Jump to content
mrbigglebongs

Alternator AGM Charging?

Recommended Posts

Just upgraded to an AGM Leisure battery (thanks leaky lead acid) however will my alternator be able to charge it, if at all? Or, am I wasting my time because it's an AGM battery it'll require a specialized battery to battery style charger and my regular alternator won't get it anywhere with it.

 

Any thoughts? 

Edited by mrbigglebongs
  • Like 1

Share this post


Link to post
Share on other sites

Can't answer your question but just replaced mine and it as to be AGM because the car as Stop/Start system.

Share this post


Link to post
Share on other sites

Might help if you told us what car you've got and why you thought it was a good idea to go for an AGM. Does the car have stop/start and what sort of battery did it have

Share this post


Link to post
Share on other sites

Car's an older Euro 4 Diesel so it's got a regular alternator. Basically my last lead acid leisure battery became leaky when the cold weather hit and the acid has left a dreadful mess. Didn't want to risk it again.

Edited by mrbigglebongs

Share this post


Link to post
Share on other sites

Todays conundrum.

With the advent of modern technology most new and recent cars are equipped with stop start technology.

They will also have smart alternators which vary the charge the system requires. The car will also have either a EFB orAGM type of battery.

Most caravans will have a standard lead/acid battery .

Is there a problem mixing the two technologies?

Will the alternator default to the car battery therefor not charging the caravan battery enough?

Will the fridge suffer we connected for power when towing?

 

just come across this?

 

https://www.12voltplanet.co.uk/auxiliary-battery-charging-in-vehicles-with-smart-alternators.html?fbclid=IwAR17SIDcUTS5-aTBPayZKp7lc5o7LKxVfBzVrG_JBgXlHJaStCttDJwOMIM

Edited by MrRVW

Share this post


Link to post
Share on other sites
20 minutes ago, MrRVW said:

Todays conundrum.

With the advent of modern technology most new and recent cars are equipped with stop start technology.

They will also have smart alternators which vary the charge the system requires. The car will also have either a EFB orAGM type of battery.

Most caravans will have a standard lead/acid battery .

Is there a problem mixing the two technologies?

Will the alternator default to the car battery therefor not charging the caravan battery enough?

Will the fridge suffer we connected for power when towing?

 

just come across this?

 

https://www.12voltplanet.co.uk/auxiliary-battery-charging-in-vehicles-with-smart-alternators.html?fbclid=IwAR17SIDcUTS5-aTBPayZKp7lc5o7LKxVfBzVrG_JBgXlHJaStCttDJwOMIM

Good find!

Makes sense to me but then I am/was and electronics engineer.

About £150 for a 30A system box designed and made in Germany then.

Cables and fitting would of course be extra.

Glad I have a standard alternator as my car is pre Euro6.

I don't see the point of having a Gel battery in the van but this unit will be needed for either type of liesure battery as we learn that the Smart alternators back off when the starter batteries hit 80% capacity as so could leave your fridge un supplied for long periods.

GB

Share this post


Link to post
Share on other sites

My twopenneth:

: My car is Euro5 but it has a smart alternator. You can spot its action if you observe the voltmeter - when the foot comes off the throttle the voltage goes up, and vice versa.

 

:My CTEK charger will charge an AGM battery at 14.7 volts compared with 14.4 for a wet battery.

 

:If the car's ECU has been configured correctly it will detect when a trailer is attached and will modify the alternator behaviour to accomodate the auxiliary battery.

Share this post


Link to post
Share on other sites
6 hours ago, onewheelonmywagon said:

My twopenneth:

: My car is Euro5 but it has a smart alternator. You can spot its action if you observe the voltmeter - when the foot comes off the throttle the voltage goes up, and vice versa.

 

:My CTEK charger will charge an AGM battery at 14.7 volts compared with 14.4 for a wet battery.

 

:If the car's ECU has been configured correctly it will detect when a trailer is attached and will modify the alternator behaviour to accomodate the auxiliary battery.


