2 Battery Chargers Over Heating

[GrandPappyMike]

I have 2 battery chargers and 4, 48v 2018 batteries all purchased from RAD. The chargers will charge all the batteries but the chargers never go green and then they get extremely hot. I have to set a timer for 4 hours and just unplug them. I was just going to buy an aftermarket charger thinking that the chargers were just cheap, but from searching the forums I seem to be the only one having this issue. Considering I may be the only person with this issue I would guess that although all 4 batteries hold a full charge and discharge as normal, one has an issue that damages the chargers so they won't recognize a full charge. Any other ideas would be appreciated.

Thank You,
Mike

 

[Craigrnelson]

Why only 4 hours on a timer? Try straight into the battery bypass the timer and those chargers get hot which is normal. Anything over 2 amp charger will have a fan so try the Luna (Link Removed - No Longer Exists) . Another is the (Link Removed - No Longer Exists)

 

[BTfl]

I have 2 battery chargers and 4, 48v 2018 batteries all purchased from RAD. The chargers will charge all the batteries but the chargers never go green and then they get extremely hot. I have to set a timer for 4 hours and just unplug them. I was just going to buy an aftermarket charger thinking that the chargers were just cheap, but from searching the forums I seem to be the only one having this issue. Considering I may be the only person with this issue I would guess that although all 4 batteries hold a full charge and discharge as normal, one has an issue that damages the chargers so they won't recognize a full charge. Any other ideas would be appreciated.

Thank You,
Mike

My stock chargers get hot, and take about six hours to charge the battery to full before they go green

 

[GrandPappyMike]

Thanks, maybe they would go green if I waited.

 

[GrandPappyMike]

Why only 4 hours on a timer? Try straight into the battery bypass the timer and those chargers get hot which is normal. Anything over 2 amp charger will have a fan so try the Luna (Link Removed - No Longer Exists) . Another is the (Link Removed - No Longer Exists)

Thank you. I thought the maximum time they took to charge was 4 hours. I have no idea where I got that number from.

 

[AHicks]

Nothing wrong with keeping an eye on them though. At no point should they get hot enough where you can't pick them up and hang on to them.

Charge time varies, is dependant on state of charge when you plug them in.

 

[RangerDave]

I thought my charger got extremely hot while charging, so I use a small usb powered fan to blow air on the charger. It only takes 2 watts and blows a lot of air to keep the charger much cooler.

 

[BTfl]

Thank you. I thought the maximum time they took to charge was 4 hours. I have no idea where I got that number from.

Please post if you get a greenlight, thanks

 

[GrandPappyMike]

I thought my charger got extremely hot while charging, so I use a small usb powered fan to blow air on the charger. It only takes 2 watts and blows a lot of air to keep the charger much cooler.

View attachment 53388

I just measured the temperature of the charger after 1 hour. It's a 151 degrees Fahrenheit. That seems awful hot to me.

 

[AHicks]

Agreed. That's worth a call to Rad.

 

[ExPatBrit]

40 + year EE here.

48 volt at 2 amps is 100 watt.

Ever "tried " holding a 100 watt household lightbulb in your hand, yes it's hot.

Check the temperature of the charger when the green light illuminates or after 6 hours or so of charging. If it's still hot you have a problem.

 

[GrandPappyMike]

40 + year EE here.

48 volt at 2 amps is 100 watt.

Ever "tried " holding a 100 watt household lightbulb in your hand, yes it's hot.

Check the temperature of the charger when the green light illuminates or after 6 hours or so of charging. If it's still hot you have a problem.

Thank you, I'll give it a try, problem is I've never seen it turn green.

 

[AHicks]

Theres that, and the fact mine doesn't get near that hot. It's warm, but it's darn sure not 150 degrees....

 

[hughresearch]

I have 2 battery chargers and 4, 48v 2018 batteries all purchased from RAD. The chargers will charge all the batteries but the chargers never go green and then they get extremely hot. I have to set a timer for 4 hours and just unplug them. I was just going to buy an aftermarket charger thinking that the chargers were just cheap, but from searching the forums I seem to be the only one having this issue. Considering I may be the only person with this issue I would guess that although all 4 batteries hold a full charge and discharge as normal, one has an issue that damages the chargers so they won't recognize a full charge. Any other ideas would be appreciated.

Thank You,
Mike

I was worried about that at first as well. The charger gets bloody hot but that is how they work. I have a big chuck of steel that I sit the charger on as a heat sink. Also a well discharged RR battery can take 7 hours to charge.

 

[AHicks]

Though I have had my Rad charger on the warm side of things, and I would never leave it on the bike's seat for instance, it doesn't get THAT hot. For instance, I can keep my hand on it without burning my hand.

I would add that many manf's come with fan equipped chargers that don't run near that hot. The downside is the fan may require maintenance at some point. If it doesn't get it, that charger may get dangerously warm....

And yes. The charger may take 6-8 hours to go green, indicating a full charge....

 

[BKing]

40 + year EE here.

48 volt at 2 amps is 100 watt.

Ever "tried " holding a 100 watt household lightbulb in your hand, yes it's hot.

Check the temperature of the charger when the green light illuminates or after 6 hours or so of charging. If it's still hot you have a problem.

100 watts is not being dissipated inside the case. It would melt. The correct way to calculate the heat dissipation inside the charger case is input power minus output power. There are some tweaks to this depending on the charger but these are not variable chargers. They only know when the load reaches a preset point and turns on the green light.
120w input minus 96 watts output equals 24 watts. This is for a typical 80% efficient unit. 24 watts inside a closed up plastic case starts adding up over time which is why it gets so hot. If there is a shorted cell or two in the pack the charger won’t shut off unless it has a thermal cutout designed in. If the battery is not reading 48v when 2/3 charged it’s bad. The additional power put into the battery is large between 48v and the final 52 volts. The ambient temperature affects the charger too, big difference between a room at 60 vs 75.

 

[AppMan88]

I use a 12v 10amp charger and charge my batteries one at a time. Once the light turns green it switches to a 2 amp maintaing charge. I had the same problem when I'd charge all my batteries at once. I've fried 3 chargers in a year. Best bet is to charge one at a time. Then once they all charged, connect them in parallel and reconnect the charger. Once it switches to maintaing mode, let it sit on that for a few hours and they will be as good as new. I also use SLA batteries.