Propex heater with split charger for smart alternators

[Deleted member 5731]

Good evening,

A new split chargers for smart alternators usually push 15 to 15.3v to AGM batteries as results Propex heater sensing high voltage even in a switched off position.
Is there any work around for the issue?
Thanks

 

[wildebus]

Good evening,

A new split chargers for smart alternators usually push 15 to 15.3v to AGM batteries as results Propex heater sensing high voltage even in a switched off position.
Is there any work around for the issue?
Thanks

I would say you need to sort out your split charger as the voltage is too high generally. Fix that issue first and the Propex issue will go away by itself.

 

[Deleted member 5731]

Anyone might be interested I have contacted Propex and they replied back:

Heaters manufactured from the beginning of this year (2020) have a revised compliant PCB which has modification, one of which is the increased high voltage cut-out setting to 17v.....

I would say you need to sort out your split charger as the voltage is too high generally. Fix that issue first and the Propex issue will go away by itself.

I might be wrong but what I heard is that AGM batteries should be bulk charged @ 14.8-15.3 this way they get healthy lifespan and reduce buildup of sulfates etc

 

[wildebus]

Anyone might be interested I have contacted Propex and they replied back:

Heaters manufactured from the beginning of this year (2020) have a revised compliant PCB which has modification, one of which is the increased high voltage cut-out setting to 17v.....



I might be wrong but what I heard is that AGM batteries should be bulk charged @ 14.8-15.3 this way they get healthy lifespan and reduce buildup of sulfates etc

Would you like to post where you heard that? I would be surprised if that was a recommendation for the majority of AGM batteries. (It is certainly not one I have ever heard (or even read on the specification sheets of numerous AGM batteries))

I would go so far to say that if you are putting in a voltage of upto 15.3V as a norm and for many many hours (which is what happens when a battery is being charged and is in Absorption Mode (bulk mode will be an increasing voltage as the battery is getting charged until it settles on the voltage set by the charger in Absorption aka CV mode)) you will be doing the opposite of giving your batteries a healthy lifespan.

 

[maingate]

Anyone might be interested I have contacted Propex and they replied back:

Heaters manufactured from the beginning of this year (2020) have a revised compliant PCB which has modification, one of which is the increased high voltage cut-out setting to 17v.....



I might be wrong but what I heard is that AGM batteries should be bulk charged @ 14.8-15.3 this way they get healthy lifespan and reduce buildup of sulfates etc

That's correct, the Yuasa AGM battery states on the case 14.4 ~ 15.0 volts (boost charge) and 13.65 volts float charge.

 

[Deleted member 5731]

I would go so far to say that if you are putting in a voltage of upto 15.3V as a norm and for many many hours (which is what happens when a battery is being charged and is in Absorption Mode (bulk mode will be an increasing voltage as the battery is getting charged until it settles on the voltage set by the charger in Absorption aka CV mode)) you will be doing the opposite of giving your batteries a healthy lifespan.

I watched on YouTube manufacturing agm batteries in US with 10 years warranty and they said in bulk mode agm likes high voltage charge.

My split charger gives 15.3v for the first 10-15 minutes and then gradually reduce to 14.6-14.8v in bulk mode and drops to 13.8v in absorption stage.

 

[wildebus]

I watched on YouTube manufacturing agm batteries in US with 10 years warranty and they said in bulk mode agm likes high voltage charge.

My split charger gives 15.3v for the first 10-15 minutes and then gradually reduce to 14.6-14.8v in bulk mode and drops to 13.8v in absorption stage.

Without seeming to be pedantic (but I guess I am), you are confusing your stages.

Bulk Charging Mode - also known as Constant Current mode - is where the charger is putting in as much current as the battery can take (so usually in fact as much as the charger can deliver) and the voltage gradually creeps up to the Voltage that the Absorption Mode is set to.
Absorption Charging Mode - also known as Constant Voltage mode - is the stage where the Voltage stays at the set voltage and the current slowly declines as the battery reaches a full charge
The mode where a multi-stage chargers voltage will drop to 13.8V (or similar) is actually the Float Mode, which is much more of a maintenance charge rather than a battery charging mode
Some Chargers also have a Storage Mode, which is a lower voltage again.

This is a good chart showing the different stages and the Voltage (top line) and Current (bottom line) you would see on a Lead Acid technology battery (so Wet Cell, AGM, GEL, etc.)

Battery Charging Pattern by David, on Flickr

A voltage of 15.3V would be considered a equalization charge (aka Recondition in the chart above) and would be used periodically on some batteries (usually unsealed Lead Acid) to perform plate desulfation but you would not want to do this on every charge and on an SLA (Sealed Lead Acid) or AGM battery would only do on a needs-must basis.
There may be some batteries that like a 15.3V hit each time but that is not the norm. Have you actually checked the spec sheets for YOUR batteries to see it that is ok?

 

[FULL TIMER]

Isn't this normally only a problem with vehicles with regenerative braking etc, some problems with fridges etc as most of the time the vehicles alternator provides a pretty low voltage and when under braking a very high voltage ( well for 12v appliances ) usually when converters have scrimped on the split charging system ie using basic cheap voltage sensing relay's where they should be using battery - battery chargers

 

[in h]

If your domestic batteries are getting over 15v through a split charge relay, you should be removing the split charge relay and fitting a good battery to battery charger that will look after the batteries properly.