6 volt batteries in a golf cart

[Old_Crow]

Dead is 0%. The chart may not show that but 0% is a valid discharge point, and is what the rated Ah of a lead acid battery is based on. The chart is open circuit voltage for a "typical" battery, which is only valid after being idle for 24 hours, at 77 Fahrenheit. Not the most ready data reference for batteries in use.

Mark B.
Albuquerque, NM

Dead may be 0% in a flashlight, but to me, if my batteries are low enough that they won't run the furnace, or that I have to use the boost button to start the generator, then they're dead. Maybe not technically. To someone who has the fancy monitors and such they probably can say that there's 30% or 20% remaining. But if I can't use that 20 or 30%, what good is it?
This is one reason I've been looking at the L-16 batteries. I can get almost twice the aH in one pair of batteries. My coach has the height necessary in the battery compartment for the taller batteries, but not the real estate for a second pair of GC2's. I would prefer to have enough battery power in the morning, after running a furnace all night to be able to start the generator with no problems.

 

[Mark_K5LXP]

if I can't use that 20 or 30%, what good is it?

That does become the effective discharge limit. But that's an equipment, not a battery limitation. My RV furnace is spec'd to operate to the 100% DoD point and my genset starts with fully discharged house batteries, so it's possible RV equipment can operate over that full range. If there's a higher minimum voltage to accommodate then the effective capacity is commensurately reduced, so one has to decide to accept that, add capacity or replace the equipment.

Mark B.
Albuquerque, NM

 

[Old_Crow]

if I can't use that 20 or 30%, what good is it?

That does become the effective discharge limit. But that's an equipment, not a battery limitation. My RV furnace is spec'd to operate to the 100% DoD point and my genset starts with fully discharged house batteries, so it's possible RV equipment can operate over that full range. If there's a higher minimum voltage to accommodate then the effective capacity is commensurately reduced, so one has to decide to accept that, add capacity or replace the equipment.

Mark B.
Albuquerque, NM

C'mon now. If the batteries are dead flat, how are they going to start the generator without the "boost" button unless yours runs off the chassis battery?
As far as the furnace, the fan will run until it's so slow it won't trip the sail switch. I then wake up at 3 am with the same result as if I ran out of propane...fan blowing cold air. So, yes, the furnace will "operate" down to zero battery, it just won't keep me warm.
My lights are all LED's, so they'll work even when the furnace blows cold. How else would I know that it's cold enough to see my breath?

As a side note, why is it that the batteries go dead or the propane runs out at 3am? I can never get back to sleep after going outside to switch tanks (Class A with and extend-a-stay setup). It doesn't seem to matter the size of the tank, either. I spend the summers hooked up to a 100lb tank provided by my employer, and it still runs out at 3 am.

 

[Mark_K5LXP]

C'mon now. If the batteries are dead flat, how are they going to start the generator without the "boost" button unless yours runs off the chassis battery?

"Dead flat" is 0V. At 100% discharged there is some charge remaining, depending on what load brought it to that point (there is some SoC variability due to Peukert). This is something I want to know - how low can I go and still start the generator? I do a 100% discharge test at least 2 times a year (winterize and dewinterize) and sometimes more, so it is a trivial to hit the starter on the genset after the test and see what happens. It turns out with my batteries and generator, I can discharge to 10.5v at the 20hr rate, hit the starter and the generator fires. I know too that I may not get more than one shot at it but this is something that I test. That may not be the case with everyone, there are lots of variables so you have to test what specific equipment you have. In the event 0% is too low, then at what point is the minimum? You won't know until you try. Some folks may not care to discover how low you can go but I want to know how far I can push it, because I regularly do.

Mark B.
Albuquerque, NM

 

[Rene T]

A issue I’m having with my golf cart is after driving it for 15 or so minutes and I go up a incline, the cart stops sometimes. If I try to take off slowly it may go but if I floor it, typically it will die again.

My eight 6 volt Trogan batteries are 7 years old.

After charging them all night, One of them is at the 60% charge and the other ones are around 70%. When the cart starts acting up, one is at 50% and the others are at 60%.

I’m wondering if I have a battery issue and I’m also wondering if there is a safety circuit in the system that starts to shut down the cart from moving if the voltage gets a little low.

 

[Mark_K5LXP]

One of them is at the 60% charge and the other ones are around 70%.

Is this based on some monitor/meter, electrolyte SG or ? I would expect that after "all night" they all would be 100%, even if they were somewhat wounded. It's usually easier/quicker to charge weak batteries than strong ones.

wondering if there is a safety circuit in the system that starts to shut down the cart from moving if the voltage gets a little low

Quite likely, monitoring them while underway will tell you what's happening. Could also be that a couple are more weak than others and allowing the pack voltage to decline quickly under load. It's a basic exercise to do a discharge test and look for the stinkers if you're so motivated. I would be looking at terminals first, making sure there isn't a bad connection or cable before deeming batteries bad. Put a nominal load on the bank and check for voltage drops.

Mark B.
Albuquerque, NM