[pward69]

Having read some threads about battery upgrades/replacement for the Skyline with the rear mounted battery I thought I'd document the upgrade on my 96 GTST car, hopefully it may be of use to some...

The std Skyline battery was spec'd at around 28Ah and my vehicle had a 40Ah aftermarket "small" bettery fitted. If you are running a 28Ah battery with a Cat 1 alarm and high spec ICE etc, your battery will flatten if left parked after 9 to 11 days, assuming it was fully charged before you parked the car. This is due to the high "key off" loads these additional features impose on the battery.

I opted to upgrade my car to a 60Ah AGM battery, this will extend the time taken to flatten the battery to 25 days and out perform the cold cranking perfomance by more than 100% (330A v's 680A). Also AGM means no liquid acid - no leak risk and nearly zero gassing so no vent required.

The dimension of the Varta AGM battery I used is w235 x d190 x h205 (compared to OE w185 x d120 x h205). This size battery fits the Skyline tray snuggly, in fact I had to remove the lower clamp moulding from 1 side of the new battery.

I reworked the standard cables to fit the new battery terminal clamps (full size). Alternatively a neg (15") and pos (12") cable from your local motor factor shop (£6) will also resolve the terminal size difference between batteries.

I addressed the top hold down bracket with a Mondeo item, I'm sure there are many ways to fabricate a suitable hold down bracket.

Photos:
Original Battery installation

New Battery installation:

I'll happily answer any questions if you are unsure about any aspect of this upgrade.

Cheers,

Phil

 

[carvolution]

just a quick question?
How much power do you think a gereral cat 1 alarm drains??? Because surley your ice would not be left on?
I have had loads of customers go away on hoilday and come back to their car and it starts stright away.
All the alarm system takes power wise is to power the led and a sensor.
Dont get me wrong, i am not having a go or anything, but the battery would last a lot longer than 9 days. It may be worth looking at your wiring around the car to see what else is draining the power?

 

[pward69]

The LED alone could draw 20-30mA, the interior/exterior scanning can push the total to around 100mA. Obviously depends on make and spec of Cat 1 used. The std stock vehicle probably had a total key of load of less than 20mA.

 

[carvolution]

just looked at my dealer spec sheet for a cobra cat 1, it states a draw of "<9ma" and thats fully armed, power one led and a set of ultrasonics

 

[carvolution]

anway good work on the battery upgrade.
Whats the number on the battery, or what is it mostly found on so that others can easily purchase one.

 

[davegtst]

Not sure what type that one is but i have fitted an 065 to mine and it fits just perfectly. An 075 and 027 should also fit but the 027 is a bit taller so it ,ight be a bit dodgy conecting and disconecting leads.
065's are commonly found on old shape vectras and 027's are found on honda accords.

 

[pward69]

ICE contributes to the key off load through the memory functions (memory of stations, tracks etc) If inbuilt GPS then polling of Sat at regular intervals to keep your system updated with latest info also consumes lots.
I'll measure my CAT 1 alarm and post the loads, but 9mA sounds low.

 

[carvolution]

what make to you have, cliffords normally have the biggest draw due to the vast extra's and sensors on them

 

[pward69]

Yes I have a Clifford Concept 650.

 

[jedi-masta]

I got a Halfords battery for the Micra. Battery lasted a little over two weeks (without being driven) before dying. Was bigger than the standard one that was in there too.

 

[Aitch]

Our car has been in the UK for nearly 5 years, we've had it over 3. The battery is the original battery supplied with the car in Japan, a Nippon Denso unit, but unfortunately I cannot see what rating, and am not about to pull it out to look. It is frequently left for weeks at a time at airports in the UK, as we spend 5 months a year abroad. It's never failed to start on our return, not even when the car's been covered in inches of snow, and we have a Clifford G5 cat 1 system with every extra available.

I'd suspect a fault on any vehicle flattening any battery in 9 days.

Aitch

 

[pward69]

Let’s just clarify, time to flatten a battery is dependent on the loads applied and the duration they are applied for.

If you have a vehicle with (only) a 28Ah battery fitted and the stock vehicle key off load of ~30mA the battery will be flat in 29 days assuming it was 75% charged when you parked the vehicle. If you increase the key off load by only 9mA (buy using a Cobra alarm load as carvolution above), the time to flatten the same battery will be reduced by 7 days to 22 days. In the same example a 50Ah battery will last 40 days, and a 60Ah 48 days.

3 weeks+ is not a problem for most, the problem comes when loads greater than an additional 9mA are applied either intentionally (higher alarm loads, ICE loads, hardwired phone charger etc.) or as fault condition.

Obviously if double the key off load is applied, then half the duration till flat can be expected, therefore fitting a larger capacity and you'll be more robust. I know it’s obvious but I know people who think the battery can provide unlimited power indefinitely !

The downside of course is carrying an extra few kg around with a larger battery – I guess you can’t get something for nowt !

Cheers.

 

[carvolution]

pward69 - what do you do for a living? just curious! lol