Solar Feed To Vehicle Battery

[czmate1999]

Hi All,

Question - Could I take a male to male cigar lead and plug from the 12v leisure system to the dash and keep the vehicle battery topped up or would this not work?

Cheers

Cz.

 

[Pete C]

Any difference in voltage between the 2 batteries would result in an arbitrary amount of current flowing from one to the other. If you were lucky it would blow a fuse. If you were unlucky it would set fire to the wiring.
The DC-DC converters we use are the way of limiting this flow of current. There are devices designed to do what you want, but they need to be considered alongside the rest of your electrical systems.

Pete

 

[Pete C]

Also, in your description, I am not sure where solar plays a part ?

Pete

 

[Loz]

I read it that he has solar on the leisure side and wants to create a manual shunt back to the starter battery.

 

[Farnorthsurfer]

I have recently bought this Renogy unit, not fitted yet, after reading @Dellmassive post on it
It will take in Solar as well as control DC-DC. The reason I mention it is that it has a feature to charge your vehicle battery on solar after the leisure battery is topped up. Sounds like what you want to do.

!!! HAS RENOGY JUST SOLVED ALL OUR PROBLEMS IN ONE UNIT !!!!

Heres a new solution to LTD with Lifepo4 Batteries:

A 50A DC-DC charger with built in MPPT,

That has a lithium profile WITH Low Temp Disconnect,

That will reverse charge the starter battery !!!!!

That has a IGNITION feed for smart alternator.

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DESCRIPTION
Renogy's DCC50S DC to DC MPPT on-board Battery Charger is designed to give you options! This multi-stage, multi-input battery charger can charge a service battery from an alternator connected to a starting battery or by utilizing solar panels connected directly to the unit. While your vehicle's alternator prioritizes your starting battery, this unit will allow your solar system to charge your service battery first! It's the smart way to keep yourself fully charged and off-grid longer! And with multi-stage charging and multi-chemistry functionality, Renogy's DC to DC MPPT Charger has you covered whether you're using Flooded, Gel, AGM, or Lithium batteries.

If you have any questions regarding this product, please call us at 1 (909) 287-7111 or email sales@renogy.com.

KEY FEATURES

• Designed to charge service batteries from two DC inputs—solar panels and alternator.
• Built-in Maximum Power Point Tracking (MPPT) to maximize the solar power.
• 3-phase charging profile (Bulk, Boost, and Float) ensures your service battery will be accurately charged at the correct voltage levels to 100%.
• Built-in Voltage Sensitive Relay (VSR) for easy setup with traditional alternators.
• Compatible with smart alternators (with variable output voltage).
• Trickle charges the starting battery via solar panels if the service battery is fully charged.
• Isolation of the starting battery and the service battery.
• Temperature and voltage compensation features prolong battery life and improve system performance.
• Smart Protection Features: battery isolation, over-voltage protection, battery temperature protection, over-current protection, overheat protection, reverse current protection, solar panel and alternator reverse polarity protection.
• Compatible with multiple battery types: AGM, GEL, Flooded, and Lithium.
• Compact with a sturdy design, it was built tough for all conditions.

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SPECIFICATIONS
System Voltage : 12VDC Battery Voltage Range : 9-16VDC
Maximum Charging Current : 50A (25A Alternator / 25A PV) Battery Type : SLA, GEL, FLD, LI, USER
Backup Battery Charging Mode : MPPT Charging Efficiency : Up to 97%
Max. Solar Input Voltage : 25V Maximum Solar Input Power : 660W
Alternator Input Voltage : Traditional Alternator: 13.2-16VDC Smart Alternator (Euro 6): 12-16VDC"

Maximum Alternator Input Power : 660W
Self-consumption : 60mA Operating Temperature Range : -22°F~149°F / ﹣35°C~65°C
Dimensions : 9.6 x 5.7 x 3.0 in / 244 x 146 x 77 mm Weight : 3.13 lbs / 1.42 kg

WARRANTY INFORMATION
Accessories 1-year material warranty


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some details from the install,

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DCC50S 12V 50A DC-DC On-Board Battery Charger with MPPT

https://www.renogy.com/content/RBC50D1S-G1/RRBC50D1S-G1-Manual.pdf

https://www.amazon.co.uk/Renogy-DC-..._1_3?keywords=renogy+dc&qid=1574256131&sr=8-3

***********************************

fwiw I've just gone on Amazon UK and grabbed one.

 

[Dellmassive]

The 12v sockets have a max amp rating of 10amps.

If the batterys are at different levels, which they will be due to the starter 80% SOC max there will be a large current flow between the batterys as they try an equalize when connected in that way.

So technically you could do that, but in reality you will just blow fuses and possibly damage the cabling....

There are special cables made for that purpose I saw some years ago that had a 5amp or so current limiter in them to stop the mad current inrush...... I think they were marketed as idiot proof jump cables..... but you had to plug in both cars and leave for an hour before attempting to start the car.

So you might be better looking at alternative options:

Dc-dc with reverse charge function.

