Abigai:
Gurus diagram 1 and 2 which one is more accurate for 24v setup looking at the AH. thanks

Abigai:
Gurus diagram 1 and 2 which one is more accurate for 24v setup looking at the AH. thanks

NiyiOmoIyunade:
Both diagrams are not ideal because they are taking power to charge source or power loads from the same side of the battery bank - cable resistance through the battery links will mean less current to the lower portion of the battery bank while charging and more strain on the upper part of the battery bank while discharging.

Ideally you should move either the positive or negative inverter cable to the lower part of the battery bank so that positive and negative cables are tapped from opposing sides of the bank.

In a pro install, you would not parallel the two 24v banks directly but rather keep each bank separate and independent and connect each bank directly to a suitable bus bar for positive and another busbar for negative. You would then tap the inverter positive and negative connections directly from the bus bars.

Abigai:
Oga Niyi pls can you show me a diagram that will further guide me. thanks

mctfopt:


I think this is what he meant

NiyiOmoIyunade:
Yup! Thank you very much.

Madam Abigai should please keep cable lengths as short as possible and use at least the mininum spec'd cable sizes or better still go for an even thicker cable size and all should be well.

Abigai:
Gurus diagram 1 and 2 which one is more accurate for 24v setup looking at the AH. thanks

Malevonent:
am thinking of replacing my 8 x 12v 200ah smf battery bank soon, as am tired of trying to keep them all balanced, 1 or 2 will usually drift off, and cause problems for me.. HA02 is connected, but doesnt seem to be doing anything, except emitting a high pitched sound

so whats the cost of an equivalent LIPO4 Bank that i can use to replace tis 48v x 400ah smf bank, is it true that a 48v 200ah LIPO4 is an equivalent replacement??

Malevonent:
am thinking of replacing my 8 x 12v 200ah smf battery bank soon, as am tired of trying to keep them all balanced, 1 or 2 will usually drift off, and cause problems for me.. HA02 is connected, but doesnt seem to be doing anything, except emitting a high pitched sound

so whats the cost of an equivalent LIPO4 Bank that i can use to replace tis 48v x 400ah smf bank, is it true that a 48v 200ah LIPO4 is an equivalent replacement??

ceaser:
Please a little.heads up.

12v system with 24v panels thru 60A 12v/24v/36v/48v MPPT SCC 100v max input voltage.

Is it allowed to increase MPPT SCC panels input to 36v (that's 3s config assuming each panel is 12v) or to 48v input (2s if panel is 24v) and still maintain the 12v system?

If yes, does this allow safely breaching the allowable 720 watts (12v X 60amps) 60A SCC specs for 12v system by increasing the input above 720 watts or is it criminal to do it?

Thanks.

NiyiOmoIyunade:
I can say with a fairly high degree of confidence that lead acid 48v 400Ah is not generally equivalent to Lithium 48v 200Ah.

The issue is with the DoD assumption - lead acid generally at 50% and Lithium at 100% - discharging a Lithium battery to 100% is not practical if you want the bank to go to 4,000cycles and above.

80% DoD for Lithium is a reasonable use case in which case 48v 400Ah of Lead Acid at 50% DoD is equal to 48v 250Ah of Lithium at 80% DoD.

One thing people forget is that battery charging is actually a chemical reaction potentiated by electricity - if you let your Lithium battery get discharged to low voltages, dangerous chemical reactions occur which degrade the battery significantly vs lead acid.

A lead acid battery may survive several ultra deep discharges with some capacity loss, a Lithium battery may not survive more than one deep discharge without serious degradation - it may be rendered unuseable and require special handling to be brought back to life at all.

There is also the matter of emergency use or special situations, a 48v 400Ah bank may be taken occasionally to 350Ah discharge in an emergency e.g additional loads with guests in the house. A 48v 250Ah Lithium bank has no surplus capacity for extra needs except you upsize at significant cost - you cant pull 350Ah out of a 250Ah battery, the battery would have conced out long before.

ceaser:
The spambot has gone mad again!

n9jaboy:
Good morning,

Please I just bought 2No 150ah inverter batteries (auction). I'd love to charge it on both solar and NEPA. Which should be my best bet(hybrid inverter). My expected load is five 30watts Fan.

I will also like to know how many hours my fans will work. Thanks

ojeysky:
Can someone kindly recommend a usb to serial adapter that actually works? The one have been using just intermittently stops transmitting data, unless I restart the pi.

ojeysky:
Can someone kindly recommend a usb to serial adapter that actually works? The one have been using just intermittently stops transmitting data, unless I restart the pi.

NiyiOmoIyunade:
I can say with a fairly high degree of confidence that lead acid 48v 400Ah is not generally equivalent to Lithium 48v 200Ah.

