well i will need to charge this batteries when i get them here because they will not going to be put in use right away ...
Need some advise regarding my first build.
- Thread starter Johnyguy
- Start date
Series connected batteries will result in lower battery current at a given wattage meaning lower gauge wires that are cheaper. However, verify that the BMS you buy can handle the higher voltage. Parallel connected batteries will provide greater discharge current that may be required to run heavy loads. Higher voltage inverters (24V+) are more expensive but allow greater power output than 12V inverters. In general, high power inverters benefit from series connected batteries to keep the battery current low and reduce voltage drop losses in battery wires and interconnect. Low power inverters typically use low battery voltages to allow operation from cheap 12volt batteries.
Thanks can you recommend a charger ?
MisterSandals
Participation Medalist
Search results for query: Bench charger
diysolarforum.com
WIll's favorite chargers are here: https://www.mobile-solarpower.com/battery-chargers.html
Since I haven't used any of the ones he recommends I'll leave it to someone else to add their experience.
Also, realize that many of the All-In-One Inverter/Solar Charge controller units (like MPP and Growatt) will have a built in charger and can charge your batteries when the sun isn't charging albeit at a slow rate.
All-In-One's from Will
Since I haven't used any of the ones he recommends I'll leave it to someone else to add their experience.
Also, realize that many of the All-In-One Inverter/Solar Charge controller units (like MPP and Growatt) will have a built in charger and can charge your batteries when the sun isn't charging albeit at a slow rate.
All-In-One's from Will
All-in-One 12/24/48V Packages
MPP and a few other manufacturers now sell a "complete off grid system in a box" that has: AC Inverter Solar Charge Controller AC Battery Charger Automatic Transfer Switch (if grid power is...
www.mobile-solarpower.com
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nice but pricey haha
i find this seems very good :
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Hello
I am looking at some inverter/charger /transfer switch with 3000 W pure sine wave 9000 W for 20 sec
looks like a good option practical solution to use up the battery power i would get from the sun , it would switch from battery to grid not to use the fridge but maybe i can use a hairdryer and lights and low power devices ...What do you think about that Mr Sandals or any expert?
Also i am debating if i should get the 4000 W or just the 3000 W ,inverter
And i have room on my balcony for 4 panels maybe 5 ( before it looks ridiculous so if i would get more battery to make a 48 volt system i need to be able to charge them up with those 5 panels lets say 300 W /panel most likely i would be struggling to charge up a 48 volt system or even if i go with the 24 volt system and i decide to add more battery i would need more panels to be able to charge them....
maybe the 24 volt system with 8 batteries is a nice balance in my case i feel like it ?
Is the 48 volt system is much more powerful for home use?
Thanks for your input
HiWIll's favorite chargers are here: https://www.mobile-solarpower.com/battery-chargers.html
Since I haven't used any of the ones he recommends I'll leave it to someone else to add their experience.
Also, realize that many of the All-In-One Inverter/Solar Charge controller units (like MPP and Growatt) will have a built in charger and can charge your batteries when the sun isn't charging albeit at a slow rate.
All-In-One's from Will
All-in-One 12/24/48V Packages
MPP and a few other manufacturers now sell a "complete off grid system in a box" that has: AC Inverter Solar Charge Controller AC Battery Charger Automatic Transfer Switch (if grid power is...www.mobile-solarpower.com
i just had time to look into this more and yes it is seems like a great option with the switching , i also was looking at the sungoldpower inverter,charger ,transfer switch but it does not have a charge controller but i think i would rather have the charge controller separate ..... not a bad deal only thing it is has a high ideal power draw 39W or 19 W power save mode
MisterSandals
Participation Medalist
I am no expert but am looking into this as well. The term I have seen used most is “self consumption” where your inverter uses battery before grid.
There are quite a few, ranging from Growatt, to Victron Multiplus, Schneider Conext 4024 and more.
