Built A tiny home, but it has solar issues

[The_realTW]

I have found that when I use the lead acid batteries for a heavy load like a toaster, and I measure the SOC just based off the volts, it will be low, but as the battery rests, it recovers when the battery idles. I never saw quite the drop you did.

There is a max discharge rate to these batteries. My trojan’s have a max discharge rate of 350, but I don’t know for how long. I also don’t ever see myself pulling 350 amps off my batteries. I’d hope my 200 amp fuse blows first.

Well the toaster thing just tells me I need more battery baño to pull from. When the new system is in and all the needs have been properly put into an energy audit, things should make more sense.

[chrisski]

I have found that when I use the lead acid batteries for a heavy load like a toaster, and I measure the SOC just based off the volts, it will be low, but as the battery rests, it recovers when the battery idles. I never saw quite the drop you did.

There is a max discharge rate to these batteries. My trojan’s have a max discharge rate of 350, but I don’t know for how long. I also don’t ever see myself pulling 350 amps off my batteries. I’d hope my 200 amp fuse blows first.

[The_realTW]

100%. Congrats.

There was enough power to even use the toaster for a few minutes, but it did drop to 60%, however it did go back up right after I turned it off.

I also did a volt meter test on the battery’s , on the left was 6.98 volts, on the right was 6.87 volts.

when the sun goes down it will be lower again, I’ll keep you informed.

[chrisski]

100%. Congrats.

[The_realTW]

Good to see that shunt working! I get a lot of useful data from it. The 200 amp shunt is for how many amps can flow across it. If you go above 1500 watts on your inverter, you’ll see that you will start to come close and exceed that 200 amps. I don’t know what happens if you exceed it.

The shunt rating does not really correlate to the battery AH, but more than the max discharge. In my case I have a 500 amp shunt, and I don’t want more than 200 amps of current from the battery, so I have a 200 amp battery fuse.

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The PWM may have an equalization mode. So the SCCs may be able to be swapped.

For your current SCC, if you chose a battery type of sealed lead acid, that may be AGM, so as a safeguard, it would not allow equalization.

That really depends on how your FLA batteries are doing, and when the lithium’s come in.

i

Not sure I just know that this is not the shunt that came with the monitor, but also this happened today

First time I have ever seen this

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[The_realTW]

At 186 posts and counting, reading back isn't going to happen for most readers. Actually, I'm done following, myself.

Hey There, thanks for your feedback, I found a very competent forum user, so its ok if you not follow. Have a great day

[littleharbor]

At 186 posts and counting, reading back isn't going to happen for most readers. Actually, I'm done following, myself.

[chrisski]

Good to see that shunt working! I get a lot of useful data from it. The 200 amp shunt is for how many amps can flow across it. If you go above 1500 watts on your inverter, you’ll see that you will start to come close and exceed that 200 amps. I don’t know what happens if you exceed it.

The shunt rating does not really correlate to the battery AH, but more than the max discharge. In my case I have a 500 amp shunt, and I don’t want more than 200 amps of current from the battery, so I have a 200 amp battery fuse.

========+===•+•==

The PWM may have an equalization mode. So the SCCs may be able to be swapped.

For your current SCC, if you chose a battery type of sealed lead acid, that may be AGM, so as a safeguard, it would not allow equalization.

That really depends on how your FLA batteries are doing, and when the lithium’s come in.

i

[Bala]

Ok I think I have it setup, problem is the shunt that came with this monitor (which I never saw lol) was rated at 200A, the system is 420 AH, so I am presuming the shunt must be rated for at least the same as the fuse, which is 500A as well.

Well reading this post does not indicate that you have a full understand of A, Ah etc.

[The_realTW]

You are focusing on getting SOC readings from a cheap meter when you have much more serious things to learn.

A and Ah are two different things. The 200A rating for the shunt is its current carrying capacity. Ah is what the battery can supply over time when new and fully charged, which yours are not.

