Why Has My 6-Month-Old "Once Perfect" Solar System Failed?

jesfl

Solar Enthusiast
Again, fantastic helpful information. THANK YOU ! ! !

(1) I didn't know I could safely connect all 3 10-amp 120-volt chargers to one lithium battery. Later today I will certainly try that as a test. It doesn't sound at all off the wall to me.

(2) I also like the idea of a separate battery to start the generator. It may be a great use of the cheap Walmart marine SLA I bought to start it for a previous test. (The SLA battery has 1000 cranking amps, which is why I guessed it would be best.)

Is there a simple way to connect the battery directly to the generator to start/run it, for now? (By that I mean not connecting it to the full system instead of the lithium batteries, as is the case only way I know to do it, for now.)

My generator is mounted on steel brackets under the rear of my 2004 fifth wheel. It came installed that way when I bought this trailer a couple of years ago. It is really hard for me to work on (especially at my advanced age of 75). But, I think I see a reachable solenoid/starter bottom left after the front panel is off. I can't see where the 2 AWG cable that runs to the RV's front compartment and connects to the system goes once inside the generator's housing. Any thoughts -- even whether plausible -- will be helpful.

(3) I do not have any detailed specs for the batteries. On Friday mid-afternoon, I asked the U.S. selling company (BtrPower) for two things: (a) procedure for resetting the BMS, and (b) solar charge controller voltage settings for the battery. No response, yet; but it is the weekend. I will now also request other specifications. I am not hopeful of a fast response. Buying these batteries was clearly a very bad decision, but I didn't know any better in the spring of last year.

(4) Your mention that starting the generator with the lithium batteries could have "damaged" the BMS in the batteries (again, didn't know better) is discouraging. How does one tell if the BMS is damaged vs. just needs to be reset? When I connect the 3 10-amp chargers to a single lithium battery later today after I have the generator running . . . and they don't charge the battery at all or only very slowly . . . does that signal damage to the BMS, or only the need for a BMS reset? Or neither?

Thank you again for the teaching. I think I am slowly catching one. Trying hard.

Jim S.
 

jesfl

Solar Enthusiast
Here's a manual for one brand AGM. Page 35 has voltage vs. SoC


Thank you for the manual.

Does this mean an AGM battery behaves exactly like an SLA, or very close?

I found a 50% discharge rate chart on page 40-something with a 50% discharge range of 11.83V to 12.18V. I'm comfortable thinking in terms of the higher number for this single temporary battery and being safe until I can get back to permanent batteries.
 

HRTKD

Boondocker
2. On a travel trailer I could tell you how to disconnect the generator from the "house" batteries. On a fifth wheel, I don't know that my method would work the same. I think you're going to have to trace the DC wires that are used to start/run the generator. That's not going to be fun.

4. Before you charge the batteries, check the voltage. If it's above 14, they're probably already charged. If not, charge and see what happens.
 

Just John

Photon Sorcerer
Again, fantastic helpful information. THANK YOU ! ! !

(1) I didn't know I could safely connect all 3 10-amp 120-volt chargers to one lithium battery. Later today I will certainly try that as a test. It doesn't sound at all off the wall to

I just wanted to point out that the earlier battery spec sheet linked says charge current is 10 amps or less. It was for a 150 amp hour battery, and that is unusualy low current.
That is from the spec listed by the manufacturer, not the ebay link (that says 100 amps).

(2) I also like the idea of a separate battery to start the generator. It may be a great use of the cheap Walmart marine SLA I bought to start it for a previous test. (The SLA battery has 1000 cranking amps, which is why I guessed it would be best.)

I am thinking most RV dealers should easily be able to configure a starter battery for you. Probably won't be cheap, quality battery cable isn't cheap either.
 
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jesfl

Solar Enthusiast
Here's an update:

First the voltage readings today, as requested previously.
-- at the 2-pole breaker for incoming solar: 76.1 volts in, and 76.1 volts out;
-- at the EPEVER Tracer 4215BN solar controller: 76.0 volts in, and 14.54 volts out; and
-- at the battery (now connected to a single SLA battery): 14.49 volts. (Is that slight line loss normal?)
All of which again points away from the charge controller and to the batteries, either the BMS or the battery cells themselves.

Right now I am running my generator using the three 10-amp chargers on one battery -- 30 amps into one of the LiFePO4 batteries, disconnected from everything -- to see if it will charge?

