Voltage vs Current

[Branch Gordon]

So I am working on rejuvenating 8 12V deep cycle batteries that I recovered from a golf cart dealer. They are 150AH models.

I have never tried to charge batteries this big with an SG before...only worked with lawn/tractor batteries. With that said, I really am not sure how much current to give these.

I know with the SG we are more concerned with less current/high voltage spikes in mode 1, but I know you need a little to get things moving. I currently have my wheel set to draw an amp, which is right around where I start to get 1 spike. I have already done multiple cycles, but does anyone with experience with these larger batteries have any insight? Could I be giving it too much current?

[jelloir]

Hi Branch, Great to see you acquired some batteries!

I have 4 of the the same batteries. For me I started off with my comparator in Gen mode because I wanted to cycle them from to back, they still had some capacity. I could never top them because of the sulphation plus I needed more juice to push them that high since they are such a chunky battery so I just stuck them on my 10A12 TST5 to push them higher once the charge flattened out on the SSG. Eventually after a few runs like this the TST5 was able to top them at 15.3V, it didn't take very long, maybe 4 - 6 cycles. They're not completely rejuvenated but good enough to use for using as input on my SSG's to rejuvenate the 8V Trojans I have.

Recently I ran an SSG with 24V input to one of these 12V Trojans in mode 1. I was drawing about 1.75A with over 600RPM which was pummeling the 12V Trojan and could get it up near 15V.

I killed my TST5 due to a storm breaching my shed roof. so I may experiment more with Mode 1 on these.

Not very specific to your question sorry but figured I would share anyway.

James.

[Branch Gordon]

Thanks for sharing man. How are your batteries coming along? Improving?

Hi Branch, Great to see you acquired some batteries!

I have 4 of the the same batteries. For me I started off with my comparator in Gen mode because I wanted to cycle them from to back, they still had some capacity. I could never top them because of the sulphation plus I needed more juice to push them that high since they are such a chunky battery so I just stuck them on my 10A12 TST5 to push them higher once the charge flattened out on the SSG. Eventually after a few runs like this the TST5 was able to top them at 15.3V, it didn't take very long, maybe 4 - 6 cycles. They're not completely rejuvenated but good enough to use for using as input on my SSG's to rejuvenate the 8V Trojans I have.

Recently I ran an SSG with 24V input to one of these 12V Trojans in mode 1. I was drawing about 1.75A with over 600RPM which was pummeling the 12V Trojan and could get it up near 15V.

I killed my TST5 due to a storm breaching my shed roof. so I may experiment more with Mode 1 on these.

Not very specific to your question sorry but figured I would share anyway.

James.

[aln]

Branch, I have rejuvenated some 6 volt golf cart batteries and quite a few large 12 volt deep cycle boat batteries and many car batteries. once I get them to accept a charge, very important so as not to wreck your circuit with the spike, then I put up to 4 of them in series on the back and let them rip. When one of them reaches 15-16v I pull it off and put a auto bulb on it to draw it down. As far as answering your question, potential for rejuvenation, current after that is my opinion for what it is worth, not much, my 2 cents. Al

[jelloir]

Yes, some the 8V Trojans responded well even after only 2-3 cycles and have almost their rated capacity back! I was running 24V and 16V (testing various combinations of voltage and resistance) input because it's the only way I can push these 170AH chunks of lead to 10V in mode 1 to really hammer the sulphation away. Have to be careful with high voltage input because everything starts heating up, even the coil. I found a balance where everything runs cool except the series resistor which gets quite warm.

I have a couple of duds but I'm learning what to look for when I see them. For instance. physically inspecting the cells when they are near topping voltage and seeing a cell with no off gassing when the others are boiling away. I put those to the side and will have another crack at them later. Some cells you can actually see the start of hard crystalline structure which can be tough to move. Most of them have a nice grey soft coating so I'm confident I can recover a good percentage..... if I hadn't killed my darn TST5 anyway... And the AU dollar has hit an all time low with the US to it's costly for me to buy a replacement or higher spec TST5 at the moment.

James