To determine fuse size, you need to determine load, then size the cable to take the load then fuse to protect the cable. Having a 200A shunt and a 500A fuse means you your system is fused at whatever will blow/catch fire first out of the shunt and fuse, or the cable if it is not sized correctly.

I do know the difference between Amps and Amp Hours, I have taken two solar courses since joining this forum (Discussed further back in the thread). I am not really focused on anything that meter says, I just wanted to get it to function correctly. None of what I have been doing is to make the system work, I know already this system will never work the way I wanted it to, which is why my energy will be focused on replacing the system. Right now, with nothing to do as Chrisski pointed out, I am just fiddling with what is here, I do not expect it to change.

As for the way the system was wired, I did not do that, if you read back through the thread, you will see an installer who was supposed to know what to do, set all this up.

The primary reason I am suing him is because after I had already told him what I wanted, he set me up with a bad system.

With my new knowledge, and the help from the people on this forum, the new system will work and will be matched perfectly.

Thanks for all the feedback, I really do appreciate it.

[Bala]

Ok I think I have it setup, problem is the shunt that came with this monitor (which I never saw lol) was rated at 200A, the system is 420 AH, so I am presuming the shunt must be rated for at least the same as the fuse, which is 500A as well.

I think its as good as its going to get, this monitor is not setup for this system (just another reason why it is all getting changed out), OH BTW I set the Amps for 50A (Options were 50-100-200-300) and now the amps charging on the SCC and the monitor are close to synced, but they are still off.

SOC is better though

You are focusing on getting SOC readings from a cheap meter when you have much more serious things to learn.

A and Ah are two different things. The 200A rating for the shunt is its current carrying capacity. Ah is what the battery can supply over time when new and fully charged, which yours are not.

To determine fuse size, you need to determine load, then size the cable to take the load then fuse to protect the cable. Having a 200A shunt and a 500A fuse means you your system is fused at whatever will blow/catch fire first out of the shunt and fuse, or the cable if it is not sized correctly.

[The_realTW]

if I understand, you are putting Li batteries on the trailer tongue ? That leaves them vulnerable to frost. Frosty Li batteries CANNOT be charged without destroying them. You BMS may have a temperature cut off at 33F, most do not.

Li batteries do not ever get Equalized. They get balanced, which is a long, slow, gentle process 1x a year.

Hey there , thanks for the reply, I fear you may not be “up on” this whole thing, which is now 12 pages long.

the batteries ARE NOT LI, they are flooded lead acid and they are on the tongue because they vent when they charge (which is hardly ever lol) and they have NO BMS system (with exception of the SCC regulation.

the NEW setup (down the road) WILL be lipo4 and they WILL NOT be on the tongue, but rather inside in a temperature regulated enclosure.

hope that clears that up for ya.

I did do some research and saw they do not like being below 32 degrees (the Li batteries) but then again no battery seems to do good in the cold lol .

[Mike90250]

if I understand, you are putting Li batteries on the trailer tongue ? That leaves them vulnerable to frost. Frosty Li batteries CANNOT be charged without destroying them. You BMS may have a temperature cut off at 33F, most do not.

Li batteries do not ever get Equalized. They get balanced, which is a long, slow, gentle process 1x a year.

[The_realTW]

Oh btw ( would have edited the previous post to add this but we all know what happens when we do that) the SCC DOES NOT allow the equalization to change, that I can see. So I am not sure how that would work!

[The_realTW]

Ok I think I have it setup, problem is the shunt that came with this monitor (which I never saw lol) was rated at 200A, the system is 420 AH, so I am presuming the shunt must be rated for at least the same as the fuse, which is 500A as well.

I think its as good as its going to get, this monitor is not setup for this system (just another reason why it is all getting changed out), OH BTW I set the Amps for 50A (Options were 50-100-200-300) and now the amps charging on the SCC and the monitor are close to synced, but they are still off.

SOC is better though

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