Panel Placement and Wiring Options

[Rocketman]

The easiest way to know the state of charge is to add a Victron Smartshunt or BMV712.

This could be helpful because if you have poor solar for a few days while you are at the cabin and use more power - you will know exactly what your state of charge is on the battery and will know if/how long to run the generator.

 

[Whitty21]

The easiest way to know the state of charge is to add a Victron Smartshunt or BMV712.

This could be helpful because if you have poor solar for a few days while you are at the cabin and use more power - you will know exactly what your state of charge is on the battery and will know if/how long to run the generator.

Our Inverter/charger combo does provide some degree of battery levels with a 4 bar system. A shunt may be nice, renology seems to have a cheaper one that doesn't require an app, which may be a benefit for my parents. Guess I could get one and bring it home with the batteries in the winter.

 

[Whitty21]

It can be a lot of trouble for nothing, because the voltage of a LFP battery is almost the same from 30% to 70%.
If you are interested, you can buy tool to monitor SOC fairly accurately, but to me, charge them at 27V with low end of charge current* (1A to 20A) and after consider them at around 70-90%.

By the way, if that happen to you to read 0V at battery terminals, this is simply because the BMS shut down it self.
There is some chance that simply hook 24V at terminals could restart the BMS.

*considering 200Ah battery, 20A represent 0.1C charge rate

Can you expand on that? Redodo sells a charger, seems kinda pricey. It is a 20amp charger and has a dead battery charging mode to wake the BMS of a dead battery apparently. Is this something you mean?

Redodo 29.2V 20A LiFePO4 Battery Charger

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ca.redodopower.com

 

[yabert]

Can you expand on that? Redodo sells a charger, seems kinda pricey. It is a 20amp charger and has a dead battery charging mode to wake the BMS of a dead battery apparently. Is this something you mean?

It's up to you to choose the right charger if you need a charger.
You can find everywhere regular adjustable power supply (0-30V 0-10A). But you need AC source.
You can choose a small hobby kind charger working on DC to charge your 24V battery from car 12V battery.
You can find two cheap lead acid 12V, connect them in serie and try to wake up your 24V LFP.
You can buy Redodo charger, but you need AC source.

Let say that at the moment, you don't need charger.
Maybe start to use and understand your system and after you will be in a better way to choose proper charger for your needs.

 

[Whitty21]

It's up to you to choose the right charger if you need a charger.
You can find everywhere regular adjustable power supply (0-30V 0-10A). But you need AC source.
You can choose a small hobby kind charger working on DC to charge your 24V battery from car 12V battery.
You can find two cheap lead acid 12V, connect them in serie and try to wake up your 24V LFP.
You can buy Redodo charger, but you need AC source.

Let say that at the moment, you don't need charger.
Maybe start to use and understand your system and after you will be in a better way to choose proper charger for your needs.

My question is more for storage at home when they are not at the cabin. We have the batteries now, and Redodo says that they ship at 30-50% SOC and we wont be installing them until the endo of may, so they may need a top up before then. At home in the basement, we will have an AC power source. Hopefully this clarifies my question

 

[yabert]

You already have a charger: SRNE 24v All-in One
If no, a small and cheap 0-30V power supply is handy.

 

[Whitty21]

You already have a charger: SRNE 24v All-in One
If no, a small and cheap 0-30V power supply is handy.

The Inverter/charger will be up at the cabin during the offseason, not going to bring the whole system home during the winter.

But, point taken on the cheap charger. Thanks

 

[Brucey]

My question is more for storage at home when they are not at the cabin. We have the batteries now, and Redodo says that they ship at 30-50% SOC and we wont be installing them until the endo of may, so they may need a top up before then. At home in the basement, we will have an AC power source. Hopefully this clarifies my question

They will be fine as is until you install them in May. The self discharge of an LFP battery like these are low. They sit in their warehouse for months. I have four Redodo mini 12V 100Ah, rock solid.

 

[xcentric]

How about boxing your batteries and adding a small low wattage heater to keep them at a better temperature. Could then actually have them active and running small oil-filled electric radiators in the cabin to keep out damp etc?