Drop in lithium batteries

[Tradie]

If you install a "drop in" lithium battery to replace your old FLA or gel battery, do you set your charge rate for a lithium battery or FLA/ gel ?

If you are replacing an FLA/gel battery with a drop replacement, you would leave the settings the same.

As we all know the charge/discharge characteristics of a lithium battery is not the same as FLA/gel, just like the regulations wouldn't be the same for battery placements.

IF you buy a trolley type inverter and upgrade to a lithium drop in battery, could you still position the trolley inside the lounge next to the TV cabinet ?

Would the lithium battery capacity regulate the location of the battery, for example if there are 2 x 100 amp/hr batteries used in a 24 V trolley?

At what capacity would you consider the type of battery and risk used inside the house?

Dropping an 18 amp/hr lithium battery into your bedroom cupboard to replace the old 18 amp/hr gel battery a much higher risk ?

The big question is at what point does the lithium battery because a risk for insurance cover. It seems insurance companies are getting smart and auditing locations where lithium batteries are installed, they dont seem to care where you install the battery, they ar emore concerned about the fire suppression and type and size of fire extinguisher. You are in for a rude awakening when you see what they cost.

[Tradie]

Considering the trolley type backup system is not connected to the electrical installation and is mobile, we dont have to worry about electrical installation regulations.

The supplier would have made sure the units are approved by some approval organisation somewhere in the world, you have notified your insurance company and attached photos of the location the trolley is being used, who will send you a list of requirements, so you should be covered.

What you do need to consider is the destruction capacities of these small lithium batteries and the fact that it part a system that is physically attached to the building used for system like an alarm, gate, garage door and the liked, linked to a constant trickle charger plugged into a wall socket (making it an interesting discussion because it doesn't form part of the electrical installation)

Considering the high risk a lithium battery creates, shouldn't all lithium batteries have some form of fire suppression built in?

We are not going to stop them being installed in side of properties, so should we not be looking at ways to make it safer ?

[Tradie]

The FLA (flooded lead acid) battery in your 1200va inverter, goes dead after a couple of months, because of the high demand and cutout voltage of between 10.2 - 5 VDC, it's time to upgrade to a lithium battery, you shop around for one that fits your budget.

A couple of months later you inverter switches off and a annoying beeping sound attracts your attention, you see the fault on the screen and find out it is not worth repairing the unit, nor replacing.

Because you already have a 100 amp/hr (1.2 kwh) lithium battery, you decide to upgrade to a 1000 watt inverter and that is where it gets even more interesting.

Now you have a 1000 watt inverter and a 100 amp/hr battery, 1 kw connected load shouldn't be a problem, right ?

No, you are now faced with another challenge, charge discharge rate, the old FLA battery should only be charged at around 10 amps, but could be discharged at a much higher rate, provided you don't go below around 80% SOC (state of charge) or drop the battery voltage below around 11.5 VDC, which become rather tricky depending on the load.

The new lithium battery may seem like a lot better battery because it can discharge to a lower SOC, has more cycles (around 2000 compared to 200-500 cycles of a FLA battery), you can drop lower than 11 volts (depending on the BMS)

You back to square one, because the lithium battery can only charge and discharge at around 50% some as low as 40%, so was installing a 1000 watt inverter a better option, in the long run I would say it depends on the inverter parameter settings.

It is not a total failure because you could spend another R8-10k on another lithium battery which would allow you to double the load to around 80 ample (the 1000 watt inverter max current is 85 amps @24 volts), however the 1000 watt inverter might only have a max charge current of 20 amps. Which means it could take 20 hours to recharge the batteries.