The Dreaded Battery Discussion - with a twist - Page 2

Monaco38 · 10-17-2009, 01:52 AM

Quote:

Originally Posted by MrTransistor

Hi Wayne,

May I suggest the echo~charge by Xantrex instead of the Trik-L-Start by LSL Products.

Mark

In reading the specs on the echo~charge by Xantrex they state that "both battery banks must be the same DC voltage and battery type" (emphasis added). If the house batteries are 'deep cycle' and the chassis batteries are not can the echo~charge unit be used with this battery configuration? Also, is the difference in out put the main reason for recommending the echo~charge over the Trik-L-Start or are there other considerations that enter in? Thanks in advance for helping sort out the available options in addressing this charging issue.

Wayne M · 10-17-2009, 06:57 AM

I'm going to let some one else answer the specifics about the models, but as far as "same type," it is my understanding, as told to me by technicians, that there are 3 types of "auto" batteries, Flooded, AGM, and Gel. Even though a battery is sealed, unless otherwise stated, it is an AGM Flooded.

In my coach, I have the two chassis batteries, and the two house batteries. The chassis batteries are a sealed, flooded battery, and the house batteries are capped flooded batteries. I check the house batteries periodically, and not more than a month passing by, and add distilled water as necessary.

I have also been informed that to trickle charge the batteries, they should all be brought up to the same voltage before connecting the trickle charger. Now, I will assume that if a coach charger is wired correctly that it will get the batteries up to the same state and then provide a trickle charge as necessary. As for hooking up an external trickle charger, all batteries should be at a fully charged level and very close to the same voltage before using a trickle charger. This will keep the current to a minimum between batteries. Most people when charging will connect a jumper between the sets of batteries, and although this is alright it is necessary to have the full charge. A battery that is low on charge will try to get as much current as possible to equalize and this may be to excessive for the wiring.

It does not matter the the starting capacity or storage capacity (deep cell or not) of the batteries as long as they are the same type, "Flooded," "AGM," or "GEL."

That's my story until some one else corrects me.

MrTransistor · 10-17-2009, 12:59 PM

Hello Monaco38 & Wayne,

Gel Cell batteries are fairly unique in that they must never be overcharged hence the reduced voltage allowances and reduced peak charge currents. Other than that, the chemical reactions inside the battery are pretty much the same.

AGM and Flooded have the same chemistry. The difference is that in Flooded, the lead plates and separators are immersed in the acid solution with a space at the bottom to allow for flaking of the plates to fall free. Whereas in AGM, the plates are separated by a very fine glass matt that is almost saturated with acid solution and squeezed into the case which does not allow the flaking to fall off. With AGMs, you usually get more bang for the buck (except that they are very expensive) because there is more lead and less solution (by weight). Other than that, the chemical reactions inside the battery are pretty much the same. The difference in specified charge voltages has a little to do with the composition of the lead alloy and a lot to do with allowable charge currents. As long as the currents remain low, the chemistry allows for mixing of different types without much problem. Beware of high charge currents when mixing different battery types (especially gel).

The goal of a trickle charge is to maintain the batteries charge at or near 100%. To do this, there will need to be sufficient charge voltage and current to overcome self-discharge currents and residual loads. That is why I chose the echo~charge over the Trik-L-Start. The residual loads on a 2004 Freightliner chassis are up around 2.5 Amps. The self-discharge of the two chassis batteries is calculated to be around 1 Amp./Hour per day, which is only around 41 mA. It seems as though the Trik-L-Start would work well for this application. Then you consider that the steps, slides, jacks, and awnings are powered from the chassis batteries. The jacks pull very high current when operated (solenoids and pump). Therefore, to recharge be chassis batteries after using one of these items requires a lot more that 5 Amps. to do it expeditiously.

I installed panel meters up front and ran sense wires to the coach and chassis batteries so I could see if the tie contactor was working properly when I started the engine. Here is a picture of the meters with the coach on top and the chassis on the bottom. The difference in the readings (I calibrated the displays using my Fluke) is caused by the residual currents on the chassis batteries.

If you chose to use the Trik-L-Start, I’m sure it will do a superb job of keeping the chassis batteries topped off. I just think it was more intended for use on installations with only one chassis and one coach battery.

