Amp Hr Battery Rating

[Wilko76]

Hi Guys

How can you tell what the amp/hr rating of your aux battery is?

[bazooked]

should be a sticker on ur battery?

[-Scott-]

Not all automotive batteries display an Amp-hour (Ah) rating, because most buyers are interested in cold cranking capacity (CCA) or reserve capacity (RC.) Neither are directly related to Ah rating.

[MART]

Probably arround 63 amp hours going by size,we use them at work,slightly different style,they are discharge batteries,Cheers Paul.

[shamozzle]

Some batteries, like the Delkor, will have a sticker that measure ampere hours and a reserve capacity in minutes. The specs on mine rae 65A/h over a 20 hour cycle. Reserve capacity is usually measured in minutes and in my case is 115 mins.

Cheers,

Chris.

[pongo]

Some batteries, like the Delkor, will have a sticker that measure ampere hours and a reserve capacity in minutes. The specs on mine rae 65A/h over a 20 hour cycle. Reserve capacity is usually measured in minutes and in my case is 115 mins.

Cheers,

Chris.

mine has something similiar. can you explain the 65a/h over the 20 hr cycle a bit more for me please

Thanks

[festy]

The battery will deliver 65 amp-hours over a period of 20 hours in a normal 'cycle'.
This means you can draw 3.25 amps constantly for 20 hours (3.25 amps x 20 hours = 65 ah).
20 hours is the standard for measuring ah capacity.

If you tried drawing 65 amps, it would probably not last an hour though.

[HotFourOk]

Also, a deep cycle battery should not be taken past 50% discharge if you want it to live for a long period.

Yes, they are good at cycling repeatedly down to 50% charge.. but anything over this and it will begin to die.

So, a 100Ah battery should only be used to about 50Ah capacity before being cycled.

To get the most out of your battery, you should use a smart charger when possible so it charges to the best of its capacity, rather than just relying on your alternator alone.

[Wilko76]

Thx

The battery has a sticker sayong 105ah @ 20 hrs.

It is controlled by a little box made by tjm. What does this actually do? Does it manage the dual battery?

[-Scott-]

To get the most out of your battery, you should use a smart charger when possible so it charges to the best of its capacity, rather than just relying on your alternator alone.

Until you provide further information, I call BULLSHIT!

There's this depressingly pervasive "wisdom" circulating in off-roading/camping circles that an automotive charging system is incapable of fully charging a lead acid battery.

BULLSHIT!

Drunken diatribe follows.

A 12V lead acid battery is fully charged when it's terminal voltage (no load, long time after charging/discharging) is 12.6V. I measure this regularly, on both the batteries under my bonnet.

The problem is NOT a fault of the charging system, it's a fault of the usage patterns. Your charging system is designed to recharge a shallow "starting" discharge, and supply ALL the current your car requires while driving - ignition, engine management, difflock compressor, lights, ventilation, stereo, power windows, power mirrors, power sunroof, electrically adjustable heated seats... Fast recharge of a severely discharged (> 10% discharge) battery is not part of the design spec.

The problem comes when you run your fridge all night, and only drive for a few hours each day. When the battery is at 50% discharge, it will accept a high charge rate, and charge quickly. The higher the state of charge, the lower the charge rate from an automotive charging system. So charging from 50% to 70% is MUCH faster than charging from 70% to 90%, and that last 10% takes longer again - but your alternator WILL do it, if given the opportunity.

So, while on your one or two week touring trip your auxiliary battery WON'T be fully recharged every day. But, on a longer drive (like returning home) your aux will be better charged. When/if your 4by returns to regular commuter duties, and your fridge isn't draining your aux every day, your charging system WILL fully charge your aux battery again.

If you're a real fanatic, there are in-car switch mode "smart" chargers which will recharge your second battery faster than your alternator system can. If you're aware of the limitations of your charging system, and you behave accordingly, you don't need it.

If you're not having trouble at the moment, don't worry about it.

Scott

[HotFourOk]

Taken from http://www.fridge-and-solar.net/agm.htm

They have some very helpful articles, though I cannot directly comment on the accuracy of them.
They might have thier own agenda like most people... I'm not sure.

I know that my charging system struggles with the task of charging both my batteries.. And there's not much I can do, bar put it on a charger.

