Daymak EM2 suddenly cutting power

AngeloDeligi

New Member
Hello, recently I got a 2017 Daymak EM2 and I took it for a drive and about 15km in the drive it started cutting power once I gave it too much throttle. The battery is at red when I go full throttle and it seems dead but is a dead battery a possible cause for this? Will I need new batteries? I’ve checked all the connectors and all that. I tested all batteries and each one of them got 12.6V indicating they are healthy.
 

rich c

Well-Known Member
Look up voltage sag. The battery is too low to support the current draw and shuts off. Charge up the battery, it will work fine then.
 

AngeloDeligi

New Member
Look up voltage sag. The battery is too low to support the current draw and shuts off. Charge up the battery, it will work fine then.
I charge the battery and about 15km into the ride it does it again, is my range just that low? I’m pretty sure I had read that the EM2 gets 60Km of range.
 

hellsdragon

Member
I charge the battery and about 15km into the ride it does it again, is my range just that low? I’m pretty sure I had read that the EM2 gets 60Km of range.
Have them check you batteries to see if there good then check the app to see voltage cut off I had the same problem with my em2 it had bad batteries when I bought it brand new they replaced the batteries and was fine for 6 months then I had to replace them again as the charger was over changing them now I have better batteries and a better charger for my bike and works great as for range it depends on the terrain you travel if a lot of up hill u won't get the 60 kn
 

hellsdragon

Member
Hello, recently I got a 2017 Daymak EM2 and I took it for a drive and about 15km in the drive it started cutting power once I gave it too much throttle. The battery is at red when I go full throttle and it seems dead but is a dead battery a possible cause for this? Will I need new batteries? I’ve checked all the connectors and all that. I tested all batteries and each one of them got 12.6V indicating they are healthy.
Even if the batteries are bad the read 12.6 volt as mine did I took mine into get tested at another ebike store had them full charged and they tested bad u need to use a battery tester that checks the draw on the batteries to see if there good
 

AngeloDeligi

New Member
Even if the batteries are bad the read 12.6 volt as mine did I took mine into get tested at another ebike store had them full charged and they tested bad u need to use a battery tester that checks the draw on the batteries to see if there good
Wow I literally just posted a forum asking how to test lead acid batteries. Thanks a lot, I’ll probably be buying new batteries for my other bike, it’s just kinda hard to find some place to test them at these times you know.
 

Svard75

New Member
The low voltage on the app should not be lower than 10v less than the rating. For example if it’s a 72v machine it should be 62v as the low cutoff. Anything lower means deep discharge which destroys batteries.
Fact is either all or some of your batteries need reconditioning. Take them to Daymak for replacement or the alternative would be to grab a lithium pack off eBay.
Next year I’ll pickup a 72v 40ah pack and charger for $2000. And a 100a controller to replace the factory unit of an EM3.