The issue is with the DoD assumption - lead acid generally at 50% and Lithium at 100% - discharging a Lithium battery to 100% is not practical if you want the bank to go to 4,000cycles and above.


80% DoD for Lithium is a reasonable use case in which case 48v 400Ah of Lead Acid at 50% DoD is equal to 48v 250Ah of Lithium at 80% DoD.

One thing people forget is that battery charging is actually a chemical reaction potentiated by electricity - if you let your Lithium battery get discharged to low voltages, dangerous chemical reactions occur which degrade the battery significantly vs lead acid.

A lead acid battery may survive several ultra deep discharges with some capacity loss, a Lithium battery may not survive more than one deep discharge without serious degradation - it may be rendered unuseable and require special handling to be brought back to life at all.

There is also the matter of emergency use or special situations, a 48v 400Ah bank may be taken occasionally to 350Ah discharge in an emergency e.g additional loads with guests in the house. A 48v 250Ah Lithium bank has no surplus capacity for extra needs except you upsize at significant cost - you cant pull 350Ah out of a 250Ah battery, the battery would have conced out long before.

mank1234:


The one you're using, is it FTDI chip or prolific?
FTDI seems to work better with pi.

FTDI: https://a.aliexpress.com/_dVBA5Qm

Prolific:
https://a.aliexpress.com/_dWzZCBy

NiyiOmoIyunade:
This is a problem with the Pi and more especially with el-cheapo asian components sourced off Ali-Express.
.

So connecting via ethernet or wifi may be more stable than USB modem if you happen to have a spare router lying around.

mctfopt:
Newbies will be like

n9jaboy:
Good morning,

Please I just bought 2No 150ah inverter batteries (auction). I'd love to charge it on both solar and NEPA. Which should be my best bet(hybrid inverter). My expected load is five 30watts Fan.

I will also like to know how many hours my fans will work. Thanks

n9jaboy:


I guess I am on my own

ojeysky:


I think same can be said for lead acid, you can't get up to a thousand circle at 50% DoD. So I think a fair equivalent will be a 80% DoD of 200Ah lithium and 30% DoD of 400 Ah lead acid. Even at that circle wise a lead acid will have died when a Lifepo4 is just getting to its 80% usable capacity.



Agree but really this is why folks need to have a way of monitoring their lithium cells, it's as simple as that. However lithium cells are usually rated below their capacity, so a 100Ah is actually 105 or 110Ah to give room for 100% discharge at 100Ah without negative impact on the battery.



While I agree with the above, I think it addresses just a scenario in the emergency use cases. Here are a few more:

1. A lithium will have been recharged and used at least twice while a lead acid is still going through her first round of charging. Imagine you have electricity/solar only for a few hours and you have the juice to charge your battery but you are limited to 0.1C (or max 0.2c) on lead acid

2. A lithium handles current surge better in an emergency/normal situation than lead acid. My washing machine does a 2kw surge, this normally trips my former 300Ah lead acid, but the story is different using my current 200Ah Lifepo4

3. We also need to recognize that the occasional below 50% DoD on lead may actually cost 3x or more in overall circle life.

Overall I would still agree that it's a good thing not to get exactly 200Ah lithium just that my reasons and motivation for that is different.

mctfopt:
Newbies will be like

essegis:


I am at this stage when it comes to Lithium, no vex. Me too will soon catch up to all the phrases cos I've never used WiFi or USB for any of my inverters before.

But of course, we learn everyday.

NiyiOmoIyunade:
This is a problem with the Pi and more especially with el-cheapo asian components sourced off Ali-Express.

Your best bet is a regular scheduled restart of the Pi with say Cron? Or otherwise refresh/restart the USB subsystem via a script.

Personally I would rather just restart the whole Pi say 2am everyday and refresh the entire system.

At home I use a TP link router for internet with the main internet source being a FibreOptics modem provided by FiberOne, the Pi and other devices are connected for weeks at a time and the connection never breaks or freezes.

So connecting via ethernet or wifi may be more stable than USB modem if you happen to have a spare router lying around.

adrusa:


There is a major fallacy in the supposed usability of Lead Acid battery beyond 50% DoD. It is totally dependent on what load you have on the system. And this is where Lithium shines. While drawing up to 80% of its capacity, you still have very high voltage to keep your inverter on. But with Lead acid, the only way you can go that deep is if you are only pulling 2 or 3A depending on your total AH. If you are pulling any significant amount of current, you may not even get to 50% DoD before your voltage sags enough to shut down your inverter.

Because of the way I use my system, I don't think I have ever seen a DoD of 50%. On rare occasions when I had deep discharges, the system will shut down once my water pump comes up in the morning in addition to my fridge and freezer. I sometimes have to temporarily take off the pump to prevent this.