[Guide] Battery Maintainer (for Starter battery) -- How I Done It --
Right so its that time of year again . . . . . . . . Winter & (Lockdown 2020)
The van might be layed up not being used, which will lead to a flat battery in around 3 weeks.
The cold weather doesn't help the battery's either.
This Thread is about using "what you have" to "back charge" the starter battery...
lets look at some options. . . . . . . .
1# Connect a 240v/EHU charger to the starter battery and leave it connected, that's fine if you have a drive way etc, have a look for the quick disconnects that make things a bit easyier.
more on that here: Battery Chargers - How I Did It -
2# What about mobile solar . . . . . ? well that possible, though the solar yield during winter time is very low, the normal 50w dash panel may generate enough mA to counter act the drop in charge over time. The mobile solar needs to be connected to the middle dash socket so it connects to the starter battery . . . . . or just hard wire it to the starter battery . . . either way will work. in summer time 50w or up is enough, in winter time you may need 100w or more.
More on that here: [Guide] Mobile Solar Panels ? . . . - How I Did It -
3# What about my DC-DC charger (with attached solar on the dc-dc charger) ? . . . .
well some DC-DC chargers ( Like the Renogy & Ctek D250) WILL "reverse charge" the starter battery, but there is a caveat . . . it only works by taking power from a solar panel, it will charge the AUX battery first, then its only a small charge back to the starter battery . . . . but it does work . . . . . . if you got enough solar panels (for the time of year)
4# What about DC-DC and Separate solar? . . . . . . . .
This is an interesting one. . . . . Most people have a DC-DC that charges the AUX battery when the engine is running . . .
and a solar system connected to the AUX battery for when static or in fact at any other time there is enough solar about. . . .
in this configuration, with the van static for a long time the start will run flat . . . but there is any easy fix.
If the Solar was re-connected to the starter battery (instead of the AUX battery)
And there was enough solar to generate a charge . . . . . . . that starter battery will be charged, then at some point when the starter battery voltage was high enough, The DC-DC charger would kick in and start to charge the AUX . . . . . NET effect is that the one solar setup can charge both battery's (Solar power dependent and yes the DC-DC will cycle on/off as the starter battery voltage rises & falls.
i called it "reverse charge" or "auto VSR"
more on this can be seen here: [Guide] DC-DC Charger (for leisure battery) -- How I Done It --
.
5# what else . . . . ?
well what about "KISS" - (Keep it simple stupid)
what about a small black box that connects the batteries together? . . . . . so as the AUX battery charges up, it trickle charges the Starter battery?
That way you can leave your solar alone if its connected to the AUX battery.
and you can leave your 240/EHU charger connected to the AUX battery too.
The Basic unit is the Diode/Resister unit, heres mine, with the teardown.
more on that here : [Guide] DC-DC Charger (for leisure battery) -- How I Done It --
you just connect the two batteries to it and it will "trickle charge" power from the AUX battery back over to the Starter . . its a dumb unit with no smarts . . . .
its just a diode to control the direction of power flow and a resistor to limit the power flow.
****************
What about a simple black-box-with-smarts?
well, this is where ABLEMAIL ELECTRONICS comes into play,
They have come up with a great little magic box that will solve your problems.
It's called an AMT12-2 Battery to Battery Trickle charger.
Again you just connect the two batteries (plus a ground) and the black box will trickle charge your starter batterys,
its small in size,
its got M6 bolts/nuts for the battery connection.
less than 2mA standby draw,
up to 4A charge rate (5sec pulse every 15sec),
ignition overide input,
built in protection,
Its Programmable too . . .
.............
AMT12-2 Trickle Charger charges Vehicle Battery from Leisure Battery with Solar Charger /Mains Hookup
The AMT12-2 has many names Trickle Charger, Battery Maintainer, Battery Saver, Reverse Charger, Top Up Charger, Battery Equaliser, but its purpose is to keep a Source / Vehicle Battery charged & protected from damage during prolonged periods of Vehicle, Boat & Motorhome inactivity or storage. The charger feeds a low current into the Source Battery to compensate for self discharge, alarm & tracker loads while ensuring the charge of the Auxuiliary / Leisure Battery is maintained. In the ideal scenario a Solar Charger or Mains Charger is attached to an Auxiliary / Leisure Battery to protect it from damage during the period of inactivity & the Trickle Charger draws a small current off to maintain the Vehicle / Source Battery.
The Trickle Charger also feeds charge from the Auxiliary Battery to the Vehicle Battery until they reach 11.5V & 11.7V repectively ensuring that both Batteries are kept as healthy as possible even if no Solar Charger or Main Charger is present.
The unit has 4 User selected programmes & so is suitable for use with any Auxiliairy Battery Charging System including a simple Voltage Sensing Relay & a Battery to Battery Charger.
