Std battery vs agm battery

[ADD150N]

Hi, I currently have a bosch s5 008 battery 77ah and was thinking of fitting a varta e39 70ah agm battery , I don't drive the car that much, but do want my dashcams to record in either low bit rate or just motion at night viofo a139, what im wanting to know is what battery would allow the dashcams to last longer before voltage cutoff, a 70ah agm down to 11.8v VS a 77ah std to 12.4v , thank you.

 

[kamkar]

You should not run a lead acid battery below 12.2 volts, which is said to me 50 % of one of those, the AGM batteries on the other hand are safe to discharge a bit lower.
So i am going to guess the AGM battery, but i am guessing here.

Both will happily run your camera over night ( 12 hours )
If you run your battery all the way down, it also take some driving to restore it to 100 %, but how long a drive that actually need to be i have no idea.
But you need to strike some balance in between how much you drive ( charge ), and for how long that charge last in parking mode.

 

[kamkar]

Also your alternator while it can recharge a flat battery while you drive, it is not really meant to be used like that, but you need to drive for about 1 hour at highway speeds.
Also hitting a flat battery with a high charge rate are not really healthy either, if a battery are really flat it is recommended to slowly bring it up to 12.5 volts, before hitting ( charging ) it harder like the alternator would do.

 

[Nigel]

I don't drive the car that much,

If you don't drive much then the AGM will definitely win because it will charge a lot faster, so will have more charge when you park.

But don't expect a 3 channel camera to run for days after a short drive, you will need to drive every day to keep it going 24/7.

 

[kamkar]

I think the A139 only do 2 camera ( front and rear ) when in parking mode ?

 

[Nigel]

I think the A139 only do 2 camera ( front and rear ) when in parking mode ?

Need someone with a hardwire kit to answer that!
I had assumed it records all 3, but it would be a nice option to be able to depower one or two for a longer record time.

 

[ADD150N]

Cheers , Iv only got the 2ch one, I'm going to order the battery tom, I will drive it more after lockdown, my old job i used to drive a vw transporter around the whole UK 2000 miles per week, so driving isn't quite as pleasurable anymore.

 

[Nath]

Need someone with a hardwire kit to answer that!
I had assumed it records all 3, but it would be a nice option to be able to depower one or two for a longer record time.

Don't know if the DR isn't turned off after some time (i checked only few minutes) but otherwise it records all three channels in parking mode, at least LowBitrate in my case.

 

[Mtrev]

I’m assuming some people have swapped from a standard lead acid to agm battery successfully?

Cars tend to run a different charge profile when they have an agm fitted, I know on BMW’s that some cars that came with lead acid could have an agm fitted but had to have their coding changed afterwards otherwise the life of the battery may be reduced.
On battery chargers they are usually set at a slightly higher voltage for agm in order for the battery to reach its full charge.

 

[ADD150N]

I’m assuming some people have swapped from a standard lead acid to agm battery successfully?

Cars tend to run a different charge profile when they have an agm fitted, I know on BMW’s that some cars that came with lead acid could have an agm fitted but had to have their coding changed afterwards otherwise the life of the battery may be reduced.
On battery chargers they are usually set at a slightly higher voltage for agm in order for the battery to reach its full charge.

I have vcp for my scirocco so ill programme it in to the car, cheers.

 

[Nigel]

I’m assuming some people have swapped from a standard lead acid to agm battery successfully?

Cars tend to run a different charge profile when they have an agm fitted, I know on BMW’s that some cars that came with lead acid could have an agm fitted but had to have their coding changed afterwards otherwise the life of the battery may be reduced.
On battery chargers they are usually set at a slightly higher voltage for agm in order for the battery to reach its full charge.

There is no need to change anything when replacing a standard lead acid battery with an AGM battery.

Some cars do have AGM modes to take advantage of their faster charging, generally with the aim of improving the score on the standard emissions tests, maybe by doing most of the charging in one part of the test rather than another more critical part.

