Oh Boy Two Car Batteries

[icsys]

To be honest I wouldn't have expected Japan to experience snow seeing as the most northerly part is not much higher than the med? (45 deg north) ...but then it is close to Russia!

Interesting, mine had an 'Aitchi Toyota' sticker on the bumper when I got it.

Toyota is also in Aichi district.

[Vagrant No2]

The two batteries is an option on the Surf (I think it is called the winter pack and also comes with the rear heater). They are wired in parallel so they are both used for all functions. By having two batteries it enabled Toyota to use cheaper and smaller batteries and still provide the required CCA (I think 700amps) to start the Diesel engines. Diesel engines are harder to start than petrol engines dues to the much higher compression ratios.

When adding accessories the only reason for chosing one battery or the other is to make it easier to run the cables and to keep the terminals tidy.

Cheers

When I was a mechanic I dabbled in alot of auto electrics and went on a couple of courses . Basically the only reason a vehicle has a battery is to start it . Once running it is the duty of the alternator to supply the current to to components . The alternator only supplies the current on demnd , so when the headlamps are turned on there could be a slight drop in engine revs . This is the alternator putting a load on the engine and demanding some power . Commonly a loose fan belt will only be heard in this case by the screaching noise on revs .
Two batteries are as described for extra start amps and smaller batterys .
Usual thing that happens is one battery starts to fail and drags the second down with it . Or one battery fails and the second then fails due to over working .
When the alternator fails the electrics then rely on the batterys until they then run flat and the vehicle stops , or you crash at night because the headlamps go out !

Basic vehicle electrics part 1

Rick

[Guest]

When I was a mechanic I dabbled in alot of auto electrics and went on a couple of courses . Basically the only reason a vehicle has a battery is to start it . Once running it is the duty of the alternator to supply the current to to components . The alternator only supplies the current on demnd , so when the headlamps are turned on there could be a slight drop in engine revs . This is the alternator putting a load on the engine and demanding some power . Commonly a loose fan belt will only be heard in this case by the screaching noise on revs .
Two batteries are as described for extra start amps and smaller batterys .
Usual thing that happens is one battery starts to fail and drags the second down with it . Or one battery fails and the second then fails due to over working .
When the alternator fails the electrics then rely on the batterys until they then run flat and the vehicle stops , or you crash at night because the headlamps go out !

Basic vehicle electrics part 1

Rick

Agreed except the batteries will also provide the power when idling or when running more accessories than the alternator can provide the amps for - for instance when running lights etc. The Alternator on the Surf is only a fairly low amp output and when you start running lights, big stereo etc, you can easily push the alternator beyond it's capabilities. I think the Alternator on the Surf is something like 60 amps. If you add up the following you can easily beat it.

1. Charging the batteries - not sure but would probably take at least 15 amps.
2. Pair of Fog lamps (110 watts total = 9 amps)
3. Pair of Headlamps on dip - total 8 amps
4. Stereo - 100 watts total or there abouts - 8 amps
5. side lamps, dash lamps, heater blower, heated rear window - probably a total of about 10 amps
6. Engine ECU, fuel pump, probably about another 5 amps.

Total of 47 amps without even thinking to hard about what else might be running.

Also the alternator will only supply the peak output when running fast - which is why a common mod on some cars is to reduce the size of the alternator pulley so that it runs faster and provides peak output earlier. However this is a pretty good way to kill and alternator unless it is designed to running on a high reving engine.

But in the end I think like has been mentioned before the main reason for fitting the batteries was so that they can fit cheaper and smaller underspecced batteries. Running them in parallel overcomes the fact that each of the batteries couldn't do the job on their own.

Much better to use the space up but fit one good starting battery and one leisure battery, then use a charge splitter.

Cheers

[baggins]

two batteries

Tanks guys I just got my Toy and was wonering about that one

[UKWolf]

Agreed except the batteries will also provide the power when idling or when running more accessories than the alternator can provide the amps for - for instance when running lights etc. The Alternator on the Surf is only a fairly low amp output and when you start running lights, big stereo etc, you can easily push the alternator beyond it's capabilities. I think the Alternator on the Surf is something like 60 amps. If you add up the following you can easily beat it.

1. Charging the batteries - not sure but would probably take at least 15 amps.
2. Pair of Fog lamps (110 watts total = 9 amps)
3. Pair of Headlamps on dip - total 8 amps
4. Stereo - 100 watts total or there abouts - 8 amps
5. side lamps, dash lamps, heater blower, heated rear window - probably a total of about 10 amps
6. Engine ECU, fuel pump, probably about another 5 amps.