How would/ do you know the ecu is correctly configured?

Can the ecu  detect that two batteries  of different technologies are connected  ?

Would the ecu default to the lead/acid/ wet battery and deprive the AGM battery of charge?

 

Or are we over thinking the problem?

Share this post


Link to post
Share on other sites
1 hour ago, MrRVW said:


How would/ do you know the ecu is correctly configured?

Can the ecu  detect that two batteries  of different technologies are connected  ?

Would the ecu default to the lead/acid/ wet battery and deprive the AGM battery of charge?

 

Or are we over thinking the problem?

 

Yes!

 

Voltage drop between the car alternator and caravan battery will mean that a wet caravan battery is very unlikely to be overcharged, or even fully charged.

Share this post


Link to post
Share on other sites
11 hours ago, GB1309 said:

 

I don't see the point of having a Gel battery in the van but this unit will be needed for either type of liesure battery as we learn that the Smart alternators back off when the starter batteries hit 80% capacity as so could leave your fridge un supplied for long periods.

GB

Err, a gel battery and AGM battery are different, the OP was talking about AGM (absorbed glass mat) which uses a limited amount of liquid acid.  Gel mixes the acid with a thickening agent.  Both are Maintenance Free, the main advantage of AGM is that they stand a deeper depth of discharge than flooded Lead Acid

 

How does the smart alternator differentiate between the caravan battery and the car battery? To charge the van battery it must be effectively "paralleled" with the car system, so you get a balance between the two systems.  The car system will be supplying the caravan battery and therefore lower the voltage in the car system, so if the smart alternator stops charging at 80%, it'll be across both batteries. Empirical proof is that my Euro 6 Kuga when towing auto stop/start will not kick  in for a long time (but it will eventually kick in), and the pre-conditions for SS include battery voltage being high enough

Share this post


Link to post
Share on other sites

I don't have stop/start but the Jeep has an AGM battery as standard.  I know that in caravans if you have an AGM battery charging from a solar panel, the controller needs to be set to AGM and not lead acid. 

I am guessing but if a car was designed to operate with a lead acid battery then maybe it will not be able to charge an AGM battery correctly?

Share this post


Link to post
Share on other sites

a lot of AGM batteries come to an untimely end because they dont get charged properly, so you really do need to find out the correct charging regime for your particular battery and ensure that the caravan charger, car charging and any battery charger has the correct charging profile.

 

This is what happens to my caravan battery, over a journey of around three an a half hours. The car is an S-Max Euro6 with smart charging fitted with a Ford towing module.

The initial 13.7v is the van charger, then the motor mover was used. Car connected and driven for around 130 miles. The dip at the end is the motor mover again.

 

image.thumb.png.244d35e15cffa1cc4f43e74a35708b4e.png

and this is what the fridge supply looked like over the same journey. The drop to zero are probably when the stop/start activated



 

 

image.png

Edited by matelodave

Share this post


Link to post
Share on other sites

Do not know if it helps on charging but I have a new AGM on my S/S  car and I checked charging voltage and was 15 volt,  do not recall previous non Stop/Start cars of mine being so high.

Edited by David 38

Share this post


Link to post
Share on other sites

I've come in a bit late on this, but the first question that you should ask yourself is why is the battery leaking and from where ?

There could be several causes:

1) A split battery case, unusual these days unless it's been dropped etc.

2) Overfilling with distilled water when checking electrolyte, it should be just over the top of the plates not to the top of the cells, under these circumstances, due to heat from the engine bay, slight increase in heat and gassing whilst charging, electrolyte will escape, again unusual these days due to most batteries being sealed, to a lesser or greater degree.

3) A faulty cell or cells where excess gassing is pushing electrolyte, as small droplets, out of the battery, but under this scenario other problems would be expected, i.e. reduced cranking speed, a higher rate of self discharge.

