Lead acid Batteries

They quit selling them somewhere around the late 40's, early 50's. Many were still using them for some time after. My father was an electrical engineer and we had them well into the

And before the glass case came the lead-lined wooden box cells. Both wood and glass boxes were still in use in telephone exchanges I worked at during the late 1950's but they were all gone by the early 60's. I even installed some of the wooden cased cells (made up from parts which had been kept in storage for 20 years or more) because there was a shortge in supply of the new polycarbonate cell types.

Changing plates in these old cells was not so simple and it was never done where I was. You would simply re-build the complete cell with all new plates. The interconnects between plates were lead-burned in place

- which was an art in itself - and it was next to impossible to simply cut one plate out for replacement.

Jim Adney wrote in news: snipped-for-privacy@4ax.com:

Gee,who wants to mess around with sulfuric acid and lead paste?

It`s only a few years ago when I worked in an entertainment venue where all the emergency lighting was powered by huge glass lead acids, each about 12" high and wide. there was probably 30 or so cells all connected together by exposed lead bars bolted to the terminals, you had to watch where you layed down anything conducting like a spanner!. The charger was in a filing cabinet sized enclosure with a huge transformer, selenium plate rectifiers and wobbly meters on the front ;o)

Ron

I used the method that Jim suggests a number of times over the last

In fact, leaving a trickle charge (50-100 ma) or so on forever has never caused me a problem, providing I check the water level every week or so just in case there is a leak or evaporation..... If you do it in your auto, make sure that there is no possibility of the battery becoming disconnected or the terminals being corroded or intermittent , since if the battery isn't "there" to stabilize the voltage, the charger could put a much higher voltage on the car electrical system, damaging components such as the alternator voltage regulator , radio, or computer....... Rarely happens, but is very possible....

However, if you want to start your lawn tractor in an hour, this doesn't work well ( grin ).

Just my experience,

Andy

I remember seeing something similar but they were the old Edison nickel-iron batteries, used to start emergency generators. They had high self discharge rates.

I never heard of them being used in autos although IIRC Edison wanted to use them for an electric auto.

Know what you mean.A few years ago they sent me up to Blackpool to take over a failing casino.Sorted it out and had it up running and making a healthy profit.I went down to the basement on a tour and noticed banks of batteries that looked like junk.The handyman said they were the emergency lighting as the standby genny sometimes failed to kick in.Had them tested and it took 3 grand to have them renewed! Ate into my profits for the year end. Luckily I had a big loser in December to make my budget.Regards

"To Soon we get Old,Too late we get Smart!"

That was mostly in the day's of the model A's and T's.(I grew up on a fam and we still had a working T in the shed, that's where I remember seeing them first. Later my father, and electrical engineer, who worked in industrial power service had some of them that were indeed used for backup power.

Know what you mean. My father who was and electrical engineer started his career out as an electrician's mate in the Navy on electric boats.(submarines) where the entire bottom side of the boat was a long in-series battery array. He had some real stories to tell, what with all that hydrogen sulfide floating around in the crawl space.

Well... there is the issue of the high cost of having to routinely swap out dead batteries, not to mention the high cost. ( The actually cost to manufacture a battery is a small fraction of what we have to pay retail for them.) Replating a serviceable battery is much more cost effective and allows for a greater degree of self-sufficiency.

When I watched my old man rebuild them he always replaced all the plates. Seemed pretty straight forward, unbolt the box cap then the retaining bolts for the plates and pull them out. Dump the electrolite, flush case with a neutralizer, put in new plates and acid and bolt it all back together.(Of course these units were designed for ease of service) I did years back restore an old German motorcycle, prewar, called a Fluka and it had a glass case battery which we had to have custom plates made for.

"Boltable" plates would be useless where very high current demands were present, as in telephone exchanges. While each individual battery was designed to connect to the adjacent cells in a series battery using bolts, this practice was shown to cause major problems due to the bolted joint developing high resistance. Consequently, both the individual plates in each cell were lead-burned together as well as the connections between cells in order to minimise any added resistance. The end connections to the copper distribution bus-bars were the only place bolts were found and these were constantly checked for temperature rise or signs of oxidation.

I was once working in an exchange in the late 1950's where bolted battery joints were still in existence and accidentally dropped a 12" crescent spanner right across the bus-bars feeding several suites of equipment. There was a mighty loud bang as the spanner was melted and every switch dropped out in the affected suites. In the time taken for the 500A feeder fuse to blow every bolted joint in the 48V duty battery had molten lead blown out of it due to the heat generated in the minute resistance in each joint. The battery room was filled with smoke and I was not very popular with the maintenance staff. Needless to say, after that episode, the battery interconnection joints were lead-burned.

If we take an extreme case where each bolted joint has only 1 milli-ohm resistance (this is a "very high" resistance in this environment) then a 48V battery of 24 x 2V cells would have roughly 48 milliohms total resistance in the bolted joints. In heavy traffic a current draw of 500A would drop 24V across the joints alone which would stop the exchange from working. Any resistance at all in the battery would also lead to cross-talk between circuits since the battery is common to all circuits.

Typically, the internal resistance of a 48V exchange battery including all joints between cells would have a design volt drop of 100mV at maximum current drain. For a design goal of 1000A maximum drain this would equate to a total internal resistance in the battery and all connections of 0.1 milli-ohms, and that is hard to achieve in practice.