exploded battery

[Angélique]

. . . . battery disconnect relay . . . .​

That seems to be the right description, I googled it and found some interesting stuff . . . :idea:

What is a latching relay in an RV battery?​

This is an Intellitec battery disconnect relay that latches. The latching is a mechanical addition to the standard relay where the energizing force either attracts and activates or repels and de-activates a stop or latch to keep the relay closed without the need for power. The only problem with this design is that the return spring is very thin and compressible and can weaken over time especially with rv/boat storage heat which can allow the relay to essentially close on its own when it is supposed to be open. Staying open requires the return spring to have enough force to keep the copper plunger plate away from the copper load contacts. To fix this you can take the relay apart and carefully stretch the return spring beyond its elastic limit making it naturally longer at rest. This makes it apply more force when compressed and it will do its job better inside the relay keeping the contacts apart.

Intellitec Battery Disconnect System


INTELLITEC 100 AMP BATTERY ISOLATOR RELAY

Intellitec Battery Disconnect Relay - Prevents Dead Batteries

http://www.wellsve.com/system_schematics.html

And there's more here . . . ​

 

[TeddyDiver]

I have both situations in our boat. Each engine has a single battery isolated from any other battery and the ability to be charged from only the alternator on the engine.


Our house bank is 5 1100 ah agm batteries in parallel. When one cell went, I had to replace all 5 batteries due to the heat issue

As a 1100Ah 12v battery bank six 1100Ah 2v batteries in series would be much better configuration.
BR Teddy

 

[philSweet]

Barry, check your specs. I bet you have don't have 1100 Amp hour batteries. They would weigh about 700 pounds each (the five together, maybe?). An 8d 12 volt battery is only about 250Ah. What is the battery series? What is the MCA (CA or CCA), and reserve capacity in minutes.

 

[TeddyDiver]

He surely meant five paralled making together 1100Ah..

 

[Barry]

BCI Group Number Specialty
Height with Terminal 12.6 in
Width 4.9 in
Length with Rib 22.0 in
Weight 128 lbs
Terminal Configuration Bolt in
Pulse Cranking Amps 2,150 A
CA/MCA Rating at 32°F 1,700 A
Cold Cranking Amps at 0°F 1,400 A
Cold Cranking Amps at -20°F 992 A
Reserve Capacity 400 min
Capacity - 20 Hour Rate 185.8 Ah
Capacity - 10 Hour Rate 176.5 Ah
Internal Resistance 2.7 mΩ
Short Circuit Current 6,000 A
Warranty 2 years full

Attached is the battery spec. These are Northstar AGM 400, times 5
Good snag Phil, somehow this was the number that stuck in with me, but obviously incorrect.

But the situation is much worse than I expected as the short circuit current is 6000 amps and pulse crank is 2,150 amps

So if each battery trying to charge the dead cell shorted battery, it would have the availability of somewhere between 24,000 amps (4x6,000) to 8,600 amps (5X2150)
These are serious numbers and leads me to believe that the dead cell shorted battery would not draw this much current as there would be an immediate meltdown of any wires in the loop.

 

[TerryKing]

That seems to be the right description, I googled it and found some interesting stuff . . . :idea:

INTELLITEC 100 AMP BATTERY ISOLATOR RELAY

Hi Angelique,

Hey, we didn't have such a dumb idea after all

This is a type of "magnetic Latching Relay" but I have never seen one like that with that current rating before. I used small ones in automation systems I built for broadcast transmitter sites, back in the pre-microcomputer dark ages.

So these days an Arduino with current and temperature sensors could control this type relay and manage a battery bank well. Hmmm...

 

[Angélique]

Hi Terry,

This is a type of "magnetic Latching Relay" but I have never seen one like that with that current rating before. I used small ones in automation systems I built for broadcast transmitter sites, back in the pre-microcomputer dark ages.

Here Rufus has an 23:51 min talk about one, I didn't watch it yet, maybe there's some good information in it . . ? ?

I like the idea of changing the polarity of the current on the solenoid to let it switch to the other position like shown in this video. So you don't need a second solenoid to do that like I previously suggested. I don't know if this polarity change works for all, and of course you need a different power source to do it. I wonder though if the reset also can be done manually, and which button or handle has to be operated to do it, I don't see any manually reset option on these devices . . -- see P.S. --

Here some other big ones, but most for less money -- link $10.24 -- link* -- link* -- link** --

* both are the same article but different price: ‘‘ 150A CONTINUOUS / 300A IN RUSH ’’ - - - ** ‘‘ 200 AMP CONTINUOUS ’’

- - ** picture from last above link - -​

So these days an Arduino . . .

I don't know the jargon so I looked it up, pretty small stuff I saw, and new ones even smaller I guess . .

- - click pic for source - -​

. . . with current and temperature sensors could control this type relay and manage a battery bank well. Hmmm...

