I have a similar set up on my C22 with two batteries connected together, but I do not have access to AC. I purchased a solar panel that clips to the positive and negative posts when I am moored and thinking the solar panel would charge the batteries. I bought what I thought was a big enough panel (I know nothing about amps/watts/etc), but I can not get the batteries over 8 on the battery meter. Can someone recommend a solar panel that will charge these batteries, please bear in mind that I am electrically challenged. Thanks in advance.
Charging batteries in Parallel question
- Thread starter BillyK
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We are just sailors and practical recommendations on what works and what doesn't is all we may need.
I dont know how to draw diagrams to post here, but if i could i would....
as you already know, hooking two batteries together will increase your capacity. a parallel connection increases amperage capacity and a series increases voltage capacity.
but in a parallel connection, to maximize the usage and life of the batteries you need to hook them up to draw and charged in a balanced manner. and you can do this even if the batteries are far apart from one another.
it is simple to do.... and you may already have it wired this way, unless it is wired like you show in the diagram you have listed.
hook the two batteries together positive to positive, and negative to negative........ you now have one large capacity battery. now you can call it a bank of batteries.
the positive lead that comes from the cabin will hook to the positive post of one battery, and the negative lead that comes from the cabin should be hooked to the negative post of the OTHER battery..... the charger should be hooked like this also.
any amperage or voltage that is being taken or given will HAVE to be equally passed to or from both batteries this way.
with the way your diagram is drawn, the usage is being taken and given primarily at the first battery, and the battery in the rear of the box is not being used as much.... current will always take the path of least resistance, and the least resistance in your diagram is thru the first battery, because its the shortest path.
and... if the batteries get drawn down substantially, and you charge them with a hot charger (high amperage) the first battery will come up first and then has to take all the heat while the last battery in still in need of charge. but you wont be charging that fast anyway..... but to maximize your battery usage and life, they need to be hooked up in a balance.....
as you already know, hooking two batteries together will increase your capacity. a parallel connection increases amperage capacity and a series increases voltage capacity.
but in a parallel connection, to maximize the usage and life of the batteries you need to hook them up to draw and charged in a balanced manner. and you can do this even if the batteries are far apart from one another.
it is simple to do.... and you may already have it wired this way, unless it is wired like you show in the diagram you have listed.
hook the two batteries together positive to positive, and negative to negative........ you now have one large capacity battery. now you can call it a bank of batteries.
the positive lead that comes from the cabin will hook to the positive post of one battery, and the negative lead that comes from the cabin should be hooked to the negative post of the OTHER battery..... the charger should be hooked like this also.
any amperage or voltage that is being taken or given will HAVE to be equally passed to or from both batteries this way.
with the way your diagram is drawn, the usage is being taken and given primarily at the first battery, and the battery in the rear of the box is not being used as much.... current will always take the path of least resistance, and the least resistance in your diagram is thru the first battery, because its the shortest path.
and... if the batteries get drawn down substantially, and you charge them with a hot charger (high amperage) the first battery will come up first and then has to take all the heat while the last battery in still in need of charge. but you wont be charging that fast anyway..... but to maximize your battery usage and life, they need to be hooked up in a balance.....
sorry... I just took a closer look at your drawing..... your charger is working against itself. you only need one output from the charger to get the best and quickest results to a single bank of batteries. and hooked up as i explained in my previous post.
the way the diagram shows, it can do damage to the charger or the batteries depending on how sophisticated the circuitry is in it..... and/or may not ever bring the batteries up to full charge. each side of the charger is sensing the voltage input voltage of the other side and will shut down prematurly..... it thinks the batts are full of charge. it will keep turning on and off. you are welcome to pm me and I can fax or email you a diagram....
the way the diagram shows, it can do damage to the charger or the batteries depending on how sophisticated the circuitry is in it..... and/or may not ever bring the batteries up to full charge. each side of the charger is sensing the voltage input voltage of the other side and will shut down prematurly..... it thinks the batts are full of charge. it will keep turning on and off. you are welcome to pm me and I can fax or email you a diagram....
centerline
I don't think you have read all the posts. The charger the op has needs to have every output attached to a battery as it is battery sensing. See post #10
As far as the load wiring you are correct.
I don't think you have read all the posts. The charger the op has needs to have every output attached to a battery as it is battery sensing. See post #10
As far as the load wiring you are correct.
The drawing posted above came directly out of ProMariner's instruction manual. I have their ProSport 20 charging and maintaining 2 batteries. The unit that I use has two individual outputs in AC one unit. It also has LED indicators showing the state of charge. It's completely water proof. It has worked perfectly for over three years. For home use I have a Battery Tender with dual outputs charging and maintaining my two motorcycle batteries.
For future reference for other readers.
When buying a ProSport charger PLEASE note the maximum bank size they can charge. Water proof chargers should not be used to charge banks bigger than what the manual specifies as they have no additional cooling options.
Contrast that to a newer power factor corrected and more efficient charger that has a built in fan and you can use most of them to charge what ever sized bank you want. They will control their temp well and work at full output for days if necessary. A ProSport sized to a large bank, incorrectly, will burn itself up.....
These chargers were really designed for Bass boats where they may have a single 12V, 24V or 36V trolling battery to charge...
I stand corrected! both leads of the promariner charger can be hooked to different batteries in the same parallel bank. or for that matter, the same battery, on the chance that you should only happen to have one battery and a promariner charger...
it has always been possible to do this in a series bank, but ProMariner took it to another level and made it fool proof.... so you are getting a balanced charge.
sometimes there isnt always convenient space allowing 2 batteries to sit side by side to be wired together, and with promariners charger it eliminates the need to worry about the far battery getting its charge properly...... they take care of making sure the batteries are being charged correctly, but its up to the boat owner to make sure his draw wires are pulling from each battery in a balanced manner.....
