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24v 280ah build, need help

Jusbechillin

Jusbechillin

New Member
Joined
Aug 5, 2020
Messages
86
Location
Mesa, AZ
I ordered 8 3.2v 280ah cells to build a 24v battery for my camper. Can someone confirm the parts I’ve ordered will all work well together?

I.e. how do I know if 100a is a sufficient rating for the BMS?
How do I make sure my charge and discharge rate is going to be ok?

8 3.2v 280ah prismatic cells.

overkill solar BMS 100a 8s LifePo4.

CellMeter 8 battery voltage capacitor checker/balance discharged/servo tester

samlex evo 2224 inverter/Charger. 40amp breaker.

Dc/dc 24v to 12v 30 a 450 watt converter. 30 amp fuse

4 Rich Solar Poly 100w 12v solar panels (I might upgrade to 6 in the future if the system doesn’t keep up with my needs) with 10 gauge wire to the charge controller.

300 amp mrbf terminal main fuse.

1awg wire for inverter and charge controller.
 
Here’s the specs for the cells I have on the way.


ModelLF280
Nominal voltage3.2V
Charge voltage3.65V
Nominal capacity280Ah
Battery typeLifepo4 battery cell
Internal resistance≤0.25mΩ
Max charge current280A
Standard discharge current(25±2) °C, 1.0C constant current discharge
Max discharge currentAt 0 ° C ~ 45 ° C, the battery is the most
The large charging current does not exceed 1C.
Discharge cut off voltage2.5V
Charge methodCC/CV
Net weight5220±200g
Lifecycle3500 times
Warranty12 months
Charge temperature0°C ~ 45°C
Discharge temperature-10°C ~ 60°C
 
I also have:

victron smart battery sense (battery voltage and temp sensor)

victron smartsolar charge controller MPPT 100/30

AiLi voltmeter 350a shunt
 
Got it. If I add a battery protect to the system I can get past the 100 amp limit on the BMS. I’ll look up Victron options.
 
Ok. I'll give this a quick go in the time I have. Yes. No. (Depends on what you do with them).

What are your power requirements? Have you figured that out yet?

Might I suggest you draw out the parts together as a system? That will help you work out how to put them together and make it easier for the folks here to give you suggestions. Look at my drawing here to get an idea of what I mean.

Your 100A BMS will give you 2400W, which is more than your inverter will produce based on your information.

The BMS IS the battery protection -- so why do you want to go past the 100A limit? You can buy larger ones (I looked at 150A for mine) but why?

Your panels will at most give you 320W an hour of max sunlight (assuming 80% production to batteries). How many hours of max light do you get? How many do you need?
 
I will draw up a new schematic and post it today. The last one I drew up was before I switched from separate ATS, Charger, and inverter to a Samlex evo Charger/inverter.

My biggest load will be when we are using the microwave.

Using the solar calculators (that most people recommend against) I figure 2000 watts a day would be more than sufficient. We use the camper for mostly 3 - 4 day trips. The solar panels are mostly to slow my draining of the batteries on a trip and to top them off while not in use.

I was confused on the use of a battery protect as you can probably tell. Some of Will’s videos have them and some don’t. Some of his schematics have them drawn in, but then there’s a not saying he doesn’t recommend Their use anymore.
 
Jusbechillin said:
I also have:

victron smart battery sense (battery voltage and temp sensor)

victron smartsolar charge controller MPPT 100/30

AiLi voltmeter 350a shunt
Click to expand...
you probably need more panels like 1200 watts worth and a bigger MPPT.

The battery protect is for DC only load, like lights and other 12/24 volts things. DON'T put it inline with the Inverter.
 
okay, here’s the list of items in the diagram. I plan to use 10awg from the panels and 1awg for the inverter/batteries/charge controller.

8 3.2v 280ah prismatic cells.

overkill solar BMS 100a 8s LifePo4.

CellMeter 8 battery voltage capacitor checker/balance discharged/servo tester

samlex evo 2224 inverter/Charger.

40amp breaker.

Dc/dc 24v to 12v 30 a 450 watt converter.

30 amp fuse

4 Rich Solar Poly 100w 12v solar panels (I might upgrade to 6 in the future if the system doesn’t keep up with my needs) with 10 gauge wire to the charge controller.

