Why are there two batteries?

[maverick_sr71]

The big problem with leaving the batteries connected in parrallel is a situation I recently had. One of the batteries died and as a result it killed the other battery. The battery that had a collapesed cell was draining the good battery down to 5v overnight. Lead acid batteries don't like being drained like this and it died a couple of days latter.

Best advice I can give is to put a 700CCA N70Z sized battery, or better, in the position where the heavy starter motor wiring connects (air intake side of a 1KZ-TE) and have some means of isolating the two batteries and control the charging of the second one.

This also means that if the main starting battery does fail or go flat for some reason you have a perfectly good battery sitting there waiting to be used to start the beast.

[mrkeeg]

installing a deep cycle battery

Hi all,
Thanks for the info in this and other threads!

I've have just a single battery in my 89 pickup since I bought it, but had noticed the conspicuous space on the other side!

I just bought a new primary battery and it works great. I also bought a deep cycle for the other side, and am hoping to install it as outlined in the link posted earlier here
( http://www.showmesome.info/hilux/workshop/battery.htm ).

Has anyone on this forum tried this system?

I am not much of a mechanic, and I have a few questions:

1: the article stresses the importance of having a fused relay - I couln't find one, but I assume I can just put a 30A fuse inline along the wire, before the relay?

2: I noticed at the auto store some rather expensive boxy thingies with cooling flanges (yes, technical terms) sold as battery isolation packages - what are they, if this simple relay system does the job?

3: the article calls for 35 amp wire running between the batteries - I couldn't seem to find rated auto wire... will 10 gauge auto wire work?

Thanks,
Keegan

[mrkeeg]

I found a few wire charts on the net... this one shows 10 gauge wire good for
55 A "Maximum amps for chassis wiring", but only 15 A "Maximum amps for power transmission". Hmmm... maybe I'd best find some 7 gauge ... but then... the wire that came with my inline fuse will be the weak point (10 ga) hmm...

[TonyN]

in this thread it says that the main battery is on the drivers side and being in paralel so could you put two different ampage batteries on ? and mine is on the passanger side but all the wires are still there on the other side so i presume it had two fitted is there any way of checking as to whether there is a split charge circuit already fitted ?

There is no main battery in the standard set up, sound like someone has just dumped a iffy battery from the drivers side. No single battery Surf I've ever seen had a single battery on the passenger side.

Also single battery truck wouldn't actually have the battery connections hanging there, its dangerous in case the +ive touches anything.

[da SLUG man]

i like this thread... i asked a question, hormygollop mentioned a flux capacitor and simon.o.'s first post!!

them was the days!!

[Apache]

I seem to recall reading or hearing that it is part of the 'Arctic Pack' of options available on the Surf. More reliable starting in colder climates was the spouted reason.

A single battery is OK in this country. I ran mine with one for a while after one went down, before I could get to Roughtrax to buy another. No problems on one, though two does make for 'whizzier' starting when the oil gets thick!

[MattF]

Hi all,
Thanks for the info in this and other threads!

I've have just a single battery in my 89 pickup since I bought it, but had noticed the conspicuous space on the other side!

I just bought a new primary battery and it works great. I also bought a deep cycle for the other side, and am hoping to install it as outlined in the link posted earlier here
( http://www.showmesome.info/hilux/workshop/battery.htm ).

Has anyone on this forum tried this system?

I am not much of a mechanic, and I have a few questions:

1: the article stresses the importance of having a fused relay - I couln't find one, but I assume I can just put a 30A fuse inline along the wire, before the relay?

Yes. Generally, keep fuses as close to the current source as possible.

2: I noticed at the auto store some rather expensive boxy thingies with cooling flanges (yes, technical terms) sold as battery isolation packages - what are they, if this simple relay system does the job?

A relay, (with its coil connected to a feed which is only live when the
ignition is on), will isolate the battery as required. The split charge
relays you have seen just tend to be high current solid state units, if
I remember correctly.

3: the article calls for 35 amp wire running between the batteries - I couldn't seem to find rated auto wire... will 10 gauge auto wire work?

Thanks,
Keegan

6mm cable is usually ample for upto a 50A circuit. Can't remember
gauge conversion, unfortunately. That is the open air rating.
As a rule, derate the current capacity of the cable if it is to be enclosed.

[jm31141]

One more re the 2 batteries

Re the two batteries being for starting the diesel - I have done some overlanding in Africa and many 4X4 people choose to add an extra battery for camping use (lights and general camp use at night). They use the spare battery for this but have it hooked up to charge during the day while driving. This way there's no danger of a flat battery in the morning. Could the Surf set-up be used in a similar way? ie: would 1 charged battery in the morning be enough to start?

Have just read the rest of this thread - pls ignore.

[Shaft120]

There is no main battery in the standard set up, sound like someone has just dumped a iffy battery from the drivers side. No single battery Surf I've ever seen had a single battery on the passenger side.

Also single battery truck wouldn't actually have the battery connections hanging there, its dangerous in case the +ive touches anything.

Old thread I know and Tony is now living in Yoda style exile, but wanted to point out that my Truck has a Passenger side only single battery!

Was hoping somebody might have some pics of the dual battery set up and how you would go about converting to it from a single battery??

[floatingkiwi]

The dual batteries are indeed part of an option that was available in Japan called the "winter pack".

It involved the dual batts, rear heater, sometimes heated fuel filter and diff wiper blades.

Matt

[Karma Supra]

I thought some of the petrol, ones had it mounted on the passenger side...

I actually converted mine from single to twin battery, I took pics and was going to do a write up at some point (I thought I had, but can't find it with the search)

Basically I got a scrapped twin battery surf, cut out the battery tray, and bolted it in mine.

Easy

And totally not needed with the V8 (Which came along later)

[lord_flashart]

I thought some of the petrol, ones had it mounted on the passenger side...

I actually converted mine from single to twin battery, I took pics and was going to do a write up at some point (I thought I had, but can't find it with the search)

Basically I got a scrapped twin battery surf, cut out the battery tray, and bolted it in mine.

Easy

And totally not needed with the V8 (Which came along later)

I did the same winter-pack retrofit thing about 2 years ago; I also uprated both batteries as for a while (before learning a lot about these vehicles) I was having starting issues and thought it needed more power!

I recently have fallen into the "one battery died and has been pulling the other down" scenario so I worked out which one it was and then ordered another.

The second battery +ve is fitted with the bolt on +ve cable from the donor Surf that sits along the top of the radiator but the earth cable had to be made so I joined it to the body and it seemed fine. Now the main battery has died and although it's still in situe awaiting it's replacement with the -ve disconnected I am obviously starting the truck using the second battery only and it seems sluggish again.

I am faced with a few reasons that I can see;
1. I'm used to 2 batteries firing up the starter and notice the difference,
2. The other battery is also on it's way out,
3. The earthing is not good enough to take the current.

With a new battery on it's way to replace the main one I'll have the second tested and see what the readings are.

As for your install, how did you earth the second battery? Just to body or chassis or engine or all three?!


Cheers.