24V / 1000W DC Power supply for lawn mower needed?

[CableTangle]

Hi guys,

The batteries in my electric lawn mover died after ~8 years, which is to be expected. Unfortunately i cannot get a new one from the manufacturer. I opened the plastic case which holds the battery cells, and Jaycar sells them as spares (2x 12V cells), however they would cost more than a new lawn mower and would also only last ~4-6 years or so before the remaining capacity becomes unusable.
Idealy i want a more permanent solution and build a maintenance-free lawn mover that my children can inherit!

I was thinking of using a PC power supply that can support a beefy gaming graphic card and is rated for ~1200W, however they only supply 12V, while the motor expects 24V DC. I found a few 240AC to 24DC coverters online, but they are bulky, expensive and look like Lab equipment that probably wont last long outside.

What would be the worst that could happen when i run the Motor on 12V? What other options do i have?
I only opened the battery cover; i dont want to rebuild the whole lawn mover since i neither have the right tools or parts for that.

[Phil1977]

The most reasonable solution seems to be for me to purchase two 12V-LFP-batteries with integrated BMS. They (theoretically) last longer than the usual NMC-cells and are not as spicy to handle. Probably they don't work together with the original charger, so you would have to charge them up externally.

Using a power supply is more difficult. It starts with finding a weatherproof 1000W-supply and then you practically do not now if it cooperates with the motor controllers of the lawn mower.

[CableTangle]

I don't really expect the motor to have any sort of controller. The lawn mower dosn't have any fancy features or low battery warning and wasn't that expensive. It dosnt turn itself off when the battery power is low; the motor just keeps going until it is to weak to cut the grass. My guess is that it is just battery (with some charging controller), switch and motor.

[Stray Electron]

  1000 W sounds like a LOT of power for a lawn mower!  What kind of cells were used in the original batteries? Yeah, replacement batteries for just about an kind of rechargeable electronic device that uses a proprietary batteries are EXPENSIVE. And here is Life Lesson #1; NEVER buy anything that uses proprietary electric batteries! 

    But you can probably break open the battery pack and replace the individual batteries. There are lot of companies out there such as Batteries+ that will do that for you, for a fee.  But they're all going to use cheap crappy batteries so you need to buy good batteries and do it yourself or plan on going through the same process every few years. 

   If you are considering dragging around a 1000w power supply and an AC power cord with your mower, you'd be miles ahead to just go buy an AC powered mower such as the one made by Black and Decker.  I have one and it works fine but it only has a 18" wide cut, (probably the same or even a bit larger than what the battery powered mowers have).

   I have about 1/3 acre semi-suburban lawn (no tall weeds or heavy thick grass) and the B&D mower cuts it just fine. Several of neighbors have much smaller yards and use battery powered mowers and it takes them considerably longer to mow since their mowers only cut 14 to 16 inches at a time AND their batteries always die before they can finish mowing their lawns.

   I just took a quick peek and the Black and Decker mower is listed at $219 at one site that I looked at and they have an America Lawn Mower Company electric mower with a 14" cut for $165.

   I still have several very good gasoline powered mowers such as the ones that use the Honda engines and that have 22 inch cut, but I now use the B&D mower most of the time.  It's dammed nice to just be able to go out and plug in the power cord and then start mowing with absolutely no muss and no fuss.  I have electric outlets in the front and the rear of my house and I keep a 100 foot extension cord on a hose reel next to each outlet so I can literally pull out the cord, plug in the mower, then put the cord into an outlet and then start mowing.

[themadhippy]

get a goat or sheep,no batterys to go flat,no trailing power cords.keeps the grass fertilized and in a few years time they can be used  as dinner.