Battery Desulfator

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scoobyh123
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Re: Battery Desulfator

Post by scoobyh123 » Sun Nov 19, 2017 8:58 pm

Thanks Nick - mostly my idea with a bit of input from someone else although many moons ago when i did the ball joints and CV joints on the Sterling, i removed the hub carriers and changed the ball joints on the bench. This helped nudge me in this direction this time.

The bit that really "jars" me off (every pun intended! :lol: ) about recycling is i can put empty jars in the blue recycling bin but not bottles. They're all made of glass but apparently i must take the bottles to the bottle bank!
I don't have many bottles so i sneak the odd one in every now and again, purely out of protest!

Sounds like you had your moneys worth out of that battery! Maybe it's time to give it a decent burial? Sure you can find a member of the local "traveling fraternity" to give you a few quid for it as part of his next scrap pile. I recently listed 10 7-spoke Roversport wheels on fleabay and they were snapped up by a similar person who then asked me if i had anything else like batteries so made a few quid on those as well.

Before anyone gets upset about the wheels, if they hadn't been scrap they would still have been on my cars as they are my favourite Rover wheel. Some were buckled, others were damaged by fast-fit tyre places using windy guns to do the nuts up, others had miscellaneous kerb damage (not by me either!) and i couldn't make 4 decent wheels out of all of them.
Cheers,
Dave

'02 Honda CR-V SE Executive
'99 Jag S Type 3.0 V6 SE


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zcar12
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Re: Battery Desulfator

Post by zcar12 » Thu Nov 23, 2017 2:05 pm

I charged my good Rover battery for two whole days, then left it for a day and it showed 12..64 volts So it looks Like it has suffered no harm. I had the desulfator connected to it and on the second day, I got a reading of 16.6 volts. This is the highest reading I have ever recorded on a charging battery, and I have no explanation for this. It blew the desulfator fuse, which is 5 amp.

It looks increasingly likely that my old battery has a damaged cell and will not be recoverable. After a few hours off charge, the voltage falls to just below 11 volts.

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scoobyh123
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Re: Battery Desulfator

Post by scoobyh123 » Thu Nov 23, 2017 8:31 pm

zcar12 wrote:
Thu Nov 23, 2017 2:05 pm
I charged my good Rover battery for two whole days, then left it for a day and it showed 12..64 volts So it looks Like it has suffered no harm. I had the desulfator connected to it and on the second day, I got a reading of 16.6 volts. This is the highest reading I have ever recorded on a charging battery, and I have no explanation for this.
You do have an explanation Nick :
zcar12 wrote:
Sat Nov 18, 2017 11:04 am
The Rover has not had much use over the past few months so not surprised it has gone flat. Its a 3 year old Lion Brand with 550CCA. Sealed Calcium with a magic eye.
It's a Calcium Battery, the voltage on those can easily rise to 16-17V during charging. Could be another reason why it went flat suddenly because the Rover isn't set up for a calcium battery. :wink: :D
Cheers,
Dave

'02 Honda CR-V SE Executive
'99 Jag S Type 3.0 V6 SE


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Re: Battery Desulfator

Post by zcar12 » Thu Nov 23, 2017 10:37 pm

Dave, I never knew that Calcium batteries could reach such a high voltage so I am indebted to you for the education. My understanding of a Calcium battery is that compared to the lead acid type, it contains only 1% Antimony as opposed to 3% and so produces less gas when charging and hence less electrolyte evaporation.

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Re: Battery Desulfator

Post by scoobyh123 » Thu Nov 23, 2017 11:07 pm

The other thing Nick is the alternators on cars designed for calcium batteries have a higher output voltage so will often overcharge a normal lead acid battery.
I seem to recall you mentioned some time back the Mondeo had a higher voltage output for the calcium battery, also that the battery on the Mondeo is lead acid - might pay to swap the Rover and Mondeo batteries so the Mondeo gets the calcium battery and the Rover gets the lead acid battery.

