Bab Bad Zoom batteries?

[Tran Family]

Hi Will, your 0.2C (~250 watts) discharge test might not be enough to grade this battery. Serious issues here with two of these in parallel using 2000watts GoWise pure sine, or 2200watts Giandel pure sine from your website( plus 3 other highly rated pure sine inverters by other RVers). First i thought there was something wrong with all these inverters because all these new amazon inverters when connected to these two zooms batteries (100 amp BMS each so together they can handle up to 200amp) all can deliver continuous 500 watts for 10 mins or more. I didn't go beyond 10 mins because i thought it was long enough. However, when applied 700 watts then these inverters shut down after 3-5 mins; 1000 watts shut down in 1-2 mins, 1500 watts shut down in 30 - 50 secs .

I did multiple isolation tests including attaching a light directly to the batteries to see if the lights would go out when both BMS shut down. The light never shut down but all the inverters did... even at 700 watts . Weird thing is, even if 1 battery bms shuts down then the other parallel should be able to handle 700 watts (~ 65amp) but that is not the case ... all inverters shut down after 3-5 mins with the lights still on without a slightest flicker. my DC amp meter and volt reading (12.4v constant) were always attached and monitored. No shore power.

so i swapped to 2 lead batteries and ran the same tests. All the inverters powered through no problem even with fluctuating voltage from 12.7V start to 10.8V. The lead batteries boiled my 1000w 1L electric kettle, ran 1500w heat gun full power (though not as strong) without shutting down once. please help. I don't know what else to do other than asking you and contacting Zooms for support. thank you Will.

 

[Bud Martin]

Did Will test this Zoom batteries or what? Link to Will video?

 

[Tran Family]

 

[740GLE]

How are you charging these zoom batteries and verifying they are fully charged?

 

[Tran Family]

Fully charged to 13.5 volts via 200 watts parallel solar and/or converter with charge wizard up yo 14.4 volts.

 

[Tran Family]

Amazon still allows return for these batteries passed 30 days … I may need to go that route.

 

[JoeHam]

Fully charged to 13.5 volts via 200 watts parallel solar and/or converter with charge wizard up yo 14.4 volts.

13.5 volts is too low. 14.4 until full will be more like it.

A shunt for coulomb counting would be useful.

 

[Tran Family]

13.5 volts is too low. 14.4 until full will be more like it.

A shunt for coulomb counting would be useful.

100% State of charge for lifep04 is 13.4 v resting. I measured the voltage 2 hrs after fully charged.

 

[JoeHam]

I measured the voltage 2 hrs after fully charged.

I did not realize that from your post, sorry.

Coulomb counting is a great way to confirm SOC for LiFePO4

 

[A.Justice]

100% State of charge for lifep04 is 13.4 v resting. I measured the voltage 2 hrs after fully charged.

That's not entirely true. That's the voltage that the cells will settle down to after they've been fully charged. The closer you get to 13.4 volts (if the charger is set at that) the slower the charging will be, to the point that it could take a VERY long time to charge the top end up at 13.4 CV. By the time your cells are at 13.35v your charger may be pushing only an amp or two at 13.4v. There's very little difference of potential between those two voltages.

LiFePO4 has a very tight voltage curve. 13.3 could be anywhere from 99% to 50% or so, depending on load, voltage drop, and a bunch of other factors. In my experience testing batteries, about 80+% of the capacity of those cells are between 13v and 13.4v which means that voltage is not a good indicator of state of charge.

13.4v could easily be 13.3v with voltage drop over a charging wire. And your cells won't charge to anywhere near full at that voltage.

13.75-14.4v is the generally accepted voltage for charging LiFePO4. Try charging at 14.4v for a while and report back.

A cheap shunt (under $20) would take all the guesswork out of this.

 

[Tran Family]

That's not entirely true. That's the voltage that the cells will settle down to after they've been fully charged. The closer you get to 13.4 volts (if the charger is set at that) the slower the charging will be, to the point that it could take a VERY long time to charge the top end up at 13.4 CV. By the time your cells are at 13.35v your charger may be pushing only an amp or two at 13.4v. There's very little difference of potential between those two voltages.