4) This is alternator overcharging, which sometimes catches folk out, consequently ruining the new battery, this is where the alternator regulator is faulty and is not reducing the charge as the battery nears its fully charge state, this leads to excessive gassing, excess plate heat which tends to distort the plates and sometimes also causing loss of the paste from the plate matrices.

 

Ref. latest tech 'smart' alternators and 'smart' chargers, if you have a totally flat battery, i.e. a load left on for a day or two, ( but not for a few weeks ) you will most likely find that neither will start to charge  the battery due to them needing to 'see' a minimum voltage, a couple of ways around this are to use a 'dumb' charger for half an hour or so to up the voltage sufficiently enough to enable the smart equipment to work, or piggyback the discharged battery to a reasonable charged battery connected to the smart charger, then disconnect the donor battery after half an hour or so and let it complete the charge cycle.

The same process is used when using jump leads, don't attempt to start the car with the flat battery until running the donor car at moderate revs for 10 - 15 mins, then start the flat car leaving the jump leads connected for  another 10 mins, next switch on headlights and heater fan before disconnecting the jump leads, this helps to prevent a volt spike when disconnecting the leads.

 

I'm just experimenting with some battery acid  at 35% to anodize some small aluminium parts for a modified motorcycle at home.................. but that's another story. :o:rolleyes:

 

 

Share this post


Link to post
Share on other sites
5 hours ago, Guzzilazz said:

Err, a gel battery and AGM battery are different, the OP was talking about AGM (absorbed glass mat) which uses a limited amount of liquid acid.  Gel mixes the acid with a thickening agent.  Both are Maintenance Free, the main advantage of AGM is that they stand a deeper depth of discharge than flooded Lead Acid

 

How does the smart alternator differentiate between the caravan battery and the car battery? To charge the van battery it must be effectively "paralleled" with the car system, so you get a balance between the two systems.  The car system will be supplying the caravan battery and therefore lower the voltage in the car system, so if the smart alternator stops charging at 80%, it'll be across both batteries. Empirical proof is that my Euro 6 Kuga when towing auto stop/start will not kick  in for a long time (but it will eventually kick in), and the pre-conditions for SS include battery voltage being high enough

Err....well thanks for putting me right on the battery distinctions....😬

Anyway, if I dare risk another opinion I'd say the interface box in question is probably a DC/DC converter and hence will take a range of input voltages say 9-15v and output the correct voltage to charge a peripheral leisure battery of whatever type. I'd say it will likely be transparent to the smart alternator. 

Happy to be shot down on this one. 

GB.

Share this post


Link to post
Share on other sites
1 hour ago, GB1309 said:

Err....well thanks for putting me right on the battery distinctions....😬

Anyway, if I dare risk another opinion I'd say the interface box in question is probably a DC/DC converter and hence will take a range of input voltages say 9-15v and output the correct voltage to charge a peripheral leisure battery of whatever type. I'd say it will likely be transparent to the smart alternator. 

Happy to be shot down on this one. 

GB.

 

I doubt whether there's a DC-DC converter, I can't believe they'd want to spend money on a highish current converter... In any case it would still result in increased current usage in the car - and hence more output from the alternator.  I think it's much more likely that it's just a simple 12v connection, with all the voltage drop along the length of cable involved... :)

Share this post


Link to post
Share on other sites
24 minutes ago, Guzzilazz said:

 

I doubt whether there's a DC-DC converter, I can't believe they'd want to spend money on a highish current converter... In any case it would still result in increased current usage in the car - and hence more output from the alternator.  I think it's much more likely that it's just a simple 12v connection, with all the voltage drop along the length of cable involved... :)

Quote from data on linked unit type:

"The charging converters excel by their compact design, low weight (high-frequency switch mode technology) and powerfully dimensioned power components for safe operation."

I rest my case. ;)

Share this post


Link to post
Share on other sites
16 hours ago, GB1309 said:

Quote from data on linked unit type:

"The charging converters excel by their compact design, low weight (high-frequency switch mode technology) and powerfully dimensioned power components for safe operation."