[MART]

Hotfourok,can't you upgrade your alternator,I run a UNI POWER alt which pumps out 220 volt dc,charges my batteries easy as,also provides the ability to weld,It will run 3.25 rods,you adjust the amps by reving the motor,also has a 3 pin plug for power tools and fluro lights,distributed in W.A. Cheers Paul.

[-Scott-]

Taken from http://www.fridge-and-solar.net/agm.htm

They have some very helpful articles, though I cannot directly comment on the accuracy of them.
They might have thier own agenda like most people... I'm not sure.

I know that my charging system struggles with the task of charging both my batteries.. And there's not much I can do, bar put it on a charger.

Yep. Common source for this argument.

A bit about Alternators.

Standard car and truck alternators are designed, for various good reasons to recharge car batteries to only 70-80%.

Big statement - where's the evidence?

Really, standard alternators are designed primarily to top up quickly the surprisingly small amount of energy that is removed from the battery by the starter-motor on engine start up, and then to keep up with all your accessories, radios, head lights etc,

Agree 100%.

They were never designed to recharge deeply discharged batteries,

...quickly...

and they fall short in this area unless modified or replaced with a specialised charging alternator, and smart multi stage regulator.

I like Fridge & Solar, and love their prices and service. But I believe this argument is aimed at the long term tourer/grey nomad market who want to draw a LOT from their batteries EVERY DAY and recharge them quickly EVERY DAY - for weeks or months on end.

For the average OL member, who runs a fridge over the weekend and drives inbetween, a decent second battery (like a Full River AGM from Fridge and Solar ) and a decent alternator (70 or 80A) is sufficient.

For somebody who runs two or more fridges, camp lights, inverters for laptops/TVs/DVD players/other battery chargers, and camps for extended periods in one spot with only occasional short drives - talk to Val at Fridge and Solar (or PM drivesafe at Outer Limits 4x4?)

If you understand the limitations, an alternator is all that is required by many people.

Another 2c,

Scott

[HotFourOk]

Hotfourok,can't you upgrade your alternator,I run a UNI POWER alt which pumps out 220 volt dc,charges my batteries easy as,also provides the ability to weld,It will run 3.25 rods,you adjust the amps by reving the motor,also has a 3 pin plug for power tools and fluro lights,distributed in W.A. Cheers Paul.

Short answer no. As told by the locak auto sparky.

My alternator has a vacuum pump on the back which severly limits upgrade options.

I also can't install a second one due to power steering and air con pulleys.

However, I did see that the Mitsubishi Delica has a 90 or 100A alternator.. So I have to look into it.

And Scott, I agree with you about that site referring to most users as very heavy ones. They maybe are referring to a user with a large bank of deep cycles that require charging... not just one or two 'small' batteries that we have in terms of things.

[festy]

You should be able to replace your alternator with a late model commodore/falcon one (will need to swap pulleys, make brackets etc) and use an electric vacuum pump instead of an alternator-driven one.
Electric vacuum pumps were used on a bunch of different american v8s in the 80s due to insufficient manifold vacuum - you should be able to get one from an auto electrician, repco etc. With one of those, you should be able to run any alternator you like.

[HotFourOk]

Someone said on here a decent vacuum pump would set you back $600

Has anyone ever used an electric vacuum pump instead??

I thought if it was that easy, a lot of the Cruiser/Patrol guys especially would have gone down that route.

[festy]

http://martelbrothers.com/catalog/Elect ... -8787.html $269US for a kit

Crane make a vacuum reserve system for about $110

there seems to be a few on ebay (us)
http://cgi.ebay.com/ebaymotors/Electric ... dZViewItem

http://cgi.ebay.com/ebaymotors/Drag-Rac ... dZViewItem

and some pulley driven ones too -
http://cgi.ebay.com/ebaymotors/NOS-83-9 ... dZViewItem
http://cgi.ebay.com/ebaymotors/1988-93- ... dZViewItem
http://cgi.ebay.com/ebaymotors/NOS-Engi ... dZViewItem
http://cgi.ebay.com/ebaymotors/VW-TDi-1 ... dZViewItem
http://cgi.ebay.com/ebaymotors/Ford-Pow ... dZViewItem

$107US for these ones - http://www.dieselspecialists.net/nonpow ... tml#vacuum