Battery Resistance

The internal resistance other the battery construction and design is dependant upon the state of charge. Since the battery cells are usually charged in series. If the state of charge from cell the cell differs it will be felt on the other cells. If one cell is say shorted out then the other cells would distribute it's load among them. Causing them to over charge.

59 cells? Just curious, for what is this being used? why not 60? When resistance goes up, the charge time is longer (the current input is lower). This is normal when a battery is nearly fully charged. Abnormal high internal resistance, slows recharge and discharge. (peukert's effect) With a battery (or bank of batteries) at low voltage, initial charging is at higher current (unless you have heat sensors within the bank), which could heat up the battery(ies) enough to make things go boom, or pop. If they are open to air wet cells, and one cell goes 'bad', the other cells will pull more of the load on discharge and charging ... losing Hydrogen, oxygen and probably electrolyte, depending on the chemistry you are using. Are these wet cells flooded lead acid, AGM or gell? What is causing this internal resistance? Are they just old? Lead sulphate deposits ran rapid internally?

These are station batteries for a power plant. I know, 59 cells but at a float voltage of approx. 2.24 vpc for a 132 vdc as supplied it works. By the way these are lead-calcium flooded cells with the oldest at about 15 yrs. and newsest at 1 yr. resistance runs from 400 ohms to about 60 ohms.

400? did you mean mΩ? because 400 Ω seems high.

Go to top of page 4 of this document ... https://datapowermonitoring.com/pdfs/Sudden_Impedance_Resistance_Rise.pdf and I think you will find the answer for which you are looking. In fact the whole Document is a good read.

I hate to say this but your post was unhelpful insofar there was a mixture or truths, half truths and errors. The OP would have trouble sorting out which was which - maybe!

For example you wrote:-

"........losing Hydrogen, oxygen and probably electrolyte.......

Electrolyte only loses the water part (H2O) by gassing. This gas is an explosive mixture of hydrogen and oxygen....so one should really say either losing water (the acid stays mostly behind), or gassing hydrogen and oxygen!!!

Not as you put it as though that was possibly three different things........

When they go BOOM they lose all 3. I guarantee it!

You obviously still do not understand what you are (trying) to say. you still make no sense at all.....misleading others.

Remember a little knowledge is far more dangerous that no knowledge at all.

Now if you want to learn something properly, I can recommend some good reading for you, are you interested in learning something about LA Batteries?

You have never seen a LA battery with a dead cell bubble enough to throw electrolyte out of the container while charging? Dude, you just haven't been around the block enough times.

Simply because I don't damage my batteries and then stick them on a charger.

Also when working with other batteries, I make sure they are in a good condition FIRST!

If i want to charge a battery that may be damaged, I charge at a reduced voltage, so that only a small charging current flows, not enough to get any cells boiling!!!

I did a battery course many years ago in the RN, it took 2 weeks if I recall correctly and was very intensive, I have never forgotten it, only added to the knowledge over the years.

Safety was the first commandment.....

Boiling a battery so that the electrolyte jumps out would be considered a chargeable (pun intended) offence in the RN. If it happened, you would keep very quiet about it, believe me!!!

Civilians take too many chances it would appear!!! The liquid is corrosive, the gas highly explosive!!

Going to agree 100% that 'civilians' take chances when they don't even know they are.

If you have been in enough 3rd world countries, you will see all kinds of things that will leave your head shaking.

I don't live there (anymore anyway!).

Even if I did, I would still follow the safety rules that I learnt and try to impress them on the "natives"......

I don't want somebody with no proper knowledge/background killing or maiming either himself or myself!!!! Not on my watch!

Been there, done that and got the T-Shirt!!

But seriously, If they get tipped over they can lose electrolyte. If they are open to air, bugs can fly in and can often fly out losing electrolyte over time. That is why I asked if they where open to air. Not a half truth ... a total truth.

I've seen some very unusual set-ups especially in the S.P. Islands. Jars, pvc tubing, etc. and they don't cap them off. They just add water once in a while. But they forget about bugs. They usually had a bunch of 'jars' or 'cells' to save enough 'juice' to get through the night running a radio or night light. So when I saw '59' cells it made me think of those in the SP islands immediately and that maybe he was trying to get enough juice to run a house ... also made me think how many PV's he had (how many solar powered calculators he used).

With a glass jars you can see the bugs at the bottom, with other jars and the PVC set-ups they forget about them. I'm talking about folks who have the where with all to test the SG in the cells and pull out the electrodes and can't figure out what the heck is wrong ... till I told them to strain the bugs out from the bottom. Laugh, but I have 'solved' the bug problem for 3 people and have heard it happen bunches.

BTW ... I do see your point ... I was definitely unclear. Thanks for helping to clear things up.

When a car battery for instance is new & fully charged, there will be a slight resistance between it's + & - posts- as the bat ages this resistance will slowly rise- so a measurement taken when new will give valuable indication as against a measurement taken later, to indicate end of useful life of batt in supplying current,taking current,holding current. The tester is based on mos-n-fets, & yes I have made 1- but frankly there are easier ways to monitor batt health. In a bank of batts however, this tester would be VERY useful.

GA for a good accurate post.

Internal resistance is different than "back emf". It is helpful to remember the difference...different batteries will have different internal resistances even if their back emf is the same. If you place several batteries in parallel, the internal resistance will be lowered.

I am sure there is a better name than "back emf" to describe the internal voltage of the battery which counters the charge but I can't think of it at the moment.

Ionic resistance and electrical resistance make up the total resistance

I've seen it called Back EMF or Potential Difference.

It's better than calling it counter emf IMO.