LiPo 48v Ryobi Mower problem

[mowertest]

I have a 48v Ryobi mower and I am trying to make it work with a LiPo battery that I have from an old e-bike conversion project.
I cannot seem to find the wattage for the Ryobi 48v mower anywhere but the battery that I am trying to use is a 48v 12Ah battery that drove the 1000w ebike motor without any problem. The battery that comes with the mower is 2-24v 10Ah Lead acid batteries. Seems to me that the new battery should be more than enough power to make something happen but so far nothing. Any suggestions or advice would be great.

 

[gogo]

Did the mower work with the SLA batteries? Is there a fuse anywhere?

 

[mowertest]

yes, for sure it is a working mower, has 60A fuse and it too is good.

 

[dnmun]

can you show a picture of the '48V12Ah' pack and what is the charger voltage? is it really lipo or lifepo4 and how many cells in series? you can use a brushed motor controller for a 48V 500W motor and use that to control the motor.

i assume you meant 2 12V SLA packs in series to make 24V ?

 

[gogo]

View attachment RY14110.pdf
[youtube]mTkwFe5FEw8[/youtube]
The exploded view parts list shows two discrete batteries. I think I remember researching these types of 24V batteries and found they were fairly expensive.

This seems to be a straight DC setup with a switch and no sort of controller. There are two fuses, one for each battery and then some sort of 'fuse key'. Where are you hooking in your lithium and do you have a volt meter to test for voltage along the electrical path to the motor?

[EDIT] It looks like you ought to be able to hook the lithium at #1 and #4 on the terminal block? Is the circuit breaker tripped? I like dnmun's idea of using a controller so you get the LVC and current limiting to protect the lithium. A 500W controller with 10 battery Amp limiting would probably allow 25 motor Amps and maybe more in a start-up spike, so would be well matched to the 15A circuit breaker? Maybe a 1000W controller, with 20 battery amps and 50 nominal-max motor Amps and larger start-up spikes, would be closer to what the lead acid batteries were putting out. Like Dogman says below, 15A seems low for spinning the blade and a belt drive to the drive wheels.

You could experiment with different size controllers until you have enough power for the high loads without tripping the circuit breaker, but still protect your lithium with a suitable battery current limit by the controller.

So that resistor circuit shorts the motor as a 'brake' (after the battery is disconnected by the main switch) to stop the spinning blade and dissipates the energy of the spinning blade/motor as heat?

 

[dogman dan]

No hint of a start up, or is it a starts then shuts off immediately. If it runs, it could easily pull 3000w in thick grass. crazy amp spikes on these mowers.

The only thing that makes any sense to me at all, is that the pack has a bms, and something is not right, then the bms trips. I'm assuming you have good connections, so power could flow to those fuses. But check that anyway, tracing the voltage through the mower till you find the problem. The safety key switch is a likely suspect for example, as are the connections at the fuses. Maybe a fuse needs a wiggle?

More info on that battery please?

In other threads, I have mentioned how my 24v mower murdered a couple batteries, till I started using really high discharge rate RC lipo on it. So depending on what your battery can do, it might be a good idea not to put it on the mower, unless it's as expendable as the batteries my mower murdered were.

 

[werner32]

Ive just converted my Ryobi 48V to Lipo4.
All working great and more powerful then my old electric

Got the batteries from vpower.hk
Took some time to get here but worth the price

 

[wineboyrider]

https://www.google.com/#psj=1&q=40v+ryobi+mowerIt's a 40v lithium mower? If so that's 10s lipo or 8s lifepo4 and a 48v would/might fry something?

 

[werner32]

https://www.google.com/#psj=1&q=40v+ryobi+mowerIt's a 40v lithium mower? If so that's 10s lipo or 8s lifepo4 and a 48v would/might fry something?

48V10Ah LiFePO4 was 48v nicad before

Works great.

 

[wineboyrider]

gotcha