Doosan (& Daewoo) B20T-5:
Forklift will not travel over 3mph...

Hello... i was tasked by my company to fix a forklift. I was told by the operator that the forklift wasnt going at the normal speed of about 6 mph. when i drove the forklift to the maintenance area. The forklift drove about 4mph. The mechanic before me ordered a L/S brake kit. which was for the wrong side, but i could use the inner brakes (5) and spacers (6). so i replaced the the brakes and spacers. After putting it all back together. The Forklift is now a bit slower. well, when i just started off it speeds up to 5 mph.. press the brake, start up again and its at 4 mph and gradually goes down to 3 mph. also seems to have a smell of the oil in the hub or motor. but when checking the temps. they seems to be ok.

Im pretty stumped on where to begin my trouble shooting. I believe it could be the motor but yet. the problem only happens when i accelerate when the forklift has been sitting for a long period of time. It can easy get up to 5 mph quickly, but after that first stop no matter brake pedal or not using the brake pedal. it goes down just like i explained up there. Something tells me this could be very simple but i dont know where to start. im new at this and i have no idea... i dont know if adjusting the speed is possible maybe? i believe its adjusted out all the way from checking the panel on the forklift. oh and i also bled the brake lines as well.

I could really use some of your input. its a Doosan B20T-5 electric fork lift.
  • Posted 16 Nov 2013 18:09
  • Discussion started by supaman253
  • Washington, United States
Showing items 1 - 6 of 6 results.
i`ll send you a manual, just need email. dont put @ symbal, or.
they will remove the email
Are there any fault codes? Is there an economy switch?
  • Posted 1 Dec 2013 06:35
  • Reply by EasiTek
  • Ontario, Canada
Votage seems good there even using the diagnostics on the forklift. Temps on the inverter seem good and on the motors. After a charge the vehicle was up to 5 mph but justs to 4mph and now the battery drains. 6am full charge to 9am it at a little over half. I had a worker tell me the forklift is capable of the avg of 8 to 9 mph.does that have to do with the inveters npt putting out engouh. Just not sure where to start with no manuals... thank you for the help so far
  • Posted 20 Nov 2013 03:35
  • Reply by supaman253
  • Washington, United States
ok sounds good.
  • Posted 17 Nov 2013 06:11
  • Reply by supaman253
  • Washington, United States
Doesn't matter where you check the battery voltage so long as you are reading battery voltage.
Battery voltage is battery voltage. What you are looking for is to see how much the standing battery voltage drops when a high current draw load is placed on the battery.
Voltage will be the same everywhere in the system.
  • Posted 17 Nov 2013 06:04
  • Reply by L1ftmech
  • Tennessee, United States
so id be checking for a voltage drop? ill try to check that when i get there on monday. so basically check this at the motors? to see if theres a difference in the power between the starting out at 5 mph, then the drop at 4 to 3 mph?
  • Posted 17 Nov 2013 04:26
  • Reply by supaman253
  • Washington, United States
if it was me, (and I have looked at a couple of electric forklifts) I would start with knowing the battery is good.
Do this by doing a "load test", where you read (I prefer a digital Volt meter) the voltage of the battery 'at rest' and then tilt back or (best) to run the forks to their max height, then read the battery voltage while the hydraulics are at "stall" [it takes more current to lift than to drive and it is sort of dangerous to try and read a meter while the machine is travelling]. if you have more than a 10% voltage drop between 'at rest' and 'hydraulic stall', you will need to get the battery up to stuff first. Do NOT stall the motor more than 5 seconds, it should only take 3 seconds to get a good reading.
  • Posted 16 Nov 2013 23:50
  • Reply by edward_t
  • South Carolina, United States
"it's not rocket surgery"

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