Can I replace or hybrid LA battery with Li battery

[Kai]

I bought a small portable 150AH 12V Li battery with 12.6V AC charger. Once fully charged it can run 12V TV over 3 hours. I am wondering if I can plug in 12V port in caravan and/or by turning off LA battery isolator so that it replace or provide extra power for off-grid. Next question is if I can connect to 100W solar panel in parallel with LA battery via PWM controller?

 

[IanB1485]

I have a 280W Li ion battery ( with a 3kW inverter connected to it) The combination is too big to fit inside the caravan battery compartment it lives in the awning and whilst the inverter only has a 13A outlet I have made up a short cable and interface box ( to connect the earth and neutral wires together and a ground spike) and it goes into the mains inlet connector in the caravan , thats one option , I am now in the middle of running 10mm cables underneath the caravan from the leisure battery and fitting a housing on the left hand side similar to the one which has the BBQ outlet and fit a commercial 20A connector ( fused) this would couple both batteries together. the solar controller will charge both up together. The minor difference in voltage between the batteries is not a problem. My inbuilt 20A 2/3 stage charger charges up the Li-ion battery no problem when on grid , it just takes longer. If you are worried you could always disconnect one terminal off the leisure battery.

 

[JTQ]

I bought a small portable 150AH 12V Li battery with 12.6V AC charger. Once fully charged it can run 12V TV over 3 hours

Have you miss typed this and meant it can run a 12V TV for nearer 30 Hours? If a 150 Ah battery last just 3 hours, it must surely be knackered, as the TV can't realistically pull getting on for 50 Amps, 600Watts.

 

[Kai]

Have you miss typed this and meant it can run a 12V TV for nearer 30 Hours? If a 150 Ah battery last just 3 hours, it must surely be knackered, as the TV can't realistically pull getting on for 50 Amps, 600Watts.

It is cheap, bought from Aliexpress, I doubt it has 150 AH. But it is enough for me to run TV 3 hours every day. I need to source a solar panel for it.

 

[JTQ]

It is not recommended to connect in parallel differing Ah LA batteries, nor even matching Ah capacity LA batteries of differing make and or age. So putting batteries of differing technology and likely differing Ah and age in parallel, is something I would not consider, at all.

Also don't forget here you are talking of very high levels of stored energy* so the ability for things to go seriously wrong, like with a lithium battery a risk of a very high temperature fire.

*The lithium, if genuinely rated at 150Ah, alone storing 1.8kWh of energy.

 

[IanB1485]

@JTQ thats a fair point I should know better . In my defence the cables from each battery are fused at 15A and in tests in my workshop there was no appreciable current(less than 10mA) from one battery to the other) but it is bad practice, so I will slap my own hand!