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Auxillary Battery - charging?

mhead

NAXJA Forum User
Location
Encinitas, CA
Anyone installed an extra battery? I want to put a 12 VDC refrigerator in the back of my XJ. I'll need extra battery power.

I'll need a deep-cycle battery. Suggestions for mfgr, source?
I'll want to charge it from the main alternator but when the motor shuts down I'll want to draw only from the extra battery, not from the normal battery. Any fancy circuits for this?

Thanks!
 
as far as battery, I'd go optima... just cause we've has such a good experience with them in our boat. they require no maintenance, and can take all the shock you throw at 'em. only downside is the cost...as far as the alternator..... any chance you gould jerry rig a second alternator in? it would get you two seperate 12V sources.....?
 
mhead said:
Anyone installed an extra battery? I want to put a 12 VDC refrigerator in the back of my XJ. I'll need extra battery power.

I'll need a deep-cycle battery. Suggestions for mfgr, source?
I'll want to charge it from the main alternator but when the motor shuts down I'll want to draw only from the extra battery, not from the normal battery. Any fancy circuits for this?

Thanks!

they do this a lot in boats. i did a quick search on marine dual battery switch and found this http://shop.genuinedealz.com/items/item.aspx?itemid=3990854
it allows you to select one or the other or both..or off when the engine in not running
 
I'm running a battery Isolation solenoid, also known as a constant duty solenoid. My setup is not quite done yet, all I need is the second battery. All the wiring is done, when the key is on the second battery will be active.

Justin
 
The National Luna DIY Split Charging Kit is a complete turnkey Dual Battery system, complete with an Intelligent Solenoid, Dual Controller, and all the necessary materials to complete the job. The Split-charge kit will monitor the state of your batteries and the charging source. Connection is automatic, so you don't have to remember to connect your auxilliary battery whilst driving. The Split-charge controller will automatically isolate the auxilliary battery when the batteries are no longer receiving a charge voltage.
**********
And apparently it allows you to jump start from the aux batt. Pricy but seems to do it right.
Might want to check out Overland Journals review of fridges too.
 
Go to this website...
http://www.wranglernw.com/

Order their catalog and then drool...actually they have all the switches, the milspec battery terminals, isolators and cables you'll need. If you want to amp up your alternator, they have that too.

Hope you get it installed, then you can over me a cold drink on the trail in Moab :rolleyes:
 
I can help you sort out the wiring (I've got wiring instructions for my solenoids posted on the site.) It's not that difficult - and I actually prefer using solenoids over solid-state isolator packages (run cooler, cost less, higher current ratings, and smaller.)

It's really not that difficult to wire up a solenoid (vice an isolator,) and you have more options with the solenoid.

Link's in my sig.
 
Shogun said:
The National Luna DIY Split Charging Kit is a complete turnkey Dual Battery system, complete with an Intelligent Solenoid, Dual Controller, and all the necessary materials to complete the job. The Split-charge kit will monitor the state of your batteries and the charging source. Connection is automatic, so you don't have to remember to connect your auxilliary battery whilst driving. The Split-charge controller will automatically isolate the auxilliary battery when the batteries are no longer receiving a charge voltage.
**********
And apparently it allows you to jump start from the aux batt. Pricy but seems to do it right.
Might want to check out Overland Journals review of fridges too.

I am running something similar but built for the marine industry instead. Cost $120.00+ but very reliable. It also allow you the charge different battery types from the same alternator and doubles as a parallel switch. I requires no input from me.
Before that I had a constant duty solonoid wired into the ignition switch. That was not exactly what I wanted. I did not allow for efficient charging of different batterry types.
 
lowrange2 said:
Why don't you just run a second battery parallel to the original and get your alternator amped up.

You should never run two different battery types this way, plus without an isolation circuit, he would just drain both batteries at the same time.

Most diesel trucks run two batteries this way to get plenty of power for starting. However they are the exact same battery, and you need to replace both at the same time.
 
Tayman - Optima sounds like a familiar name. Seems like there are two types, red top for starting service and yellow top for deep cycle. I'll want yellow top. Where should I buy?

