HELP - AGM Dual Battery or Bttery pack

[tinkera Member Find all posts View Profile Close tinkera]

Re: HELP - AGM Dual Battery or Bttery pack

HI ALL.Bit of a tip take it or leave it.I here people saying they run there fridges etc.for 2-3 days at a time I just hope your putting some charge back in daily,drains like that are battery killers.Speaking from experience.TINKERA.

[Deeptank Senior Member Find all posts View Profile Close Deeptank]

Re: HELP - AGM Dual Battery or Bttery pack

My battery set up at the bottom of the page at this link - scroll right down to the bottom of the page: viewtopic.php?f=16&t=5539&st=0&sk=t&sd=a&hilit=thu mper

Works a treat too... Easily four days for a 40L Waeco. A 'proper' deep cycle battery is designed to do just that - cycle deep.

[bitdist Senior Member Find all posts View Profile Close bitdist]

Re: HELP - AGM Dual Battery or Bttery pack

Works a treat too... Easily four days for a 40L Waeco. A 'proper' deep cycle battery is designed to do just that - cycle deep.

While deep cycle batteries can take deeper discharges than standard batteries, it is still true that the more you discharge and the deeper you discharge the shorter the life of the battery

Here is an example graph showing the discharge cycle of a deep cycle battery (the graph is charging/discharging cycles vs depth of discharge)


You will notice if you let it run right down you will get a short life out of it. If you look after a good deep cycle battery (dont let it get too discharged/hot etc) you should get 6-8 years out of it

cheers

[Deeptank Senior Member Find all posts View Profile Close Deeptank]

Re: HELP - AGM Dual Battery or Bttery pack

I hear what you're saying, but the overall amount of amps available will be the same as the graph is more or less linear.

You can drain it by 25% about 2,000 times - or by 75% about 600-odd times, which both amount to roughly the same amount of amps. Of course you'll get less cycles the further you discharge it as the chemical reaction inside the battery has a finite life span.

Having said that, if on your third discharge you drain the battery well below the manufacturer's recommended minimun (10.5v-11.0v depending on battery make/model) then you can shaft it when it's still pretty much brand new.

As a rule of thumb, I'd never go below about 80% discharge, but again, some batteries are simply more resilient than others.

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

Re: HELP - AGM Dual Battery or Bttery pack

I have an ABR Flyer 3 battery box. The question is do I put in an AGM battery at up to $400 for 105AH or do I go for a SEALED deep cycle battery of similar size for about $200 + ish? The battery box will be secured to the rear floor behind the passenger seat. Some tell me this latter is an explosion risk and others say no- most boats run deep cycle batteries below deck and some cars have batteries in the boot or under seats [ think old VW]. I know the benefits of AGM but I am not sure that their extra cost is justified- a 5- 10 year life is not necessary for me. Confused. Neil :?:

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Re: HELP - AGM Dual Battery or Bttery pack

Hi 404pug,

The main advatage of a AGM battery over a deep cycle battery is it has a lower internal impedance
and will therefore charge faster. A deep cycle battery that has been deeply discharged can take up to 8 -12
hours to charge to 80% using an alternator. An AGM battery will take about 2.5 - 3 hours.

If both are fully sealed, and provided they are not overcharged to the point of gassing, an explosion
shouldn't be a problem.

Cheers
LeighW

[bevwone Member Find all posts View Profile Close bevwone]

Re: HELP - AGM Dual Battery or Bttery pack

nagalim,
For this reason some maunfacturers don't recommed the use of AGM batteries under the bonnet. Though there are others that do advertise the use of their AGM batteries for under bonnet applications.

Thanks Leachy,

I currently have a dual battery with a redarc isolator. I am looking at changing my aux battery as my current one is just about had it.

I have a Challenge Camper with a AGM battery in it and a Projecta IC1500 (http://www.projecta.com.au/catalogue.../asset_id/173/) charger. The aux battery and CT battery are connected via anderson plugs.

Because I have to select the type of battery charging on the Projecta - and I have a Calcium battery as an Aux and a AGM in the CT - I am unable (or am I?) to use the battery charger with the two connected by the anderson plug. I don't want to stuff the charger or the batteries up by trying to charge two different types of batteries at the same time... So I am thinking of putting a AGM under the bonnet of the Prado.

I have not been able to find any AGM batteries that will still offer the warranty when placed under the bonnet. Can you point me in the direction of one that offers this protection.

I am aware of the weight issues - I figure a 100 A/H at about 30kg is only 5 or so heavier than what I already have so this should not be too much of an issue.

Appreciate any advise.

Bev

[leachy_9 Advanced Member Find all posts View Profile Close leachy_9]

Re: HELP - AGM Dual Battery or Bttery pack

Thanks Leachy,

I currently have a dual battery with a redarc isolator. I am looking at changing my aux battery as my current one is just about had it.

I have a Challenge Camper with a AGM battery in it and a Projecta IC1500 (http://www.projecta.com.au/catalogue.../asset_id/173/) charger. The aux battery and CT battery are connected via anderson plugs.

