amazon.com/Blue-Sea-Systems-Circuit-Breaker/dp/B00GZOOOMK the next down is the 60A so maybe to close at 50A

Luke B

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May 31, 2021, 5:33:16 PM5/31/21

to electrodacus

Ok ill get a better breaker ordered, thanks for the reference. I double checked my shunts they are 75mv and I have the pv and adc set to 0.7500. I am only using the shore charger idk if that matters or not. Not sure if Ive done something else wrong. Thanks for the help!

Dacian Todea

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Jun 1, 2021, 12:23:11 PM6/1/21

to electrodacus

Are the shunts both 100A 75mV ? if so then 0.7500mOhm is correct but if for example they are 200A 75mV then it will be 0.3750mOhm

In any case if they are 100A and they are set up correctly then current measurement should be super accurate within maybe 5% tolerance as those 100A 75mV china stunts have some larger tolerances (sometimes they do not factory trim them).

Luke B

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Jun 4, 2021, 10:51:18 AM6/4/21

to electrodacus

Ahh that explains it. They are both 250a .75mv shunts. If I did your math right I believe I need to set it to .3mv? Thanks again for the help.

Dacian Todea

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Jun 4, 2021, 2:43:42 PM6/4/21

to electrodacus

Yes in that case it will be 0.3000mOhm but 250A 75mV is not very common. The inexpensive china made 75mV shunts are usually multiple of 100 so 200,300,400,500A

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