I have two House batteries, different sizes, capacities, and ages. They are both being charged from a single house-charger connection. There is obviously a charging conflict, as the charger can only "see" the combination of both batteries, so charging is not ideal for either battery. My charger has a spare charging connection and can handle three batteries (Starter battery is separate and isolated). My plan is to add an additional battery switch or to change the single house-switch to a 1, 2, or Both-type switch. The problem that I see is that while in berth, with battery charger On, and should both house batteries be switched On, the charger might/would be cross-charging both house batteries, perhaps screwing with the charger's electronics. I've looked at a dozen on-line schematics for add-a-battery, etc., but haven't found a resolution for this potential problem. Other than placing signs on the battery switch(es) and/or at the charger panel switch to only have one house battery On at a time, is there a simple resolution, or should I not worry about the cross-charging problem? Many thanks for your help.
Batteries, Isolators, Charging
- Thread starter jmkinsfbay
- Start date
KISS. Make your two batteries into one BANK, and remove the isolator. Isolators end up dropping valuable voltage and are 29080s technology.
Continue to use your single house-charger connection to the house bank.
How are you charging your start bank now? Just from another isolator?
What kind of switching do you have now?
These may help for further discussion:
Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: http://c34.org/bbs/index.php/topic,6604.0.html
This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowners.com/showthread.php?t=137615
Continue to use your single house-charger connection to the house bank.
How are you charging your start bank now? Just from another isolator?
What kind of switching do you have now?
These may help for further discussion:
Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: http://c34.org/bbs/index.php/topic,6604.0.html
This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowners.com/showthread.php?t=137615
Hi Stu. Thanks. The boat is a 2006 Beneteau 343. All of the battery compartment wiring is very complicated, and the way the house batteries are situated now is a "bank". There is one battery switch for the engine battery and one switch for the house bank. The charger has three separate outputs for three separate batteries; the engine battery is on one output and the house bank (two batteries) is on another output. The third charger output is unused, the one I wish to use for the second house battery. It may be a dumb thing to consider, but because when I disconnect one house battery or the other, the voltage at the panel meter is different for each battery, therefore my thoughts that the house batteries as a "bank" are not each getting their proper charge, but some sort of in-between charge because of the battery differences. The primers you sent are good - I've read quite a number of them, BUT, I still would like somebody to spell out the bottom line with regards to how efficiently the charger is working when it's charging two batteries of different size and age at the same time; the feedback from the batteries to the charger cannot be ideal. BTW, I have a T-handle switch for the starter battery and one for the house bank, typical for Beneteau (the switches are of French make, I believe, and almost impossible to find). There is no 1/Both/2/Off switch at this time.
Is your wiring like this? At least for the battery bank wiring for switching. I recognize that you have two house batteries, but let's start from there.
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Here's a Beneteau wiring diagram in this link: please read both pages
http://forums.sailboatowners.com/index.php?threads/electrical-question.134692/&highlight=beneteau wiring
Beneteau multiple switches
http://forums.sailboatowners.com/index.php?threads/electrical-question.134692/&highlight=beneteau wiring
Beneteau multiple switches
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#1 Batteries in a contiguously wired parallel house bank, permanently wired in parallel even with the switch off, should be same type, size, brand and preferably same date code and lot code. If they are not then this needs to be addressed first.
#2 Nearly every Beneteau or Jenneau owner I work for does not comprehend the battery switch configuration. They all tend to assume the start battery is "isolated" from house when the switches are ON. This is 100% FALSE! Beneteau wires a permanent jumper on the "load" side of each ON/OFF switch so that when both switches are turned ON both banks are in PARALLEL..... Beneteau & Jenneau, as brand,s are the two of the boats I see most with two dead battery banks and no way to start the motor. Once you are done with the motor the start switch MUST be turned OFF or you are wired in parallel with the house bank during discharging..
#3 The alt is wired to the load side of the switches so that only the banks that are turned on get charged. Problem is that if you leave both banks ON all the time you can discharge ALL the batteries on the boat.
#4 The charger is wired to the battery side of the switch so that when the switches are OFF both banks can still be charged dock side. You only need to use two outputs. It is still one charge with one voltage regulation circuit and both banks charge using the same charge profile. The multiple outputs are simply diode isolated inside the charger so that when it is OFF the banks are not wired in parallel.
#5 Beneteau & Jenneau Rx:
A) Install a negative distribution busbar and get rid of the switch in the NEGATIVE circuit. This is not compliant with US safety standards anyway and serves no purpose..
B) Remove the paralleling jumper wire between the HOUSE and START switches.