LiFePO4 has a very tight voltage curve. 13.3 could be anywhere from 99% to 50% or so, depending on load, voltage drop, and a bunch of other factors. In my experience testing batteries, about 80+% of the capacity of those cells are between 13v and 13.4v which means that voltage is not a good indicator of state of charge.

13.4v could easily be 13.3v with voltage drop over a charging wire. And your cells won't charge to anywhere near full at that voltage.

13.75-14.4v is the generally accepted voltage for charging LiFePO4. Try charging at 14.4v for a while and report back.

A cheap shunt (under $20) would take all the guesswork out of this.

My rv converter fitted with smart wizard puts out 14.4v . I has it up 24 hrs. Tested again this morning but still shuts down at 50 secs for 1500watts load.

 

[A.Justice]

My rv converter fitted with smart wizard puts out 14.4v . I has it up 24 hrs. Tested again this morning but still shuts down at 50 secs for 1500watts load.

Assuming that it is in fact fully charged, I'm wondering if the BMS (or a bad connection) gets hot under load and the temperature protection triggers after a certain time.

Over-current protection should kick in immediately, but heat could take a few minutes to register. It could also be heating up, and the temperature calibration could be way off, which would make it THINK it was much hotter than it was inside of the case.

Generally, cheap batteries use cheap BMS's. Lower quality stuff can have weird issues like that, I got an infrared thermometer gun from Amazon, and right out of the box it was off by 30°.

 

[Tran Family]

Assuming that it is in fact fully charged, I'm wondering if the BMS (or a bad connection) gets hot under load and the temperature protection triggers after a certain time.

Over-current protection should kick in immediately, but heat could take a few minutes to register. It could also be heating up, and the temperature calibration could be way off, which would make it THINK it was much hotter than it was inside of the case.

Generally, cheap batteries use cheap BMS's. Lower quality stuff can have weird issues like that, I got an infrared thermometer gun from Amazon, and right out of the box it was off by 30°.

I did so many isolated tests and the next one will be hooking up two identical inverters and run both at the same time from the same Zooms lifeP04. On at 500 watts and the other at 1000 watts.

if the 1000watts should shut down while the 500watts still runs then bad inverter. If both shut down then definitely bad bms since all tested inverters can handle 500watts without shutting down.

 

[A.Justice]

I did so many isolated tests...

Have you monitored the temperature? Might be worth a shot...

 

[Tran Family]

Have you monitored the temperature? Might be worth a shot...

Bms is inside the oversized casing on all sides and never felt warm to the touch so I don’t think I can monitor the bms or battery temperature .

 

[Bud Martin]

BTW, what is the fault code you are seeing on the inverter when it goes into shutdown?

 

[Tran Family]

Think I found the problem. It is the auto disconnect 150 amp breaker that stayed “on” but silent disconnected and reconnected without tripping. Inverters and batteries performed passed 4 mins at 1500watts after I bypassed the breaker. Thank you everyone for your inputs.

 

[Bud Martin]

Think I found the problem. It is the auto disconnect 150 amp breaker that stayed “on” but silent disconnected and reconnected without tripping. Inverters and batteries performed passed 4 mins at 1500watts after I bypassed the breaker. Thank you everyone for your inputs.

Pot #1:
"so i swapped to 2 lead batteries and ran the same tests. All the inverters powered through no problem even with fluctuating voltage from 12.7V start to 10.8V."
So is it the same breaker that you use when you swapped the Lead batteries?
Can you show us the pictures of the breaker? is it one of those $15 Amazon breaker?

 

[Tran Family]

Pot #1:
"so i swapped to 2 lead batteries and ran the same tests. All the inverters powered through no problem even with fluctuating voltage from 12.7V start to 10.8V."
So is it the same breaker that you use when you swapped the Lead batteries?
Can you show us the pictures of the breaker? is it one of those $15 Amazon breaker?

I took the inverter to stand alone lead batteries (didn’t want to remove Zooms from Rv). no breaker here. Direct connect.

Yes it was $15 from Amazon with 1000 plus 4.2 stars reviews. Even the expensive breakers have issues. Mine was a fluke when it “healed itself “ after silent trips. Wasted a good 2 weeks buying and returning inverters …I feel bad.

 

[Bud Martin]

Ah, the cheap Amazon breaker strikes again with great review to boost..