The other benefit of lower antimony content in calcium batteries is that they retain their cold cranking performance longer in to their lifetime. In other words at say 5 years old, a lead acid battery might still pump out let's say 400A from an original figure of 500A but the calcium battery will pump out 450A - don't quote me on those figures as exact, scientifically proven figures, i used them to illustrate the point i was making.

There's a few other benefits as well but can't think of them now, trouble is to get the most from them you need a charger capable of charging calcium batteries and also a car designed for them. Often a standard charger won't put out enough power to fully charge a calcium battery.

A thought on the desulphator - something i've found with LED bulbs from China and similar is they work out the current limiting resistor on the basis they are being run on 12V, completely forgetting that an alternator or battery charger goes up to about 14-15V. That might not sound much but on an average LED that means the resistor is half what it should be.
If a similar design ethic has been applied to the desulphator, it might be fine for 12V but running on its limits at 13.2V and if it does go higher, it could well be that it can't take it.
Cheers,
Dave

'02 Honda CR-V SE Executive
'99 Jag S Type 3.0 V6 SE


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'94 827 Sterling saloon
'88 Volvo 760 V6 Estate
'95 827 Coupé LPG gone but not forgotten!

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Re: Battery Desulfator

Post by zcar12 » Fri Nov 24, 2017 3:47 pm

A bit of research on my Delta desulfator shows that it works by producing a square wave form to work on the plates. Both of my chargers are now old technology so I may look for a more modern smart type charger. But I am reluctant as always to embrace the idea of binning something that works, just seems wasteful to me.

Yes, the Mondeo has a smart charging system. If it senses that the battery is getting low, one thing it will do is raise the idle by 150 revs until such time as the battery state returns to normal. I never joined the dots to realize a Calcium battery ideally needs a newer type charger and that the CCA fall more slowly with ageing on a Calcium battery.

Will not be changing the batteries over as I have put the Mondeo up for sale locally. Tried a Guntree add but that produced a few experiences that I have no wish to repeat.

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Re: Battery Desulfator

Post by scoobyh123 » Fri Nov 24, 2017 4:24 pm

Sorry Nick - i wasn't suggesting binning the desulphator, after all the fuse blew to protect it so it obviously has some protection built in. Probably wise to not use it on a calcium battery again though.
It worked on a lead acid battery as well so there can't be too much wrong with it.

The 800 range (certainly petrols) sense when the battery is low and raise the idle speed as well - cast your mind back to when your 820 had an unexplained increase in idle speed after not being used for a while.
Cheers,
Dave

'02 Honda CR-V SE Executive
'99 Jag S Type 3.0 V6 SE


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'94 827 Sterling saloon
'88 Volvo 760 V6 Estate
'95 827 Coupé LPG gone but not forgotten!

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Re: Battery Desulfator

Post by zcar12 » Mon Nov 27, 2017 7:30 pm

Thanks Dave. I dont plan on binning the desulfator, it can only work on a battery that has no internal damage and it looks like my old battery has just that. As you say, it was not intended for calcium batteries where the voltage can rise quite high. I have replaced the fuse and it seems to work OK again.

I never knew that the 800 can sense the battery state and increase the idle speed. As for the battery being discharged being the cause of my high idle problem, you may be correct. Its behaved itself perfect;y since I gave the battery a two day charge session.

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Re: Battery Desulfator

Post by scoobyh123 » Tue Nov 28, 2017 12:09 am

There you go Nick - new fuse and the desulphator is as good as new again! :P

Certainly on the 825/827 (that's the Honda 825 BTW) there is an input line on the ECU to sense battery voltage and raise idle speed if it's low. It also raises the idle speed when the air-con is switched on as well.

On the MEMS cars (820 and 825 KV6) there is a similar sensing circuit for battery voltage, however i think this is sensed internally from the supply line but i could be wrong.

Either way many cars have this, i know shortly before the battery on my Volvo died the idle speed kept raising higher than normal, especially after a cold start. Since renewing the battery it's been fine. :wink: :D
Cheers,
Dave

'02 Honda CR-V SE Executive
'99 Jag S Type 3.0 V6 SE


Image
'94 827 Sterling saloon
'88 Volvo 760 V6 Estate
'95 827 Coupé LPG gone but not forgotten!

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