Still no response from BtrPower, the battery seller in the U.S. I have requested:
(1) the details of the procedure for resetting the BMS units on all three batteries;
(2) the recommended settings for charging the LiFePO4 batteries with a solar charge controller;
(3) other detailed specifications for the batteries, such as the charge/discharge amperage.

Given that BtrPower is primarily an ebike battery seller, I suspect they may have no idea about the answers to (2)? But, it seems to me they should be able to answer (1) and (3).

I first emailed on Friday afternoon. I will email again today as a follow-up. If no answers by tomorrow mid-day (given the time difference), I'll start calling. However, I recall the communication with the seller from whom I bought the batteries, and it was slow and difficult. (That should have been a clue, I know.)

Having now looked at their current website, given their ebike focus, I doubt they have any clue how LiFePO4 batteries are used in RV's . . . except that they could/did make sizes (100Ah, 150Ah, 200Ah) that were like other batteries being sold for the RV and marine markets, so they advertised and sold them for RV's. This newbie was gullible.

I'll let you know the result of my single LiFePO4 battery 30 amp charging test ongoing right now. And, hopefully, whatever response there is from BtrPower.

Thanks again to everyone. I would never have gotten even this far without your gracious assistance. And my new learning is off my chart! I am pleased about the new knowledge, even though I am still despondent that my problem is the batteries.

Jim S.
 

jesfl

Solar Enthusiast
I just wanted to point out that the earlier battery spec sheet linked says charge current is 10 amps or less. It was for a 150 amp hour battery, and that is unusualy low current.
That is from the spec listed by the manufacturer, not the ebay link (that says 100 amps).



I am thinking most RV dealers should easily be able to configure a starter battery for you. Probably won't be cheap, quality battery cable isn't cheap either.

John,

I just saw your message after I sent my "update" message moments ago.

I also panicked and immediately disconnected the 3 battery chargers sending 30 amps to the single battery for my charging test.

Did I fry that battery with the 30 amp charging for about 30 minutes)?

Where did I miss a linked spec sheet?

I am searching for that and looking on the BtrPower website again.

Thanks for the important alert.

Jim S.
 

Forbisher

Փփքխմպձժճֆըվմ
John,

I just saw your message after I sent my "update" message moments ago.

I also panicked and immediately disconnected the 3 battery chargers sending 30 amps to the single battery for my charging test.

Did I fry that battery with the 30 amp charging for about 30 minutes)?

Where did I miss a linked spec sheet?

I am searching for that and looking on the BtrPower website again.

Thanks for the important alert.

Jim S.
That 10A is referring to the battery charger output!!

Do not panic and use common sense when taking advice from a forum.

Not the max 150Ah battery charging spec!!
A LFP 150Ah battery can usually accept 75A depending on the BMS.
 

HRTKD

Boondocker
That 10A is referring to the battery charger output!!

Do not panic and use common sense when taking advice from a forum.

Not the max 150Ah battery charging spec!!
A LFP 150Ah battery can usually accept 75A depending on the BMS.

Exactly. Thank you for saving me from typing the same thing.
 

jesfl

Solar Enthusiast
That 10A is referring to the battery charger output!!

Do not panic and use common sense when taking advice from a forum.

Not the max 150Ah battery charging spec!!
A LFP 150Ah battery can usually accept 75A depending on the BMS.

Thank you. After the immediate panic because I was charging at 30 amps, I kinda' assumed it was a misread of the charger specs. But, I did disconnect the 30 amp charging to be safe.

I also turned off my generator, so I will wait until tomorrow to reset the 30 amp charging test when I can let the generator run for a longer time.

I'm hoping for some info from the seller of the batteries tomorrow morning.

Meanwhile, I need a break.

Thank you.

Jim S.
 

HRTKD

Boondocker
Meanwhile, I need a break.

Take the rest of the day off and have a beer on us.
beer.gif
 

Just John

Photon Sorcerer
That 10A is referring to the battery charger output!!

Do not panic and use common sense when taking advice from a forum.

Not the max 150Ah battery charging spec!!
A LFP 150Ah battery can usually accept 75A depending on the BMS.

I suspect it likely is a typo judging by how they spelled description.
The battery GXMnow linked to.

specs_batt.jpg

I could be wrong, but Max Charge Current <=10A means less than or equal to 10 amps.

Seems a pretty wimpy charge current for that size battery.

