PWM and lithium battery?

[Orgasmic window cleaning]

Hi. Been thinking of changing from lead acid to lithium, this is to pump water up on to commercial roofs when there is no mains pressure available. We use a fairly hefty 12v pump and large leisure batteries at the moment, but thinking of building the next pump box with a lithium battery to make it easier to move around, we have to charge batteries overnight at accommodation etc.
Has anyone used a PWM with a lithium battery? Did it behave well?

 

[AW Services]

Hi. Been thinking of changing from lead acid to lithium, this is to pump water up on to commercial roofs when there is no mains pressure available. We use a fairly hefty 12v pump and large leisure batteries at the moment, but thinking of building the next pump box with a lithium battery to make it easier to move around, we have to charge batteries overnight at accommodation etc.
Has anyone used a PWM with a lithium battery? Did it behave well?

The battery chemistry is a lot different however the determined use of the battery isn't.
12-volt LiFePO4 batteries offer a reduction in weight with longer run times and shorter charge intervals
You will need to be mindful of weather especially when it's cold as the batteries can be affected and you'll need a dedicated charger
I would recommend staying away from cheap PWM motor controllers and use a higher quantity flow controller such as a Spring Europe Ltd V16 which offers better running and power saving advantages

You're not the first person to use a battery and motor combined as electric wheelchairs, boat trolling motors, power tools have been doing this for ages now

 

[ched999uk]

Using a decent controller (Spring V16 - sold under various brands, look for V16) will save you power as they are more efficient plus will extend the life of your pump.
If you switch to any lithium battery you MUST use the correct charger for that battery chemistry. Over charging Lithium can cause a fire and lithium burns very hot and is difficult to put out.
That said you can normally discharge a Lithium battery down to 20% of it's capacity where as a lead acid should only be taken down to 50% to maintain it's capacity. So you need less AH on Lithium but as @AW Services said Lithium don't like cold, they won't give out as much power or have as much capacity when the batteries are cold so you need to keep that in mind although there are batteries that have heating elements in them to cope with the cold.

 

[spruce]

Hi. Been thinking of changing from lead acid to lithium, this is to pump water up on to commercial roofs when there is no mains pressure available. We use a fairly hefty 12v pump and large leisure batteries at the moment, but thinking of building the next pump box with a lithium battery to make it easier to move around, we have to charge batteries overnight at accommodation etc.
Has anyone used a PWM with a lithium battery? Did it behave well?

You need to talk to someone who knows what they are talking about with regard to lithium batteries.

We don't know what you mean by a fairly hefty 12v pump. That does sound like a common window cleaning pump. There were several 40amp PWM controllers on eBay a while back. As with anything Chinese made, they would probably battle to provide a 15amp power requirement.

Again, a good source of help will be from @Ian Sheppard . You will probably need something more substantial than a V16 controller to drive a hefty pump.

I found Fogstar very good to deal with.

Fogstar Batteries | The UK’s #1 18650 Battery Retailer

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www.fogstar.co.uk

You need to provide any supplier with detailed info on what amperage the pump draws and what capacity the lead acid batteries you currently have are.

"We have to charge our batteries overnight at accommodation" is not an advisable thing to do. Fogstar specifically advise against charging their lithium batteries indoors. I ordered a starter battery for my van from Tanya at the end of last year. They advised to open the package outdoors and never recharge the battery indoors. A well ventilated area is a commonly used term.

As others have said, you need a battery charger suitable for lithium.

Coupled to a large capacity alternator (mine is 160 amps) and a good battery 2 battery DC charger programmed for lithium, there is no reason why you shouldn't be able to charge a Lifepo4 battery on the move.

But again, you need to talk to an expert who knows what he is talking about.

 

[Orgasmic window cleaning]

Cheers people. Thanks for your input.

 

[spruce]

You need to talk to someone who knows what they are talking about with regard to lithium batteries.

We don't know what you mean by a fairly hefty 12v pump. That does sound like a common window cleaning pump. There were several 40amp PWM controllers on eBay a while back. As with anything Chinese made, they would probably battle to provide a 15amp power requirement.

Again, a good source of help will be from @Ian Sheppard . You will probably need something more substantial than a V16 controller to drive a hefty pump.

I found Fogstar very good to deal with.

Fogstar Batteries | The UK’s #1 18650 Battery Retailer

18650 Battery Retailer | Batch Tested & Authenticated | Wide range of chargers & accessories | UK Based | 5* Reviews | Fast & Free Shipping - Same Day Despatch

www.fogstar.co.uk

You need to provide any supplier with detailed info on what amperage the pump draws and what capacity the lead acid batteries you currently have are.

"We have to charge our batteries overnight at accommodation" is not an advisable thing to do. Fogstar specifically advise against charging their lithium batteries indoors. I ordered a starter battery for my van from Tanya at the end of last year. They advised to open the package outdoors and never recharge the battery indoors. A well ventilated area is a commonly used term.

As others have said, you need a battery charger suitable for lithium.

Coupled to a large capacity alternator (mine is 160 amps) and a good battery 2 battery DC charger programmed for lithium, there is no reason why you shouldn't be able to charge a Lifepo4 battery on the move.

But again, you need to talk to an expert who knows what he is talking about.

Sorry. Should have read; That doesn't sound like a common window cleaning pump.