Just some comments on Combiners, Shore chargers, etc.
- I have a single start battery, and a pair of 27s as a house bank.
- I have a bluesea ACR between the start and house bank that "combines" when
the engine is running. Not perfect/optimal charging of each bank, but it does ok.
- My shore power charger has multiple independent outputs.
- I have one output connected to the start bank and one to the house.
- Normally, turning on the Shore charger would activate the ACR, and defeat the
value of having a multi-bank shore charger.
- To avoid this, I have a relay that, activated by the AC going to the shore charger,
disables the ACR.
The end result is that when on shore power, the two banks are charged at their optimal rates, and are completely independent. When charging on the engine, the alternator output is sent to both banks, which likely means sub optimal charging, but sufficient to ensure that both get some charge (I don't usually motor for very long)
When the engine is off and we're not on shore charger, the banks are isolated (ACR notices the voltage drop and un-combines), and there is no risk of draining the start battery.
The system is almost completely free of the need for human interaction and thus human error or forgetting to flip a switch.
A final improvement would be to eliminate the ACR and use a Echo charger so that under engine charging, the start bank and house bank are charged independently and according to the appropriate battery needs/chemistry/characteristics.
Right now, if I get in the morning after a previous day of draining my house bank down (but my start battery is still fully charged), and start my engine, my start battery will likely be overcharged (voltage too high), while my alternating is dumping most of the current into the house bank. An Echo charger for the start battery would help prevent that.
Chris
- I have a single start battery, and a pair of 27s as a house bank.
- I have a bluesea ACR between the start and house bank that "combines" when
the engine is running. Not perfect/optimal charging of each bank, but it does ok.
- My shore power charger has multiple independent outputs.
- I have one output connected to the start bank and one to the house.
- Normally, turning on the Shore charger would activate the ACR, and defeat the
value of having a multi-bank shore charger.
- To avoid this, I have a relay that, activated by the AC going to the shore charger,
disables the ACR.
The end result is that when on shore power, the two banks are charged at their optimal rates, and are completely independent. When charging on the engine, the alternator output is sent to both banks, which likely means sub optimal charging, but sufficient to ensure that both get some charge (I don't usually motor for very long)
When the engine is off and we're not on shore charger, the banks are isolated (ACR notices the voltage drop and un-combines), and there is no risk of draining the start battery.
The system is almost completely free of the need for human interaction and thus human error or forgetting to flip a switch.
A final improvement would be to eliminate the ACR and use a Echo charger so that under engine charging, the start bank and house bank are charged independently and according to the appropriate battery needs/chemistry/characteristics.
Right now, if I get in the morning after a previous day of draining my house bank down (but my start battery is still fully charged), and start my engine, my start battery will likely be overcharged (voltage too high), while my alternating is dumping most of the current into the house bank. An Echo charger for the start battery would help prevent that.
Chris
Chris, unless you're pumping tons of amps into your banks when on shorepower, the battery acceptance will limit the current to your start bank. You second relay seems a tad overkill. Why not just take the shorepower leads off the start battery and let the ACR do the work on shorepower, just like it does with the alternator? I agree that an echo charger would be a "better" solution than the ACR, but once you go into float, it's pretty much the same.
Your boat, your choice.
Your boat, your choice.
Actually they are very good devices though many folks misunderstand them and how they work. There is a lot of misunderstanding and misinformation about ACR's out there.
While some charger do have "multiple independent outputs" most really don't. A true "multiple independent output" would mean your start battery could be charging at 13.2V while your house bank was taking 14.8V. This is VERY rare until you get into expensive Mastervolt or Vicron units. It is rare because you need two complete charge control circuits in one box.
Most battery chargers have just one charging algorithm yet they still have multiple outputs. The outputs use diodes of FET's to keep one bank from flowing into another. Basically the outputs simply go through diode isolators but all outputs see the SAME algorithm or charging voltage. So, does a full start battery really need the 14.8V that the house bank may be getting? Usually not.
I question whether you really have a "multi-bank" charger with independent outputs or a single charger with diodes for each bank? Either way you've gone to a lot of trouble and did not really need to. Unless you have a real "multiple independent output" charger and ACR can arguably do a better job than a multi-output charger.. With a multi-output charger you can be over charging the start battery while the house bank requires absorption voltages. With an ACR both banks are at the same voltage thus you can't over charge one bank.
If this is true then your charger will be charging the start battery at a float voltage while the house gets a different voltage. Some do this but there are very few chargers that really do this. This is why an ACR can be such a great device.
There is nothing sub optimal about charging with the batteries combined unless they are different chemistry banks.. However if you reside at a dock mostly then you may not even need to combine for the start battery, but there is nothing wrong with it.
This is where the ACR or an B2B type charger beats a human, they never forget....
Here's where the misunderstanding part of ACR's comes into play. When you combine batteries you are now charging ONE battery. There is no "optimal" for a start battery or a house battery as they are now ONE bank, with ONE voltage. Once combined they reach an equilibrium voltage fairly quickly and this prevents the start battery from be "over charged". It is impossible to over charge either bank or feed one bank a voltage higher than what it needs with a voltage sensing relay. The benefit of an Echo is that you can mix bank chemistry except for GEL House + WET or AGM for starting as the start batts would then be chronically under charged.
Again the myths, wives tales and urban legends about ACR's abound. This is not your fault there are many out there who don't fully understand how they work and they perpetuate these myths.. What you said in bold absolutely positively can't happen with an ACR... After a few minutes of charging combined BOTH banks will be at an equal voltage thus you can not over charge one bank without over charging both banks. If you're over charging both banks then you have another problem that the ACR did not cause...
Hope this makes sense...
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