1998 TXT New Batteries, still slow. Where to start?

[JohnnieB]

It is a 19989 TXT, so it is either a series drive or a DCS drive. Which is it?

In either case, the typical speed at 36V with stock controller and stock height tires is about 14 MPH, which means the motor spins at about 3250RPM.

Going to 22" tall tires will theoretically increases the speed by 22.2%, but it also decreases the effective torque where rubber meets road by 18.2%, so the motor will no longer reach 3250RPM when powered by a 36V battery pack.

Also, you said they were had off-road tires. If they are the low pressure type (max inflation pressure of <10PSI) more tore is needed to turn them , so there is a further toque loss and the motor won't reach the stock RPM by a further margin.

Additionally, the 200AH batteries have roughly 11% less storage capacity than the stock 225AH batteries normally used in a 36V pack.
Plus, new batteries only have about 75% of their rated storage capacity until they are broken in.
Those two factors won't effect speed very much, but will effect torque a bit.

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Things that can be done incrementally that might improve performance now and prepare the amp delivery system for future upgrades.

High current cables. Replace all of them with 4Ga or thicker, 13 for a series drive and 10 for a sepex drive. Since you are likely to use six 8V batteries if you upgrade to 48V in the future, get cable set for 8V batteries. The interconnecting cables inside the battery pack need to be longer for 8V batteries since the both terminal are on same side, but they'll still will work with the 6V batteries now in the 36V pack.

Replace the stock solenoid (85A contacts) with a 48v MZJ400 (400A continuous - 1000A peak) Super-Duty solenoid that will work with 36V now and 48V later.

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I got interrupted while composing and didn't see the additional posts.

[Dsiekman]

Since I just bought the six, I was considering just adding two more 6's in the bag well assuming I get this done in the next 9-12 months.

Yes, the offroad tires are the low pressure variety. That makes sense that there is more rolling resistance. I had not thought about replacing wheels and tires but it might be a good idea.

[jhop869986]

I converted my 36v txt to a 48v, added two batteries, changed to 2awg wire all around, alltrax controller and new solenoid.. I have 22x11-12 off road tires, I hit 26-27 mph on flat road, I climb hills with a cart load of people no problem.


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[Dsiekman]

Originally Posted by jhop869986

I converted my 36v txt to a 48v, added two batteries, changed to 2awg wire all around, alltrax controller and new solenoid.. I have 22x11-12 off road tires, I hit 26-27 mph on flat road, I climb hills with a cart load of people no problem.


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That's perfect if not a little faster than I need. You can control top speed with the Alltrax controller, right?

[scottyb]

Originally Posted by JohnnieB

It is a 19989 TXT, so it is either a series drive or a DCS drive. Which is it?

In either case, the typical speed at 36V with stock controller and stock height tires is about 14 MPH, which means the motor spins at about 3250RPM.

Going to 22" tall tires will theoretically increases the speed by 22.2%, but it also decreases the effective torque where rubber meets road by 18.2%, so the motor will no longer reach 3250RPM when powered by a 36V battery pack.

Also, you said they were had off-road tires. If they are the low pressure type (max inflation pressure of <10PSI) more tore is needed to turn them , so there is a further toque loss and the motor won't reach the stock RPM by a further margin.

Additionally, the 200AH batteries have roughly 11% less storage capacity than the stock 225AH batteries normally used in a 36V pack.
Plus, new batteries only have about 75% of their rated storage capacity until they are broken in.
Those two factors won't effect speed very much, but will effect torque a bit.

-------------
Things that can be done incrementally that might improve performance now and prepare the amp delivery system for future upgrades.

High current cables. Replace all of them with 4Ga or thicker, 13 for a series drive and 10 for a sepex drive. Since you are likely to use six 8V batteries if you upgrade to 48V in the future, get cable set for 8V batteries. The interconnecting cables inside the battery pack need to be longer for 8V batteries since the both terminal are on same side, but they'll still will work with the 6V batteries now in the 36V pack.

Replace the stock solenoid (85A contacts) with a 48v MZJ400 (400A continuous - 1000A peak) Super-Duty solenoid that will work with 36V now and 48V later.

---------------------------------
I got interrupted while composing and didn't see the additional posts.

