Batteries

David & Carolyn · 07-29-2009, 03:40 AM

Our Cruiser has the control panel that lets you know the state of the 12 volt batteries - charged, good, fair, & low. Does anyone know how this relates to the actual voltage of the batteries? Also how low should the voltage be allowed to drop before the batteries are recharged. We do a lot of dry camping and was wondering when we should recharge the batteries so as we do not over task them and have to replace to soon.

rock1424 · 07-29-2009, 05:58 AM

Great question, I don't have an answer, but would really like to know if the 2/3 and 1/3 level indicators actually relate to a voltage. I have wondered if there is a control panel that actually has a digital readout that would be an easy swap. I have always thought that you shouldn't let the battery voltage drop below 12.5 volts, but I'm sure someone will have a more educated answer for you.

csham · 07-29-2009, 06:24 AM

I can't comment on the control panel as my ST does not have that. I can tell you that I do a lot of dry camping also and even being conservative a single battery would barely get me from Friday evening to Sunday afternoon before being too drained to run the water pump. I have added a 2nd battery and a switch to allow me to change batteries without leaving the comfort of my trailer.

Also, welcome to the forum.

Korbe & Diana · 07-29-2009, 07:25 AM

Here is a great web site regarding dry camping battery use. Hope it is helpful.

http://www.macandchris.com/ElectricalSystemSizing.htm

FB1965 · 07-29-2009, 07:49 AM

The way I do mine is let the voltage go until it becomes a problem for me than recharge.I would assume that the panel you ask about is voltage,because there isn't anything else connected to the battery.I usually charge my battery late in the evening to make sure it will last thru the night if I had to run the heat.I have been screwed by the dealer on my last trade,I ask him about the battery he used and didn't check it my self.He had put in a marine starting battery instead of a deep cycle,so that had to be changed.

mosledder · 07-29-2009, 01:07 PM

I agree with csham, Don't count on your batteries alone to get you by for very long.Bite the bullet and go buy you a Honda generator, we got the 2000 and its more than enough to runfurnace, lights, tv. runs 15 hours on 1/2 gal. gas.(that will beplenty of time to charge batteries)and can't hardly hear it. We also have a noisy 5000 to use when we use the toaster or waffle iron, coffee pot,microwave, hairdryer.

Robbie Ribbins · 07-29-2009, 01:55 PM

Somewhere I read when voltage gets below 11 volts its time to recharge. Now I have a question: last year when traveling I could go all day and at night I still had battery power for the ref. controls, but this year at the end of the day battery so low it would not let the ref. work. My question is should the truck be charging the battery while driving. I pulled the battery and took it to the battery shop and it checked ok. This is a 2007 tt. Thanks

FB1965 · 07-29-2009, 03:12 PM

Yes your truck should charge the battery while on the road.I think that the different heat conditions have a lot of effect on the charging of a battery ,so that may be why your battery charge is different than last year.Also the year older battery may be some difference.

fhenn · 07-29-2009, 11:03 PM

Check your fuse in the truck. If that is blown, you will not charge the battery.

Hamops · 07-30-2009, 05:34 AM

When a battery drops to 10.5 volts (1.75V per cell) it is considered discharged. I suspect that the battery monitor is preset to read a "L" value at about 11VDC, "F" at about 11.6VDC, "G" at about 12.2VDC and "C" at about 12.8VDC. The indication is relative and needs to be verified with a DVM.

Robbie Ribbins · 07-31-2009, 08:49 AM

Thanks for the insight of the fuse, as my A/C also quit working on my last few days and this same fuse corrected both problems I think. I have a chevy and the fuse is listed as aux 20 amp. It also has 2 other fuses listed as A/Cheater and HVAC and both of them were ok. Again thanks for the info. Robbie

fhenn · 07-31-2009, 09:29 AM

Good I am glad that this worked for you. Another tip for those who have the factory tow packages, there is a fuse for the left side and a fuse for the right side in your trucks fuse box. if you have a tail light or turn indicator light out and it is not the bulb, check these first

Chrisnan23 · 07-31-2009, 07:35 PM

<H3>State of Charge</H3>

<H4>Here are no-load typical voltages vs state of charge</H4>

(figured at 10.5 volts = fully discharged, and 77 degrees F). Voltages are for a 12 volt battery system. For 24 volt systems multiply by 2, for 48 volt system, multiply by 4. VPC is the volts per individual cell - if you measure more than a .2 volt difference between each cell, you need to equalize, or your batteries are going bad, or they may be sulfated. These voltages are for batteries that have been at rest for 3 hours or more. Batteries that are being charged will be higher - the voltages while under charge will not tell you anything, you have to let the battery sit for a while. For longest life, batteries should stay in the green zone. Occasional dips into the yellow are not harmful, but continual discharges to those levels will shorten battery life considerably. It is important to realize that voltage measurements are only approximate. The best determination is to measure the specific gravity, but in many batteries this is difficult or impossible. Note the large voltage drop in the last 10%.

