Replacement 12V auxiliary battery for MGS5

[stevedee]

...I think I'm probably better off starting another thread, this is a complex subject...

Yes please, I'll join you.

 

[MG Clive]

Yes please, I'll join you.

See here - Recovering a Lead Acid battery after it has been deeply discharged

 

[T1 Terry]

I've searched long and hard to try to find a decent quality replacement 12 volt auxiliary battery for my troubled MGS5 with zero success.

The 35Ah battery as supplied is puny at best and may benefit from doubling the capacity to 60 or 70Ah, there doesn't appear to be a like for like (35Ah) swap in a reliable brand made yet.

But there's plenty of of slightly taller and longer, with similar width available which may be persuaded to fit.

Ideally I'd prefer to up the capacity, but I don't really want to mess with the warranty conditions by making new and possibly irreversible battery mounting kit.

Have any of our fellow DIY, happy to "have a go" guru's thought along similar lines?

Can you give me the dimension of the battery please, from there I expect I can guide you to a suitable alternative that is fast charging so will charge in the short blips of charge current/voltage it receives ....

T1 Terry

 

[Joningy]

A lead acid battery needs to remain at charging voltage, above 13.6 V min, to actually recharge. 13.6 V will maintain the charge at 100% if it is already at 100%, it will bring a battery up to about 50% SOC if it stays at that voltage for 24 hrs or more, but that is no enough voltage to over come the inherent internal resistance of any type of lead acid battery.

Now, if the battery was not saturation charged when built, it will already begin sulphating ..... within 12 hrs actually .....

If the terminal voltage is held at 14v for 12 hrs or more, you can get closer to fully charged, as long as the plates are not sulphated. Once the sulphation starts on lead acid plates, no chemical reaction can occur in that part of the active plate, so capacity is lost.

I think I'm probably better off starting another thread, this is a complex subject, I'll skim over it as much as possible, but I'm happy to dive deeper if anyone wants to know more

T1 Terry

Very interesting Terry, I'd be interested to know more!