Matt1994xj - thanks for switch info. My objective is to charge both batteries at the same time, to use the factor battery for starting services, and to use the aux battery for refrigerator. So for charge they can be paralleled but for use they must be seperate. I'll forget so I need a system that accomplishes this automatically. Now it would be nice to use the aux battery in times of need as a 'jump' start and switches, heavy wiring could be added for this purpose. But to save weight, cost, and effort - and recognizing I don't often need a 'jump' I'll skip this and simply plan to use my jumper cables that I carry anyway should the need arise.

Xjjeeper19 (Justin) Thanks for constant solenoid. Does this device come with a smart controller so that the solenoid connects the aux battery when the motor is running and alternater charging current is available, then disconnects when motor stops? If so this sounds simple.

Shogun - National Luna - is there a USA supplier? Looks $$$ but they have a complete system package. I'm thinking I can just purchase a battery isolator (transistorized gadget) and use lighter gauge wiring. But I'd really like to read 'Overland Journal' review of fridges. An Internet hunt returns a list of off-topic URL. Do you have a better description or URL? Thanks!

Lowrange2 - No, a permanently paralled aux battery would allow the main battery to service refridgerator demand and possibly discharge to the no-start point. I need aux to charge in parallel but power the refrigerator independently.

Boatwrench - wow I see $465 for a complete solution, MINUS the battery. Too much cash for me! I'll make my own battery rack. But nice stuff as you say...

5-90 Same question as above - is solenoid automatic? Looked over your site and didn't find solenoid info under 'electrical' section. But I built jumper cables in a similar way as you, from welding cable. I like the Greylock connectors. I ended up using welding connectors to plug my winch. Cost a lot...

Techno1154 - Guess you are using a transistorized battery isolator, based on $120 price. Which one? Mfgr? Supplier? Thanks!

TrailreadyXJ - Agree about different battery types. Especially different chemistry batteries since different chemistries have different full-charge voltages. One will pull the other down. Also different service types, start & deep-cycle, shouldn't be paralleled for the same service. But I think that different types can be paralleled during charging provided that both are designed to be charged in the normal 12 VDC XJ electrical system.

Thanks all for the input. I'm guessing I'll go with an isolator or maybe I can find a fully automatic solenoid.

I guess the next phase is installation, which will require moving of the intake air cleaner and installation of a battery rack.

I've a good idea for the intake air cleaner. I have a Quadratec hood with a scoop which gives additional space above the 4.0 I-6. Figure I'll just cut off the airbox bottom, flip the lid-filter-cut bottom over upside down and locate just above the 4.0 towards the firewall. I'll have to make a bracket but there is room and this will get my intake up out of the XJ water bow wave. As for mounting battery I'll have to weld up something out of angle iron that bolts to the old intake air box screws. I can't understand why the commercial mounts are sooooo mucccch moooonnnneeyyyy!

Mike
 
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we use blue top for our deep cycle need... our bowmount trolling motor. we got ours at costco, but other places may be cheaper. I'm not even sure costco has them anymore... it's been a while
 
mhead said:
Tayman - Optima sounds like a familiar name. Seems like there are two types, red top for starting service and yellow top for deep cycle. I'll want yellow top. Where should I buy?

Matt1994xj - thanks for switch info. My objective is to charge both batteries at the same time, to use the factor battery for starting services, and to use the aux battery for refrigerator. So for charge they can be paralleled but for use they must be seperate. I'll forget so I need a system that accomplishes this automatically. Now it would be nice to use the aux battery in times of need as a 'jump' start and switches, heavy wiring could be added for this purpose. But to save weight, cost, and effort - and recognizing I don't often need a 'jump' I'll skip this and simply plan to use my jumper cables that I carry anyway should the need arise.

Xjjeeper19 (Justin) Thanks for constant solenoid. Does this device come with a smart controller so that the solenoid connects the aux battery when the motor is running and alternater charging current is available, then disconnects when motor stops? If so this sounds simple.

Shogun - National Luna - is there a USA supplier? Looks $$$ but they have a complete system package. I'm thinking I can just purchase a battery isolator (transistorized gadget) and use lighter gauge wiring. But I'd really like to read 'Overland Journal' review of fridges. An Internet hunt returns a list of off-topic URL. Do you have a better description or URL? Thanks!

Lowrange2 - No, a permanently paralled aux battery would allow the main battery to service refridgerator demand and possibly discharge to the no-start point. I need aux to charge in parallel but power the refrigerator independently.