<DIV align=center>

<TABLE border=1 width=400>

<T>

<TR>

<TH =#ffffff width=132 align=middle>State of Charge</TH>

<TH =#ffffff width=132 align=middle>12 Volt battery</TH>

<TH =#ffffff width=132 align=middle>Volts per Cell</TH></TR>

<TR>

<TD width=132 align=middle>100%</TD>

<TD width=132 align=middle>12.7</TD>

<TD width=132 align=middle>2.12</TD></TR>

<TR>

<TD width=132 align=middle>90%</TD>

<TD width=132 align=middle>12.5</TD>

<TD width=132 align=middle>2.08</TD></TR>

<TR>

<TD =#00ff00 width=132 align=middle>80%</TD>

<TD =#00ff00 width=132 align=middle>12.42</TD>

<TD =#00ff00 width=132 align=middle>2.07</TD></TR>

<TR>

<TD =#00ff00 width=132 align=middle>70%</TD>

<TD =#00ff00 width=132 align=middle>12.32</TD>

<TD =#00ff00 width=132 align=middle>2.05</TD></TR>

<TR>

<TD =#00ff00 width=132 align=middle>60%</TD>

<TD =#00ff00 width=132 align=middle>12.20</TD>

<TD =#00ff00 width=132 align=middle>2.03</TD></TR>

<TR>

<TD =#00ff00 width=132 align=middle>50%</TD>

<TD =#00ff00 width=132 align=middle>12.06</TD>

<TD =#00ff00 width=132 align=middle>2.01</TD></TR>

<TR>

<TD =#00ff00 width=132 align=middle>40%</TD>

<TD =#00ff00 width=132 align=middle>11.9</TD>

<TD =#00ff00 width=132 align=middle>1.98</TD></TR>

<TR>

<TD =#ffff00 width=132 align=middle>30%</TD>

<TD =#ffff00 width=132 align=middle>11.75</TD>

<TD =#ffff00 width=132 align=middle>1.96</TD></TR>

<TR>

<TD =#ffff00 width=132 align=middle>20%</TD>

<TD =#ffff00 width=132 align=middle>11.58</TD>

<TD =#ffff00 width=132 align=middle>1.93</TD></TR>

<TR>

<TD =#ff0000 width=132 align=middle>10%</TD>

<TD =#ff0000 width=132 align=middle>11.31</TD>

<TD =#ff0000 width=132 align=middle>1.89</TD></TR>

<TR>

<TD =#ff0000 width=132 align=middle>0</TD>

<TD =#ff0000 width=132 align=middle>10.5</TD>

<TD =#ff0000 width=132 align=middle>1.75</TD></TR></T></TABLE>

rock1424 · 08-01-2009, 01:39 AM

Thanks Chris, that's good information. The text mentions green and yellow zones. Do you know wherethe yellow zonestarts? I'm assuming at 50%, but I would like to know for sure.

David & Carolyn · 08-01-2009, 03:49 AM

Thanks to everyone who posted a responce. Chris and George, your information was very helpfull. Korbe, the web site you gave was excellent. It has really helped me and I have saved it as a favorite.

Thanks again to everyone

pulpwood007 · 08-01-2009, 09:31 AM

Quote:

Originally Posted by Chrisnan23

<h3>State of Charge</h3>

<h4>Here are no-load typical voltages vs state of charge</h4>

(figured at 10.5 volts = fully discharged, and 77 degrees F). Voltages are for a 12 volt battery system. For 24 volt systems multiply by 2, for 48 volt system, multiply by 4. VPC is the volts per individual cell - if you measure more than a .2 volt difference between each cell, you need to equalize, or your batteries are going bad, or they may be sulfated. These voltages are for batteries that have been at rest for 3 hours or more. Batteries that are being charged will be higher - the voltages while under charge will not tell you anything, you have to let the battery sit for a while. For longest life, batteries should stay in the green zone. Occasional dips into the yellow are not harmful, but continual discharges to those levels will shorten battery life considerably. It is important to realize that voltage measurements are only approximate. The best determination is to measure the specific gravity, but in many batteries this is difficult or impossible. Note the large voltage drop in the last 10%.

<div align="center">

<t>

</t><table border="1" width="400">

<t><tr>

<th align="center" width="132">State of Charge</th>

<th align="center" width="132">12 Volt battery</th>

<th align="center" width="132">Volts per Cell</th></tr>

<tr>

<td align="center" width="132">100%</td>

<td align="center" width="132">12.7</td>

<td align="center" width="132">2.12</td></tr>

<tr>

<td align="center" width="132">90%</td>

<td align="center" width="132">12.5</td>

<td align="center" width="132">2.08</td></tr>

<tr>

<td align="center" width="132">80%</td>

<td align="center" width="132">12.42</td>

<td align="center" width="132">2.07</td></tr>

<tr>

<td align="center" width="132">70%</td>

<td align="center" width="132">12.32</td>

<td align="center" width="132">2.05</td></tr>

<tr>

<td align="center" width="132">60%</td>

<td align="center" width="132">12.20</td>

<td align="center" width="132">2.03</td></tr>

<tr>

<td align="center" width="132">50%</td>

<td align="center" width="132">12.06</td>

<td align="center" width="132">2.01</td></tr>

<tr>

<td align="center" width="132">40%</td>

<td align="center" width="132">11.9</td>

<td align="center" width="132">1.98</td></tr>

<tr>

<td align="center" width="132">30%</td>

<td align="center" width="132">11.75</td>

<td align="center" width="132">1.96</td></tr>

<tr>

<td align="center" width="132">20%</td>

<td align="center" width="132">11.58</td>

<td align="center" width="132">1.93</td></tr>

<tr>

<td align="center" width="132">10%</td>

<td align="center" width="132">11.31</td>

<td align="center" width="132">1.89</td></tr>

<tr>

<td align="center" width="132">0</td>

<td align="center" width="132">10.5</td>

<td align="center" width="132">1.75</td></tr></t></table>

And I'm assuming 6 volts divide by 2? And how do you physically measure individual cells?

Hamops · 08-01-2009, 11:32 AM

Quote:

Originally Posted by pulpwood007

And I'm assuming 6 volts divide by 2? And how do you physically measure individual cells?

You can't, unless the cell jumpers are external to the battery. What you do is measure the total battery voltage to get the average cell voltage. The cell voltages will stillremain the same as on the chart.

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