Charging House Batteries
- Thread starter mattdanger
- Start date
The inefficiency doesn't much matter. Getting a properly dialed in muti-stage charge would make up for it.
Inefficiency matters with some things, like solar, in other situations...bleh, who cares?
Though using a big inverter to feed a big battery charger is also highly inefficient in financial terms.
Best would be ACR + solar. But inverter to charger works too.
Again... This...^.. run large conductors from house charging system.. this will likely not efficiently charge as you get close to fully charged as the voltage will not be high enough, but it should help a great deal for the bulk stage of charge, a decent solar system will finish and maintain, as well as charge when your not underway. I would suggest a morningstar or bogart charge controller, and a bogart trimetric to monitor the actual state of charge of you batteries. That last part is important, battery voltage alone is not enough. The trimetric would be able to keep track of all current in and out of the battery, and in the case of combining it with a bogart charge controller you will have a very smart, and configurable charging system that will keep your batteries healthy. The trimetric can also monitor your starting battery voltage as a bonus.
_hein_
Observer
OP has the Magnum BMK (Battery Monitor Kit) which tracks Ah consumption and provides %SOC (state of charge). The Sprinter alternator puts out 14.1V. Good to check the Y-cable for corrosion before combining house batteries and have a way to monitor chassis voltage while underway. (scangauge, etc.)
We have the Magnum SBC (smart battery combiner) but its capacity (25A) isn't really enough for our 500Ah AGM bank when it gets to 70% SOC. It actually goes into a 50% duty cycle if the current passing through it is too high. It does have adjustable voltage thresholds and can be used to drive a solenoid for more current capability. I have planned to upgrade it but with 200 watts of solar we are getting enough charge in most instances.
We have the Magnum SBC (smart battery combiner) but its capacity (25A) isn't really enough for our 500Ah AGM bank when it gets to 70% SOC. It actually goes into a 50% duty cycle if the current passing through it is too high. It does have adjustable voltage thresholds and can be used to drive a solenoid for more current capability. I have planned to upgrade it but with 200 watts of solar we are getting enough charge in most instances.
FDM2012
Adventurer
Following this post intently.
I am hoping someone can help shed light on how to tie in my 1000Ah Deep Cycle battery bank with my
dual 110amp alternator set up and 450watts solar array.
Rarely would I need to charge with the alternators, but imagine this, if you will:
With most everything in the Driving at night for several hours with people in the back using the tv, lights, chargers,
and the occasional microwave. I would prefer to show up at a camp/stopping site with charged batteries, and not
have to word about a red line of usage without having to be a Power Nazi. "Hey, turn that light off, No more popcorn,
why is the TV still on." lol
Most importantly, when I do stop, I HAVE to be able to cook my hot pocket!
I am hoping someone can help shed light on how to tie in my 1000Ah Deep Cycle battery bank with my
dual 110amp alternator set up and 450watts solar array.
Rarely would I need to charge with the alternators, but imagine this, if you will:
With most everything in the Driving at night for several hours with people in the back using the tv, lights, chargers,
and the occasional microwave. I would prefer to show up at a camp/stopping site with charged batteries, and not
have to word about a red line of usage without having to be a Power Nazi. "Hey, turn that light off, No more popcorn,
why is the TV still on." lol
Most importantly, when I do stop, I HAVE to be able to cook my hot pocket!
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Joe917
Explorer
You may want to rethink that set up.
Flooded batteries in a sealed box with a source of ignition. Not good.
FDM2012
Adventurer
The box is factory vented, and I am adding a small fan on top of that.
It will be no different than all the other RV's driving down the road like that already...
It will be no different than all the other RV's driving down the road like that already...
dwh
Tail-End Charlie
Same as you would a 500ah bank, single alternator and 250w solar.
I'm assuming you already know you'll need a charge controller for the solar.
Get a 500a rated Blue Sea ACR to handle connecting the house bank to the alternators/chassis battery.
Get some welding cable rated to carry 220a and a fuse to protect it.
As long as the loads don't exceed 220a while the engine is running, then they won't draw down the house bank.
With that much money into batteries, I'd recommend carrying a small generator and and decent battery charger as a backup on extended trips. Honda 2000 plus Iota DLS-55 would be about the minimum. Two of each would be better.
luthj
Engineer In Residence
FDM:
I would suggest a Blue Seas ML ACR as linked below.
http://amzn.to/2e55FpO
Use 0 or 2/0 cable to connect the ACR to the chassis battery or alternator. The exact location depends on your current wiring under the hood. Install a fuse at BOTH ends of the chassis to house battery connection. It should be rated to protect the wire, so in the 250-400A range would be reasonable. Using a larger fuse with a slower blow would allow for boosting/starting the engine from the house batteries.
