Bad earth or bad battery ?

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supercookie
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Bad earth or bad battery ?

Post by supercookie »

I started noticing the engine in my Mk2 turning over slower than a few months ago. I'll admit I have a smaller ampere hour (40A) battery fitted than the original (60A I believe). I fitted the smaller battery cos (1) the built-in battery condition window shows 'good' as it was only a few months old about a year ago (2) it fitted easily & came free ! & (3) the car is always garaged & only used during the summer months. The other day I started it & reversed it out the garage & when I came to start it only 2 hours later, the battery was flat. It's normally permanently connected to a smart charger 24/7. I've started to wonder about the car's main earth connection from the battery but am unable to find it. I'm on the verge of buying the correct 60A battery but would like to dismiss the possibility of an bad earth. Problem is where is it ?
Thanks in advance.



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Re: Bad earth or bad battery ?

Post by supercookie »

Further to my post above....

The car/battery has been connected to my smart charger for about 6 hours of which 4 saw the smartcharger in 'recondition mode'. The car started perfectly afterwards. I'm not using the car for a few days so will leave the smartcharger disconnected & try then. The battery voltage reads 13.8v.

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Re: Bad earth or bad battery ?

Post by Snorkie »

You need to test for a drain on the battery with an amp meter, Get a garage to load test the battery.

Sounds like your battery is u/s, but without testing that's a guess.

13.8 volts is OK. check it after a day not on the charger.
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Re: Bad earth or bad battery ?

Post by MR2DI4 »

Also it comes down to pure age and quality of the battery.

The worst I have seen is 18 months and the best is my Yuasa which will still start and run the car for 20 minutes after the alternator failed and its dated 2007.

Most batteries last between 4 to 6 years and they are stuffed. They all lose capacity over time. Fully charge it and then just leave the lights on, if the lights go out or dim in 10 minutes its stuffed.

Always get a permanent marker and write the date you fitted it to the car to the top of the battery. Time flies and before you know it the battery is 4 years old.

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Re: Bad earth or bad battery ?

Post by supercookie »

Thanks all. I've disconnected the smart charger last night...will try starting it in a couple days & report back.
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Re: Bad earth or bad battery ?

Post by peteV6R5 »

40Ah battery will not have sufficient CCA (cold cranking amperes) to spin the engine fully on MR2
40ah = around 340 CCA
60Ah = around 540 CCA

agree with Carl batteries degrade over time.
after putting in V6 my 60ah standard battery would last around 2 years from new to give you an idea
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Re: Bad earth or bad battery ?

Post by jeff »

tbh, wouldn't waste time messing around for the sake of circa £60 just buy a new battery as im 99% sure thats the problem
Not Plan B again!! Why don't we just go with plan B in the first place?
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Re: Bad earth or bad battery ?

Post by MRHAPPY62 »

:th:
MK2 3sge Uk sold.
MK3 Chilli red sold.
MK2 Smg Gltd Super Edition now with V6
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Re: Bad earth or bad battery ?

Post by Wilkie Senior »

I put one of these in never had a issue since £75.48

Tight fit but worth getting.

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Re: Bad earth or bad battery ?

Post by jimi »

Same one I have in my MK1 :th:
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Re: Bad earth or bad battery ?

Post by MR2DI4 »

Yuasa rocks, You can get one that takes up the entire battery compartment.

Size is 257(L)x173(W)x222(H) and its new code over here is 75D26LMF

https://www.yuasabatteries.co.nz/resour ... 26lmf/info

Much more expensive over here now, about $275 when I last enquired about a year ago and no doubt way more expensive than that now that the price of shipping has gone up by like five times.

Probably get 10 years out of it if kept fully charged and never fully discharged. Standard car batteries are not "Deep Cycle" they hate being fully discharged and left in that state for any length of time.

Got mine connected to a 50W solar panel and MMPT charger these days as it hardly gets driven but the battery remains fully charged.
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Re: Bad earth or bad battery ?

Post by jimi »

jimi wrote: 09/09/21 15:31 Same one I have in my MK1 :th:
Just checked, mine is a YBX5005, same family, same spec, slightly different dimensions :cool1:
I've had dealings with Yuasa batteries for many years offshore, in various uses, UPS's, engine starting, emergency standby etc. From a professional point of view they are a very good quality, reliable batteries :th:
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Re: Bad earth or bad battery ?

Post by Wilkie Senior »

That one we put in, it took Wilki the younger, with his nice shoulders show em off show em off!!!

to push the b b b blasted thing in
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Topic author
supercookie
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Re: Bad earth or bad battery ?

Post by supercookie »

supercookie wrote: 07/09/21 12:34 I started noticing the engine in my Mk2 turning over slower than a few months ago. I'll admit I have a smaller ampere hour (40A) battery fitted than the original (60A I believe). I fitted the smaller battery cos (1) the built-in battery condition window shows 'good' as it was only a few months old about a year ago (2) it fitted easily & came free ! & (3) the car is always garaged & only used during the summer months. The other day I started it & reversed it out the garage & when I came to start it only 2 hours later, the battery was flat. It's normally permanently connected to a smart charger 24/7. I've started to wonder about the car's main earth connection from the battery but am unable to find it. I'm on the verge of buying the correct 60A battery but would like to dismiss the possibility of an bad earth. Problem is where is it ?
Thanks in advance.
Well guys....I took the majority advice & bought a new 60Ah battery....so far so good....starts immediately.
Couple of things I've since realised since my original post. The suspect battery was a 50Ah not a 40Ah as I originally stated. And I found the original 50Ah battery receipt which to my surprise revealed the battery was in fact 4 years old ! Time indeed goes quick. No wonder I was having problems.
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