You should shoot for an even number of panels or you would need an inverter that accepts the 5x panel voltage as input (rare and very speedy). With 4 panels, 2S2P, 6 panels 3S2P or 2S3P are all reasonable array configurations.
this looks good ...https://sungoldpower.com/collections/24v-inverter-charger/products/3000w-peak-9000w-dc-24v-pure-sine-wave-inverter-with-charger?variant=39652727619721
MisterSandals
Participation Medalist
I believe the Sungoldpower and Aimes units are made by Sigineer.
they look exactly the same
it goes into power saving mode uses 17W standby
but the sungoldpower turns off from power saving mode when senses 25 V
the aims needs 50 V
so that is the advantage of the sungoldpower one
what inverter are you using?
MisterSandals
Participation Medalist
I am currently shopping and waiting. In California PG&E is about to make net metering very expensive for new solar installations (every new home requires it to, what a coincidence). So there is a mass scramble to get in the old NEM 2 rules/fees.
When that shakes out, new solar will be dead except for new builds. Prices and availability should become more sane. Installers that sprung up, I suspect will start to go under.
I have my eyes on the Schneider Conext 4024. My main goal will be self consumption because I get about 25% back from selling back to the grid compared to what my average buy rate is. I have 16x 280Ah at the ready for a 8S2P or 2P8S battery bank.
I am expecting to connect my micro inverter array (3.2kW) to the self consumption side of the inverter. Still working out the details (if someone knows, please let me know!).
so the 8S2P would make 48 V and the 2P8S?
MisterSandals
Participation Medalist
25.6V
3.2V x 8 in series.
so if i have 2 sets of 8 battery in series and if i connect them in parallel that would make a 560 Ah battery bank?
MisterSandals
Participation Medalist
Yes, 8x 3.2V cells in series is 25.6V. (Retains cell Ah, 280?)
2 batteries in parallel adds Ah of both batteries, so 280 + 280Ah.
Cell Configurations for 12V 24V and 48V LiFePo4 Batteries
Click on the orangebutton to get the document. This short deck shows 1P and 2P cell configurations for 12V, 24V & 48V LiFePO4 batteries. Note: This resource is a duplicate of the resource of the same name in the 'How-to PDFs or Ebooks'. This...
diysolarforum.com
Here is this nice demonstration of the goldsun power inverter if you likeYes, 8x 3.2V cells in series is 25.6V. (Retains cell Ah, 280?)
2 batteries in parallel adds Ah of both batteries, so 280 + 280Ah.
Cell Configurations for 12V 24V and 48V LiFePo4 Batteries
Click on the orangebutton to get the document. This short deck shows 1P and 2P cell configurations for 12V, 24V & 48V LiFePO4 batteries. Note: This resource is a duplicate of the resource of the same name in the 'How-to PDFs or Ebooks'. This...
Do you think for a 24 volt battery to go down to 21V is too low that is when this inverter trasnfers over to AC current power and starts to charge the battery at the same times supplying the power to the load.
sunshine_eggo
Happy Breffast!
I regard these as high value (cheap but good) inverters with excellent surge capability and low efficiency (high idle drain AND low efficiency).
That unit likely burns 50W all the time, even when not powering loads. That's 1.2kWh/day - a notable chunk of the 560Ah capacity discussed. Unlikely to get more than 85% conversion efficiency on top of the high idle draw.
Something else to watch out for on these inverters when charging from AC...
They have ABSURDLY LONG absorption times, which is not good for LFP.
Their absorption TIME is based on 10X the time to charge to a voltage slightly below absorption. So if it takes you 30 minutes to get to absorption, it will spend 300 minutes (5 hours) at the absorption voltage.
Checked the manual:
If you have it set for Lithium, then the charge current is only 3.45V/cell with the same float. This is mostly okay, but you are signed up for a fairly long charge period.
That unit likely burns 50W all the time, even when not powering loads. That's 1.2kWh/day - a notable chunk of the 560Ah capacity discussed. Unlikely to get more than 85% conversion efficiency on top of the high idle draw.
Something else to watch out for on these inverters when charging from AC...
They have ABSURDLY LONG absorption times, which is not good for LFP.
Their absorption TIME is based on 10X the time to charge to a voltage slightly below absorption. So if it takes you 30 minutes to get to absorption, it will spend 300 minutes (5 hours) at the absorption voltage.
Checked the manual:
If you have it set for Lithium, then the charge current is only 3.45V/cell with the same float. This is mostly okay, but you are signed up for a fairly long charge period.
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