How do I get more torque without more speed?

[MikeFairbanks]

The trike has a front hub motor (9c dd), a 22amp controller and 36 volt, 12ah battery setup. The batteries are a crap brand and do not want to release much juice at one time. They apparently aren't high discharge rate batteries. Plus, they sat for three months totally drained. I charged them back up, but they aren't so great.

Yesterday I did a few "speed" runs on the flats and topped out at about 16mph. Not only was the top end slow, but the bottom end was very weak. It took a lot of time to get it going. The trike should have pretty strong pick up with a top speed of about 22mph.

I'm going to stick with SLA, and now that I have the trike in my possession again it'll stay charged properly.

So my question is this: without upping volts, will getting three 12-volt Powersonic batteries with 18ah help with torque? I don't really need more speed, just more torque and the 18ah will certainly help with range.

I realize torque and speed are mostly voltage and controller amps, but what about the quality of the battery and the ah? Any effect there?

Thanks, as always.

 

[justlooking]

for starters, if your batts are sla ones and been flat for three months, you will probably find that they have the volts but not much amps, i had this about a year ago with a scooter, the bats very quickly went low, even though the voltage was there,
i bought new sla batts, but even though it went alot further , it was not impressive,
i changed for the more expensive option and bought a 48v lithium ion battery. and the difference was unbelivable,

if you can, save the money you have for the sla and put it towards a lithiun pack and charger, they will be worth it, they also last alot longer, years longer,

the other thing is your motor, is it a brushed motor or sensored motor ?? you can tell this by the number of wires going into the motor, if it has 2 wires then its a brushed motor,

my expertise with brushed is that they dont like hills or even inclines, the one i had tended to over heat after 2 or 3 miles,

 

[MadRhino]

More watts are giving more torque, more volts are giving more speed.
If you want more torque and the same speed, up the Amps.
This will give you slightly better speed though, mostly at the places your motor was slowing down because of lack of power.

Alternatively, more torque can be achieved with the same power that you have now, by lacing your motor in a smaller wheel. This will give you slightly lower speed though, mostly at the places your motor had it easy.

 

[hjns]

Multiple ways to skin a cat.

Lower gearing, like getting the 9c into a smaller wheel.

Or more amps. So, here is the electronic consideration: keeping voltage the same, doubling your amps will get you something like 25-30% more torque, like acceleration from zero. So, with your current setup, running maximum amps (22A according to your controller) would get you a maximum of 57Nm of torque. Getting a 40Amp 4110FET controller with maximum of 40Amp would increase torque at slightly above zero to 76Nm. Allowing 60Amps would get you above 90Nm.

So, that makes it the combination of batteries and controller. Obviously, if your SLA can only provide a limited amount of current, and will be unlikely to provide anything over 25Amp despite the high capacity. That makes it quite a difficult task to get more torque out of this setup. Take a look how many amps these Panasonics would give you, and then see if it meets any of your expectations as above. Then buy the appropriate controller to go with it. You may want to modify your current controller first by adding a blob of solder to the shunt. That would fool the controller into allowing higher currents, but has different disadvantages as well.

 

[docnjoj]

Too bad that you can't change out that DD hub for a geared one like a MAC. It would cut your consumption of watts at low speed and give much better low speed torque. This would help even SLA to last a bit longer and not be as stressed.
otherDoc

 

[MikeFairbanks]

Thanks, guys. That all makes perfect sense. I'll work on it.

 

[FfredDRredD]

i did alot of reading when i first found es, one of the things i read about battery care was sla developes lead sulfation left in uncharged state even for a short period

 

[DAND214]

Mike,
all you need is some good batteries. Sla is the worst but if in fresh condition you will see more torque and a little top end.
Oh, like it was when new.

Dan

 

[parajared]

 

[MikeFairbanks]

^^^
That looks more like a braking system. Probably pretty effective.

 

[d8veh]

Once you get your new batteries, open up the controller and add some solder to the shunt. Some 22 amp controllers have two shunts. Whatever you have, consider the overall length of the shunt wire. Start with about 20% of the length of it soldered and you'll get a useful gain in torque that doesn't cost anything.

In case you've not done it before, here's one done about 30%:

 

[dogman dan]

There it is, what I was going to say. You need a new set of batteries so they can provide some amps, then solder that shunt.

What you really need though, is the 6x10 motor. That's the perfect trike motor, about 15 mph on 36v. Then give it about 40 amps of that with a new controller, so you have the wattage to have tons of power, but still not go even 20 mph. At about 1600w, it won't fry the motor either.