Sounds good, maybe also let it guard voltage to protect the batteries against an on the loose charger and prevent overcharging and over-discharging of each battery apart.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

P.S. - Referring to the so to see lack of a manual reset option on the latching battery disconnect relays...

Maybe it needs to mount a push-button switch between the battery and the solenoid in order to enable a manual reset and for the start up from a zero power to the system situation . . ? ?​

 

[CDK]

Another battery slowly died

After removal of the remnants and rinsing the acid away I temporarily connected one of my oldest batteries to the bank. This Varta 70AH has never been in actual use, it was installed in my boat as a last resort in case we would be marooned somewhere and the other batteries were too far discharged to start the diesels. It was kept charged for more than 12 years through a diode, so it never experienced the full power of the alternators.

The label says "Varta black dynamic E13" and there are no provisions to check the electrolyte level and no "magic eye" to indicate its condition, but before I connected it the open voltage was 12.8V.
Yesterday one end of the white plastic case was slightly warped and felt warm, while the other members of the bank, two 120AH and one 100 AH were cold. The 30 Amp fuse was not blown, the bank voltage was 13.2V, but I'm a bit weary of battery surprises since the explosion, so I removed it at once.

Within half an hour the bank voltage rose to 14.0V, while the isolated battery only had 2V left!
So in a parallel bank with fuses to each member, one dud can still bring the performance of the whole bank down. You need to check on a regular basis or install an intelligent system that does it for you.

I do not believe in big ugly relays with or without magnets. There are plenty of semiconductors on the market, like the Vishay SUM120N4 that can carry 120 Amps continuous and over 400 Amps peak, priced at approx. $ 2.00. Combined with a small microcomputer that gets input from temperature and current sensors a reliable monitoring system can be built for less than $ 100.

 

[Angélique]

Wow... seems to be just in time to prevent an other explosion . .

Nice thing you measured so much valuable data before, during and after the replacement battery was in the bank

Yes, the semiconductor solution sounds better . .

 

[CDK]

Wow... seems to be just in time to prevent an other explosion . .

This white battery was the subject in another discussion on this forum several years ago, where I maintained that a battery that was kept charged could virtually live forever, while others said it would still deteriorate and fail when it was ever needed. This event proved me wrong

Batteries in a bank should be of the same type, capacity and age, that is common knowledge. But should I now throw away the 3 others that are still performing well? I am reluctant to do so.

 

[Angélique]

. . . But should I now throw away the 3 others that are still performing well? I am reluctant to do so.

Maybe build a hydrogen plant, buy a fuel-cell and throw away the batteries . .

 

[jehardiman]

After removal of the remnants and rinsing the acid away I temporarily connected one of my oldest batteries to the bank. This Varta 70AH has never been in actual use, it was installed in my boat as a last resort in case we would be marooned somewhere and the other batteries were too far discharged to start the diesels. It was kept charged for more than 12 years through a diode, so it never experienced the full power of the alternators.

Wet cell batteries have to be used and the electrolyte circulated to prevent shorts between the plates. If a battery just sits, eventually there is a buildup of oxide on the plates. The more/closer the plates (i.e. higher amp and smaller factor of the battery), the sooner the build-up connects and the cell shorts. For this reason, and for dissipating H2, most large wet cells (like submarine batteries) have air agitation to prevent oxide buildup.

See here...http://batteryuniversity.com/learn/article/sulfation_and_how_to_prevent_it

 

[TerryKing]

Wet cell batteries have to be used and the electrolyte circulated to prevent shorts between the plates. If a battery just sits, eventually there is a buildup of oxide on the plates. ...

Shipboard batteries HAVE some mechanical agitation!

BUT my home-backup 12V batteries?? Should I periodically move them / tip back & forth? Other ideas??

 

[Angélique]

BUT my home-backup 12V batteries?? Should I periodically move them / tip back & forth? Other ideas??

The Battery University* has 26 hits for ‘‘vibration’’ (put it in the ‘‘Search For’’ window in the upper right corner), maybe there is a good tip . . ? ? ?

* Thanks for the link Jehardiman ​

Windows tip: hit the keys ‘‘Ctrl’’ and ‘‘F’’ simultaneously and fill in ‘‘vibration’’ in the search window, that appears in the upper left corner of the screen, to find the word on the page.

P.S. - Found here 35 hits for ‘‘vibration’’ on the Battery University site.

 

[Angélique]

Wet cell batteries have to be used and the electrolyte circulated to prevent shorts between the plates. If a battery just sits, eventually there is a buildup of oxide on the plates. The more/closer the plates (i.e. higher amp and smaller factor of the battery), the sooner the build-up connects and the cell shorts. [ . . . ]

So, in this respect wet cell batteries are kinda like muscles, use them or lose them . . :idea: