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separate house load from Port Starting Batteries
- Thread starter BVasily
- Start date
- Joined
- Jan 1, 2000
- RO Number
- 3238
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- 4,831
I thought you were given a good starting point in the previous thread, but parhaps a little expansion will be useful.
http://www.boatered.com/forum/topic.asp?TOPIC_ID=209063
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In words, the concept is easy. Set up the engine start battery and engine/alternator as a stand alone, serving NO other loads.
This will allow the engine to use the start battry to srart up, and also allow the alternator to resrote and maintain the stat battery at full charge.
Next:
Use either a diode type or a relay type :battery isolator to deal with charging the house bank.
THe relay type device will activate only once the start batery circuit maintains a "fully charged" voltage. It then opens ( paralleling the banks ) and this will cause the original bank abnd alternator to charge the house bank.
The catch: a) Not only will the alternator charge the House, but also the Start battery will contribute to the charging process.
Not ideal, but it is very simple to set up and requires no user input to operate. Many boaters use such a setup.
A diode system is similar, with two ( actually three ) differences: THe Original stary battery section will not drop below "fully charged" voltage, and there will be no reverse flow. The third item is how to wire it which can get confusing. The diode will cause a 0.6 volt drop in the circuit so the house side of the circuit will be about a half colt lower than the srart side. THere are workaroounds...
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I have not addressed the issue of mixing battery types. I do not personally know the charging requirements of a Lithium bank. Which is why I skipped all of this explanation and suggested going direct to the Lithium battery vendor. Who should ( if competent ) have all of the required info handy, in an easy to explain package.
There are different Lithium chemistries, which have different stats. And they all differ from Lead acid. Consideering that you want a robust and safe system, it would be best to get the info from someone who should have the knowledge ( and tools ) required. Messing up a large battery bank can get very messy and hazardous... You want it right the first time.
IMHO, of course. But is should be an entertaining learning experience.
Let us know what you decide!
http://www.boatered.com/forum/topic.asp?TOPIC_ID=209063
-----------
In words, the concept is easy. Set up the engine start battery and engine/alternator as a stand alone, serving NO other loads.
This will allow the engine to use the start battry to srart up, and also allow the alternator to resrote and maintain the stat battery at full charge.
Next:
Use either a diode type or a relay type :battery isolator to deal with charging the house bank.
THe relay type device will activate only once the start batery circuit maintains a "fully charged" voltage. It then opens ( paralleling the banks ) and this will cause the original bank abnd alternator to charge the house bank.
The catch: a) Not only will the alternator charge the House, but also the Start battery will contribute to the charging process.
Not ideal, but it is very simple to set up and requires no user input to operate. Many boaters use such a setup.
A diode system is similar, with two ( actually three ) differences: THe Original stary battery section will not drop below "fully charged" voltage, and there will be no reverse flow. The third item is how to wire it which can get confusing. The diode will cause a 0.6 volt drop in the circuit so the house side of the circuit will be about a half colt lower than the srart side. THere are workaroounds...
---
I have not addressed the issue of mixing battery types. I do not personally know the charging requirements of a Lithium bank. Which is why I skipped all of this explanation and suggested going direct to the Lithium battery vendor. Who should ( if competent ) have all of the required info handy, in an easy to explain package.
There are different Lithium chemistries, which have different stats. And they all differ from Lead acid. Consideering that you want a robust and safe system, it would be best to get the info from someone who should have the knowledge ( and tools ) required. Messing up a large battery bank can get very messy and hazardous... You want it right the first time.
IMHO, of course. But is should be an entertaining learning experience.
Let us know what you decide!
Thanks Bill. This explanation helps.
The battery vendor simply stated the port and starting loads can be separated but offered no insight as to how or where in the wiring harness this is to be done. The LiFePO4 battery has a different charge profile but can accept almost any charge profile from the current battery charges. The advantage is that it charges fully and as rapidly as the charger can handle. The 400w solar I have installed will charge the LiFePo4 directly when on hook, and it will be also charged by the current charging port when on shore power. (The charger has a LiFo profile but it does not offer individual profiles for each of the charging ports (3) so I will use the AGM profile that matches the rest of the batteries.
My thoughts are to charge the port starting batteries via an intelligent isolator from the starboard charging port.
The battery vendor simply stated the port and starting loads can be separated but offered no insight as to how or where in the wiring harness this is to be done. The LiFePO4 battery has a different charge profile but can accept almost any charge profile from the current battery charges. The advantage is that it charges fully and as rapidly as the charger can handle. The 400w solar I have installed will charge the LiFePo4 directly when on hook, and it will be also charged by the current charging port when on shore power. (The charger has a LiFo profile but it does not offer individual profiles for each of the charging ports (3) so I will use the AGM profile that matches the rest of the batteries.
My thoughts are to charge the port starting batteries via an intelligent isolator from the starboard charging port.
- Joined
- Jan 1, 2000
- RO Number
- 3238
- Messages
- 4,831
The key phrase here is "the harness".
The engine harness will go to the start battery, the boat harness will go to the house.
There will be "some" wire tracing required. Be careful of using supplies diagrams. I know that my boat was "completed" at the dealership. That dealership is now long gone, and for good reasons... Nothing was wired correctly. So trusting the provided diagrams, unless they have been ( personally ) verified may be a problem.
Anything "stuck onto the battery post" most likely should be attached to the house bank. But you will need to verify all of the connections. This is especially true at this stage as leaving something connected that does not belong could potentially cause a high current load to ( in error ) pass along a small wire. This is not desirable. ( and is dangerous )
But you will need to go "hands on" and start tracing. Make lists, take photos, document. When done, not only will your boat be more reliable, but there should be no surprises ( such as finding that an always "on" CO detector was attached to the start bank and completely discharged it. )
Keep beverages handy and try creative cuss words. Sometime that helps.
But odds are that you will discover errors that have been around since day one, and you can make it right in the process. ( I know I did )
The engine harness will go to the start battery, the boat harness will go to the house.
There will be "some" wire tracing required. Be careful of using supplies diagrams. I know that my boat was "completed" at the dealership. That dealership is now long gone, and for good reasons... Nothing was wired correctly. So trusting the provided diagrams, unless they have been ( personally ) verified may be a problem.
Anything "stuck onto the battery post" most likely should be attached to the house bank. But you will need to verify all of the connections. This is especially true at this stage as leaving something connected that does not belong could potentially cause a high current load to ( in error ) pass along a small wire. This is not desirable. ( and is dangerous )
But you will need to go "hands on" and start tracing. Make lists, take photos, document. When done, not only will your boat be more reliable, but there should be no surprises ( such as finding that an always "on" CO detector was attached to the start bank and completely discharged it. )
Keep beverages handy and try creative cuss words. Sometime that helps.
But odds are that you will discover errors that have been around since day one, and you can make it right in the process. ( I know I did )
A quick update to RadioActive post.
Explored the wiring diagram and DC distribution panel in the engine compartment. It looks straight forward to separate the "cabin" harness which powers 2 fridges and a freezer, from the rest and leave the regular batteries in place. I have ordered a battery isolator/relay and will wire the new Lithium battery through it. I assume I can parallel the control wiring from the existing isolator so that the port battery switch in the switch panel will turn both batteries on/off?
Explored the wiring diagram and DC distribution panel in the engine compartment. It looks straight forward to separate the "cabin" harness which powers 2 fridges and a freezer, from the rest and leave the regular batteries in place. I have ordered a battery isolator/relay and will wire the new Lithium battery through it. I assume I can parallel the control wiring from the existing isolator so that the port battery switch in the switch panel will turn both batteries on/off?
- Joined
- Jan 1, 2000
- RO Number
- 3238
- Messages
- 4,831
"... I assume ..."
Might I suggest that you test that this is so? At this point, any error "will always be there". If you confirm proper operation, then you will "know" vs " I think".
At least, that is how/why I would do it.
Hang in there. Get the "fiddly bits" done and verified, then you will end up with a solid performer.
Might I suggest that you test that this is so? At this point, any error "will always be there". If you confirm proper operation, then you will "know" vs " I think".
At least, that is how/why I would do it.
Hang in there. Get the "fiddly bits" done and verified, then you will end up with a solid performer.