How Do I To Prevent People From Over-discharging Batteries

[Muddog]

We have a vacation cottage we rent out when we're not using it and leave a cart there for the guests . Most have never used a cart before, so they have no idea that you can ruin a $700.00+ set of batteries by running them dead. I tell them to charge when not in use and from what I've seen they're pretty good about that.
I'm looking for the simplest,foolproof way to prevent people from killing the batteries by overuse. Most of them have traveled 6-10 hours and they're not in a mood for a lecture on battery care. I need a simple , don't let this happen.
I have a 99 DS 48v series limo cart with amber battery light in dash. How accurate are they ? Can I tell them when the light comes on, it's time to charge? When I bought it, it had a state of charge analog meter installed. Would that be better, it's like a gas gauge?
I have a Curtis controller in my buggie and I can control low voltage cutoff/cutback, but that's an expensive alternative. I also have a in dash DVM, but I don't think that will work either.
What I'm asking, is the amber battery warning light accurate? How accurate are the analog battery gauges? Can I rely on them to warn people it's time to charge?

[scottyb]

I got onboard with this project last year.
I set up my PDS cart with a low voltage alarm, available in 12v from ebay etc. and an alarm. The 12v alarm was connected to 2/6v and set to 10.something volts (using the pot adjustment by trial and error) this would tell me when the pack. The system worked find alarming the user when the voltage dropped below 35v
The problem is this; golf cart pack do momentarily dip below acceptable constant rates. The alarm kept going off while hard acceleration or going up hill when the pack did not need charging.

Good luck & keep us posted

[teecro]

Originally Posted by scottyb

I got onboard with this project last year.
I set up my PDS cart with a low voltage alarm, available in 12v from ebay etc. and an alarm. The 12v alarm was connected to 2/6v and set to 10.something volts (using the pot adjustment by trial and error) this would tell me when the pack. The system worked find alarming the user when the voltage dropped below 35v
The problem is this; golf cart pack do momentarily dip below acceptable constant rates. The alarm kept going off while hard acceleration or going up hill when the pack did not need charging.

Good luck & keep us posted

Add an adjustable time delay relay to the buzzer and set it for say 60 seconds...

[Volt_Ampere]

I built a low voltage alarm into my battery voltage monitor on my Lithium powered cart. It goes off if any cell goes below my calibrated minimum voltage. It only makes a loud noise - doesn't stop the cart from functioning.

[Muddog]

What are the thoughts on this meter? It came with the cart. It is simple enough, but are they reliable?

[Kashmir]

^Not reliable for the function you want.
If I were you I would get a 48 v digital volt meter for the dash.
Install it and tell your renters that if they stop and the volt reading is 49.0 or less (after sitting for about a minute), it's time to charge!
I wish there were a way to set up something to cut power in half if the volt meter gets below 49...

[fjlabarbera]

> Let's start with a fully charged battery. The plates are lead dioxide - sponge lead - the electrolyte is sulfuric acid (the acid ions produce the voltage).
>As the battery discharges: lead dioxide + sponge lead + sulfuric acid = lead sulfate + water. If the battery is fully discharged, lead sulfate completely covers the surfaces of the plates.
>Initially, the lead sulfate coating is soft, thin and easily recovered into lead and sulfuric acid when the battery is recharged. If the battery is left in a discharged state too long, the lead sulfate will be hard and will not be removed.
The sulfuric acid content will be smaller which will lessen the battery power. So, what do we do. Exactly how long lead sulfate hardens is not known. Some sources believe about 2 weeks.
The best approach is to charge the battery every few days - shorter if you went a long trip. Newer chargers will decrease the charge level as the battery charges so the battery won't be overcharged. About 90% of golf cart batteries are killed by the owner. If you have questions reply to me.

[Muddog]

Originally Posted by fjlabarbera

> Let's start with a fully charged battery. The plates are lead dioxide - sponge lead - the electrolyte is sulfuric acid (the acid ions produce the voltage).
>As the battery discharges: lead dioxide + sponge lead + sulfuric acid = lead sulfate + water. If the battery is fully discharged, lead sulfate completely covers the surfaces of the plates.
>Initially, the lead sulfate coating is soft, thin and easily recovered into lead and sulfuric acid when the battery is recharged. If the battery is left in a discharged state too long, the lead sulfate will be hard and will not be removed.
The sulfuric acid content will be smaller which will lessen the battery power. So, what do we do. Exactly how long lead sulfate hardens is not known. Some sources believe about 2 weeks.
The best approach is to charge the battery every few days - shorter if you went a long trip. Newer chargers will decrease the charge level as the battery charges so the battery won't be overcharged. About 90% of golf cart batteries are killed by the owner. If you have questions reply to me.

Huh?

[Kashmir]

uhhh...were you replying to him?

You should address him only as El Conquistidor