I rest my case. ;)

Thanks, very  interesting...:D

Share this post


Link to post
Share on other sites

 

  • Thanks 1
  • +1 1

Share this post


Link to post
Share on other sites

Well, I live and learn. I had never heard of a EFB battery. However, I found this :-

 

EFB batteries are an enhanced version of standard wet-flooded technology. The primary benefits of EFB technology are improved charge acceptance and greater cyclic durability when operating in a reduced state of charge (typical of Stop Start applications). As an approximation, EFB batteries will provide 85,000 engine starts, compared to 30,000 starts from standard flooded product.

 

Mentioned in the video is a Euro 6 vehicle.

Anyone who is interested can find information on Euro 6 HERE

Edited by BOAC
Add url

Share this post


Link to post
Share on other sites
43 minutes ago, MrRVW said:

 

I fully understand the concept of using a boost converter to increase the voltage to something that is more acceptable for battery charging or even trying to run the fridge, but what it cannot do is boost the current as well.  So don't believe that you'll get 30amps out of the thing (or whatever else it's rated at) unless all the cabling and the alternator can deliver a lot more than 30amps to the input of this magic box.

 

If you want say 120watts for your fridge and you want 10amps at say 14.4v for your battery (=144watts), then you are trying to deliver near enough 250watts at 14.4 v, which is roughly 17.5amps but if your alternator is only shoving out 12.4v and you are losing say one or even two volts between the alternator and the box, you may only get around 11 volts at the input. Which means you got to try and deliver nearly 23amps (possibly more to take up conversion inefficiencies) to the box .

That's also assuming that the alternator has enough power left over whilst it's trying to charge the car battery, running the lights, heater and the miriad of other electrical loads that are being imposed on it.

 

If you cant deliver the current, then although the unit will improve the voltage that's delivered to the battery, you might only get 5 or less amps instead of the 10amps or so that you were hoping for.

Edited by matelodave

Share this post


Link to post
Share on other sites
3 minutes ago, matelodave said:

I fully understand the concept of using a boost converter to increase the voltage to something that is more acceptable for battery charging or even trying to run the fridge, but what it cannot do is boost the current as well.  So don't believe that you'll get 30amps out of the thing (or whatever else it's rated at) unless all the cabling and the alternator can deliver a lot more than 30amps to the input of this magic box.

 

If you want say 120watts for your fridge and you want 10amps at say 14.4v for your battery (=144watts), then you are trying to deliver near enough 250watts at 14.4 v, which is roughly 17.5amps but if your alternator is only shoving out 12.4v and you are losing say one or even two volts between the alternator and the box, you will only get around 11 volts at the input. Which means you got to try and deliver nearly 23amps to the box and that's assuming that the alternator has enough power left over whilst it's trying to charge the car battery, running the lights, heater and the miriad of other electrical loads that are being imposed on it.

 

If you cant deliver the current, then although the unit will improve the voltage that's delivered to the battery, you might only get 5 or less amps instead of the 10amps or so that you were hoping for.

Absolutely agree! Sterling Power produce more misleading bull than any company I've seen with all their "magic boxes"

Share this post


Link to post
Share on other sites

From my admittedly little knowledge on this subject I would guess that if the car alternator was set up to charge a wet battery and an AGM required a higher voltage.  If an AGM was used in the caravan then, with the voltage drop as well.  The caravan battery will be getting little or nothing.  Unless a voltage converter was utilised.

 

My situation is a little different.  Tow car has one AGM starter battery plus a smaller AGM for reasons I don’t understand.  So perhaps, if the car charges at a higher voltage than it would for a wet battery, it may be at a more acceptable voltage by the time it reached the caravan wet battery.   I haven’t tested anything but it all seems to work well.

 

Another thought for the OP.  Is an AGM wise for the caravan if, when on hook up, the vans charger is balanced for a wet battery?

 

John

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...