Guidance on new Lifepo4 SOC

[Willowflowage]

Moving from golf cart to lithium. 200 watts of solar going to 200 amp Ampere Time LiFePO4 battery. To be used for minimal needs boondocking, say 100 amps a day or less. I will be putting this into a portable tool box for now as a supplement to my still decent golf cart batteries to extend my trips.
This has worked so far on my existing setup with a cheap battery monitor to give me an idea when to cut back on my usage when I hit 12.3 or so volts with the lead cells.
So this lithium stuff sounds like finding the SOC is more difficult and I suppose more expensive to do.
How can I easily and affordably know my battery's fullness at anytime?
I've yet to buy a charge controller but am looking at this one.....
30amp Charge Controller, PWM Solar Controller 30A Fit for MAX 1500W Solar Power 12V 24V 36V 48V Lithium/AGM/Gel/Flooded Battery https://www.amazon.com/dp/B087BC9X4S/ref=cm_sw_r_apan_i_4K1JKYKV8W9EK0X8ZS0V?_encoding=UTF8&psc=1
And will be using this if needed for ac charging....
ExpertPower 12V 20A Smart Charger for Lithium LiFePO4 Deep Cycle Rechargeable Batteries https://www.amazon.com/dp/B082LZNDRH/ref=cm_sw_r_apan_i_ATKPNAJ7FBKY866WS0B9
Any help on what I should do or buy would be great.

 

[Bob B]

Something like this will work fine ..... https://www.amazon.com/gp/product/B07CTKYFTG/ref=ppx_yo_dt_b_search_asin_title

Or you could step up to something like the Victron Smart Shunt. https://www.amazon.com/Victron-SmartShunt-500AMP-Bluetooth-Battery/dp/B0856PHNLX/ref=sr_1_3?

 

[OTRwSolar]

Before we upgraded to a bluetooth capable BMS with a coulomb meter, we used a voltmeter to roughly determine state-of-charge (SOC). Could be an interim solution until you decide on a shunt meter. No, not a lot of precision doing it this way, but it's certainly better than waiting for the BMS to hit low-voltage cut-off.

I assume your Ampere Time is a sealed 12v lifepo4 with no access to the individual cells. If so, you'll need a voltmeter that can read 1/100 of a volt in the 10-14v DC range (xx.xx).

Take a voltage reading 5-10 min. after making sure there is no charge or discharge current present.

>13.30v = 90-100% SOC
13.10v - 13.25v = 40-75% SOC
12.20v - 13.00v = 10-30% SOC

Once voltage drops below 13.00v, may want to start making plans to charge.

 

[joanna_lannie]

Some BMSs are very good. They will have an LCD display to show the SOC status. In the case of ensuring the LiFePO4 battery safety, they can also detect the capacity of the battery in real-time. It is recommended to use them.

 

[Willowflowage]

Before we upgraded to a bluetooth capable BMS with a coulomb meter, we used a voltmeter to roughly determine state-of-charge (SOC). Could be an interim solution until you decide on a shunt meter. No, not a lot of precision doing it this way, but it's certainly better than waiting for the BMS to hit low-voltage cut-off.

I assume your Ampere Time is a sealed 12v lifepo4 with no access to the individual cells. If so, you'll need a voltmeter that can read 1/100 of a volt in the 10-14v DC range (xx.xx).

Take a voltage reading 5-10 min. after making sure there is no charge or discharge current present.

>13.30v = 90-100% SOC
13.10v - 13.25v = 40-75% SOC
12.20v - 13.00v = 10-30% SOC

Once voltage drops below 13.00v, may want to start making plans to charge.

Shunt meter like I use on my lead battery? DC Power Meter, DROK 6.5-100V 100A 12V 24V 36V 48V 60V 72V Volt Amp Watt Meter, LCD Display Multimeter Voltage Current Energy RV Battery Monitor Voltmeter Ammeter Wattmeter Panel with 100A Shunt https://www.amazon.com/dp/B07KPXVNY5/ref=cm_sw_r_apan_i_W3NECK1N2WYTAV0S0PP1?_encoding=UTF8&psc=1

Seems to be endless types of these all different claims and prices. Its difficult to tell what gives a reasonable estimate of your battery. I can certainly use my fluke meter to roughly tell. So a cheap shunt meter is close enough like the one I listed for my lead batteries?
Seems like endless choices on a what I hoped could be a simple system.

 

[OTRwSolar]

Shunt meter like I use on my lead battery? DC Power Meter, DROK 6.5-100V 100A 12V 24V 36V 48V 60V 72V Volt Amp Watt Meter, LCD Display Multimeter Voltage Current Energy RV Battery Monitor Voltmeter Ammeter Wattmeter Panel with 100A Shunt https://www.amazon.com/dp/B07KPXVNY5/ref=cm_sw_r_apan_i_W3NECK1N2WYTAV0S0PP1?_encoding=UTF8&psc=1

Seems to be endless types of these all different claims and prices. Its difficult to tell what gives a reasonable estimate of your battery. I can certainly use my fluke meter to roughly tell. So a cheap shunt meter is close enough like the one I listed for my lead batteries?
Seems like endless choices on a what I hoped could be a simple system.

Never used the drok in your link. I've used some of their other products. IMO, you get what you pay for.

I'd second Bob B's two recommendations (below) that he posted earlier in this thread. I know folks who have used both of these units with good results:

Something like this will work fine ..... https://www.amazon.com/gp/product/B07CTKYFTG/ref=ppx_yo_dt_b_search_asin_title

Or you could step up to something like the Victron Smart Shunt. https://www.amazon.com/Victron-SmartShunt-500AMP-Bluetooth-Battery/dp/B0856PHNLX/ref=sr_1_3?

Or, if you want bluetooth and a display you might consider the Victron BMV-712. This unit also has a very good rep.

 

[Willowflowage]

Well this is what I think I'll go with ordering tomorrow. Hope it's good for my small system.
AiLi Battery Monitor Voltmeter Ammeter Voltage Current Meter 8-80V 0-100A Auto Car Motor Boat Caravan RV Motorhome https://www.amazon.com/dp/B07CTKYFTG/ref=cm_sw_r_apan_i_28487BPJ1N2CKVA2ZZ7D?_encoding=UTF8&psc=1

HQST MPPT Solar Charge Controller 20 Amp Negative Ground Controller with Bluetooth LCD Display, 12V/24V DC Input Solar Panel Regulator for Gel Sealed Flooded and Lithium Battery https://www.amazon.com/dp/B0989NV7M1/ref=cm_sw_r_apan_i_VSTV4HAKSBCCJNJG5QMM?_encoding=UTF8&psc=1

ExpertPower 12V 20A Smart Charger for Lithium LiFePO4 Deep Cycle Rechargeable Batteries https://www.amazon.com/dp/B082LZNDRH/ref=cm_sw_r_apan_i_Y5NFNDVRB92JX9EJW30G?_encoding=UTF8&psc=1