Wolf Spider · Jan 21, 2023

This is my first post........ woohoo.
I have a 1996 Defender 90 CSW 300Tdi. I have owned this vehicle for just over 3 years. It has always seemed to have a slow battery drain when the vehicle is parked and unused: it's OK for 3 weeks, or so, but then the battery becomes too drained to crank the engine over. This may just be background and not relevant to the main point.
Last week I charged it overnight, but a couple of days later it struggled to crank enough to start. After driving ~40 miles a couple of days ago, It struggled to start again today (but did). Temperatures have been hovering around zero +/- 5C here this past week. I drove about 7-8 miles and measured the battery voltage (engine off) about an hour later. Battery voltage was 12.32 volts. Too low methinks?
The battery is a Varta 110Ah 850A EN which was in the vehicle when I bought it (I have a receipt in the part-service record suggesting a new battery was fitted in January 2009). I have found the manufacture date (thank you YouTube) on the -ve terminal post - 10 08 (10th week 2008!). So, I assume that this is the one referred to on the receipt (a simple garage receipt - no manuf/model details). Whilst I'm impressed it's got this far, I think it is time for a replacement. I'm considering:
- VARTA I1 Silver Dynamic 12V 110Ah 920A car battery 610 402 092
- Bosch car battery S5015 12V 110Ah 920A/EN Type 020
Both are around £130-£140, it seems (from Battery Group)

Does anyone have any advice or comments. Anything constructive is welcomed.
Thanks

miktdish · Jan 21, 2023

When the engine is running. around 1500rpm (or more) what is the voltage then ?
Any of those batteries you mention will be fine (as long as they fit in the battery compartment)...

KISSMYAURA · Jan 21, 2023

KISSMYAURA · Jan 21, 2023

go to TAYNA batteries, get the one with the largest CCA that will fit in yer space, simples.

see here:
page-25

dag019 · Jan 21, 2023

KISSMYAURA said:
go to TAYNA batteries, get the one with the largest CCA that will fit in yer space, simples.

see here:
page-25

Second vote here for tayna. I have this one in both mine link (yuasa YBX3642). Might not be the cheapest but at 925cca you should never struggle To start. I will be fitting one to the tractor shortly as well.

kermit_rr · Jan 21, 2023

Or battery megastore.
Also consider a battery is considered fully flat at 50% charge, from the table above

KISSMYAURA · Jan 21, 2023

2 things

SOC state of charge
SOH State of health

My batt was 100% charged but SOH was pants

if you have 12.35 after a day or so battery is fooled

tottot · Jan 22, 2023

At some 14 years old your batt has done pretty good. All battery's lose charge when not used. When new it will be very little but as it they age loss can increase until it is like yours. Check for vehicle loss by disconnecting and checking volts and again after a couple of days. If still going down at same rate its the batt.

Disco1BFG · Jan 22, 2023

What everyone else has said above is good advice. I'm a big fan of the biggest battery which will fit, as post #4 ..

According to the LR / OEM specs, 470 cca is enough for a 300Tdi !! which is probably true in Oman / Saudi / Egypt - but not in Yorkshire! ( or Derbyshire

)..

We've had good experiences with Varta, Bosch and Hankook batteries - the MF31-1000, currently cheapest, AFAIK, on battery megastore:-

https://www.bmstechnologies.co.uk/product/hankook-heavy-duty-commercial-battery-mf31-1000/

is where I would be looking... 1000cca = what's not to like

( if it fits!

)

Wolf Spider · Jan 22, 2023

Thank you for your comments. I've been out on the fell tops today (not using Defender), but I checked the battery voltage when I got back. It was 12.12volts (down from 12.32 volts in 24 hours). So, the battery seems to be going EOL and as I said in my original posting, I'm surprised it has served 14 years of use and 15 years since manufacture.. However, I will check the charging voltage tomorrow per the posting by @miktdish yesterday.

kermit_rr · Jan 22, 2023

That's one dead battery. Anything that's dropping to 12.4 when you turn off is dodgy ground.. dropping to 12.1, assuming that's no draw, is toast

Wolf Spider · Jan 22, 2023

Thank you @kermit_rr. Everyone has pretty much confirmed and elaborated on my initial diagnosis. I will check the charging voltage 'cos I'm at this point and would like to know! I'll then order a new battery - I'm drawn towards the Varta because I rate them and have had good experience with them (plus the current one has done 14/15 years!). The Hankook suggested by @Disco1BFG is attractive, based on price, but I have no experience of them. Luckily, I don't need to use my Defender every day.

kermit_rr · Jan 22, 2023

I have an mf31-100 too, can't fault it.

miktdish · Jan 23, 2023

I bought mine off eBay, it appears to be Turkish ... Type 110 70AH(C20) 85AH(C100), starts the car first go, powers the winch, been good for 2 years.
Garentee isn't worth anything (i'd imagine).

What i really fancy is one of these ... https://www.antigravitybatteries-uk...rcars/antigravity-h6group-48-car-battery.html

Disco1BFG · Jan 23, 2023

miktdish said:
What i really fancy is one of these ... https://www.antigravitybatteries-uk...rcars/antigravity-h6group-48-car-battery.html

OUCH! the cheapest is £800!

Wolf Spider · Jan 23, 2023

I've just been out and measured the battery voltage this morning (outside temp is 3C according to my other vehicle, but it feels noticeably warmer than the past week and everything is not covered in frost today). Battery voltage is 12.08 volts.
So, would it start, I thought? Turned the key and the engine fired up straight away!
Checked the voltage across the battery at steady revs: around 14 volts.
So, I still think my battery is going EOL (and it deserves a long service medal anyway). As a final thing, I'm going to charge it right up with my Norco charger, disconnect the battery and check voltage decay on no-load over a day, or so (out of interest).
I shall probably buy a Hankook MF31-1000 as a few of you recommend it and it's a good price at about £105.86 with free delivery.

Wolf Spider · Jan 23, 2023

You guys with the Hankook MF31-1000 batteries: what vehicle do you have them fitted to?

The height of the Hankook terminal post is 242mm according to the data sheet. The battery box (the standard one under the front passenger seat) in my 1996 Defender 90 CSW has a sloping top: 295mm at the front but only about 240mm at the back so I don't see how I can fit the Hankook in there with having top clearance and I will have to choose something with a lower profile ( e.g. Varta/Bosch/Yuasa all have a height of 190mm).

kermit_rr · Jan 23, 2023

Must have been something on drawing the battery down

kermit_rr · Jan 23, 2023

Wolf Spider said:
You guys with the Hankook MF31-1000 batteries: what vehicle do you have them fitted to?

P38 4.0 v8

kermit_rr · Jan 23, 2023

Disco1BFG said:
OUCH! the cheapest is £800!

Exclusive RE-START Technology (Wireless Remote Jump-Starting).
Wireless jump leads, I'd say I've seen it all.. but you can't see what's not there

Hahahaha

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