What I need to buy for AGM dual battery system??

Oh,I want to ask him to install dual battery system on my car..but
I'm at Sydney now.. too far away..
I will call him for more information.. thanks..!

I read your blog and one more question..

I already bought DC-DC convertor for my laptop.
Now I fully understand that 100Ah AGM battery is more good for me.
the bigger,the better. But,
Q1) how many hours of driving is needed to charge 100Ah battery almost fully?
If it takes time too long,
for example, 3 hours driving do charge 50% of 100Ah,
(I don't know how long it will take,just for example)
I think it's the same with 50Ah battery if it can be 100 % charged by
3 hours driving.

Q2)How can I check my car alternator's charging voltage?
Checking battery voltage when engine is highly idling?
I want to know for AGM battery.

Q3) If I use redac isolator,is this working as a controller?
Disconnec Aux battery when engine is not working or main battery is not
fully charged? If I use another cheap 12V isolator,is it OK to use?

Q4)How about Dual purpose battery ?(Cranking and deep cycle)
I find that 140Ah dual purpose battery.
SSB HIGH PERFORMANCE.SLA AGM BATTERY.
12V 140AH @20HR CAPACITY. 1350cca.
Price is 385 AUD.
(This is almost same price of 100Ah AGM. 300 USD + isolator 85 USD)

How about get rid of original battery and install this dual purpose battery?
Then cabling will be super easy..Is this a good idea??

I prefer to buy a new battery as I will use it everyday for 1 year or more.

For the last 4 years,I've been traveling around the word by motorcycle.
No job,No working...Only traveling everyday for 4 years..
North,Central and South america. then Russia via mongolia,Stans..then
South Asia..
Now I become very tired of doing it,so I bought a brand new car
to around Australia. After finish it,I will ship it to Europe for more travel.

I will looking forward your answer..thanks very much for information

Also,I check the full river AGM battery spec.

Charge voltage is
from 15.3V (Low temp) 15.06V...14.82V...14.70V..
to 14.34 (High temperature)

So my car alternator have no problem to charge this?

change Q1)

If the alternator voltage is lower than AGM charging voltage,
for example, 13V,
AGM battery don't do charge or it just take more time?

If it take more time,does it take the same charging time of normal battery
of 12V charging voltage?
So,it's more efficient to install 100Ah normal battery?
and this is why AGM parallel is not highly recommendable?

As I know,AGM battery charging more quickly than normal battery
(But I don't know how fast it is),but it needs a higher charging voltage.

But,if I put normal battery parallel,it will take a long time to charge
(But I don't know how slow it is)

Which is more better?

Hi Motoride,

Sounds like you have had a very big trip and been to some very special places..

I see that you have a laptop and projector, not 2 laptops. That will change the power requirements, probably by quite a lot. How much power (volts and amps) does the projector need?

Recharging - This is always a problem. Your alternator should be able to recharge in an hour or 2 all the power you will use each day. BUT, the Fullriver charge voltages are fairly high and you may not be able to fully charge it with the voltage available from the alternator. The alternator voltage is set to suit the vehicle battery and probably wont be more than about 14V. Fullriver has a very good reputation, but perhaps you could find a different deep cycle AGM battery that has a lower voltage requirement. If you are buying a new battery, a 50 Ah should be big enough, depending on the power required for the projector.

Q2 - suggest you buy a small multimeter. These are readily available from places like Jaycar, Dick Smith..... from about $10. It will be important to know the alternator and battery voltages. There's a link in the blog to a good "how-to-use-it" site.

Q3 - Your electrician will have his own ways of doing things and the redarc is certainly one of the standard ways. He might find a way to economise a little with the controller.

Q4 - No - dual purpose batteries are a compromise and are not recommended because they don't do either job as well as 2 seperate batteries. Having 2 batteries also means that you will always (?) be able to start the engine, even if the laptop battery is fully discharged. The big battery you have found - seems very big and will probably weigh 40-50 kg. Also - is it in America? Will cost heaps to get it to Australia.

A thought - you could probably save a lot of $$$ by using a battery the same as your starting battery, not an AGM deep cycle one. This is not ideal for your sort of use, but will work, there will be no problems with charging voltage, and you will have a spare battery in case the starting battery fails. You will still need the same isolator. The only difficulty I can see with going this way is that you may not have space outside the cabin to carry a wet cell battery.

Hope that helps

John

Hi Motoride

"If the alternator voltage is lower than AGM charging voltage,
for example, 13V,
AGM battery don't do charge or it just take more time?"

From your numbers the AGM needs at least 14.5 volts to fully charge it. The alternator will probably supply less than 14V (less when it gets hot.). This will provide some charge to the AGM, but it will be slow. I don't know how much power your projector requires so can't estimate how long it will take to replace that power.