Great post JB

Adding 2 more 6v does make 48v but at a cost that is 150 pounds more than 6/8v. The result is like having a passenger in the cart that never gets out. Add a rear seat (another 100-150#) and its a 30% increase in cart weight. All of which does effect the power to weight ratio adversely. So while the increase is noticeable - it could be better with less weight

[mgray70]

Originally Posted by scottyb

Great post JB [emoji106]

Adding 2 more 6v does make 48v but at a cost that is 150 pounds more than 6/8v. The result is like having a passenger in the cart that never gets out. Add a rear seat (another 100-150#) and its a 30% increase in cart weight. All of which does effect the power to weight ratio adversely. So while the increase is noticeable - it could be better with less weight

I converted my cart to 48 about a year ago with 6-8 volt batteries, and I just upgraded a friends cart recently that already had new batteries, so I just added two more. He will spank my butt! Both heavy duty solenoid. I have Scotty's reverse contactor, he still has the standard switch, both are 400 amp Alltrax the only difference is mine is the SPM, and his is the NPX (we both already had the old technology control installed already). All that to say this, I think the extra batteries makes the cumulative voltage just a tad bit higher resulting in a little more speed even with the xtra weight of the batteries.

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[scottyb]

48v is 48v and unless your pack is failing to deliver the amperage called for there will be no difference in performance. There are so MANY factors at work in the performance equation it's easy to get the wrong impression. Never underestimate the importance of the power to weight ratio.... if you doubt the importance of it ask any one of these lithium pack guys who have shed 300# of batteries.

[JohnnieB]

Originally Posted by mgray70

I converted my cart to 48 about a year ago with 6-8 volt batteries, and I just upgraded a friends cart recently that already had new batteries, so I just added two more. He will spank my butt! Both heavy duty solenoid. I have Scotty's reverse contactor, he still has the standard switch, both are 400 amp Alltrax the only difference is mine is the SPM, and his is the NPX (we both already had the old technology control installed already). All that to say this, I think the extra batteries makes the cumulative voltage just a tad bit higher resulting in a little more speed even with the xtra weight of the batteries.

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The total pack voltage is the same with 6x8V or 8x6V, but the typically larger storage capacity of a 8x6V pack reduces the amount of voltage drop when amps are drawn from the pack. That may be what is giving your friend's cart better performance, despite the added weight of two more 6V batteries, but there may be other factors also.

If you built 48V packs with six 200AH 8V batteries and eight 200AH 6V batteries, they would both weigh roughly the same and the voltage drop per 100A of current draw would be roughly the same, so both carts (if otherwise identical) would perform roughly the same.

The closest I can come up with from readily available specs, is eight T-605 vs six ranger 160.
T-605 = 6V 210AH weighing 58 lbs for a total of 464 lbs and 10.1kWh of storage.
Ranger 160 = 8V 204 AH weighing 75 lbs for a total of 450 lbs and 9.8kWh of storage.

The 48V pack using eight T-605 batteries is 3% heavier and has 3% more storage capacity, so that might cancel out the difference.

[mgray70]

Originally Posted by JohnnieB

The total pack voltage is the same with 6x8V or 8x6V, but the typically larger storage capacity of a 8x6V pack reduces the amount of voltage drop when amps are drawn from the pack. That may be what is giving your friend's cart better performance, despite the added weight of two more 6V batteries, but there may be other factors also.

If you built 48V packs with six 200AH 8V batteries and eight 200AH 6V batteries, they would both weigh roughly the same and the voltage drop per 100A of current draw would be roughly the same, so both carts (if otherwise identical) would perform roughly the same.

The closest I can come up with from readily available specs, is eight T-605 vs six ranger 160.
T-605 = 6V 210AH weighing 58 lbs for a total of 464 lbs and 10.1kWh of storage.
Ranger 160 = 8V 204 AH weighing 75 lbs for a total of 450 lbs and 9.8kWh of storage.

The 48V pack using eight T-605 batteries is 3% heavier and has 3% more storage capacity, so that might cancel out the difference.

I hadn't thought about the voltage drop. That's probably a lot of it. My theory was 6.4x8 vs 8.4x6. There is a little less than a volt difference. Both packs are within 6 months of each other in age. I know the full charge status can be different on the different batteries. I didn't mean to hijack the thread, just share my experience with 8 vs. 6 thing

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[cgtech]

I was thinking the same thing. High performance carts with 4x 12v batteries drop a whole lot under load, it's bad.