Ryobi ZT480EX Charging/Battery Issues

[dwfiederichs]

I have a Ryobi ZT480EX 48V mower that's maybe 2 1/2 years old (bought it secondhand a year ago). I bought it with 21 hours and it now has 60. The battery/charging behavior started off seemingly normal, but started behaving more oddly toward the end of the season, and now following the winter is acting more strange.

Toward the end of last season, the battery readout started showing 70% immediately after a full charge, though it seemed to have normal runtime.

I left it plugged in over the winter in an outside shed (we're in Kansas City, so while there can be cold spells it's not dramatically cold). Early in the season I used the mower to pull a spreader for fertilizer, insecticide, etc., without engaging the blade. The battery readout still showed 70% after unplugging. When I started cutting the lawn and engaging the blade, I was only getting about 30-40 minutes of cutting time, much less than half what I was getting the year before.

Yesterday after this same thing happened (battery readout started at 70%, then ran down to 10% after 30-40 minutes and the blade wouldn't stay engaged, I assume to prevent full battery discharge), I plugged it in for an hour. When I came back, the it showed 100%. I ran it for 30-40 minutes, and it got down to 45% when the blade wouldn't stay engaged - same behavior I saw earlier in the day at 10% (I assume it's to prevent full discharge).

I plugged it in again overnight and to use again early the next morning. It started at 100% and ran for about 45 minutes down to 60% - much more like what I experienced last year.

I don't know if I have a battery problem, a charger problem, or a charge readout problem. It'll be tough to take to a service center, so want to self-troubleshoot as much as I can. Appreciate everyone's advice and suggestions!

 

[Rivets]

First thing that comes to mind is your battery is starting to fail and won’t be long before complete failure. Companies are struggling with how to deliver good battery life. I would contact Ryobi service and explain the problem to them.

 

[Zeevert]

I had the same problem after 2.5 years and 75hrs; I upgraded to Lithium batteries.
What did you do on yours?
Poor battery life on the lead-acid batteries is a very common problem on the Ryobi 48v mowers after 2-3 years. Lead acid batteries do not do well when taken below 50%.
There are several videos on YouTube to do the conversion. It'll cost about $1200(?). If you skip changing the battery meter, it's a fairly simple swap. I did a few videos on my conversion upgrade:
Ryobi 48v playlist to convert to Lithium

 

[bertsmobile1]

If you go to lithium make sure you only recharge OUTSIDE on a non flamable surface
Spiral cell Pb batteries are the best by far as they have a massive plate surface area and being would in a spiral are much more mechanically strong than a std Pb battery
I have some I bought for the hire cars than ran for decades then when I moved to the bush went into the tractors
Modern Pb batteries are mostly junk as the plate grids are way too thin
Back when I was a young man a heavy duty 13 plate battery was a struggle to pick up
Now days I can carry one under each arm easily and at 70 I am defineatly not stronger than I was when I was 20 .