2 Bad batteries

[kaschiro]

I have a cc 2004 48volt system....today monitored my batteries over 18 holes of golf...at the beginning 52 volts...after the 1st nine I started to monitor closer..voltage was 49.5 volt....then I start to monitor each battery and for the most they were 8 volt drop to 7 under load, with the exception of two which were 7 volts #4 and #6..under load they would drop down to 4.5 and then recover to 5.5 and if you wait would come up to 7volt. so I am thinking these are bad batteries. all the rest are normal and at rest measure 8v....so to replace these batteries all I have to do is install 2 new batteries..then I am told that I cannot do this, I have use used batteries and I have no Idea where to get used batteries...why can't I use new batteries, this battery pack is about 22 month old almost 2yrs..why can't I use new batteries

[Swartz]

You can install 2 new batteries. The problem is that the old batteries will make them work more. It is a matter of how you want to spend your money. Some people will try to buy two cheap ones and get through until the others go out. With the batteries being 4 years old (at least) based on your cart year, I would get through this season if you can and buy all new ones in the spring.

[kaschiro]

Mr Swartz thank you for your input, what I said in the post is "this battery pack is about 22 month old almost 2yrs..why can't I use new batteries" in other words this is the 2nd set of batteries..would that make a differnce??
Kas

[Swartz]

Sorry, I misunderstood the question. I am sure someone here will be able to help you.

[shadowman]

you can use new batteries but they will be drawn down to the level of the other batteries real soon thus shorting their lifespan, if the other batteries are reading 8 volts and dropping to 7 under a load i would think about replacing them all as a good 8 volt battery should read cloas to or over 9 volts................................

[kaschiro]

I just got finished with the install of the two new batteries...I road tested the batts with the voltmeter across each and the reading was 8.2 per each including the new batts and with load test(pedal to the metal-0 to 15 mph) reading was 7.7 and returned to normal voltage, this is without chargeing the batts..I am happy with the readings the cart is under going a full charge as we speak, beginning current at 11 amps and dropping to 10..so far all is good..thanks for the input, had to use new, did not have access to used
Kas

[scottyb]

For some reason you are only getting 2 yrs out of the batteries in this cart? Is that correct?
You should expect 5 years plus or minus depending on how well they are cared for....make sure all your cables and connections are clean and tight. An 8 volt battery is empty at 8.0 volts. They should not be run down below this. If they are - repeatedly, usable lifespan will be deminished
Older and newer batteries operate at very different efficiencies. So when you mix them either the old or the new is not happy at charging time. The old less efficient sulfured up batteries take much longer to charge than the new ones with their internally clean lead plates which are more chemically reactive . So essentially the new ones get over cooked waiting for the old ones to finally get done. Resulting in too high temperatures in the new ones drastically shortening their life span. Basically the pack is only as healthy as the worst battery. Hope this helps.
P.S.
There is something else that happens at charging... the charger counts volts per cell, that is how it knows when to turn off...2 new batteries charging at a faster rate may easily exceed the 2.5 or whatever volts the charger is waiting for PER CELL. When the total is reached, it shuts down. Now you have new batts at 3.0 volts per cell and old ones at 2.0 Potentially . The result is a lazy old battery...in theory, of course, your mileage may vary....

[kaschiro]

yes it does make sense...there were only 2 batterys that were bad and I replaced with new..money is kinda tight..so I did the next best, I thought...however the other batteries did have the gunk on top the batterys and the others did not get there full charge as they charging at a partial charge being the resistance across the top of battery rather going thru the full charge...so that being said all batteries have the same specific gravity of the acid and the same voltage across each battery, then the charge should be equal to all battery's.. my way of thinking and I will be keeping a close eye on each battery to see what happens and I may have to swap out batterys every 2 months until they are all new
Kas
PS thanks for the input

[scottyb]

Yeah if you really watch them...you can even take a lazy one and put 12v to it for a short while under your watchful eye until it settles back to where the others are at. Notice i said settle? True readings are taken after the initial charge has settled. Say 30 - 45 minutes after the charger goes off. Same with specific gravity readings....Good luck