Total of 47 amps without even thinking to hard about what else might be running.

Also the alternator will only supply the peak output when running fast - which is why a common mod on some cars is to reduce the size of the alternator pulley so that it runs faster and provides peak output earlier. However this is a pretty good way to kill and alternator unless it is designed to running on a high reving engine.

But in the end I think like has been mentioned before the main reason for fitting the batteries was so that they can fit cheaper and smaller underspecced batteries. Running them in parallel overcomes the fact that each of the batteries couldn't do the job on their own.

Much better to use the space up but fit one good starting battery and one leisure battery, then use a charge splitter.

Cheers

I think that 15 A is little over the top for the battery charging - however if you say that total normal running load is 45A, then that is 75% of the altinator load and 15 amps would be a fair few more toys.

As for the batteries being underspeced - I think the logic behind the use of two batteries is this
1 battery (say 1 x 80Ahr) - big, heavy and expensive (fewer made)
2 batteries (say 2 x 40Ahr) - smaller (easier to fit), lighter (easier to handle) and cheaper (if its car size there will be 1000's more made)
In the end, like anything, a battery is as good as you buy

I've had cars (petrol) with 65Ahr batteries and boy are they heavy to lift in and out.



PS I requested as part of the agreed price for mine that the dealer fitted 2 new batteries.

[Chevydancer]

Two Batteries

@ Koi,
The above reply from Andy sums it up perfectly imho! Possibly one for the FAQ section??
Pete

Can you then explain why when I disconnect the one battery, passenger side, that the radio and internal lights go out. May be a bad connection?

[Morr]

Can you then explain why when I disconnect the one battery, passenger side, that the radio and internal lights go out. May be a bad connection?

Most likely yours is not an original twin battery model, but has had an split system fitted later, or the original has been converted to a split circuit.

[da SLUG man]

Can you then explain why when I disconnect the one battery, passenger side, that the radio and internal lights go out. May be a bad connection?

when you do that does it isolate the other battery too??...

[POPEYE]

####### Batterys

Right!!! So what type of batterys do i need, ie amp hour, number etc, I've
got one gone down which wont charge at all, the other seems to have charged ok and i've had to put an old battery left over from my serria which
is a lot smaller than the original but at least holds a charge on for now, Idid notice that when i took off the off side (RH) battery some things did still work and some did'nt ie the interior lights worked but the central locking
did'nt, So have i got a split system or what, Any help and advise would be
apprecieated, I would just like to know what batterys to ask for when i phone round for quotes so i dont get fobbed off with some cheap old rubbish
Kind Regards Ian

[TechnoTom]

Is it possible to add the second battery to a 96 model that only has one battery?

Tom

[Tallyman]

Unless you have a second battery tray, probably not as you would not be able to secure it properly. And you also have to consider that if one battery goes wrong you should replace both at the same time, so doubling the cost. If you have any problems with your current battery, consider replacing it with one of a higher CCA rating.

[handyandygsxr]

Batteries, one or two?

My surf is a single battery model without the rear heater, is it worth converting it to dual battery and installing a rear heater, I'm also fitting a 42" led light bar and a winch?

[tashtego]

Hi, or should I say 'Bonjour'?

I wouldn't bother with any of those things and I would spend the money where it matters:

1) The new head, a new water pump, thermostat, radiator (if you go for the original Toyota buy the bigger one for the 1996 Colorado/Prado, it's a straight swap) and a new Aisin viscous fan from RT.

2) The usual 1996+ Surf things: upper and lower ball joints, rear hub seals (if they are leaking), steering rack bushes, rear diff breather replacement, rear springs, stabilizer bar bushes front and rear and anything else that might need renewing.

Cheers!

[BillaBob]

Battery Replacement! Important!!

Can I just put my pennyworth in to this thread. All three of the Surfs that I have had, ALL have arrived with dodgy ODD batteries. I really can't stress how important it is to change BOTH at the same time! As batteries get older they develop "Shorts" internally on the individual cells, this can drain both batteries even if 1 is new. If you just replace 1 battery it if very false economy , I had a friend who ignored my advice who paid nearly £90.00 for a new Exide battery, 6 months later it was done for - it was not replaced as they found the other older battery had these internal shorts - which just kept putting a massive strain on the newer battery.
My last 2 New Batteries were by Banner,they were £170 for the 2, and served me for 6 years of service.