Good Luck with either setup.

hamguy · 10-18-2009, 10:16 AM

Quote:

Originally Posted by MrTransistor

If you chose to use the Trik-L-Start, I’m sure it will do a superb job of keeping the chassis batteries topped off. I just think it was more intended for use on installations with only one chassis and one coach battery.

I don't think the Trik-L-Start can tell if there are 2, 1 or 10 batteries. It merely supplies a driving voltage and current to whatever it is hooked to.

Monaco38 · 10-18-2009, 12:41 PM

Quote:

Originally Posted by hamguy

I don't think the Trik-L-Start can tell if there are 2, 1 or 10 batteries. It merely supplies a driving voltage and current to whatever it is hooked to.

You are probably right. I am sure the Trik-L-Start can't tell how many batteries are hooked to it. I understood Mark's comment to mean that because of the low output of 5 amps it is best suited for an application involving fewer batteries and less current draw, ...and Mark you may correct me if I'm wrong in my understanding.

EngineerMike · 10-18-2009, 02:50 PM

1) I'm pretty sure none of the charger solutions discussed (and pretty close to all those not discussed) can tell how many batteries they are hooked to. Even my Snapon Microvat can't tell that, I have to tell it what the CCA is to test a battery.
2) I carry a Radio Shack analog VOM in addition to the Fluke digital. I find there are readings that are easier to get on analog by watching the needle rather than trying to capture on the Fluke (although the Microvat does a pretty awesome job in its "multimeter" mode of continuously capturing & reporting peaks while reporting varying readings; just used it for that to spec out a spare pump solenoid for the HWH hydraulic system).

Wayne M · 10-18-2009, 04:50 PM

Well, it's been 4 days since I hooked up the digital electrical switch. When I checked the batteries today the showed, 12.7 (Chassis) and 12.5 (House) volts. I have increased the on time of the timer to see if I can get to about 13 volts. Just what I'd like to have.

The digital timer was set to turn the electricity on for 1 hour. I changed it to 1-1/2 hours and I'll check in a few days.

MrTransistor · 10-18-2009, 11:28 PM

Hi Wayne,

12.5 on the House batteries is kind of low. Which did you install, the echo~charge or the Trik-L-Start? From the readings, it seems like the residual loads on the House system are higher than the Chassis System, comparatively. You may need to increase the time to 3 or more hours to get that voltage up. Depending on the time between the shutdown of the AC and when you take the reading, you may never see 13 Volts. Once the surface charge has been removed, you will more than likely read 12.8 to 12.7 Volts. Unless you get there right after the AC shuts off. 12.5 Volts under a light load indicates that the batteries may be down around the 50% point.

May I ask, why are you wanting to limit the number of hours of AC? If all AC loads are off, the only current draw should be the converter putting out around 13.2 volts. This keeps the batteries topped off and supplies all 12 Volt loads. This is best for battery life and only uses a little more kWh than the daily charging of the batteries and then letting them supply the 12 Volt loads. The charging current will be many times higher than the residual current draw. (i.e. 4 Amps. for 24 Hours vs. 44 Amps. for 3 Hours = 1.25 kWh/day vs. 1.7 kWh/day or 450 watt/hours per day difference) I think the extra cost of electricity may be $1.62 per month at 12¢ per kWh. This compared to the shortened life of the batteries by cycling them once per day to say 75%. This would normally cause standard deep cycle batteries to fail in as little as two years. AGMs might make it 3 to 4 years.

Monaco38 is correct, the 5 Amp. limit on the Trik-L-Start is what makes it seem as though it was designed for single battery setups. Generally, RV 12 Volt batteries are going to be in the range of 80 to 130 Amp./Hour (this is a ballpark number since starting batteries are normally rated by CCA). That places the Trik-L-Start at around the C/20 or so rating on a single battery. For a bank of three with an Amp./Hour rating of 360, the Trik-L-Start would only be at a C/72 charge rate compared to the echo~charge at C/24. My setup with the echo~charge is around C/16 with two group 31 starting batteries. Nice place to be.

Since I have two Prosine 2500s connected to charge the AGMs at 200 Amps., I have to tell them what the Amp./Hour capacity of the bank is so they know when to drop from bulk to absorption to float. Hamguy and EngineerMike are correct that no device can tell what size the bank is unless it knows the type of batteries and does an impedance test. The more batteries in parallel, the lower the impedance, but any device that can do this (and I know of none) could only approximate the number of batteries even if it was told the Amp./Hour capacity of the individual batteries. And compounding the problem is the resistance of the wiring. That’s why it’s not done.