Boatwrench - wow I see $465 for a complete solution, MINUS the battery. Too much cash for me! I'll make my own battery rack. But nice stuff as you say...

There are three basic types of Optima - Red Top (starting,) Blue Top (deep cycle,) and Yellow Top (combination.) You should be able to find Optimas at any decent parts house - if they don't have them, they should be able to tell you where you can get them. I've also heard good things about Odyssey batteries.

The solenoid does require being wired up - but you simply use a "Hot in RUN" lead somewhere to trigger the 'noid. When the engine is running or the key is in RUN, the solenoid will close the circuit and you'll be charging the battery. Turn the key off, and the batteries are separated. There are a couple of override options for the solenoid if you want to go to the trouble - Override ON (allows you to start from the auxiliary battery) and Override OFF (allows you to cut the auxiliary all the way out, in case you drain it dead flat. Then, you leave the auxiliary off until you can pull it and charge it, or you get the engine started and the alternator can charge it.) As I've mentioned, there are wiring diagrams on my site (under "Instructions" - they're .pdf, so you'll need Acrobat Reader) for the various ideas. Which lead you use to trigger the solenoid depends on what year you've got, and where you mount the solenoid (which should be underhood somewhere - keeping the heavy-gage high-current leads short is a Good Thing (tm).) And, as you've said, you can always just use booster cables to get a self-jump going. A "smart controller" isn't necessary - a solenoid is a simple solution (and that's why I use them - I found out about them doing my "industrial mechanic" thing a few years back...)
 
Mhead asked??

Techno1154 - Guess you are using a transistorized battery isolator, based on $120 price. Which one? Mfgr? Supplier? Thanks!

Yandina.com

I am using the combiner 150 rated at acontinous 150 AMPS or 200 AMPS for for 5 minutes. The price is higher now than when I bought mine 2 years ago at a West Marine in Miami.
 
mine is just a 200 amp constant solenoind....nothing special, cost me 50 bucks. Wired to an ignition on source, key on batteries are on key off, seperate systems.
 
Well, I've found 'battery isolator' on the 'net. These are the transistorized gadgets I mentioned above. I have a detailed question that perhaps can be answered...

One easy way to build an isolator is to use two high-current diodes, forward biased, from alternater one to each battery. Easy, but you loose the 0.7 Volt diode forward bias so the battery doesn't receive full alternator voltage and perhaps doesn't fully charge.

The second is to use a smart circuit that connects a semiconductor switch when alternator voltage is greater than battery voltage.

Now I haven't any idea if these methods are used for battery isolators. Does anyone know?
 
I simply used a 300amp solenoid from our snowplow pump. 45.00 at Carquest. Wired it to an on during Run only source, but also through a switch for extra control.

Save me 1-2 time before on the trail when I as having alternator fuse issues, gave me enough juice ever time to get home.
 
mhead said:
Well, I've found 'battery isolator' on the 'net. These are the transistorized gadgets I mentioned above. I have a detailed question that perhaps can be answered...

One easy way to build an isolator is to use two high-current diodes, forward biased, from alternater one to each battery. Easy, but you loose the 0.7 Volt diode forward bias so the battery doesn't receive full alternator voltage and perhaps doesn't fully charge.

The second is to use a smart circuit that connects a semiconductor switch when alternator voltage is greater than battery voltage.

Now I haven't any idea if these methods are used for battery isolators. Does anyone know?

Just use the solenoid. Size it for your max rated output less about 30-35A, since the most you can usually send to the auxiliary battery is "alternator output - engine current requirement."
 
Shogun - National Luna - is there a USA supplier? Looks $$$ but they have a complete system package. I'm thinking I can just purchase a battery isolator (transistorized gadget) and use lighter gauge wiring. But I'd really like to read 'Overland Journal' review of fridges. An Internet hunt returns a list of off-topic URL. Do you have a better description or URL? Thanks!
**************

equipt outfitters has it, around $300.

I have looked at wrangler nw years ago, still come away baffled at the $ required. Very proud of thier stuff I guess.

The diesel battery tray should be dealer available for the left side, somebody has the pn (gojeep?). Frankly I wouldnt trade away a good aircleaner for a second battery. Put the aux batt in the back.

Overland Journal should be at http://www.overlandjournal.com/ , in the summer 07 issue.
 
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