Battery charging question.

[Snuffy1757]

My 48 volt Lester charger died today. I took it to the shop and the board is fried. Long story short it cost almost as much to fix it as it does to buy a new one. I ordered a DPI Charger . The problem is it maybe two weeks before I get it. Will it hurt my batteries to run them all the way down??? The last thing I want to do is hurt my batteries.

[cgtech]

Will it "hurt them"? Yes, but let me explain-

The most harmful thing you can do to your batteries is let them "sit" in a discharged state (sitting for 48 hours dead is bad). I actually think it is beneficial to occasionally discharge your batteries to a "below 50% state", about twice a year, but the key here is to recharge them as soon as you are done using them. Not let them sit in a low state of charge. So, in your situation, yes, it would be bad. There is a lot of reading, and viewers here, who would potentially disagree, but if you use the industry standard discharge tester on a set of "lightly used" batteries, and tested them twice (it discharges them to 20%), the second test will be better than the first. i have seen this many times, it's not a fluke. I am not suggesting that constant deep discharges are better, that is bad.

[CrazyDad]

See if you can rent a charger with the same plug for a day just to get them back to full.

[yurtle]

JohnnyB posted a Lester schematic a while back. If you can find it, you may be able to bypass the relay, and manually charge. Just turn it on and check the voltage while charging. I read the 36 volt chargers turn off at 45 volts, so for 48 volts that would be 60?

[Snuffy1757]

The batteries are not completely discharged. I would say they are 50 % or less.

[yurtle]

50% is considered dead for FLA batteries. You should never leave them at 50% without immediately recharging them.

Are they really 48.40 volts or less?

[Snuffy1757]

I’m not real sure. It still has plenty of go power. I just don’t know for sure how long the charger has been dead. I don’t look at the charger every time to make sure it cuts on.

[CrazyDad]

You can get a $22 meter at harbor freight, a must have for your cart.

Your cart will run fine until around 50% then it wont go. If your batteries get to low your new charger won’t turn on and charge them. If you had a 36v cart you could use a car 12v charger to get them going but a 48 volt no such luck.

[meimk]

Originally Posted by CrazyDad

You can get a $22 meter at harbor freight, a must have for your cart.

Your cart will run fine until around 50% then it wont go. If your batteries get to low your new charger won’t turn on and charge them. If you had a 36v cart you could use a car 12v charger to get them going but a 48 volt no such luck.

Depending on your car charger, it is possible to do an emergency charge. 48 volts by 4 12 volts isn't much of a problem, just one at a time. The 6 x 8 volts gets a bit tricky, but can be done. Use a low (2 amp) setting on one battery at a time. short time duration (15 minutes or so). Keep checking with a volt meter after each 15 minute session. Takes time and attention, but can bring the batteries up gradually. You wouldn't want to do this long term, but in the short term it's better than leaving them sitting discharged.

[Snuffy1757]

So how many volts across the battery pack should I have full charged?