Likorall 200 Ceiling Hoist - Lithium battery conversion

[DanielCoffey]

I am considering a Lithium battery conversion for our Likorall 200 Ceiling Hoist as it is about at the end of its current set of batteries but I was wondering if there are any considerations I need to think about such as voltage regulation.

It is used for powered transfers of a disabled person from chair to bed a few times a day in a private household. It is our own property and is 6 years old.

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It is fitted with a pair of Yuasa 12V 2.4Ah AGM batteries in series for a 24V system. The batteries are the long thin type with the terminals on one end connected via 4.8mm spade connectors.

The charger in the UK 3-pin socket is a Pb battery charger rated at 100-240V, 50-60Hz AC outputting 24V DC at up to 0.5A with model number FW7218M/24. It ends in a standard 5525 barrel jack.

The free-floating hoist has a handset with two buttons and an LED indicator on a curly cable that docks in a cradle. When the handset is docked the hoist is electronically prevented from operating while the batteries are on charge.

The Pb charger has an LED indicator showing charging/charged. The handset has a bright yellow LED to show it is connected to the charger.

It spends almost all of its time connected to the charger for battery management so any Li cells would have to be of a type that tolerate being fully charged very well.

When the handset is removed from the charger the indicator LED dims and goes green to presumably show "good charge". It will either change to yellow or start blinking to indicate "low charge" but we have never used the hoist that much in one day to trigger that condition.

I suspect that if I was to change the wall charger to one which supported Lithium cells (that could be connected to the charger long term) and replace the pair of Yuasa cells with a single Lithium pack of around 24V with the appropriate connectors we would be good to go apart from voltage regulation.

Would I need to consider the voltage range of a 24V Pb sytem between 100% down to about 50% and make sure the Lithium pack was operating at the same sort of voltage? I have not examined the ceiling hoist to see if there is any regulation circuit on its main board yet but I could certainly do so.

Before I start drawing up a shopping list, what else should I be thinking about? So far I know I need a Lithium charger and a suitable battery around 24V, probably LiFePO4.

Thank you.