Temp Split charge relay.

Small resistor/diode charger box.

Temp fit dc-dc.

 

[czmate1999]

Hi,

Cheers for comment so far.

The question came about as I was looking at a mini panel to leave plugged into the cigarette lighter when the van is parked up for a bit. Then I thought 'hold on' there is a panel on the roof and the leisure set-up, could I not tap into that.

Main components of my leisure electrics are,

HD Series Professional for high current (160Ah Continuous BMS) Lithium Battery 12V 180Ah

Votronic 3243 Battery Charger VBCS 45/30/350 Triple

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

Votronic 3184UK MobilPOWER Inverter SMI 1700 Sinus ST-NVS UK

 

[Dellmassive]

That Voltronic Tripple charger already has that function . . . . . from how im reading it below. (reverse charge of starter battery upto 5A from EHU & Solar)

Votronic 3243 Battery Charger VBCS 45/30/350 Triple


Mains Operation, during standstill operation at the external socket of the mains supply:

• The full charging capacity in the universal wide range from 110 V AC ‐ 230 V AC without any switching is available worldwide, even in case of large deviations in the power supply (low voltage/overvoltage, sine curve, frequency).
• Efficient charging of the board battery and supply of the 12 V consumers via mains.
• Auxiliary charging 12 V/4‐5 A for support charging and trickle charging of the vehicle's (lead) starter battery in case of extended standstill periods.
• Due to the long‐term characteristic lines of charging, the unit may be connected continuously to the mains (such as for standstill periods or winter breaks).

Solar Operation, „MPP“ (Maximum‐Power‐Point):

• Controllers according to the MPP technology are continuously and automatically calculating the maximum power yield (MPP) of the solar modules several times per second. This surplus of charging current of 10 % to 30 % ensures short charging times and the best possible power yield of the solar system.
• Auxiliary charging for support charging and trickle charging of the vehicle's starter battery in case of extended standstill periods.
• Terminal „AES“, for automatic commutation of refrigerators with “AES” (Automatic Energy Selector, Electrolux / Dometic) from gas operation to 12 V operation in case of excess solar power.

it also seems to have LTD for LifePO4 battery charging....

Connection for Battery Temperature Sensor (included in the standard delivery scope): Lead batteries (acid, gel, AGM): In case of low outside temperatures, full charging of the weak battery is improved by automatic adaptation of the charging voltage to the battery temperature, and in case of summery temperatures unnecessary battery gassing will be avoided. LiFePO4 Batteries: Battery protection in case of high temperatures or particularly in case of low temperatures < 0°C. Highly recommended, if the battery temperature might drop below 0 °C during operation.




„LiFePO4“: Charging Program for Lithium Batteries, Characteristic Line IU1oU2oU3
Charging program for lithium LiFePO4 batteries with completely integrated electronic system and safety circiut (BMS). Automatic trickle charging of the LiFePO4 battery when the vehicle is stopped (seasonal operation) to maintain a charging state of 50‐80 %, which is advantageous for the battery lifetime. Powers also 12 V consumer loads, such as alarm systems, WLAN etc., as well as the vehicle's starter battery. With periodical automatic activation of the battery cell balancing BMS (Auto Wake Up Function).

The Lifepo4 charge voltage seems a bit low , , , , , but im sure they know what there doing . . .

Bord-Battery, IU1oU2oU3
Nominal Voltage Lead-Acid / LiFePO4 [V] ----- 12 / 12.0 - 13.3



****************

Though the VOC@43.4v of the panel seems to be higher than the max input of the Tripple charger VOC@36v (not sure if the charger will just down regulate or not?)

MPP Solar Charging Controller Operation
Capacity Solar Module (Pmax) in [Wp] -- 50 - 350
Current Solar Module max. [A] -- 21.0
Voltage Solar Module (Voc) max. [V] -- 36
Charging Current Board/Starter Battery max. [A] -- 25.5 / 5.0
Terminal AES Refrigerator -- yes



Solar panel specifications:

• 
  
  
  • Peak power: 310W
  • Maximum power voltage: 35.6V
  • Maximum power current: 8.7A
  • Open circuit voltage: 43.4V
  • Short circuit current: 9.0A
  • Dimensions: 1868 x 991 x 2 mm
  • Weight: 6.31 kg

 

[Dellmassive]

FYI

heres one of those dodge 12v "jump start leads" #VeryIffyIfYouAskMe

looks like this one was current limited to 12.5A and fused @ 15A . . . . . but if you ask me above 10A will run that socket red hot and probably heat up the van wires and may melt the fuse/holder if run for an extended time . . . . . - defo not recommended.

https://amzn.to/2EC53Sd


EASY START ENGINE STARTER 12V SOCKET JUMP START LEAD

• This battery charger works using the 12-volt power outlets in two vehicles eliminating the need for jump leads.
• Includes built-in short circuit protection reducing the possibility of damaging your car's electrical system.
• You never have to have contact with the vehicle's battery - no risk to you from battery acid.
• * Short circuit protection. Auto shut off. * Thermal Protection. Auto shut off.
• Specifications * Input: 12V DC, 12.5A * Output: 12V DC, 12.5A / 150W Max * Fuse: 15A Tube-Type * Cable Length: 4 Metre's

