Battery Voltage and State of Charge
I used a solar charger on a jet ski battery as a battery tender over a winter. It ended up overcharging and frying the battery. Switched to a AC powered battery tender I found on ebay for $25 (US). Has a nifty little plug so you can leave the leads hooked up to the battery but unplug the charging unit.
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From: Ireland
Sounds like I was lucky I bought the cheapt and presumably low output 2003 solar panel. My logic was that ctcles of volt out put charge appear to be what the good battery maintaining devices do..... and I didn't want any cable going out to the car which is parked outside. I also see an advantager of the solar panel method whenever I park up at the airport for 2 weeks !
After my sucessful 7 year trial of the system on an XJ8 ..... I'd use it again but make sure it was a LOW output panel.
After my sucessful 7 year trial of the system on an XJ8 ..... I'd use it again but make sure it was a LOW output panel.
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Joined: Jul 2011
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From: New York
Great post!
Two checks today:
1. 12.59V, then a load test yielded 12.35V.
2. 489 out of (guessed) 650 cold cranking amps without load, with a potential of 12.32V.
Would you guys change this battery? I know there are Gremlins that appear with low voltages.
Two checks today:
1. 12.59V, then a load test yielded 12.35V.
2. 489 out of (guessed) 650 cold cranking amps without load, with a potential of 12.32V.
Would you guys change this battery? I know there are Gremlins that appear with low voltages.
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From: Tucson
How old is the bat? Mine was 9 and still worked, but I didn't want to get stranded here in the frozen tundra of Chicago.
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From: New York
Any input from others?
Last edited by Scottish Chap; Jan 29, 2012 at 03:57 PM.
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From: on-the-edge
Found my own old post while searching for state of charge information.
So, here is a link with additional information:
Car and Deep Cycle Battery Frequently Asked Questions (FAQ) Section 4
So, here is a link with additional information:
Car and Deep Cycle Battery Frequently Asked Questions (FAQ) Section 4
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Joined: Mar 2011
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From: Texas
Hello
curious does this statement still stands true?
just purchased battery tender for the XKR and don’t want to install it incorrectly.
One of the techs on this site told me (and I am now telling you all) DO NOT install the ground side of the tender cable directly onto the negative (-) post of the battery. Instead, wire it to the spare tire hold down post. At first I went right to the ground side of the battery and that somehow "confused" the ECM into thinking the battery was low when it was indeed fully charged
thanks in advance
-dag
curious does this statement still stands true?
just purchased battery tender for the XKR and don’t want to install it incorrectly.
One of the techs on this site told me (and I am now telling you all) DO NOT install the ground side of the tender cable directly onto the negative (-) post of the battery. Instead, wire it to the spare tire hold down post. At first I went right to the ground side of the battery and that somehow "confused" the ECM into thinking the battery was low when it was indeed fully charged
thanks in advance
-dag
After a few battary/charging issues of my own, I decided to hard wire a battery tender cable to the battery in the trunk of my XK. that way, I don't have to crawl under the rear of the car to clip onto the positive (+) post behind the quarter panel each time I wanted to leave the car on a tender.
Now, the important part. One of the techs on this site told me (and I am now telling you all) DO NOT install the ground side of the tender cable directly onto the negative (-) post of the battery. Instead, wire it to the spare tire hold down post. At first I went right to the ground side of the battery and that somehow "confused" the ECM into thinking the battery was low when it was indeed fully charged. As a result, the car started shutting down secondary systems in an effort to "save" more critical power requirements.
These days, if I am leaving the XK in the garage for more than even a day or to, I simply open the trunk, connect my tender directly to the cable I pre-installed, close the trunk, turn on the juice, and as they say in my home town of New York City..."FORGET ABOUT IT"..
Now, the important part. One of the techs on this site told me (and I am now telling you all) DO NOT install the ground side of the tender cable directly onto the negative (-) post of the battery. Instead, wire it to the spare tire hold down post. At first I went right to the ground side of the battery and that somehow "confused" the ECM into thinking the battery was low when it was indeed fully charged. As a result, the car started shutting down secondary systems in an effort to "save" more critical power requirements.
These days, if I am leaving the XK in the garage for more than even a day or to, I simply open the trunk, connect my tender directly to the cable I pre-installed, close the trunk, turn on the juice, and as they say in my home town of New York City..."FORGET ABOUT IT"..
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Hello
curious does this statement still stands true?
just purchased battery tender for the XKR and don’t want to install it incorrectly.
"One of the techs on this site told me (and I am now telling you all) DO NOT install the ground side of the tender cable directly onto the negative (-) post of the battery. Instead, wire it to the spare tire hold down post. At first I went right to the ground side of the battery and that somehow "confused" the ECM into thinking the battery was low when it was indeed fully charged."
curious does this statement still stands true?
just purchased battery tender for the XKR and don’t want to install it incorrectly.
"One of the techs on this site told me (and I am now telling you all) DO NOT install the ground side of the tender cable directly onto the negative (-) post of the battery. Instead, wire it to the spare tire hold down post. At first I went right to the ground side of the battery and that somehow "confused" the ECM into thinking the battery was low when it was indeed fully charged."
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Joined: Apr 2013
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From: An archipelago tropical chain of islands
Cigarette Lighter Connection?
I bought a cheap solar panel car charger and placed it on rear shelf. Wire can be hidden down edge of rear seat and to right hand kick panel. Then add an aftermarket fused cigarette lighter to the main 12 v terminals there and plug in the solar charger. Less than 5 minutes neat and no permanent modification.
I installed this in 2004 on my xj8 which tends to stay parked up for weeks at a time. Prior to the instalation battery went flat over any 2 week park up period and I ruined a OEM three year old battery. The cheap replacement battery never let me down and lasted 7 years until the day my wife accidentally turned the solar panel upside down. Then two weeks later the battery was deeply discharged and not recoverable.
Hence it seems:
A $20 dollar solar panel charger prevents the discharge on parking and possibly saves more than its cost by lengthening the life of the battery even in winter, even in northern latitudes (daylight 8.30am to 4.30pm).
I installed this in 2004 on my xj8 which tends to stay parked up for weeks at a time. Prior to the instalation battery went flat over any 2 week park up period and I ruined a OEM three year old battery. The cheap replacement battery never let me down and lasted 7 years until the day my wife accidentally turned the solar panel upside down. Then two weeks later the battery was deeply discharged and not recoverable.
Hence it seems:
A $20 dollar solar panel charger prevents the discharge on parking and possibly saves more than its cost by lengthening the life of the battery even in winter, even in northern latitudes (daylight 8.30am to 4.30pm).
Because I’ve always seen these trickle chargers that they claim plug into your cigarette lighter and that seemed good too good to be true, so I never trusted the concept. I thought you would have to directly connect to the battery to even trickle charge.
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Joined: Nov 2011
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The factory lighter plug is on a switched circuit (at least on my 2001). Sounds like previous poster wired a seperate receptacle to a non switched circuit. In lieu of a cigarette receptacle, many of the solar chargers have a 2 prong disconnect. You could even wire it direct to battery
They do work well unless you have a serious parasitic drain.
They do work well unless you have a serious parasitic drain.
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