keep killing my lead acid 40ah battery

[gazza2006au]

I only have one start battery 12v lead acid NS40 model 380cca 40ah but now i know my trailer mover works i want a battery just for the trailer mover, my 40ah lead acid drops from full charge to 43% by moving the boat 20 meters one way

Are lead acid, agm, lithium all equil as in there amp hour ratings? Will i need 80ah lithium just to take my boat out for the day than push it back in the yard?

I was a big lipo user but never ventured to deep into electronics i still have a B5 imax charger that i use every now and again if i go lithium ion im hopping to keep using this charger i've had it 15 years

[NAGG]

I only have one start battery 12v lead acid NS40 model 380cca 40ah but now i know my trailer mover works i want a battery just for the trailer mover, my 40ah lead acid drops from full charge to 43% by moving the boat 20 meters one way

Are lead acid, agm, lithium all equil as in there amp hour ratings? Will i need 80ah lithium just to take my boat out for the day than push it back in the yard?

I was a big lipo user but never ventured to deep into electronics i still have a B5 imax charger that i use every now and again if i go lithium ion im hopping to keep using this charger i've had it 15 years

For starters - You are using a low rated cranking battery that is not fit for purpose - you've got realistically only 20amps of cycling .

What is the draw of the trailer mover .... ? This is critical to know this ...... ​ a anchor winch draws 50 plus amps

As for battery you need a dedicated deep cycle battery

No ...... AGMs & LiFePO4s are not equal . In a nutshell a 100amp AGM has a usable 50amps ( you go below 50% discharge & you shorten the life of the battery)
Most LiFePO4s (100amp) will have 80% discharge (80amps) or even 90%

I dont know your charger but I doubt very much that you can use it to charge a Lithium (LiFePO4) battery . Without the correct algorithms you will destroy the battery , so you'll need a smart charger that can handle lithium
Unlike a lead acid battery which should be charged at around 10% of the battery capacity - Lithium prefer a higher charge rate .... 40/50% (40 / 50amps for a 100amp battery).

Anyhow find out what the draw is on your trailer mover ?

Chris

[stevej]

and if its a brushed motor a lithium will probably kill it if its just being run by a basic controller

[Dignity]

As already mentioned, knowing the current draw is critical. A continuous high current will kill a deep cycle battery just as quickly, they are happier on steady current draws. Probably require a hybrid crank/deep cycle which is better but they have a very little tolerance once you draw down below a certain voltage, they will very quickly die.
Gazza, they are all equal, 100 amps is 100 amps though have totally different usage and management requirements and as Chris indicates, how much of that storage capacity you can use which is why you see LiFePO4 as being advertised as equal to a much higher amperage output. Lithium Ion is a different kettle of fish again, from what you're saying they'll shut down very quickly just from the heat generated.

[gazza2006au]

Thanks fellas i will have to get a watt meter and check the amp draw

[rayken1938]

Your battery also could be on the way out if you can get to a battery shop or even supercheap they will test it for free. Have you tried another battery?Looking at the trailer movers on ebay they are rated at between 350 and 550 watts so if you divide the wattage by 12 you get the amps.
cheers Ray

[Dignity]

Your battery also could be on the way out if you can get to a battery shop or even supercheap they will test it for free. Have you tried another battery?Looking at the trailer movers on ebay they are rated at between 350 and 550 watts so if you divide the wattage by 12 you get the amps.
cheers Ray

I reckon you're correct, 43% drop in charge on a CCA battery is pretty severe, do it twice and it's well and truly pretty well going to have the plates oxidised and hard to shift. It's the calcium that is used instead of antimony which is the real problem, with antimony batteries were far more forgiving.

[rayken1938]

How long does it take to move the boat 20m? Say the motor is dragging 25amps for 1/4 hour that will equate with you are getting from your battery. Might
be a idea to also check how hot your motor is getting as I have no idea what the duty cycle of the motor is.

[gazza2006au]

Cheers guys the motor is 550watts and it takes probably a good 30mins of starting and stopping to push the boat 20 meters i would guess its moving the trailer at about 1-2 minute per meter battery was bout about 9 months ago new and its charging to 100%

[gazza2006au]

Rayken that means the little trailer mover motor is drawing a whopping 46amps wow thats a lot

[gazza2006au]

Guys since im drawing 46amps im going to grab two of these shitters running in parallel https://www.autoelec.com.au/675-105?...EaAhD0EALw_wcB im currently running 1 of these batteries for the trailer mover

And while on the question of batteries will one of these be able to start my 90hp, run accessories and possibly run a oven chef? https://www.autoelec.com.au/675-105?...EaAhD0EALw_wcB

[NAGG]

Rayken that means the little trailer mover motor is drawing a whopping 46amps wow thats a lot

That lines up with your issue ......

you have a 40amp battery - you are drawing .76amps / min ..... thats 23 amps usage for the 30 mins it takes you to move the boat (about 57% discharge which is what you said initially)

That means every time you move your boat (30mins) you are destroying that battery more & more .

As a absolute minimum - you need a 75amp deep cycle battery to do the job & last for years.

Ultimately though ....... how many times do you move the boat or will you move the boat ? . You could just use the battery you have ..... charge it immediately after use & wait for the battery to die . The critical thing is that you have to charge it immediately after use. It may last you a few years .

Oh & btw ..... this isn't your boats starting battery is it ?

Chris

[disorderly]

Oh & btw ..... this isn't your boats starting battery is it ?

Chris

LOL...I hope he intends to join the VMR...

I wonder if this could all be avoided by practicing reversing in tight spaces...

Sounds like a hell of a fukk around to take 30 minutes to move the boat back up the driveway

[gazza2006au]

That lines up with your issue ......

you have a 40amp battery - you are drawing .76amps / min ..... thats 23 amps usage for the 30 mins it takes you to move the boat (about 57% discharge which is what you said initially)

That means every time you move your boat (30mins) you are destroying that battery more & more .

As a absolute minimum - you need a 75amp deep cycle battery to do the job & last for years.

Ultimately though ....... how many times do you move the boat or will you move the boat ? . You could just use the battery you have ..... charge it immediately after use & wait for the battery to die . The critical thing is that you have to charge it immediately after use. It may last you a few years .

Oh & btw ..... this isn't your boats starting battery is it ?

Chris

Yeah it is the boats start battery for now but i am upgrading to a 720 or 780 size marine battery for the outboard

[Dignity]

Chris, you seem to infer that a deep cycle will solve the problem. My anchor winch draws that much power and i used to use the deep cycle but found it destroys them. It is now on the cranking battery for the last few years and with the motor running works much better.