In the X-Ray field, we used a line impedance meter to test the incoming 480VAC line. It had to be adjusted to a precise amount (say 120 mOhm) for the X-Ray generator to calibrate.

Wayne M · 10-19-2009, 09:55 PM

Mark,
I did not install anything at this time. I'm still using the built in Parallax converter. I will be installing the Battery Minder as soon as my knee gets well enough to get down and dirty.

More than likely, what I am doing until the Battery Minder can be hooked up is temporary. What I have read is that if the RV is to be in storage for a long time, to just disconnect everything. With residual drain I probably would not have enough juice to start the MH. I'm probably more concerned than I should be about boil out on the house batteries.

MrTransistor · 10-20-2009, 02:07 AM

Hi Wayne,

What voltage do you read right at the batteries after you’ve been plugged in for several hours to top off the batteries? My son in NY just replaced his two 6 Volt in series battery bank and after the system charged over night, he was reading 14.4 Volts on the batteries. I advised him to find a replacement converter ASAP.

If, after fully charging the bank, you read in the neighborhood of 13.4 to 13.6 Volts, then I would not be too concerned with boil off of the water in the batteries. Just check the level periodically. Below that voltage means less boil off but also may not be fully charged. Above that would equal fully charged but higher boil off as well.

A converter that has a three stage charging system and is of really good quality will save a lot of hassle in the long run. Costs, downtime, and battery replacement time.

Xantrex bought out Prosine and now produces the Truecharge 2 (Truecharge was a Prosine product). The Truecharge 2 /40 looks like an excellent product albeit expensive at $460.00. The three things I like best about it are that it can be connected to up to three battery banks and charge them independently (eliminating the need for the Trik-L-Start), it is a three stage charger, and has remote temperature sensing. That price is just hard to swallow.

You may be able to locate one of the older Truecharge units with the part numbers of TC3012, TC4012, TC5012, or TC6012. The 12 is the Voltage and the 30 through 60 is the Amps. Pick the current you want but don’t be stingy.

hamguy · 10-20-2009, 09:13 AM

Quote:

Originally Posted by MrTransistor

Hi Wayne,

What voltage do you read right at the batteries after you’ve been plugged in for several hours to top off the batteries? My son in NY just replaced his two 6 Volt in series battery bank and after the system charged over night, he was reading 14.4 Volts on the batteries. I advised him to find a replacement converter ASAP.

I would also check the accuracy of whatever meter he used. I chased a problem with a plug in cigar lighter digital meter which reads 0.5VDC high. These are the meters sold by CW and RS.

Wayne M · 10-20-2009, 09:31 AM

I'm using a Fluke 44?? DM. (don't know the exact model #)

Guess I could break out the Simpson 260.

hamguy · 10-21-2009, 09:41 AM

Another point, any reading taken while plugged in or in any situation where the batteries are being charged will give you a FALSE reading. If you read the batteries, anywhere in the system, you willl get the charging voltage which is meaningless in and of itself.

To get the true battery voltage reading, you must be disconnected from ALL charging sources.

Wayne M · 10-21-2009, 10:47 PM

I do disconnect all before taking the readings.

I'll make a special trip to storage and get a reading right after a charge.
Then I might let it sit 24 hours without a charge and check again.

hamguy · 10-22-2009, 09:40 AM

Quote:

Originally Posted by Wayne M

I do disconnect all before taking the readings.

I'll make a special trip to storage and get a reading right after a charge.
Then I might let it sit 24 hours without a charge and check again.

I knew you would Wayne. You are a ham!

Paul R. Haller · 10-22-2009, 10:59 AM

I don't get what you are trying to achieve with using a small battery minder charger. Do yourself a favor and buy a good 3 or 4 stage 55 amp converter from Iota or Progressive Dynamics and hook it up to the house batteries. If you want to charge the chassis battery too while in storage or camping plugged into shore power, buy a relay and install that in line with the charge wire from the converter to the chassis battery so it's on and charging both sets of batteries when hooked up to shore power. A good converter will charge your batteries up from completely discharged and will also safely keep the batteries topped off while in storage. No need to buy minders and what not.