I've thought further about using an ordinary cranking battery rather than a deep cycle AGM type - I think that in your situation I would go that way and avoid a whole lot of charging problems. Even the cheapest cranking battery will last at least a year, and save you a lot of money.

"If it take more time,does it take the same charging time of normal battery
of 12V charging voltage?"

No - because of the higher voltage required for the AGM, it will take a lot longer to charge it than to charge a normal wet cell battery. In fact, it will probably never be fully charged.

"So,it's more efficient to install 100Ah normal battery?
and this is why AGM parallel is not highly recommendable?"

Yes that's right. Paralleling an AGM with a standard wet cell battery is not ideal, just easy and cheap!


"As I know,AGM battery charging more quickly than normal battery
(But I don't know how fast it is),but it needs a higher charging voltage."

Yes - AGM batteries can accept higher charging rates than standard batteries, but to do this they need higher charging voltages.

"But,if I put normal battery parallel,it will take a long time to charge
(But I don't know how slow it is)

Which is more better? "

For your purposes adding a second battery, same as your starting battery, seems a good way to go. It will save you a lot of money, supply the power you need and avoid charging problems.

This may start an argument here because it's not the best way for most people, but in your case I think it's a good way to go. Certainly much cheaper and will probably perform very well for you.

Hope that helps

John

Oh.I need to find first how much Ah I need from battery.
1.Laptop
Input: 220V. 1.5A
Output: 16V. 4.5A

2.LED Projector(New technology)
Input: 220V, 1.5A. 68W.
Output: 14V. 4.5A

So,I need 4.5A+4.5A=9A per 1 hour?. roughly 30A for 3 hours?

And which is more quick to charge?
-charge 30A of 50A battery
-charge 30A of 100A battery

Is it bettery to buy 100A battery??

If it's same I prefer to buy 50A battery.

Cheaper price and more less Kg.

Carrying a little Kg will save fuel cost for 1 year. I think

Thanks for advice.
I already bought dc-dc inveter as like you said..

Actually,I have 1 laptop and 1 projector.

Projector is LED type,so super small size with low consumption,almost
same with laptop.

I try to make a Home Theator system in my Van with Car audio.
Watch a movie inside my car with big screen..Fantastic..!!

Wont be too big a screen in a Suzuki LOL


hope you dont watch it while driving


Cheers

Thanks for your opinion.
I got still confused ..
if it will take a lot longer to charge it than to charge a normal wet cell battery,
I have no reason to buy expensive AGM.
Is there any other speical reasons?
Maybe discharge rate is more slower than normal battery?

??

Also,if AGM take more time to recharge with low voltage,
isn't it better to install 100AH normal battery
than 50Ah AGM?
Because AGM is much more expensive..

To clarify -

1. An AGM will always charge faster than any wetcell battery, no matter what voltage is available.

2. If your Alternator only puts out 13.6 volt it will charge an AGM or a wetcell battery, it will just take longer than if teh Alternator puts out 14.4 volts.

3. If you buy a wetcell deepcycle, it's unlikely it will charge up during the days driving to replace the charge you use every night - an AGM will charge up while driving for 3 hours.

4. If you use 40 amphours every night, then a 50 amphour AGM will be worn out after a year, a 100 amphour AGM should last for several years at 40 amphours per night.

Oh.I see...
As I only intend to travel 1 year now,its OK if AGM worn out after a year.
Because 100 AGM is very heavy and expensive,
I want to try 70AH Fullriver AGM battery
(70Ah 230 AUD, 55Ah 200 AUD)

Q1)Problem is that where I should put the battery?
I see that AGM don't like heat ,so is it OK to put battery inside cargo space?
If it is,it will be very easy for cabling.
Main battery is located under front seat,so cabling will be very short and also
more easy to connect cigarrett socket for laptop.
But I don't know if it produce chemical vapor,as I will sleep in the car everyday.
Battery looks like totally sealed itself...

Q2) FULLRIVER 12V 70AH AGM DEEP CYCLE BATTERY
http://www.fullriver.com/products/admin/upfile/HGL70-12A.pdf

is this wet sell deep cycle battery or AGM battery you mentioned.,.

Q3)What I need to buy for isolator?
Redac isolator is OK to use?

Q4)Cable thickness.
I find that normal cheap Battery jumper cable is very thick.
Can I use this for cabling?

Q5)No need to put a fuse between?

Please,let me know.
I will buy those things tomorrow and install myself.

"Q2) FULLRIVER 12V 70AH AGM DEEP CYCLE BATTERY
is this wet sell deep cycle battery or AGM battery you mentioned.,. "

- ALL AGM batteries work well as DeepCycle



"Q5)No need to put a fuse between? "

- You MUST have a fuse as close as possible to BOTH Battery Positive terminals to avoid creating a fire hazard.