Because I have to select the type of battery charging on the Projecta - and I have a Calcium battery as an Aux and a AGM in the CT - I am unable (or am I?) to use the battery charger with the two connected by the anderson plug. I don't want to stuff the charger or the batteries up by trying to charge two different types of batteries at the same time... So I am thinking of putting a AGM under the bonnet of the Prado.

I have not been able to find any AGM batteries that will still offer the warranty when placed under the bonnet. Can you point me in the direction of one that offers this protection.

I am aware of the weight issues - I figure a 100 A/H at about 30kg is only 5 or so heavier than what I already have so this should not be too much of an issue.

Appreciate any advise.

Bev

Bev,
I don't have a silver bullet for under bonnet AGMs. The two manufactures that I can think of at the moment that may warrant AGMs in underbonnet applications are Optima and Lifeline. The issue with Optima will be the relative low Ah capacity available and while Lifeline make excellent batteries they are very expensive. If you want to use an AGM the best option is in the cabin, so long as you have the space.

Paralleling your Calcium Aux. and AGM CT battery and charging via the Projector will not damage the charger.
The calcium setting on your charger has an equalisation voltage of 16V which is above most manufacturers recommedation for AGMs. I would suggest that if you want to occassionally charge the batteries in parallel with the projector charger it is safe to do so with the charger on the AGM setting.
This set up will probably cause the AGM to be held at bulk voltage longer as the charger continues to see the current draw of the calium battery. Since the bulk voltage on the AGM setting is only 14.4V this shouldn't cause problems so long as you limit the duration of charging to say 12hrs.

Leachy

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

Re: HELP - AGM Dual Battery or Bttery pack

The main advatage of a AGM battery over a deep cycle battery is it has a lower internal impedance
and will therefore charge faster. A deep cycle battery that has been deeply discharged can take up to 8 -12
hours to charge to 80% using an alternator. An AGM battery will take about 2.5 - 3 hours.

Hi LeighW, while it can take 8 -12 hours to recharge a deeply discharged flooded wet cell battery from an alternator BUT, the long recharge time would not be a direct result of using an alternator but would be a result of some form of problem with the dual battery set up and if an AGM of the equivalent size and discharged down to the same level, was put into the same set up, it would also take many more hours to recharge.

I take it your source for this info is a site that is supposedly posting up “Factual” data about charging different types of batteries. The problem is that this site also promotes the sale of their brand of AGM batteries and while the info is correct, it is also intentionally grossly misleading.

A deeply discharged battery would indicate that the battery, in this case a flooded wet cell deep cycle battery, was being charged up from it’s safe low level of 30% SoC.

In the case of a flooded wet cell deep cycle battery being charged by an alternator, you could literally connect this type of battery directly to the output of the alternator and no matter how big the alternator is, a flooded wet cell battery, deep cycle or cranking battery, will NOT be damaged by high currents it could draw from that alternator because flooded wet cell batteries self-regulate the amount of current they will draw while charging, no matter how many amps are being applied ti them.

On the other hand, very, VERY few AGM batteries could safely tolerate the currents needed to fully charge them from 30% SoC in 2.5 to 3 hours.

With the exception of a small number of genuine Automotive grade spiral type AGM batteries, like Optima, Odyssey and the Exide Orbital, most of the AGMs in RV use were never designed for automotive use.

Most AGMs are designed for RAPS ( Remote Area Power Supplies ) and UPS ( Uninterruptible Power Supplies ) where they are charged by low current, voltage controlled battery chargers.

As such, these types of AGMs have a maximum current limit while charging and this limit is usually some where between 20 and 30% of the total Ah capacity of the battery, depending on the brand.

For example, Fullriver AGMs, one of the most popular batteries in RV use, have a maximum charge current limit of 20%, that means a 100 Ah Fullriver battery must not recharged with currents higher than 20 amps.

So to charge an AGM from 30% to full means you need a constant current charge of 28 amps, but it’s not that straightforward. Both AGMs and flooded wet cell batteries will draw much higher currents the lower they are and while flooded wet cell batteries are designed for this sort of charging, most AGMs are not.

There is a lot more to the differences between these batteries but the point is be careful of the “Factual” data you get off some of the seller’s web sites.

[tinkera Member Find all posts View Profile Close tinkera]

Re: HELP - AGM Dual Battery or Bttery pack

HI ALL.I know this has been done to death but why is there such a wide field of views :? I know battery companies have there own agender but gees it makes it confusing for the average joe.Reading this I must have the worst combination CALCIUM crank two AGM,S aux fed with a SOLENOID.CHEERS TINKERA.

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

Re: HELP - AGM Dual Battery or Bttery pack

Hi tinkera, no such thing as a bad combination of batteries when you use an alternator as the primary charge device.

an alternator can charge any combination of batteries and at each battery’s optimum charge rate, based on the voltage output of the alternator.

Mix your batteries as much as you like, your won’t have a problem.