Charger Options

Can I use my old charger?

The short answer is yes, but there are things you should know before you do. Please read this section and the section for your specific charger.

There are two differences between lead acid and LiFePO4 chargers.

The first difference is the charging voltage. A 48V lead acid battery charges at 58.8V, while it is 58.4V for LiFePO4. This is a minor difference, less than 1%, so not something we are generally concerned about. Even with higher voltages, LiFePO4 cells are very tolerant of overvoltage and the battery's BMS (battery management system) will disconnect cells when they exceed a preset maximum voltage.

The second difference is the charge profile. Charging is typically broken down into 3 stages.

Stage 1 is constant current. The current on the charger will build up to the maximum current rating of the charger and hold at that current while the voltage slowly increases until it reaches the charging voltage

Stage 2 is constant voltage. The voltage is held at the charging voltage and the current slowly decreases. This allows the cells to top off.

Stage 3 is float charge. This stage is only used for lead acid batteries. The battery is held at 100% state of charge, with minimal current, indefinitely. Lead acid batteries lose charge quickly just sitting idle. They can discharge to the point it damages the battery and this stage prevents that. For LiFePO4 batteries, being subject to a float charge for a long time can damage the batteries.

PowerSonic has a good write up with charts on the different stage.

So yes, you can use your old charger, but, if the charger has a float stage, you will want to unplug it when the battery is charged.

Stock Chargers

Ryobi SC-48

Maximum Charge Current: 13A

This was the original charger shipped with Ryobi 48V mowers. It was made for Ryobi by Delta-Q and is a rebranded version of the the SC-48 charger used on EZGO golf charts.

As you can see from the chart below, this charger will continue to top off the battery after the battery is fully charged. If you use this charger on LiFePO4 batteries, be sure to unplug it once the batteries are charged.

Ryobi OP48RM

Maximum Charge Current: 7.5A

This is the charger that shipped with newer 48V mowers. It has a lower current rating and does not perform a float charge. The lack of a float charge was bad for the stock lead acid batteries, but works out very well for LiFePO4 batteries. While this charger isn't fancy, it appears to be well-built. It is my go-to charger for my LiFePO4 converted mowers.

Aftermarket Chargers

Haisito / HTRC P3648

Maximum Charge Current: 13A

This used to be listed under the HTRC brand, but, after a recall with a different charger, they've been transitioning to the Haisito brand in the US. The chargers are made by Shenzhen Haitan Technology Company in Guangdong, China.

Probably the most popular aftermarket charger for these mowers, it is designed to cover a large number of applications. It can charge both 36V and 48V batteries and claims to automatically detect which type of battery you're charging, so this can be used with both the stock lead acid and LiFePO4 batteries. There is also a repair mode, intended only for lead acid batteries. It comes with battery clamps and a an EZGO RXV plug. To use this plug, you will need to break off the two plastic tabs inside the mower's charge port.

There are 3 current settings: 5A, 8A, and 13A. I recommend using the 5A for a 50Ah battery and 8A for a 100Ah battery most of the time. The 13A is useful when you are in more of a hurry.

Given the large number of these chargers sold, they have relatively few issues. The most common issue is a quality issue on the charging cable where it connects to the charger. It's an XT60 connector and it's not always attached well. There are been reports of shorts and broken connections, so make sure to check it well when you get it. The connections should be solid and there should be insulation on the wire almost to the connector.

This charger is available from many sources, sometimes with different labels. Expect to pay between $100 and $130. it's availble with several different plugs, so be sure to select the EZGO RXV version.

Ebay (HTRC Store, typically the best price)

Amazon

AliExpress

Other Tested Chargers

AFU AF500 (Avoid)

Maximum Charge Current: 3 - 15A (model dependent)

This charger is available on AliExpress with or without a display. Similar models are also available under the Ohrija brand.

On the surface, this looks like a good option. It's compact and low cost, usually selling for around $50 for the 8A version. However, when I profiled it, I found the charger held the battery at 58.4V indefinitely. In the manual this is referred to as "maintenance mode", but this is your typical stage 3 float charge used on lead acid batteries. Being held at the charging voltage indefinitely like this can damage LiFePO4 batteries. I reached out to AFU to see if there is a way to disable this behavior and I still haven't heard back. My guess is they took their lead acid charger and changed the voltage slightly. I will update if I get any new information from the company.

Aside from the float charge issue, the charger is very simple, but seems well-built, with an aluminum case and removeable power cord. It reads voltage as soon as power is applied and has no power switch, or buttons of any kind. The display is fairly accurate, but only displays temperature in Celsius with no option to switch to Fahrenheit. Charging status is indicated by 2 LEDs on the side, though the display also seems to blink when charging is complete.

AliExpress