diy solar

diy solar

I think I ordered a useless battery monitor (PZEM 015)

Well I thought about something ...
If this device only counts the discharge current, that means the displayed SOC will never goes up ?? and you have to manually reset it to 100% when it is at zero ? that's a complete non-sense it's impossible. @sunshine_eggo @upnorthandpersonal
 
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No, because it just uses the voltage to do state of charge.
ah ok, so contrary to what some people said here, the displayed SOC is not function of the current but in fact is an estimation based on the voltage. Which is useless for a lifepo4 since the voltage varies only a few.
 
ah ok, so contrary to what some people said here, the displayed SOC is not function of the current but in fact is an estimation based on the voltage. Which is useless for a lifepo4 since the voltage varies only a few.

Yes - I also got you off-track at the start of the thread since I remembered it wrong. These things are one direction only, with a voltage to estimate state of charge. I used the PZEM 017 in the past (no display, RS485 interface) and used multiple of those to determine incoming and outgoing current from solar output and inverter input.
 
Yes - I also got you off-track at the start of the thread since I remembered it wrong. These things are one direction only, with a voltage to estimate state of charge. I used the PZEM 017 in the past (no display, RS485 interface) and used multiple of those to determine incoming and outgoing current from solar output and inverter input.
thanks, now all my worries are confirmed then. This device will end up in trash.
 
I have the 300a version it’s still a shunt that will shown flow just no sign for flow. I have a starter system that only 12v and minimal PV, it meets my current needs.

My lifepo BMS also as and assumed SOC so again it suits my needs. I will eventually snag a Victron smart shunt when I upgrade to a 24v system.
 
As suggested in above post, Junctek may do what you are looking for. We have 3 separate systems and I actively maintain 2 of them. They all have the Junctek KH or KF140's??, the one with the little display. Just an option if you don't want to spend a lot of dough but want decent accuracy.
 
Most problems like these can be solved by buying Victron.
My Victron Smart Shunt measures current both ways. You enter max AH, change a few settings for LiFePO4.
Does not care about voltage but can send out that data via bluetooth to Smart Solar, etc..
 
With the one-way monitoring and the stupid 1 button calibrate button, it's OK for testing a new setup. You can reset the MAH, WH and runtime as you charge and discharge a new system. But as a continuous, on the go monitor it's of little value.
Mine died at -10 and was replaced by a better unit with 2 way + - flow
 
Thanks guys for all the extra informations.
I am using it right now to calibrate my JBD BMS with my new lifepo4. I am using the Ah-meter to measure the battery's discharge to fill in the 20/40/60/80% fields in the BMS app.
After that I'll get a new batt monitor with the 2 ways measuring capability.
Victron is quite pricey, I have a victron solar charger it's good stuff but expensive.
Thanks for the junctek suggestion (I knew this name before but it didnt inspire me confidence lol)
 
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junctek suggestion (I knew this name before but it didnt inspire me confidence lol)
Haha, yeah it's a funny name in English. I think they are about the best bang for the buck at this time. And cheap enough if I want to replace them with the next shiny thing in a couple of years. :rolleyes:
 
So either my Daly BMS are very very bad at reading current draw or these things are not accurate.

I've got these hooked up to my Busbar and they all show steady load reading almost no movement, but using the Daly I can see highs and lows.

Is it just averageing the current over a second or something?

I was going to have the Displays for easy information and also hookup to my Home Assistant sharing the shunt between them but if the readings are this bad on the display I'll assume the PZEM 17 is just as horrible.

My 3 MPP and the Meters below them are reporting almost the same figures, the Daly readings are just all over the place.
 
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So either my Daly BMS are very very bad at reading current draw or these things are not accurate.
...
My 3 MPP and the Meters below them are reporting almost the same figures, the Daly readings are just all over the place.
Yes, despite their unexplainable populaty, Daly BMS are known to be among the worst on the market.
 
So either my Daly BMS are very very bad at reading current draw or these things are not accurate.

I've got these hooked up to my Busbar and they all show steady load reading almost no movement, but using the Daly I can see highs and lows.

Is it just averageing the current over a second or something?

I was going to have the Displays for easy information and also hookup to my Home Assistant sharing the shunt between them but if the readings are this bad on the display I'll assume the PZEM 17 is just as horrible.

My 3 MPP and the Meters below them are reporting almost the same figures, the Daly readings are just all over the place.
My PZEM also gives different values from my JBD ones. Basically while discharging my battery with a hair dryer, the BMS shows 42Ah while the PZEM shows 48Ah...
 
Victron product is good, it has the performance of discharge current constant, according to different discharge current regulation capacity, but the price is too expensive, the name of JUNCTEK may be the Chinese pronunciation of the manufacturer’s name
 
I think that there maybe a misunderstand about this thing. It measures in both directions charge/discharge, but it only counts in one direction+.
so you charge and pump in 50ah, then discharge 50ah and it shows100ah.
 
Victron product is good, it has the performance of discharge current constant, according to different discharge current regulation capacity, but the price is too expensive, the name of JUNCTEK may be the Chinese pronunciation of the manufacturer’s name
there was a discount coupon for the Junctek is that one still working?
 
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