 

[czmate1999]

That Voltronic Tripple charger already has that function . . . . . from how im reading it below. (reverse charge of starter battery upto 5A from EHU & Solar)

Votronic 3243 Battery Charger VBCS 45/30/350 Triple


Mains Operation, during standstill operation at the external socket of the mains supply:

• The full charging capacity in the universal wide range from 110 V AC ‐ 230 V AC without any switching is available worldwide, even in case of large deviations in the power supply (low voltage/overvoltage, sine curve, frequency).
• Efficient charging of the board battery and supply of the 12 V consumers via mains.
• Auxiliary charging 12 V/4‐5 A for support charging and trickle charging of the vehicle's (lead) starter battery in case of extended standstill periods.
• Due to the long‐term characteristic lines of charging, the unit may be connected continuously to the mains (such as for standstill periods or winter breaks).

Solar Operation, „MPP“ (Maximum‐Power‐Point):

• Controllers according to the MPP technology are continuously and automatically calculating the maximum power yield (MPP) of the solar modules several times per second. This surplus of charging current of 10 % to 30 % ensures short charging times and the best possible power yield of the solar system.
• Auxiliary charging for support charging and trickle charging of the vehicle's starter battery in case of extended standstill periods.
• Terminal „AES“, for automatic commutation of refrigerators with “AES” (Automatic Energy Selector, Electrolux / Dometic) from gas operation to 12 V operation in case of excess solar power.

it also seems to have LTD for LifePO4 battery charging....

Connection for Battery Temperature Sensor (included in the standard delivery scope): Lead batteries (acid, gel, AGM): In case of low outside temperatures, full charging of the weak battery is improved by automatic adaptation of the charging voltage to the battery temperature, and in case of summery temperatures unnecessary battery gassing will be avoided. LiFePO4 Batteries: Battery protection in case of high temperatures or particularly in case of low temperatures < 0°C. Highly recommended, if the battery temperature might drop below 0 °C during operation.




„LiFePO4“: Charging Program for Lithium Batteries, Characteristic Line IU1oU2oU3
Charging program for lithium LiFePO4 batteries with completely integrated electronic system and safety circiut (BMS). Automatic trickle charging of the LiFePO4 battery when the vehicle is stopped (seasonal operation) to maintain a charging state of 50‐80 %, which is advantageous for the battery lifetime. Powers also 12 V consumer loads, such as alarm systems, WLAN etc., as well as the vehicle's starter battery. With periodical automatic activation of the battery cell balancing BMS (Auto Wake Up Function).

The Lifepo4 charge voltage seems a bit low , , , , , but im sure they know what there doing . . .

Bord-Battery, IU1oU2oU3
Nominal Voltage Lead-Acid / LiFePO4 [V] ----- 12 / 12.0 - 13.3



****************

Though the VOC@43.4v of the panel seems to be higher than the max input of the Tripple charger VOC@36v (not sure if the charger will just down regulate or not?)

MPP Solar Charging Controller Operation
Capacity Solar Module (Pmax) in [Wp] -- 50 - 350
Current Solar Module max. [A] -- 21.0
Voltage Solar Module (Voc) max. [V] -- 36
Charging Current Board/Starter Battery max. [A] -- 25.5 / 5.0
Terminal AES Refrigerator -- yes



Solar panel specifications:

• 
  
  
  • Peak power: 310W
  • Maximum power voltage: 35.6V
  • Maximum power current: 8.7A
  • Open circuit voltage: 43.4V
  • Short circuit current: 9.0A
  • Dimensions: 1868 x 991 x 2 mm
  • Weight: 6.31 kg

thanks DM! will look into this further!

 

[czmate1999]

FYI

heres one of those dodge 12v "jump start leads" #VeryIffyIfYouAskMe

looks like this one was current limited to 12.5A and fused @ 15A . . . . . but if you ask me above 10A will run that socket red hot and probably heat up the van wires and may melt the fuse/holder if run for an extended time . . . . . - defo not recommended.

https://amzn.to/2EC53Sd


EASY START ENGINE STARTER 12V SOCKET JUMP START LEAD

• This battery charger works using the 12-volt power outlets in two vehicles eliminating the need for jump leads.
• Includes built-in short circuit protection reducing the possibility of damaging your car's electrical system.
• You never have to have contact with the vehicle's battery - no risk to you from battery acid.
• * Short circuit protection. Auto shut off. * Thermal Protection. Auto shut off.
• Specifications * Input: 12V DC, 12.5A * Output: 12V DC, 12.5A / 150W Max * Fuse: 15A Tube-Type * Cable Length: 4 Metre's

View attachment 56550

seems like a definite no go to me! not worth the risk!