The solar system should be connected to the house batteries directly using a controller of your choice. The ACR will connect two banks whenever a charge is present, and disconnect when there is no active charge.
You have a number of batteries in parallel. You must make sure the batteries wiring is balanced for each string. Even foot of extra wiring on one of the parallel strings will cause a large difference in charge/discharge currents, and thus reduce the life of the whole pack by prematurely aging one of the strings A quick google turned up this link describing the issue.
http://forum.solar-electric.com/dis...-series-parallel-balancing-help-me-understand
Your alternators are rated at 110A each, but the vehicle systems will use 25-90A of that depending on what lights and accessories you are using. Also the 110A number is usually at 1800rpm or higher. so you will have less power available at idle.
Ideally you would keep the inverter off except when you need to run high power AC devices. Cheap and/or large output inverters are very inefficient at low power output. So running a 100W TV on a 3kw inverter may use 200-300w! So switching to 12V native devices is a good idea. There are 12V chargers available for most electronics. Obviously the microwave will still need 120VAC. Another option is to use a smaller inverter (less than 500W) to supply low power devices. This inverter can be left on most of the time, and will usually have a lower standby power consumption than a larger inverter.
Flooded batteries benefit from a regular equalize charge cycle which is performed at higher voltages. You will need a higher output shore power charger, or a larger solar array to do this for such a large bank. For a 1000AH bank, you will want at least a 50A charger or 600+ watts of solar.
If you don't already have a shunt based battery monitor I would suggest installing one. They will take all the guesswork out of battery monitoring (when properly setup).
Edit: Since you have 2 alternators, it may be possible to configure one of them as a dedicated battery charger. This involves disconnecting it from the chassis system, and installing a digital external regulator. (Balmar makes them). Then connect the alternator to your house bank. The external regulator turns the alternator into a true 3 stage charger. If desired a larger alternator may be an option, up to 300A are available, you can charge your house bank in VERY fast with one of those. These external regulators will have a battery temperature sensor and a voltage sense wire which allows for small cable runs as the regulator will compensate for the voltage drop on the charging cable.
I would suggest a Blue Seas ML ACR as linked below.
http://amzn.to/2e55FpO
Use 0 or 2/0 cable to connect the ACR to the chassis battery or alternator. The exact location depends on your current wiring under the hood. Install a fuse at BOTH ends of the chassis to house battery connection. It should be rated to protect the wire, so in the 250-400A range would be reasonable. Using a larger fuse with a slower blow would allow for boosting/starting the engine from the house batteries.
The solar system should be connected to the house batteries directly using a controller of your choice. The ACR will connect two banks whenever a charge is present, and disconnect when there is no active charge.
You have a number of batteries in parallel. You must make sure the batteries wiring is balanced for each string. Even foot of extra wiring on one of the parallel strings will cause a large difference in charge/discharge currents, and thus reduce the life of the whole pack by prematurely aging one of the strings A quick google turned up this link describing the issue.
http://forum.solar-electric.com/dis...-series-parallel-balancing-help-me-understand
Your alternators are rated at 110A each, but the vehicle systems will use 25-90A of that depending on what lights and accessories you are using. Also the 110A number is usually at 1800rpm or higher. so you will have less power available at idle.
Ideally you would keep the inverter off except when you need to run high power AC devices. Cheap and/or large output inverters are very inefficient at low power output. So running a 100W TV on a 3kw inverter may use 200-300w! So switching to 12V native devices is a good idea. There are 12V chargers available for most electronics. Obviously the microwave will still need 120VAC. Another option is to use a smaller inverter (less than 500W) to supply low power devices. This inverter can be left on most of the time, and will usually have a lower standby power consumption than a larger inverter.
Flooded batteries benefit from a regular equalize charge cycle which is performed at higher voltages. You will need a higher output shore power charger, or a larger solar array to do this for such a large bank. For a 1000AH bank, you will want at least a 50A charger or 600+ watts of solar.
If you don't already have a shunt based battery monitor I would suggest installing one. They will take all the guesswork out of battery monitoring (when properly setup).
Edit: Since you have 2 alternators, it may be possible to configure one of them as a dedicated battery charger. This involves disconnecting it from the chassis system, and installing a digital external regulator. (Balmar makes them). Then connect the alternator to your house bank. The external regulator turns the alternator into a true 3 stage charger. If desired a larger alternator may be an option, up to 300A are available, you can charge your house bank in VERY fast with one of those. These external regulators will have a battery temperature sensor and a voltage sense wire which allows for small cable runs as the regulator will compensate for the voltage drop on the charging cable.
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Joe917
Explorer
Tying the house bank to the charging system and solar is relatively simple.
Run battery cables to a positive and a negative node.
Connect all power sources, solar, alternator shore and generator(If required) to the nodes.The Shore/Generator feed should go through the Magnum. NOTE: if you have a shore and generator connection they must be installed so that you can only select one or the other, never both.
