Battery Voltage at Rest and at Load

[statjunk]

I just installed a voltage meter on my cart. I verified the meter with a hand held meter.

After a good charge the batteries are reading 50.5 to 50.7. While running the cart the voltage drops down as low as 45 when going up hill or 47-49 when just running. Down hill it will jump right up to 50.

Also I noticed that if I stop the cart it takes a bit for the voltage the meter is reading to stop increasing. Meaning it rises slowly to a resting point.

Is this much of a drop in voltage while moving normal? Should the batteries take a minute to get back to max voltage?

Thanks

Tom

[mkbrower]

Tom, this is normal. Without going into alot of detail, when you increase the load on the battery (amps) the internal resistance of the battery goes up which causes the voltage to drop. Resistance causes heat and heat causes resistance so even when the batteries are no longer under load the voltage will not return to "normal" untill the heat has been disapaited.

[scottyb]

Good explanation

45 is about as low as I like to see on a running cart. Be low that You either need recharging or you have a battery problem.

[delagem]

Alltrax recommends in their document for setting battery warnings, to set the DC Warning at 42, and the DC Danger at 39.

Their suggestions, not mine. But might be good guidelines for when you watch your voltmeter, if you don't have warning lights you can set.

My voltmeter has flashing lights that are set like this, and I do get both flashing when going uphill, but my batteries sorta suck...

[erict]

Agree with all the above responses. I had asked Scotty the same question when I installed his meter on my cart. After a run my meter also rises slowly while the cart is idle.

[statjunk]

Thanks to all. Buying this cart was one of the best decisions I've made for my hunting property. I'll be recouping approximately $700 in savings this year alone.

Tom

[Golfdog]

Originally Posted by delagem

Alltrax recommends in their document for setting battery warnings, to set the DC Warning at 42, and the DC Danger at 39.

Their suggestions, not mine. But might be good guidelines for when you watch your voltmeter, if you don't have warning lights you can set.

My voltmeter has flashing lights that are set like this, and I do get both flashing when going uphill, but my batteries sorta suck...

Yup, 42v is about as low as you want to go for short periods. The A/H rating of the battery is based on the battery dropping to 1.75v per cell. On an 8v battery thats 7v per battery or 42v per 6 pack and on a 12v its 10.5v per battery or 42v per pack, but thats on a constant discharge with no recovery periods.