Battery - Had It's day

[Gagakev]

Started to prepare the van today and checked voltage on the battery read 7.6 volts.
Plugged in and on charge, will check the reading tomorrow.
But have I had my moneys worth, it's a Numax and 11 years old and rated 80 amp, if I have to change it, will upgrade to a 110.

 

[otherclive]

I suspect that you will be changing it at that voltage and age.

 

[Mike]

Its amazing how much residual power remains in a battery. I took one off a tranny van as it would no longer spin the engine quick enough. Yet i kept it a further 10 years to run a 12v chainsaw sharpener WITHOUT ever charging it again! Every time i clipped the leads on, i coudn't believe it would still power the tool, and this was probably after only 5 years. I eventually got rid of it due to moving house and vastly reduced chainsaw sharpening requirements, and it was STILL operable!

 

[Guzzilazz]

For Flooded Lead Acid, below 10V means the battery has been killed...

 

[Raywood]

Eleven years is a very good figure, I normally find once past five years they are suspect.

 

[Gagakev]

So on charge using the on board charger since Saturday, checked at 5.00pm today (Monday) and read 13.7 (still on charge).
Turned off charger.
Checked voltage 2 hours later at 7.00pm down to a more natural state of 12.7 volts
Will keep an eye on it this week but I reackon it's going to keep on going !!!!

 

[otherclive]

Mine was 12.8 v three weeks after charging so 2 hours isn’t very long.

 

[Gagakev]

Mine was 12.8 v three weeks after charging so 2 hours isn’t very long.

Thanks OC, will check it everyday for rest of the week and see what happens, as said after 11 years if I need a new one then not an issue really.

 

[Hutch]

Kev, I think in the long run , your battery has had its day, but if it's still with us at Waterrow, I will buy the beers. 🍺

 

[Gagakev]

Kev, I think in the long run , your battery has had its day, but if it's still with us at Waterrow, I will buy the beers. 🍺

Best get your hands in your pocket Hutch, it will be with me even if it's in the boot of my truck

On testing it today it dropped to 10.5 volts (not been on charge for 24 hours)
BUT switch the on board charger on and it stays a steady 13.6 volts.
Now the question is, have I been using it like this without knowing and will it keep going like this?
Thinking about it I suppose the problem would be the motor mover if I wanted to use it.
Actually think I have just answered my own questions, get a new one!!!

 

[Hutch]

If you carry it , "the old one" in the boot of your car without the proper Dangerous goods, cladding as required by IATA, then the buying of beers will be invalid and also The Prof will be down on you , possibly.

 

[Gagakev]

If you carry it , "the old one" in the boot of your car without the proper Dangerous goods, cladding as required by IATA, then the buying of beers will be invalid and also The Prof will be down on you , possibly.

NO Buckfast Tonic Wine for you then
And as for the Prof.....................I'll leave it at home!!!!

 

[Hutch]

We need the Buckfast!!! My copy of IATA dangerous goods are out of date, but I will still buy the beers, at the Rock.

 

[Guzzilazz]

Best get your hands in your pocket Hutch, it will be with me even if it's in the boot of my truck

On testing it today it dropped to 10.5 volts (not been on charge for 24 hours)
BUT switch the on board charger on and it stays a steady 13.6 volts.
Now the question is, have I been using it like this without knowing and will it keep going like this?
Thinking about it I suppose the problem would be the motor mover if I wanted to use it.
Actually think I have just answered my own questions, get a new one!!!

It will show 13.6 on the onboard charger, that's the voltage the charger is applying to the battery... The 10.5v off charge is a true indication that it's FUBAR'd

 

[Gagakev]

Didnt actually get around to purchasing a new battery, was going to get it for our trip to the Woosie Fest last week but alas that didnt happen. Dont think I will be buying one for this year somehow

 

[Raywood]

I know the problem, ours has failed but no point in buying another until I can see us using it.

 

[Hutch]

I think there might be a shortage of batteries once the curfew is removed.

 

[Raywood]

I worked on the theory that if nobody is buying them there should be a glut soon.

 

[Beachball]

When we got our caravan it came with new battery 110 amp since then we have a brand new mover fitted .

 

[Gagakev]

Had to hook the caravan up today as battery is dead as a dodo so no mover, painted the wall along the offside and hooked it back up to put it back again , felt good with the van on the back of the truck and driving 8.0 meters there and back again

 

[Mandarin]

Just brought the van home from storage not having seen it since mid March, the battery read 11.7 when we picked it up but dropped to 10.1 as soon as we tried the mover, the alarm seems to have drained it.

It's now hooked up the the mains charging at 13.7 so will unplug it later and see what happens. Finger crossed as it's only 2 years old.

There's a 100w solar panel going on in a couple of weeks so that should fix the drainage problem for the future.

 

[Woodentop]

Here's a tip for readers of this situation.

If you find the battery is low (or even lower than this) and the only available method of charging is from the fixed 13.6V (nominal) power supply in the caravan, wire a car bulb in series with the battery +ve. Usually a 21W flasher bulb will do but if it pops then use a headlight bulb instead.

When first powered up the bulb will burn brightly but as the battery plate voltage rises the bulb will get dimmer and dimmer until it might just be glowing a very dim red - this may take anything from about 3 to 10 minutes, usually around 5. At this point the battery should be above about 11V and the bulb can be removed to allow 'normal' charging to take over.

The idea is that the caravan supply can provide (usually) in excess of 20A which could make the battery boil and/or deform the plates. By putting a power resistor (i.e. a bulb) in series the charge current is limited which allows the battery to rise at its own rate to a level where the charge current applied directly from the power supply will do no damage.

For info, it is actually better to charge a lead-acid battery at constant current rather than constant voltage - which is how many smart chargers actually work. In the early days of l-a batteries constant current charging was achieved by starting with a high d.c. voltage and putting a light bulb in series with the connection to the battery. Thinking of the light bulb as a fixed resistor (which of course it isn't but nonetheless) a bit of calculation using Ohm's Law will show that the battery is effectively being charged a a near constant current. The scary bit is that in those days many homes (etc) were supplied with either 130V or 200V d.c. so the 'mains' was used directly through a normal domestic light bulb. Agghhh!!!!

Been there, done that, etc etc.

 

[Guzzilazz]

11.7 shouldn't be terminal for the battery so long as it's not lost electrolyte, it should charge up fine

 

[Beachball]

Caravan had a service last week the battery was checked he said it was great and passed with flying colours seeing you haven"t used it since october2019 .

 

[Mandarin]

It seems to be ok, overnight it achieved12.8v, I then took it off charge and a day later with just the alarm on it dropped to 12.7 which I think is ok. It's back on charge again now.