Am I dropping too much voltage

[wheelnsniper]

I had planned on putting a set of scpttys 2ga when I swap motors in the future but not anytime soon. Am I causing damage to batterys not having larger cables. I guess asking should I go ahead and do that swap now. Thanks all

Originally Posted by JohnnieB

You are seeing a mixture of things and all of them appear to be normal.

In and of themselves, the batteries in your 48V-204AH battery pack will typically drop about 1.5V per 100A of current draw. The voltage drop occurs almost instantly, but when the current flow stops or reduces, the voltage recovery happens over several minutes. Actually, full recovery take an hour or more, but it recovers at an exponential rate and most of it occurs in the first few minutes.

Then there is the intrinsic resistance in the amp deliver system (High-current cables, high-current connections and high-current contacts) that will drop up to another 1.0V, or so, per 100A of of current draw. The voltage drop across this resistance both occurs instantly and recovers instantly.

Since new batteries don't reach their rated storage capacity until the have be recharged a couple dozen times, the amount of voltage drop you are seeing now may lessen a bit as the new batteries mature.

[Clemsoncartguy]

Petal on the floor on flat ground would take probably as much power as a partial throttle on a 100% slope makes sense. Think about physically pushing that cart. It's pretty easy on flat ground, and it's about impossible for you to push it up 100% dirt slope.

[Clemsoncartguy]

Originally Posted by wheelnsniper

I had planned on putting a set of scpttys 2ga when I swap motors in the future but not anytime soon. Am I causing damage to batterys not having larger cables. I guess asking should I go ahead and do that swap now. Thanks all

Do you have 4ga cables or 6?

[Volt_Ampere]

The batteries don't really care what size cables you have. You are just losing some performance because the available voltage at higher currents is lower. As long as your connections don't overheat (due to a bad connection) your batteries won't suffer.

[wheelnsniper]

I am really not sure. I am assuming factory cable. Why do yall think mine would drop to 39 real quick and Helirich on what sounds like the same is only dropping to 44. It runs great I just don't wanna be damaging the new batterys or anything for that matter. It doesn't slow down on that incline at all and doesn't seem to struggle going up. Was just concerned

Originally Posted by Clemsoncartguy

Do you have 4ga cables or 6?

[Clemsoncartguy]

The 6ga factory ones are like the size of a pencil. 4ga is about 1.5 times that size and 2ga is like the size of a sharpie in thickness

[wheelnsniper]

These are bigger than a pencil so I am guessing 4 ga

[Volt_Ampere]

Cables are usually labeled on their insulation as to the wire size. Most carts come with 6 ga.

[JohnnieB]

Originally Posted by Helirich

I tried the hill today. It's every bit of 45 degrees. Its tough to not pop a wheely. I got the cart right off the charger. It was reading 51.7 volts. I went up the hill slow. The lowest reading was 44 volts.

This brings up another question. When I'm on the flat and floor it, it goes to 44 volts. But on the hill I only had the pedal at half throttle. (I can't go full throttle or it would go over backwards or launch for the moon) Anyways, does that make since? I would think the pedal has to be on the floor to drag the voltage down the most.

FWIW: You can back up hills that will flip the cart going forward.

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The batteries have a surface charge when right off the charger, so the amount of voltage drop appears higher than it actually is.

For a valid voltage drop under load test, either let batteries sit for about 12 hours after disconnecting them from charger, or drive about half a mile and then let the batteries rest for about half an hour to get the start voltage.

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In a nutshell, due to the field mapping of a sepex motor, you effectively have a different motor installed when climbing a steep hill slowly at partial throttle and traveling on flat ground at WOT, but even with the field mapping, a sepex motor will not draw as many amps at high RPM as it does at low RPM, so I suspect you may be seeing residual voltage depression from hard acceleration to speed when you are WOT on flat ground.

Try accelerating to speed slowly.

[Helirich]

Originally Posted by JohnnieB

FWIW: You can back up hills that will flip the cart going forward.

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The batteries have a surface charge when right off the charger, so the amount of voltage drop appears higher than it actually is.

For a valid voltage drop under load test, either let batteries sit for about 12 hours after disconnecting them from charger, or drive about half a mile and then let the batteries rest for about half an hour to get the start voltage.

--------
In a nutshell, due to the field mapping of a sepex motor, you effectively have a different motor installed when climbing a steep hill slowly at partial throttle and traveling on flat ground at WOT, but even with the field mapping, a sepex motor will not draw as many amps at high RPM as it does at low RPM, so I suspect you may be seeing residual voltage depression from hard acceleration to speed when you are WOT on flat ground.

Try accelerating to speed slowly.

Didn't think about backing. I think it would just spin the tires.

When I say "right off the charger", I just unplugged it and drove to the hill. But it was not charging when I unplugged it. It had allready run its course. I don't have a DPI charger, so I don't think there is any trickle after it stops.

My hill is just a mound of dirt I plowed up for a shooting back stop. The enterance/exit are about 45 degrees, but the sides are steeper than that. It has about 10 feet of flat on the top. It is only a little wider than the cart. So I must be very careful to stay in the center. While the enterance is smooth, the exit is so rough I must slow to a crawl. Hard for me to do much testing on it.