over tightened castle nuts :(

[kab69440]

I'd try another meter to prove that reading. That would equate to a significant overcharge. I can get a rested charge of 37.7-37.8, but a couple hours of ride will wipe that out.

[JohnnieB]

Originally Posted by lawnripper

..............
Now I am trying to figure out why my cart is reading 39.9/40.1 even 10hrs after the charge and riding around the hood for at least 1-2 hrs. Seems like a hight reading.. but I guess that will be another post.
...............

Reading ~40V on a 36V pack after they've rest 10 hours, plus an hour or two driving time, means you are not getting an accurate voltage reading for some reason.

Might be a low battery in DVM, or if it is an auto-ranging DVM, you might have a bad test lead.

Check the voltage on a single battery and if it reads the same, look very carefully at the Unit of Measurement.
If it is saying mV instead on V, your are not making good contact.

I've chased my tail a few times because I didn't make sure the meter was reading what I thought it was supposed to be reading.

[lawnripper]

I just cleaned up the batteries.. baking soda etc... (lots of dust and debris right now) the tops were coated in dust. Anyways after cleaning and let dry the reading is back to normal 37.1 which is were I would guess it should be after the amount of use we have put on it up to now. I checked the batteries individually and all were 6.19 except for 2 which where 6.15.

[lawnripper]

So can dust and debri on top of the batteries create a high reading like 39.9 when the reading should be in the 70%?

[JohnnieB]

I've seen a lot of strange things before, so I'll just say I'm 99.99999999% sure it wouldn't.

The voltage source is the chemistry inside the battery, so the only thing spills and/or debris is likely to do is give you a lower voltage reading at the battery terminals, so I believe the high readings were due to something else.

Exactly what that something else is, I don't know because I don't have your cart and DVM in front of me and even if I did, I still might not be able to figure it out.

[lawnripper]

Twice in row I have had these high readings and both times I cleaned the dust (which is caked on.... we are in the dry season here right now) and both times after the cleaning the reading is back to normal? Strange

[yurtle]

This has already been covered but, do you have access to a different meter, to validate the weird readings?

I know the consensus is that the cheapest blister pack DMM should suffice, but maybe yours is doing weird? Check the battery inside it.

I know you've checked individual voltages, but did you do the math to see if they add up to the measured pack total?

None of the above explains how cleaning your batteries makes the high readings go back to normal.

I once saw a cheap Chinese calculator that would give you wrong answers if the batteries were dying (I'm an RPN man myself).

[JohnnieB]

Originally Posted by lawnripper

Twice in row I have had these high readings and both times I cleaned the dust (which is caked on.... we are in the dry season here right now) and both times after the cleaning the reading is back to normal? Strange

That is strange.

Dust covered or not, the batteries will only have the voltage created by their internal chemistry, so the extra voltage has to be coming from somewhere else.
Do you have an auxiliary battery or power converter for 12V accessories?

[lawnripper]

hi guys, no I do not have a extra battery or a converter. I will try top locate another DVM and see what happens. I just charged it again last night and have driven the cart almost a mile. The reading is at 39v right now. Anyways looks I will try another DVM 1st.

Thanks guys!

[simple man]

Originally Posted by lawnripper

hi guys, no I do not have a extra battery or a converter. I will try top locate another DVM and see what happens. I just charged it again last night and have driven the cart almost a mile. The reading is at 39v right now. Anyways looks I will try another DVM 1st.

Thanks guys!

Just a thought here, a friend of mine got one 8V battery by mistake and was having the same issue with the voltage readings! Cart ran great, charger worked great, he had this battery in the cart for a couple of months before the mistake was found!