300 amp mrbf terminal main fuse.

victron smart battery sense (battery voltage and temp sensor)

victron smartsolar charge controller MPPT 100/30

AiLi voltmeter 350a
 

Attachments

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Jusbechillin said:
okay, here’s the list of items in the diagram. I plan to use 10awg from the panels and 1awg for the inverter/batteries/charge controller.

8 3.2v 280ah prismatic cells.

overkill solar BMS 100a 8s LifePo4.

CellMeter 8 battery voltage capacitor checker/balance discharged/servo tester

samlex evo 2224 inverter/Charger.

40amp breaker.

Dc/dc 24v to 12v 30 a 450 watt converter.

30 amp fuse

4 Rich Solar Poly 100w 12v solar panels (I might upgrade to 6 in the future if the system doesn’t keep up with my needs) with 10 gauge wire to the charge controller.

300 amp mrbf terminal main fuse.

victron smart battery sense (battery voltage and temp sensor)

victron smartsolar charge controller MPPT 100/30

AiLi voltmeter 350a
Click to expand...
put a MC4 inline fuse coming from each set of solar panels to protect the wiring. so you need 2 at least.
 
ToadHarbor said:
you probably need more panels like 1200 watts worth and a bigger MPPT.

The battery protect is for DC only load, like lights and other 12/24 volts things. DON'T put it inline with the Inverter.
Click to expand...

Im NOT trying to design the solar part of the system to keep up with my daily use. The solar is really to top the batteries off after we get back home. We use this on the weekends, so we designed the system with a big battery bank Instead of sufficient solar.

I will probably end up installing 6 panels instead of two.
 
ToadHarbor said:
put a MC4 inline fuse coming from each set of solar panels to protect the wiring. so you need 2 at least.
Click to expand...
I might not have those in the diagram, but I have the MC4 connectors.
 

Attachments

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You bms is undersized.
2200 * 1.15 / 24 = ~105 amps.
You could have the inverter/charger bypass the bms and use the bms to switch the inverter/charger
You should have a means of disconnect between the panels and the inverter/charger.
You don't need the disconect between the inverter/charger and the busbar.
Please for the love of god only use quality breakers/fuses.
If those busbars are cheap amazon I suggest you look at bluesea mrbf busbars.
Best source I have found is waytek.
 
smoothJoey said:
You bms is undersized.
2200 * 1.15 / 24 = ~105 amps.
You could have the inverter/charger bypass the bms and use the bms to switch the inverter/charger
You should have a means of disconnect between the panels and the inverter/charger.
You don't need the disconect between the inverter/charger and the busbar.
Please for the love of god only use quality breakers/fuses.
If those busbars are cheap amazon I suggest you look at bluesea mrbf busbars.
Best source I have found is waytek.
Click to expand...

the main fuse will be MRBF (because of your suggestion in another post). I haven’t actually bought this piece yet, but I’m looking at “bay marine supply”. If you recommend a specific one, that’s what I’ll get.
Same with the busbars, I’ll take your recommendation and grab Bluesea for those.

The 40amp breaker I did already buy, but can swap for a different one if you say the one I have is garbage. See the attached photo of the one I bought.

I will move the location of the disconnect as suggested. Between the charge controller and the inverter/charger?

Finally in regards to the BMS being undersized. “You could have the inverter/charger bypass the bms and use the bms to switch the inverter/charger”
How would I accomplish this? And is this what you would do if it were your system? The overkill solar BMS is already on hand, so I would prefer to make it work if possible.
 
Jusbechillin said:
Here the breaker I bought
Click to expand...
If its actually cooper bussman then its ok.

Blue Sea Systems 5196B MRBF Fuse Block, Common Source, Bulk | Waytek

Blue Sea Systems 5196B MRBF Surface Mount Fuse Block, Common Source - Bulk Packaging is in stock and ready to ship, order today!
www.waytekwire.com www.waytekwire.com
Assuming 3/8" terminal on battery get this https://www.waytekwire.com/item/45575/EATON-s-Bussmann-Series-MRBF-Mounting-Bar-/
waytek is good place to get the fuses also.
search @JoeHam's posted for a suitable dpst switch to put between the panels and the inverter.
 
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