It does not matter the Make or Type of Charger the AMT12-2 will Charge the Vehicle Battery from the Leisure Battery & the clever software means it is compatible with conventional Alternator Vehicles, the latest Stop / Start & Euro 5/6 & Regenerative Braking Technologies.
The unit has a low current draw of less than 2mA on a 12V system & so presents a very small discharge load to the Vehicle & Leisure Battery. At 1Ahr drain every 20 days the unit has negligible effect on the Battery Capacity & should will easily cover a winter storage period.
When a charging source, either a Mains Charger or a Solar Charger, is connected to the Auxiliary / Leisure Battery, the AMT12-2 Trickle Charger allows a maximum of 4A (Usually considerably less) to flow from the Leisure Battery to the Vehicle Battery thus ensuring the Leisure Battery is Charged first & the Vehicle Battery second.
The AMT12-2 works with all types of Lead Acid Batteries & Lithium Batteries, The Status Led gives feedback on the Trickle Charger Operation & State of Charge of the Vehicle Battery & Auxiliary Battery Conditions.
There is Ignition Override & Switch Enable to allow the user to externally control the charging if, for some reason, they wish to override the automatic settings.
The AMT12-2 Trickle Charger works on 12V & 24V Battery Systems, Automatically detecting whether it is connected to a 24V or 12V system. The compact potted plastic enclosure means it is easily fitted next to the Auxiliary Battery Charger & the 3 x M6 bolt connections, The Inbuilt Fuse Protection means the Installation is extremely quick & easy.
This product has been Developed by Ablemail as part of a Range & if this product does not meet your requirement, Please contact our Technical Department to see if we can meet your exact needs.
EMC:
Type approved to 72/245/EEC as last amended by 95/54/EC
Protection:
Automatic overload and over temperature protection with fully automatic reset
Spec Sheet:
Trickle Charger Info
General Product Information:
The following files may also be useful:
ablemail.co.uk
here's mine . . . (charging my solar shed SLA bank from the Green Lithium AUX battery)
.
*********************
TBC with more options as they present themselves. . .
.
.
*
******************************************************
******************************************************
Right so its that time of year again . . . . . . . . Winter & (Lockdown 2020)
The van might be layed up not being used, which will lead to a flat battery in around 3 weeks.
The cold weather doesn't help the battery's either.
This Thread is about using "what you have" to "back charge" the starter battery...
lets look at some options. . . . . . . .
1# Connect a 240v/EHU charger to the starter battery and leave it connected, that's fine if you have a drive way etc, have a look for the quick disconnects that make things a bit easyier.
more on that here: Battery Chargers - How I Did It -
2# What about mobile solar . . . . . ? well that possible, though the solar yield during winter time is very low, the normal 50w dash panel may generate enough mA to counter act the drop in charge over time. The mobile solar needs to be connected to the middle dash socket so it connects to the starter battery . . . . . or just hard wire it to the starter battery . . . either way will work. in summer time 50w or up is enough, in winter time you may need 100w or more.
More on that here: [Guide] Mobile Solar Panels ? . . . - How I Did It -
3# What about my DC-DC charger (with attached solar on the dc-dc charger) ? . . . .
well some DC-DC chargers ( Like the Renogy & Ctek D250) WILL "reverse charge" the starter battery, but there is a caveat . . . it only works by taking power from a solar panel, it will charge the AUX battery first, then its only a small charge back to the starter battery . . . . but it does work . . . . . . if you got enough solar panels (for the time of year)
4# What about DC-DC and Separate solar? . . . . . . . .
This is an interesting one. . . . . Most people have a DC-DC that charges the AUX battery when the engine is running . . .
and a solar system connected to the AUX battery for when static or in fact at any other time there is enough solar about. . . .
in this configuration, with the van static for a long time the start will run flat . . . but there is any easy fix.
If the Solar was re-connected to the starter battery (instead of the AUX battery)
And there was enough solar to generate a charge . . . . . . . that starter battery will be charged, then at some point when the starter battery voltage was high enough, The DC-DC charger would kick in and start to charge the AUX . . . . . NET effect is that the one solar setup can charge both battery's (Solar power dependent and yes the DC-DC will cycle on/off as the starter battery voltage rises & falls.
i called it "reverse charge" or "auto VSR"
more on this can be seen here: [Guide] DC-DC Charger (for leisure battery) -- How I Done It --
.
5# what else . . . . ?
well what about "KISS" - (Keep it simple stupid)
what about a small black box that connects the batteries together? . . . . . so as the AUX battery charges up, it trickle charges the Starter battery?
That way you can leave your solar alone if its connected to the AUX battery.
and you can leave your 240/EHU charger connected to the AUX battery too.