C) Re-purpose, and clearly label the old negative switch as an EMERGENCY PARALLEL SWITCH. Wire it as such by inserting it into the LOAD SIDE of the HOUSE and START switches. If you want to charge both banks from the alternator turn this switch to ON. If you need to parallel turn this switch to ON, otherwise leave it OFF. Your start battery now becomes a dedicated start battery not always in parallel with HOUSE when ON, and your HOUSE becomes a dedicated HOUSE bank.
D) BONUS: Install an Echo type charger or an ACR/VSR (voltage sensitive relay) between house and start so that both banks AUTOMATICALLY CHARGE and AUTOMATICALLY ISOLATE no matter which switch is on or off.
E) Double Bonus: Get rid of the factory Viatemis battery switches and replace them with top quality Blue Sea switches that can't be knocked OFF or ON by kids or adults legs when getting into or out of the quarter berth..
#2 Nearly every Beneteau or Jenneau owner I work for does not comprehend the battery switch configuration. They all tend to assume the start battery is "isolated" from house when the switches are ON. This is 100% FALSE! Beneteau wires a permanent jumper on the "load" side of each ON/OFF switch so that when both switches are turned ON both banks are in PARALLEL..... Beneteau & Jenneau, as brand,s are the two of the boats I see most with two dead battery banks and no way to start the motor. Once you are done with the motor the start switch MUST be turned OFF or you are wired in parallel with the house bank during discharging..
#3 The alt is wired to the load side of the switches so that only the banks that are turned on get charged. Problem is that if you leave both banks ON all the time you can discharge ALL the batteries on the boat.
#4 The charger is wired to the battery side of the switch so that when the switches are OFF both banks can still be charged dock side. You only need to use two outputs. It is still one charge with one voltage regulation circuit and both banks charge using the same charge profile. The multiple outputs are simply diode isolated inside the charger so that when it is OFF the banks are not wired in parallel.
#5 Beneteau & Jenneau Rx:
A) Install a negative distribution busbar and get rid of the switch in the NEGATIVE circuit. This is not compliant with US safety standards anyway and serves no purpose..
B) Remove the paralleling jumper wire between the HOUSE and START switches.
C) Re-purpose, and clearly label the old negative switch as an EMERGENCY PARALLEL SWITCH. Wire it as such by inserting it into the LOAD SIDE of the HOUSE and START switches. If you want to charge both banks from the alternator turn this switch to ON. If you need to parallel turn this switch to ON, otherwise leave it OFF. Your start battery now becomes a dedicated start battery not always in parallel with HOUSE when ON, and your HOUSE becomes a dedicated HOUSE bank.
D) BONUS: Install an Echo type charger or an ACR/VSR (voltage sensitive relay) between house and start so that both banks AUTOMATICALLY CHARGE and AUTOMATICALLY ISOLATE no matter which switch is on or off.
E) Double Bonus: Get rid of the factory Viatemis battery switches and replace them with top quality Blue Sea switches that can't be knocked OFF or ON by kids or adults legs when getting into or out of the quarter berth..
Maine,
Is that true of newer Beneteau's too? As far as I can tell our 2014 came with the batteries separated (the voltages definitely read differently), and there's an isolator like the one I've pictured to charge both banks.
While we're on the topic, how does this type of "voltage drop free" isolator compare with the types you've recommended in the past?
Okay, so many thanks. The bottom line was in the Maine Sail list, saying that a battery bank needed to have the same group, size, and age of batteries (I'm presuming that's because of the charging system). At this time (I can't remember the Group #'s) I have a large and standard battery for the house bank, having installed the larger so I could keep the 'fridge running while out sailing. And, there's not room for two large batteries. So, with Maine Sail's statement in mind, it's apparent that it's not good to have unequal batteries on the same charging circuit (is there any other disadvantage?). That brings about the reason for my starting the whole thread, that is, I want to put in a separate On - Off switch for the second house battery (those batteries would then be a bank only when both switches are On). Then have a charger output to each of the house batteries. BTW, the schematic that was sent showed a single charge wire going to the engine/start battery and the house battery; my system at present has separate charge wires for the engine battery and the house bank. So, here's what I should have asked initially (ignoring the engine-battery circuit): I want to have a battery switch for each of the house batteries, so that each battery gets its own charging circuit. Is there a downside(s) to that proposal? BTW, the house bank batteries would still be in parallel configuration when both of their switches are turned On. Also BTW, having left both engine battery and house battery switches On while in the boatyard for a week, found all batteries dead when boat was re-launched, as per the Maine Sail comment above, so indeed they are not isolated from each other, EXCEPT, I can't start the engine with the housebank batteries unless I jumper across.