Old lead acid batteries as a back-up during a power cut?

[bernardgreen]

Light and some electricity from an oil lamp

 

[Harry Bloomfield]

Light and some electricity from an oil lamp

Seebeck generator?

 

[bernardgreen]

Seebeck generator?

Yes

 

[JohnW2]

It's when the pressure relief valve doesn't work and the tank ruptures that the problems start.

I imagine that's true,but they presumably have some faith in their valves I think there is a bit of 'belt and braces' involved as well

 

[SUNRAY]

If you want to tinker about with knackered old lead acid batteries then carry on.

For actual lighting during a power cut a decent USB power bank and any cheapo USB light(s) to plug into it will be far easier, cheaper and a lot more reliable
and the power bank can be used for other purposes.

Why are you saying lead acid batteries are not reliable?

The one fitted in my car in 2014 is still going strong and the one fitted in my previous car in 2004 was still going strong in 2015 when I changed cars.
I have 4 - 2@80Ah & 2@120Ah which I use for portable work, sometimes discharging them to 1V/cell. They certainly don't test to their initial capicity with an ACT analyser but after well over a decade of terrible abuse I don't expect them to.

No siree reliability is well proven.

Additionally I'll ask how come you reckon they are cheaper?

 

[flameport]

Why are you saying lead acid batteries are not reliable?

You have quoted what was said and it wasn't that.

The batteries referred to were stated as being

AGM batteries which were in the car (95 Ah), no longer good enough to start it,

Used, old batteries which due to then not being able to start the car are knackered.

Other batteries that someone else has in some other application are unrelated.

 

[SUNRAY]

You have quoted what was said and it wasn't that.

The batteries referred to were stated as being

Used, old batteries which due to then not being able to start the car are knackered.

Other batteries that someone else has in some other application are unrelated.

The 4 batteries I described are incapable of starting a car as they have been abused something rotten and yes they are knackered... but that doesn't make them unreliable, quite the contrary, about this time last year I used the two 80Ah for 'street lighting' on a camping event to power 2 10W led floodlamps on a dusk to dawn sensor each. Knowing my ACT analyser shows them to be around 30-40Ah I expected no more than 2 nights useage, however testing each battery each morning showed little (if any) drop in capacity and the voltage to fall to ~10V by the end of the whole event of 8 nights.
Sorry but knackared and not able to start a vehicle or otherwise those two performed better than predicted and without doing any real analytical monitoring appeared to outperform their 80Ah capacity.

2 months ago was School sportsday season and in an 8 schoolday day period. In pairs they adequately provided the power for 11 public address systems (~3.5A idle to 9A peak) including two jobs at the same site without an overnight charge, without any issues on any of the jobs. Sorry but knackared and not able to start a vehicle or otherwise those 4 knackered batteries earned a lot of money in 2 weeks.

The inability to provide a heavy starting current is an indication of the internal resistance and terminal voltage under load, not an indication of the lower current discharge capacity (which it definitely down compared to new condition) and still very usable... despite what the expurts state.


And I still don't see the cost comparison being more expensive than a powerbank, performance : performance. I have tried running a 10WLED flood on a 22000mAh powerbank.

 

[flameport]

If you want to tinker about with knackered old lead acid batteries then carry on.

 

[morqthana]

It's when the pressure relief valve doesn't work and the tank ruptures that the problems start.

If you want to tinker about with knackered old lead acid batteries then carry on.

I think your definition of "knackered" would be useful to know.

 

[Harry Bloomfield]

Sorry but knackared and not able to start a vehicle or otherwise those two performed better than predicted and without doing any real analytical monitoring appeared to outperform their 80Ah capacity.

Weirdly, I've even known abused batteries, with very poor performance, recover much of their capacity.

 

[JohnW2]

Weirdly, I've even known abused batteries, with very poor performance, recover much of their capacity.

Even if they don't,a batter which has lost a fair bit of its capacity and/or is no longer capable of starting a car may well remain very useful,potentially for a long time, for other purposes.

I seem to live in much less of a 'throwaway world' than some people seem to

 

[ericmark]

I hope I will never need to use any of my batteries, which is why I don't want to go out and buy a proper back-up system, specially as freezers and central heating already covered.

I think to make up a lead with croc clips one end and cig sockets the other is worthwhile, much more likely a waste of money.

Thanks all for your help.

 

[SUNRAY]

If you want to tinker about with knackered old lead acid batteries then carry on.

All the time they perform as required for my purposes, is there a reason to spend £500 on no significant benefit?

Oh and again I'd like to know how/why you claim power banks are cheaper please.

 

[SUNRAY]

Weirdly, I've even known abused batteries, with very poor performance, recover much of their capacity.

I'm going through the processes at the moment with some 200Ah SLA's but I think they probably are knackered having been in service in a mobile phone site for a decade or more before they decided standby batteries are no longer required.

 

[morqthana]

And look at all the wonderful, long-life, no moving parts, no servicing required, radioisotope thermoelectric generators they made.

And...

kept...

track...

of...


Ah.