volt meter

[jim,s]

I just installed a digital volt meter on my 95 ezgo. I turned it on it read 38.0 took the dog for a ride total drive 3 miles. went up a grade approx 100 yards long meter went to 35.8 at the start of the grade midway 36.6 then up to 37.0. stopped to let the dog do his thing when I retuned meter was at 37.7 (approx 5 minutes) drove back home meter is at 37.8 so I guess after 3 miles it cost me .2 volts on my battery pack.
What I forgot to say when on level ground pedal to the floor meter will go to 35.9 for a split second then come up to 36.8-9.

Does all that sound ok?

[scottyb]

Yeah, no red flags there

[JohnnieB]

It takes a while to get used to the battery pack's voltage bouncing all over the place, but there is rhyme and reason to it.

In a nutshell, the battery pack's voltage drops when amps are being draw from it. The more amps being drawn, the more the voltage drops. The voltage drops quickly when amps start to flow, but recovers slowly when the current flow stops.

For a 36V battery pack in superb condition with electrically perfect cables and connections, you'll see about a 1V drop per 100A of current draw. With less than electrically perfect batteries, cables and connections, it'll be more like 2V per 100A of current flow.

You shouldn't routinely drop the voltage of a 36V pack below 31.5V (1.75VPC)

Except for dire emergencies such as getting off the tracks before the train gets there, you should never drop it below 27.0V (1.50VPC). That is the point where irreversible physical damage to the plates starts occurring.

When out and about and you want a quick estimate of the SoC to see if it is time to head back to where the battery charger is, let the pack rest at least 5 to 10 minutes before taking the voltage reading. Technically, the battery voltage continues to rise for over an hour after the discharging current flow stops, but most of the rise occurs in the first 15 minutes.

[jericho]

Hey Johnnie,What is (vpc)?

[csport]

I aint Johnie B butt I think its Volts per cell VPC

I am not a fast learner, but once it gets in, it stays there a good while

[jericho]

Makes perfect since.Thank you sir.