This does sound like the BMS units inside of the 3 batteries have all gone to open protect mode. If an equalization cycle did run, it very well could have pushed the batteries up to where the BMS units all turned off due to over voltage protect. Do you have a volt meter with you? Can you try connecting a 12 volt light bulb to one of the batteries? What brand are the batteries? You just answered BTR. Can you find instructions for resetting the BMS after a fault? I just found this site
www.btrpower.com

12V 150 AH Lithium LiFePO4 Battery, Deep Cycle Battery

Super Safe. Extremely safe Lithium Iron phosphate cells,never catch fire Longer battery life. lithium battery's service life is more than 2000 cycles Built-in BMS. providing multiple protections against: over-charging, over-discharging, over-current, short-circuit and over-temperature Widely...
www.btrpower.com
www.btrpower.com
Is this the battery you have?
There is not a lot of information on the page, but they do have a "Contact Us"

Don't shoot the messenger, I'm just reading what they wrote on their own website, I didn't write it.
Even so, it would most likely be a limitation of their BMS, not the battery cells.
 

Just John

Photon Sorcerer
Not the max 150Ah battery charging spec!!
A LFP 150Ah battery can usually accept 75A depending on the BMS.

That's why I pointed it out. Usually a 150 amp hour battery can accept 75 amps, but they do state 10 or less, seemed worth noting.
Of course they also show 8 gauge wires on a 100 amp rated discharge battery, hooked up to a 50 amp rated connector.
 

HRTKD

Boondocker
They mention the charge current not once, but twice, and they're consistent. That's a really, really bad charge rate that just about any solar charge controller can exceed without working up a sweat. If it's true, then it would not be unlikely that the BMS is simply toast, especially if the BMS didn't have sufficient protection from higher current.
 

Forbisher

Փփքխմպձժճֆըվմ
I suspect it likely is a typo judging by how they spelled description.
The battery GXMnow linked to.

View attachment 41931

I could be wrong, but Max Charge Current <=10A means less than or equal to 10 amps.

Seems a pretty wimpy charge current for that size battery.



Don't shoot the messenger, I'm just reading what they wrote on their own website, I didn't write it.
Even so, it would most likely be a limitation of their BMS, not the battery cells.
It does say:
CHARGE TIME 15 to 16 hours:

So that makes sense that 10A Charger for 15 hours will charge a 150Ah battery.
But there is no way that 10A is the Max Charge rate for a 150Ah LFP that is rated for 100A discharge.
This has to be a mistake.
 

Forbisher

Փփքխմպձժճֆըվմ
Er, I didn't give the advice, I pointed out what the MANUFACTURER says. I also pointed out it seemed odd.
From the eBay sales page on post #6.
Maximum Charging Current:100A

When something looks obviously wrong then use common sense.
Personally I would not charge at more than 0.5C or 75A

***************************
Battery Specifications
Normal Voltage:12.8V
Normal Capacity: 150Ah
Maximum Continuous Discharge Current: 100A

Maximum Charging Current:100A

Over Charging Protection Voltage: 14.6V
Cycle Life: 2000 cycles 100% DOD,1 C, 20±5℃
Discharge Temperature: -20℃~60℃
Charge Temperature: 0~45℃
Dimensions: 12.2x9.4x7.7in
Weight: 42Lbs
Package List:
1x 12v150A LFP Battery Pack (Charge and discharge from the same wires)
1x 14.6V 10A Charger
2x Anderson connectors
 
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Just John

Photon Sorcerer
From the eBay sales page on post #6.
Maximum Charging Current:100A

When something looks obviously wrong then use common sense.
Personally I would not charge at more than 0.5C or 75A

***************************
Battery Specifications
Normal Voltage:12.8V
Normal Capacity: 150Ah
Maximum Continuous Discharge Current: 100A
Maximum Charging Current:100A
Over Charging Protection Voltage: 14.6V
Cycle Life: 2000 cycles 100% DOD,1 C, 20±5℃
Discharge Temperature: -20℃~60℃
Charge Temperature: 0~45℃
Dimensions: 12.2x9.4x7.7in
Weight: 42Lbs
Package List:
1x 12v150A LFP Battery Pack (Charge and discharge from the same wires)
1x 14.6V 10A Charger
2x Anderson connectors
Ok, I hate to say it, but which part is the common sense part?

The ebay description, the manufacturer description, or the pictures on both with 8 gauge wires and 50 amp rated anderson connectors.

You guys jump right to "John has no clue, use common sense". All I did was point things out that don't add up. I did nothing more than point it out. I did not recommend any charge current. Seems like it really needs something to actually measure current input and voltage after a couple of hours, since he can start his generator now. Most multimeters can measure 10 amps, even if the charger is just a black box (I hate it when you get nothing to indicate what it's doing).
 
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