Trickle charger for starter battery

[vlamgat]

I read your thread and its all sound advice and I agree 100% BUT when it comes to towing with an SMB there are several factors that become more important:

There are several things in play here that the theoretical analysis of high end inflation levels do not cover. Firstly the tire manufacturers are not bound by any universal standard that has been tested in the full sense of the word. Their internal conformance to the load index is a "trust me statement" that under ideal conditions usually in a test cell the tire will support a given load at the specified speed for the approximate life of the tire given perfect alignment throughout the test.

However unless the ambient and the surface temperature is STP as used in most Boyle's Law analyses the first variable for the load capacity of the tire being "cold inflation pressure" is already rendered incorrect. And in most US Summer areas (whether you believe in global warming or not) we start the day above STP and end up 20 or 30 degrees over the nominal 68F at which Cold is defined. At about 2 lbs per 10 degrees that means the Cold pressure needs to start at 3 or 4 psi above whatever the load calculation may dictate.

But then we get into the Load definition. And while I agree individual axle load measurement is essential, unfortunately this is a static measurement and once again assumes the perfect conditions of a test rig if the manufacturer even uses one which I have reason to doubt. In reality our SMB tow vehicles face a much harsher environment. The LWB versions have considerable leverage between the hitch point and the axle which combined with the dreadful condition of some of our interstates and secondary roads means that the load leveling on the trailers (if used) is combining to create considerable bounce on the tire. This bounce produces momentary increases in weight that are several hundred lbs above the nominal static level. Very hard to calculate and certainly way outside the manufacturers test cell but logically prevailing. In addition there are the surface imperfections such as pot holes or larger joints that batter the belts. All of this combining with a surface temperatures that may be as much as 50 deg F over the nominal Cold level.

So unless the load is 30% less than the nominal tire maximum including the hitch weight AND the roads are in good condition AND the temperatures are less than mid eighties AND the combined axle weight and the hitch has some flex, I cannot see why one would risk Under inflation by using anything but the maximum adjusted (for ambient) temperature inflation rate for that tire.

I have read and heard (from Michelin) that these factors are taken into account when they designate the tire load capacity but when asked how they test this, I get blank looks. So I investigated further. My company is the largest seller of tires in its sector and with gentle inquiry I have discovered that all the above is true and possibly worse than I am representing. Because we operate in a gray area of the market (converted vehicles, uncalibrated loading, uncalibrated tow loads, undocumented environments and usage) tire damage is such after the inevitable blow outs that legal recourse is going to very hard to obtain. I just experienced two blow outs under tow of identical Michelin E rated tires, carefully inflated at various speeds not exceeding the nominal maximum of 65 on a warm day. Both tires blew out within an hour of each other. My fourth failure of this tire type in a year and my fifth in 18 months. At 2910 lbs on that wheel (static with tow hitched) I am 140 lbs under the maximum and by your suggestion i should deflate slightly. I think that would be unwise on my or any one else's part. Instead I have to find a more reliable tire at these weights without changing the gearing. There are options but all are many $$$ but possibly much less than the damage caused by blow outs that have ripped out the plumbing, a/c and wiring that surround the rear tires.

[BajaSportsmobile]

You are over inflating your tires and when they deflect due to load spiking, they are seeing unwanted momentary internal pressures.

Blow up a balloon until it is about to pop and then sit on it - BOOM!

You are way over thinking this.

I have towed extremely OVERLOADED loads thousands and thousands of miles on all surfaces.

Put three 55 gallon drums of Race Fuel, a spare 600lbs rear axle, bins of spare parts in the bed, a 3500lbs trailer with a 6000lbs Race Truck on it and half a dozen 130lbs spare tires on the hitch and the four 200lbs guys in the cab of my Superduty 4X4 6.0L on 315 D rated tires and tow to Cabo, Baja Sur, Mexico on their roads, including off-road and that is over loaded.

I've done it at least a dozen times and the only flat I have had is on the trailer when I clipped a boulder on the side of the road.