I think the battery chargers only have an AGM setting because it helps sell them at a higher price!
Although there are charging differences, for example there is no real need to charge at a high voltage for a while to "boil the electrolyte" to clean the plates, because AGM plates don't need cleaning. A standard battery charger wont do any harm though.

 

[Mtrev]

There is no need to change anything when replacing a standard lead acid battery with an AGM battery.

Some cars do have AGM modes to take advantage of their faster charging, generally with the aim of improving the score on the standard emissions tests, maybe by doing most of the charging in one part of the test rather than another more critical part.

I think the battery chargers only have an AGM setting because it helps sell them at a higher price!
Although there are charging differences, for example there is no real need to charge at a high voltage for a while to "boil the electrolyte" to clean the plates, because AGM plates don't need cleaning. A standard battery charger wont do any harm though.

When I was at bmw they released a document to tell us to change our charger voltage levels to a higher level because they weren’t able to reach 100% at a lower level. They also emphasised the requirement to have the car correctly coded for the correct battery type to prevent failure. I don’t know the technicalities of exactly why though.

I haven’t monitored the actual alternator charging voltages as I’ve never really needed to.
I know the charge rates are varied on cars with alternator control and they never aim to fully charge the battery, alternator charge rate is only maximised on overrun and under braking for efficiency and brake regeneration.

 

[SawMaster]

I think the A139 only do 2 camera ( front and rear ) when in parking mode ?

Nope, all 3 cams record and all 3 cams do the motion detect function. As tested with mine using a HWK That was a pleasant suprise indeed, as many cam's M/D function only happens on the front cam.

The standard charging profile for a L/A car battery isn't optimum for an AGM battery but it's close enough to not make much of a difference, so you can drop an AGM type in with any car and get it's benefits almost fully. The main advantages of AGM for our use is that it can run our cams longer when parked as well as that it will charge more quickly when driving without as much wear-and-tear on the battery. Because of this it should also give you a longer service life. The reverse isn't a good idea- if your car came with an AGM you don't want to swap to L/A as that can overcharge and 'cook' the battery. If your car's charging profile can be set to different battery types then of course you should do that- your dealer will know.

Phil

 

[Nigel]

When I was at bmw...

It is very important to change the setting if you go the other way, from AGM to standard!
Going to AGM should be OK, you just don't take full advantage of AGM if you don't have all the smart charging features.

because they weren’t able to reach 100% at a lower level.

An AGM will reach 100% at quite low charge voltage, eventually. If you want to take full advantage of the faster charging AGM is capable of then maybe a higher voltage makes sense for the last few % charge, although you should check the specifications of individual battery models if you are going close to the limits, not all AGM batteries are the same.

Maybe the chargers had something in them that monitored charge rate and got confused by the AGMs not reacting as expected.

I know the charge rates are varied on cars with alternator control and they never aim to fully charge the battery, alternator charge rate is only maximised on overrun and under braking for efficiency and brake regeneration.

Yes, there are various things can be done with an AGM that you wouldn't do with a standard due to the faster charge rate and reduced wear when being charged/discharged lightly. Stop-Start systems being the main reason for using AGM.

If your car's charging profile can be set to different battery types then of course you should do that- your dealer will know.

For dashcam use, maybe you want your car to fully charge the battery, not leave it only 80% charged because you are using stop-start in an urban commute. Possibly best not to change the charging profile?

 

[IAmATeaf]

My car with an AGM battery starts complaining if the battery dips below 12v and maximum charged voltage is only 12.4v so for a hard wired kit there’s not that much range/scope for AGM batteries.

 

[SawMaster]

For dashcam use, maybe you want your car to fully charge the battery, not leave it only 80% charged because you are using stop-start in an urban commute. Possibly best not to change the charging profile?

When it comes to modifying anything, I always tell folks that unless you know as much or more than the engineers who designed it, then maybe you should stay with what they intended

But if you educate yourself regards the specific matter, and understand how things work with each other, then you can almost always surpass what those engineers did. They were given constraints to work within which may not apply to your situation, or your situation may not be what they designed for. Just know what you're doing before you go mucking around or you can make things worse instead of better.

Phil