With regard to different kinds of batteries... that refers to different basic types of batteries. You should not mix flooded lead acid batteries with say a gel or mat battery. However that said you can mix and match all batteries within a flooded cell bank if you wish. So, lets say for example you have 2 6 volt golf cart batteries connected in series in one bank and 2 deep cycle lead acid 12 volt batteries connected in parrallel in another. You can safely connect the two together while charging and all batteries will equalize to the one battery bank with the highest internal resitance. It's better to have all batteries the same age and size but with a good charger capable of delivering 55 amps at 14 volts, it really doesnt matter much. The advantage of the multi stage chargers is that they double as an all out charger/ power supply as well as a trickle charger after batteries are topped off. When the batteries are discharged they supply voltage at about 14.2 volts for as long as it takes to get them to about 90 % charged then, they drop voltage again to about 13.5 volts to reach 100% charge without over heating batteries and boiling off water and then, drop voltage again to about 13 volts to keep them topped off while not getting the batteries too hot so you do not have to check electolyte level every week. Finally, once they reach float charge, every 7 or 8 days they give the batteries a jolt at 14.2 volts for about 15-45 minuts to prevent sulfides from forming.

On line you should find a PD with a charge wizzard (or even their newst model with the wizzard built in) or a muti stage Iota 55 amp converter for about 150$. Install that, along with a relay in the charge line to the chassis batteries, and you leave the rig plugged in always 24/7 and you are set. That's it, no switches, no trickle charger, nothing. Remember that 55 amps of current can get small wires pretty hot so upgrade to at least a #6 (4 would be better) wire from both + and - sides of the wiring from the converter to the batteries, relay, etc. Wire tables indicate that a # 4 can carry about 90 amps in free air. (not bundled) Use good quality wire and connectors and buy # 4 or larger wire from a welding supply. Welding wire is made up of very finely stranded copper that makes it perfect for wiring in a trailer because of it's extreme flexability and high quality with an abrasion resistant outer sheath. I tend to wrap all my wiring in split loom that's color coded also just for added protection. Red for + white for - and green for grounds.
-Paul R. Haller-

Navy Flier · 10-24-2009, 10:22 PM

After having read all of the posts my basic comment is that I think everyone is over thinking the issue. First, starting in 2005 Winnebago installed Trik-L-Starts in all diesel coaches. Unless they quit installing them there is no reason to believe you do not have one. I know that I have one. When hooked to shore power all of the house and chassis batteries are kept charged as necessary. Of course, you cannot have either set of batteries disconnected. I spend several months each winter in Florida and this system keeps the batteries fully charged the entire time. As for the battery minder just plug it in and turn it on following the directions. Do not get all wrapped up with equal states, etc. These devices are designed to be used by the lowest common denominator so it isn't rocket science. If your batteries are low it can take 4-5 days for them to reach a charged state. Before Trik-L-Start I used one of these on my coach at the winter location. Now I use one for the car left behind. Simple to use and never had a problem.

Wayne M · 10-25-2009, 10:27 AM

Chuck,
I don't want to beat a dead horse trying to revive him, but oh well!

My coach not having the Trik-L-Start is direct information from the service tech at Winnebago. He pulled up the build on my coach and stated it did not have it. He also stated that the converter I had would charge both house and chassis batteries. I already owned the battery minder before this call, and I do like to use it. The statement regarding equal states was a phone call to Battery Minder and a conversation with their technician. Again, it is because of a large current draw when one set of batteries are low in voltage. It posses a problem for the 16 guage charging wire.

You are absolutely correct in keeping all disconnects turned ON and all items that could possibly drain that can be turned off, OFF.

Thanks to all. I'm going to continue to do what I do until a failure occurs, and then I'll do what I have to do to correct it.

YngRvrs · 10-26-2009, 08:28 PM

Where did you find the charger? Battery compartment?

Wayne M · 10-26-2009, 09:53 PM

YngRvrs,
I'm not sure I understand who you are directing the question to. I didn't look for a battery charger, but the parallax converter that Winnebago uses in my MH is in the Electrical compartment.

I would hope that no one would put a battery charger in the same compartment as batteries. Even if well ventilated you risk explosion from the gasses given off.