Power up.... Power down

[yurtle]

Originally Posted by scottyb

Of course you don't get it - none of us get it - it's electrical engineer humor

Which is akin to insurance humor...... 'I got you covered' - see how i did that there ?

Seriously though for Dela - test individual batteries under cart load (as suggested). & Give us the results and we can go from there.

I ain't no 'lectrical engineer.

A short circuit is where 'lectricity takes a short-cut. A broken or open circuit is what I call a long-cut. In a battery, I guess you could have a short circuit or an open circuit.

Most of the times, when folks have a broken wire, they refer to it as a short, when in fact, it's an open circuit, not a short. What I call a long.

If you have one cell completely "shorted out", you should still have the sum of the voltages of all other cells, no? If in fact you have a partially "open circuited" cell, then you could have as little as 0 voltage from the pack. A "long".

[yurtle]

Originally Posted by Dela

Ok - fully charged over night, topped off water prior to charging.

Woke up, all was back in tact, nice torque off the line, good speed again - I was happy

Picked up a client, showed a house - misbehaving again.. SLOWWWWwww

Motor is not hot at all - batteries were charged full meter reading 44/45 while running, 51.2 when stopped..

What's happening? How do I look into the high amp system? Should I simply disconnect and reconnect all connections?

You can drive a short distance and then stop and physically touch each and every connection. If one is bad, it should be hot, to cause that much voltage drop.

In any event, I would hook up a DMM to each battery, as previously suggested, and see if one's dropping much lower than the rest. Less than a year old should have a warranty.

[yurtle]

I suspect you'll find one battery falling ridiculously low.

[Dela]

Ok, went for a short ride after a full night charge. Nothing excessively hot anywhere, only "Luke hot" connection I found was from battery to solenoid, not really excessive, just warm.

Batteries after short ride

8.59
8.66
8.57
8.51
8.44
8.61

Cart VERY slow, Scotty's dash DVM drops to 28 when I go full throttle, as it slowly climbs up the speed increases, but it's a sloooowww process

Controller is an alltrax 400 amp, getting four flashes when solenoid clicked

[yurtle]

Use "Radio Shack" type alligator clips or tape on the DMM leads to each battery while driving. I gotta believe one is dropping lower than the rest. Otherwise, they're all toast.

[yurtle]

I would agree with the question of DVM placement if you didn't have performance issues. Given that you have issues, use the on-board DMM to help trouble-shoot a possible bad battery.

[JohnnieB]

The first battery I'd connect the DMM to and monitor while driving, is the one that read 8.44V after a short drive.

The highest of the six is 8.66V and only two batteries are more than 0.1V below that, so they are the prime suspects.

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Except for how far the voltage is dropping, it is normal for the pack voltage to drop significantly when you floor it from a stand still and for the voltage to slowly recover as the speed increases. (In fact, at the top end, the speed increases slowly as the batteries recover to a higher voltage.)

You have 190AH batteries and a 400A controller, so you have the potential of putting a 2C load (Twice the AH rating) on the pack and that will drop the pack voltage way down if the motor is stalled, or under an abnormally high mechanical load (drag).

Does the cart push freely by hand?

I'm thinking along the lines of a bad bearing, or dragging brake shoes, or under-inflated tires.

[scottyb]

What motor do you have ?

[Dela]

Jacked cart up, tested each battery " under load" with motor spinning, none drop below 7.75 when throttle open and all quickly climb back up after open.

Does this tell any of you anything?

I placed the DVM on the controller and it reads 49.5 while batteries are at 52.4. That tell anybody anything?

Also, when jacked and tires spinning free, batteries only drop to around 46, not seeing 28/29 as I do when on road... THAT tell you anything


Scotty, D&D motor

[Dela]

Cart rolls freely, yes So much so that it'll roll out of my garage without parking brake on I have a slight decline out..