Connect loads via fuses/breakers.
The shunt for the battery monitor goes between the battery neg and neg node.
Cables, wires and fuses need to be calculated from tables, not rough guess.
If you have roof space I would add more solar for that bank.
You will need to equalize regularly. (the Trimetric keeps track of days since equalization, a nice feature)
Run battery cables to a positive and a negative node.
Connect all power sources, solar, alternator shore and generator(If required) to the nodes.The Shore/Generator feed should go through the Magnum. NOTE: if you have a shore and generator connection they must be installed so that you can only select one or the other, never both.
Connect loads via fuses/breakers.
The shunt for the battery monitor goes between the battery neg and neg node.
Cables, wires and fuses need to be calculated from tables, not rough guess.
If you have roof space I would add more solar for that bank.
You will need to equalize regularly. (the Trimetric keeps track of days since equalization, a nice feature)
_hein_
Observer
The Bluesea ACR is a great way to go. It is important to understand the connect/disconnect parameters. Here is an excerpt from their manual.
The OP has Magnum Energy components so may be interested in their Smart Battery Combiner. It's limited to 25A but can drive a solenoid or solid state combiner for more ampacity. It has adjustable voltage thresholds as shown.
The OP has Magnum Energy components so may be interested in their Smart Battery Combiner. It's limited to 25A but can drive a solenoid or solid state combiner for more ampacity. It has adjustable voltage thresholds as shown.
DiploStrat
Expedition Leader
Some Points to Consider
I use a Magnum SBC to drive a Blue Sea 200A relay. Works well, but:
-- If you want a dashboard override switch, you have to wire it yourself. (It is included with the Blue Sea.)
-- The maximum voltage on the SBC is 15v, and many batteries need higher than that, especially below freezing. (Which is why I wired up an override switch.)
Doing it again I would simply go with the Blue Sea ACR.
I use a Magnum SBC to drive a Blue Sea 200A relay. Works well, but:
-- If you want a dashboard override switch, you have to wire it yourself. (It is included with the Blue Sea.)
-- The maximum voltage on the SBC is 15v, and many batteries need higher than that, especially below freezing. (Which is why I wired up an override switch.)
Doing it again I would simply go with the Blue Sea ACR.
Bbasso
Expedition goofball
My van has two alternators in it and the previous owner decided to set one alternator for house battery charging alone. It wound up failing and over charging the house battery therefore costing me not just a alternator but a new house battery too.
I wouldn't recommend separating alternators based on my simple experience. Just use a large gauge cable and tap into the starter batteries then to the blue Seas ACR.
I wouldn't recommend separating alternators based on my simple experience. Just use a large gauge cable and tap into the starter batteries then to the blue Seas ACR.
mattdanger
New member
Wow! This has been super helpful.
I have decided to add a CTEK D250S with two Renogy RNG-100D 100 Watt panels wired in parallel and a connection to the alternator.
I will keep the Magnum Inverter/Charger also.
I will route the output from the D250S through a Single Pole Double Throw (SPDT) power relay that is wired to the shore power feed line. When the shore power is plugged in, it will activate the relay and disconnect the D250S from the battery.
This will keep the Magnum and the D250S from ever trying to charge the battery at the same time.
It will also allow me to keep the Magnum connected and acting as my Inverter when the shore power is not connected.
I realize the D250S is limited to 20A, but i'm hoping with my relatively small battery bank, and the solar panels keeping them topped off all the time, it will be enough. I also like that it doesn't put a huge load on the sprinter charging system.
If i discover that the 20A coming from the D250S is not sufficient, i can always add the SMARTPASS.
The power relay I intend to use is McMaster P/N 7384K21.
Anyone see an issue with going this route? I can draw up a wiring diagram if there is confusion.
I have decided to add a CTEK D250S with two Renogy RNG-100D 100 Watt panels wired in parallel and a connection to the alternator.
I will keep the Magnum Inverter/Charger also.
I will route the output from the D250S through a Single Pole Double Throw (SPDT) power relay that is wired to the shore power feed line. When the shore power is plugged in, it will activate the relay and disconnect the D250S from the battery.
This will keep the Magnum and the D250S from ever trying to charge the battery at the same time.
It will also allow me to keep the Magnum connected and acting as my Inverter when the shore power is not connected.
I realize the D250S is limited to 20A, but i'm hoping with my relatively small battery bank, and the solar panels keeping them topped off all the time, it will be enough. I also like that it doesn't put a huge load on the sprinter charging system.
If i discover that the 20A coming from the D250S is not sufficient, i can always add the SMARTPASS.
The power relay I intend to use is McMaster P/N 7384K21.
Anyone see an issue with going this route? I can draw up a wiring diagram if there is confusion.