I typically run them at 45psi but don't pay that much attention to it. I do look a the profile and feel them for temp to see if anything is out of line when we stop for fuel - I have a ~46gal capacity.

By the way, most of the race teams down there are doing the same thing.

[BajaSportsmobile]

You can also get an idea of your dynamic loading by knowing your spring rate and the amount of bump travel you are experiencing.

[E350]

This is a great thread! (But where do I hook up the trickle charger to increase or decrease my tires' inflation?)

Bajasportsmobile: OT BTW, thanks! The tailgate limiter pin switch was right where you said it was, on the driver's side tailgate latch behind the tailgage window channel. And dude, I wouldn't have been able to find it without you telling me where it was. After going to Pick-N-Pull on the hottest day of the year, I realized that I don't have an electrical problem, I had a mechanical problem -- if the striker is moved to far forward (e.g., because I want the tailgate to close tightly) the catch pincers don't close, and if they don't close, the little lever which pushes the pin switch in doesn't get deployed so the tailgate switches think that the tailgate is down. I am going to do a write up in the ford-trucks.com (i.e., FTE) Bronco forum because I think this may be a common problem for those who have ohmed out their wiring and still can't find their "electrical problem." Thanks again. Tim Hodgson

[BajaSportsmobile]

I've run into the same issue/solution on the Bronco tailgate. This thread got off track, sorry, I was replying to the latest post without realizing what thread it was in.

P.s. I use a CTEK Charger.

[E350]

Dude, your participation is golden. I don't care in what thread you post it. Thanks! I will look into CTEK chargers.

[Pschitt]

Sorry to have hijacked your thread, I just read the post of 9pb9 and answered without realizing that it was an electrical thread...

Hope you will find the right way for your next charger.

[ANZAC]

Originally Posted by E350

Dude, your participation is golden. I don't care in what thread you post it. Thanks! I will look into CTEK chargers.

I have a CTEK charger that I use for recharging batteries, and they have a maintain mode, but they require you to switch the mode to charge, I am worried that it would lose that mode when you remove 110v. I looked on their site and couldn't see a trickle charger. Which model do you have?

The ones at batterytender look pretty good, just need to pick the right one.

I want to install the charger by plugging into the 110v outlet behind the driver's seat. Need to figure out the best way to get a 12v van battery connection there though.

[E350]

My former Xantrex Prosine 2500w had a maintenance mode as well. But my guess is that the desulfate algorithms on the BatteryMinders are much more sophisticated and effective than the Xantrex and maybe your CTEK?

I really am happy with the BatteryMinder 12248 because you can select from AGM to flooded to gell. Hopefully it is breathing new life into my 250 Ah UPG. But it also loses its setting by a loss of 110v AC power.

So, you may want to get the non-selectable BatteryMinder 2012 (for flooded) or a BatteryMinder 2012-AGM for agms.

I have a chrome (or is it stainless) Marinco outlet and a chrome (or is it stainless) Marinco AC inlet on the passenger side behind the barn doors. My thinking was that I could park on the street if I had to and not run a cord into the street but rather across the sidewalk on the passenger side.
I have tubes running side to side under the floor and on top of the fuel tank to chase the wires running from the battery bank to the inverter, charger, frig, solar controller, etc.

I will post pictures and more info this weekend.

I am very, very, very intrigued by McZippie's design of running six agms on my battery frame under the barn doors for starting and house with a limiter which prevents a voltage drop below 12.1v That would obviate the reset concern since I could go AGM BatteryMinders and chargers for everything. And wouldn't a faster recharge/discharge also be better for the oem alternator?

(On the otherhand, it seems that I have dropped my voltage below 12.1v pretty routinely over a weekend, so maybe connecting starting and house batteries would be a bust for me.)

[ANZAC]

Here's another one to look at:
http://www.powerwerx.com/batteries-char ... s-12v.html

(edit)
and another marine unit:
http://www.amazon.com/Marinco-Battery-C ... roduct_top