Who knows about 18v lithium ion vacuum battery

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Dave100456

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Edit to title, should read 10.8v lithium battery.


I am looking at a vacuum that comes with a transformer (230v AC to 14v DC) to charge its internal 10.8v lithium ion battery.

Question: if I connect the charger direct to boats 12v supply will it charge it sufficiently at average boat voltage or will It only get fully charged when the boats battery Is being charged at 14v?

Thanks
 
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What you need to do is connect the vacuum cleaner to the boats 12v system via an amp meter. (you multimeter should do it) just observe what current you get into the cleaner battery. This current will be much more if ship's battery is being charged.
The current will diminish with charge state of the lithium batteries. These batteries have a voltage which varies (a lot more than lead acid battery and much more than NiMh) from about 3.0 volts per cell to 4.1 volts per cell. The point where charge should cease. Now obviously you have 3 cells in series. So from a 12v (exactly) source they could be charged to 4 volts per cell but current will diminish as the difference between the source and charged battery reduces.
I think you will find that you can get some charge into the cleaner from flat but not full charge unless you can get the ships batteries on charge ie up to 14v. olewill
 
Thanks William
I haven’t bought the vacuum yet and whilst I will have 230v available it will only be when or shore power.

The boats charger is set to 14.4 on bulk phase. How sensitive are the li.ion chargers, do you think the vacuum charger would be adversely affected with the extra 0.4v?
 
GHA said:
You can get buck/boost DC power supplies cheaply these days on ebay to keep the voltage stable. Might well be that theres a regulated supply inside anyway but maybe not.
Click to expand...

+1

I'd fit a DC-DC converter. I have two set at 14v to run my TV and soundbar, as well as some others.
 
When your engine is running or the solar panels are kicking in a charge you will find 13.8 to 14.2 v on the batteries... you'll get a full charge provided that there is no intelligence built into the wall adaptor itself. In which case you may well get a pretty little fire.
 
I suggest not using anything other than the charger supplied with the vacuum cleaner.
If you need to charge it but do not have shore power - use the supplied charger via a small inverter.
Or charge the vacuum at home . I have a similar thing and rarely need to charge it on the boat.
 
MartynG said:
I suggest not using anything other than the charger supplied with the vacuum cleaner.
If you need to charge it but do not have shore power - use the supplied charger via a small inverter.
Or charge the vacuum at home . I have a similar thing and rarely need to charge it on the boat.
Click to expand...
+1 Lithium batteries are tricky things, and using the wrong charging regime can result in them either having a substantially reduced life or even igniting and/or exploding! You should always use the supplied charger, which will have various safety cut-offs to avoid over charging and incorrect charging.
 
If the mains adapter is just that, a source of low voltage DC electricity then the battery charger (and maintenance) is built into the vac. Lithium ion batteries require very strict charge/discharge regime.
I believe it is rare that the battery management is left to an external device.
So, the question is will the battery charger in the vac run from 12V. The answer is probably.
14V DC smacks very strongly of the max you would expect to find in a car, so a device that can be charged from a car would be best powered by 14V derived from mains. The up shot of that is that it will also run from 12V.
so, do as William_H suggests, wire it to your boat and measure the current. If its minuscule then the vac wont like it, if it isnt minuscule then expect the current to be 10% higher than the 14V adapter is rated at (the internal charger will suck the same power to achieve maximum battery charging)
 
The controller for charge is more likely to be in the vacuum cleaner because it requires a connection to each cell. So 4 wires from controller to battery. Here is a typical controller https://www.ebay.com/itm/Lithium-Ba...287021?hash=item212433ac6d:g:8LgAAOSwpkFY6Iua
Try charging on 14.4v from ship using the amp meter to check current. You might expect 1 amp hour or so of battery capacity so don't charge at anything more than say .1 amp or perhaps up to .3 amp. olewill
 
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