diy solar

diy solar

Scratching my head wondering why the solar isn't keeping up.

seneysolar said:
You just dont want to spend all day charging a bad battery in a string of good batteries, the good ones dont get charged properly.
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1. You didn't say bad, you said old.
2. Energy needs to go somewhere, if you have a cell sucking down energy, the only option is to store it or turn it into heat. The latter is more common with lead acid. I've never heard of it with Lifepo4. Occasionally it happens with bad lipo cells, but I'm pretty sure those are shorted anyways. This is pretty far in the weeds from the OP's situation.
 
I tested that exact same charge controller and while most of the time it does work very well, I found that days with intermittent cloud and sun sometimes caused the MPPT algorithm to get "stuck" and it would send a much lower amount of power to the batteries until I came along and reset the MPPT.

The same problem happens on some of the other cheap powMR and makeskyblue 60A MPPTs. The newest makeskyblue versions have firmware updates that fix that problem from what I understand.

I also noticed that when it went above 40 amps the display started to flicker like crazy but it was still producing power properly.
 
400bird said:
1. You didn't say bad, you said old.
2. Energy needs to go somewhere, if you have a cell sucking down energy, the only option is to store it or turn it into heat. The latter is more common with lead acid. I've never heard of it with Lifepo4. Occasionally it happens with bad lipo cells, but I'm pretty sure those are shorted anyways. This is pretty far in the weeds from the OP's situation.
Click to expand...
Well hes not getting through the night on 25 batteries. No amount of new batteries on that string will help.
The theory of just adding new batteries on a string of old/ and or bad batteries is doomed for several reasons.
Yes there are scenarios that you can but it requires careful assessment of each battery

"If you mix different LiFePO4 batteries, one of the most obvious consequences is that the effect of your battery pack will not meet your expectations. In the battery pack, high-performance batteries will always be constrained by weaker batteries. For example, when discharging, the voltage is forced to drop to the same level as the weaker battery, which increases the risk of battery damage. In the process of using such a battery pack, the performance difference of each battery will become larger and larger, such as capacity, discharge rate, etc. These differences will cause the BMS to lose its function and fail to provide you with safety protection. Finally, one or more of the batteries will be over-discharged, causing damage or leakage, causing irreparable losses. And due to a problem with the battery pack, the output power is of course unstable, and your electrical appliances may suffer some damages and cause malfunctions." -I have found this to be true

batteryfinds.com

Can I Mix Different LiFePO4 Batteries in a Pack?

Recommended not to mix different LiFePO4 batteries, it will affect the effect of the entire battery pack.
batteryfinds.com batteryfinds.com

The simple answer is - dont do it
 
OP needs more solar (or less loads). There's no proof that their batteries are bad, just excessive.
Them not making it through the night is a function of not putting enough energy in. There's only 4000 watts of solar for something like 30kWh of battery. 30 kWh of battery that maybe has balance issues due to the order of connections and layout of battery cables.


That link is no proof and is not a reliable source of information. Heck, they can't even proofread their pages. Both spelling and nonsense sentence. What could "has been in right connected" mean?

Screenshot_20240110-072208.png
 
I think one of the most important items you can install is that shunt based battery monitor!!! - that you already have (and should have been installed a long time ago.

That will tell how how much power you are making and how much you are using. Something is not right in your system.

With that much solar and batteries, you should have no issues making it through the night.

One other tool that you probably need is a Digital Multimeter with clamp on current like this:

Klein Tools CL320 Digital Clamp Meter, HVAC AC Auto-ranging 400A, AC/DC Voltage, TRMS, DC Microamps, Resistance, Frequency, NCVT, Temp, More https://a.co/d/iPx4kRP

I have a Klein like that one - there are other cheaper ones - I just don’t know how good they are.

With this you can see how much current is flowing down a wire for example:
It’s sunny and I should be making lots of solar power - but is the current flowing? Now you can know.

You need some trouble shooting in your system- is power flowing to the first battery - is it flowing to the last battery- are those two current amounts the same?

Good Luck
 
400bird said:
OP needs more solar (or less loads). There's no proof that their batteries are bad, just excessive.
Them not making it through the night is a function of not putting enough energy in. There's only 4000 watts of solar for something like 30kWh of battery. 30 kWh of battery that maybe has balance issues due to the order of connections and layout of battery cables.


That link is no proof and is not a reliable source of information. Heck, they can't even proofread their pages. Both spelling and nonsense sentence. What could "has been in right connected" mean?

View attachment 188057
Click to expand...
Yeah that article is not written the best, but it makes the point. Most likely it was translated from a Chinese company, but hey most of these batteries are Chinese. I have yet to see any manufacturer recommend the practice of continually adding different age and brand batteries to the same string.

He says hes only using 400watts and charging with 4000watts of panels, where is all that energy going?
 
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