The Basic unit is the Diode/Resister unit, heres mine, with the teardown.
more on that here : [Guide] DC-DC Charger (for leisure battery) -- How I Done It --
you just connect the two batteries to it and it will "trickle charge" power from the AUX battery back over to the Starter . . its a dumb unit with no smarts . . . .
its just a diode to control the direction of power flow and a resistor to limit the power flow.
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****************
What about a simple black-box-with-smarts?
well, this is where ABLEMAIL ELECTRONICS comes into play,
They have come up with a great little magic box that will solve your problems.
It's called an AMT12-2 Battery to Battery Trickle charger.
Again you just connect the two batteries (plus a ground) and the black box will trickle charge your starter batterys,
its small in size,
its got M6 bolts/nuts for the battery connection.
less than 2mA standby draw,
up to 4A charge rate (5sec pulse every 15sec),
ignition overide input,
built in protection,
Its Programmable too . . .
.............
AMT12-2 Trickle Charger charges Vehicle Battery from Leisure Battery with Solar Charger /Mains Hookup
The AMT12-2 has many names Trickle Charger, Battery Maintainer, Battery Saver, Reverse Charger, Top Up Charger, Battery Equaliser, but its purpose is to keep a Source / Vehicle Battery charged & protected from damage during prolonged periods of Vehicle, Boat & Motorhome inactivity or storage. The charger feeds a low current into the Source Battery to compensate for self discharge, alarm & tracker loads while ensuring the charge of the Auxuiliary / Leisure Battery is maintained. In the ideal scenario a Solar Charger or Mains Charger is attached to an Auxiliary / Leisure Battery to protect it from damage during the period of inactivity & the Trickle Charger draws a small current off to maintain the Vehicle / Source Battery.
The Trickle Charger also feeds charge from the Auxiliary Battery to the Vehicle Battery until they reach 11.5V & 11.7V repectively ensuring that both Batteries are kept as healthy as possible even if no Solar Charger or Main Charger is present.
The unit has 4 User selected programmes & so is suitable for use with any Auxiliairy Battery Charging System including a simple Voltage Sensing Relay & a Battery to Battery Charger.
It does not matter the Make or Type of Charger the AMT12-2 will Charge the Vehicle Battery from the Leisure Battery & the clever software means it is compatible with conventional Alternator Vehicles, the latest Stop / Start & Euro 5/6 & Regenerative Braking Technologies.
The unit has a low current draw of less than 2mA on a 12V system & so presents a very small discharge load to the Vehicle & Leisure Battery. At 1Ahr drain every 20 days the unit has negligible effect on the Battery Capacity & should will easily cover a winter storage period.
When a charging source, either a Mains Charger or a Solar Charger, is connected to the Auxiliary / Leisure Battery, the AMT12-2 Trickle Charger allows a maximum of 4A (Usually considerably less) to flow from the Leisure Battery to the Vehicle Battery thus ensuring the Leisure Battery is Charged first & the Vehicle Battery second.
The AMT12-2 works with all types of Lead Acid Batteries & Lithium Batteries, The Status Led gives feedback on the Trickle Charger Operation & State of Charge of the Vehicle Battery & Auxiliary Battery Conditions.
There is Ignition Override & Switch Enable to allow the user to externally control the charging if, for some reason, they wish to override the automatic settings.
The AMT12-2 Trickle Charger works on 12V & 24V Battery Systems, Automatically detecting whether it is connected to a 24V or 12V system. The compact potted plastic enclosure means it is easily fitted next to the Auxiliary Battery Charger & the 3 x M6 bolt connections, The Inbuilt Fuse Protection means the Installation is extremely quick & easy.
This product has been Developed by Ablemail as part of a Range & if this product does not meet your requirement, Please contact our Technical Department to see if we can meet your exact needs.
EMC:
Type approved to 72/245/EEC as last amended by 95/54/EC
Protection:
Automatic overload and over temperature protection with fully automatic reset
Spec Sheet:
Trickle Charger InfoGeneral Product Information:
The following files may also be useful:
- Generic products.pdf
- Products selector.pdf
- Software interface.pdf
- Mechanical options.pdf
- Temperature.pdf
- Installation instructions Trickle Charger.pdf
AMT12-2 Trickle Charger charges Vehicle Battery from Leisure Battery with Solar Charger /Mains Hookup | Ablemail Electronics
The AMT12-2 has many names Trickle Charger, Battery Maintainer, Battery Saver, Reverse Charger, Top Up Charger, Battery Equaliser, but its purpose is to keep a Source / Vehicle Battery charged & protected from damage during prolonged periods of Vehicle, Boat & Motorhome inactivity or storage...
ablemail.co.uk
here's mine . . . (charging my solar shed SLA bank from the Green Lithium AUX battery)
.
*********************
TBC with more options as they present themselves. . .
.
.
*
******************************************************
******************************************************
Last edited by a moderator:
