Battery Charger

Mr Tweety · 05-10-2009, 07:23 AM

Hi Folks,

Does anyone know what the true capability of these WFCO battery chargers that come with many of these Sunlines really is ?? My WFCO in my 2753 says the model is 8955 from year 2006. It "claims" to be a 3 stage microprocessor controlled charger with 14.4 volts max @ 55 amp max rate including any load beyond battery charging. That sounds pretty good to me - but did Sunline really install that good of a charger ?? Anyone know the actual bulk charge rate in Amps of these WFCO units ?? I expected Sunline to install a "dumb" single stage unit -- basically just a converter that trickle charges the battery at 8 - 10 amps or so. The cable from charger to the battery is only AWG 6 which is barely rated to carry 30 Amps over the distance to the batteries (about 15 feet) hmmm

When boondocking I am trying to figure out how many hours of generator time would be necessary to replace about 90 Amp hours of juice using the on-board charger. The higher charge rate of the newer "smart" chargers will reduce that time. If you have only a trickle charge at 10 amps or so ---- it is a "slow boat to china" requiring over 8 hours.

But I don't want to replace the Sunline WFCO charger if it is as "good" as it appears. Maybe the 8955 is a newer version. Any information or reference links or actual experience you have with these WFCO chargers is appreciated.

Mr. Tweety

**JohnB** · 05-10-2009, 10:11 AM

Steve

I'll be back to this later to type some more. Here are a few factoids.

In the junction box on the front of the camper there is a circuit breaker.

Here see a zoomed in shot. This is out of the T310SR with a slide that is why there is 2, 30 amp breakers.

Here is the T2499 only 1 breaker, 30 amp. Which is I'm most likley the same as yours.

Bottom line, only 30 amps is allowed to go into the battery thru that 30 amp breaker.

My 2 cents is they give you a 55 AMP rated convertor so you can charge 25 ish amps while still using the interior of the camper 12 DC that is drawing up to an additional 30 amps inside if many things are on at once.

Can you manaully force your convertor in "boost" most? the 14.5 VDC mode?

I am going to be doing what you are trying to do but I have a Progressive Dynamics convertor that I can force the Boost mode on.

Battery chargeing is tricky some times. I will attempt to get an amp probe in the line so some day I know what is going into the battery for sure.

I would question if you can get 55 amps plus chargeing 30 amps to come out of that convertor. Have to look it up on line to see if it is even fised that way. Having a 90 amp convertor... think of how big the DC supply line if coming off the convertor

Be back later

John

**Tweety** · 05-10-2009, 12:02 PM

Thanks John - You confirm with the fuse block photo what I suspect - 30 amps is all you get - and that's a max - so it can't put out much more than 20 - 25 amps to the battery. Interesting that even if you have no-other coach load it obviously won't blow the 30 amp fuse charging the battery and so must not be devoting all of it's "advertised" 55 amps into the battery line. And so somehow limits itself to 20 - 25 amps.

I cannot force it into "bulk mode" - so I need to investigate with a depleted battery to check if it even goes into the 14.4 v mode. As you said an induction or clamp ammeter (which I don't have) would tell the tale.

And another good point you make is - even if you have a better charger - unless you increase both the cable size and fuse size - you will not be able to make any difference other than blowing your 30 amp fuse. The Sunline is simply not set-up for > 30 amps charge rate.

So at this point the answer to my boondock question of how long would it take to replace about 90 amp hours (which is about 50% of my battery capacity) to my battery bank is .. about 4 hours generator time with the current WFCO charger ( Assuming it actually does go into a bulk mode @ 14.4 v and achieves 20 - 25 amps)

You said you can force yours into bulk mode --- is it your original charger ?? Or a replacement ?

Steve

**JohnB** · 05-10-2009, 01:19 PM

Steve

Fixing spring hangers today and came in for a break.

Here see this post of mine on my convertor upgrade.

Progressive Dynamincs Convertor upgrade

I can force any of the 3 modes if I choose to.

Yes, I think we are in the 20 to 25 amp charging setup due to the setup. I'll be back to you here as this same exact thing is going thru my thought process. Just you started into it sooner.

I do have a clamp on amp probe. Problem is my battery is allways on a Battery Minder Plus even when I'm not out camping so I do not know how much she will take. I'll attempt and report back later.

What size battery do you have? Group 24, or 27? This spring I upgraded to a 27 and I need to add a 2nd one. Long term after these go I'll go the 6 volt route but I have to build a battery bank like Eman's to be able to hold them. I can barely squeeze 2, group 27's in there.

Here is 2 FAQ's off the Progressive Dynamics site.

10. How long will it take to re-charge my RV battery?
Battery recharge time is controlled by many factors, such as battery size, converter output rating the number of 12-volt lights and appliances that are “ON” during the re-charge cycle and how far the battery has been discharged. In our testing a 125-AH (Amp Hour) battery was fully discharged to 10.5-volts and then connected to a PD9160 (60-Amp) Converter/Charger set to our standard output voltage of 13.6-volts. The battery reached full charge in 70-hours.

11. I dry camp most of the time and want to recharge my RV batteries using my generator the next day. Is there any way I can get a faster recharge rate?
Yes, all 9100 Series Converter/Chargers are equipped with our TCMS (Total Charge Management System) Connector to allow you to easily install our Charge Wizard. All 9200 Series Converter/Chargers are equipped with the TCMS / Charge Wizard built in. The Charge Wizard senses that your batteries are low and that you want to charge them fast therefore, it automatically increases the output voltage of the Converter/Charger to 14.4-volts and will return a 125-AH battery to 90% of full charge in 2-3 hours. Full charge is achieved in approximately 15 hours.

http://www.progressivedyn.com/about_...erters.html#10

Note that 125 amp hour battery I think is a group 30 so mine will be less , unless I put 2 on then maybe more if they are both run down. The real good question is, did they use all 60 amps of the charger to do what they stated? Can't tell from that statement.

John

Mr Tweety · 05-10-2009, 02:40 PM

Hi John,

Thanks again for another helpful post. I plan on 2 group 27 batteries @ about 125 Amp hour each = 250 total AH. However useable Ah = about 50% of that -- so working Ah = 120 Ah. I understand that to avoid battery life degradation you want to recharge at a max rate of about 25% of your total (not useable) battery ah rating. So MAX rate of 25% of 250 = about 60 amps.

Now - for the standard Sunline set-up of a low grade 70 ah battery - obviously the stock charger is plenty (about 20 - 25 amps) and in fact you would damage the battery by blasting 60 + amps into it over and over.

However - like you, I would like to upgrade for boondocking (Not the full e-man set-up where Solar panels, four 6v golf or gel cell and a 2000 watt Xantrex inverter provide the ultimate electrical system - and he explains well on his blog) with a "poor-man's" interim upgrade with 2 group 27 wet cells and a better charger / wiring / fuse set-up so that the generator will replenish the 2 batteries using the on-board charger to 90% in 2 - 3 hours. Less if you haven't fully depleted the batteries.

I forgot you already upgraded your charger when I re-read your post on that. So you are all set it seems if you have adequate wire AWG run from charger to battery - and appropriate fuses. What wire size do you have ?? Did you change the old 30 amp fuse ?? Keep us posted and particularly if you ever get a true amp read with your charger running on 2 depleted group 27's in bulk charge mode. Would be interesting....

Steve

**JohnB** · 05-10-2009, 09:09 PM

Quote:

Originally Posted by Mr Tweety

Hi John,

Thanks again for another helpful post. I plan on 2 group 27 batteries @ about 125 Amp hour each = 250 total AH. However useable Ah = about 50% of that -- so working Ah = 120 Ah. I understand that to avoid battery life degradation you want to recharge at a max rate of about 25% of your total (not useable) battery ah rating. So MAX rate of 25% of 250 = about 60 amps.

Now - for the standard Sunline set-up of a low grade 70 ah battery - obviously the stock charger is plenty (about 20 - 25 amps) and in fact you would damage the battery by blasting 60 + amps into it over and over.

However - like you, I would like to upgrade for boondocking (Not the full e-man set-up where Solar panels, four 6v golf or gel cell and a 2000 watt Xantrex inverter provide the ultimate electrical system - and he explains well on his blog) with a "poor-man's" interim upgrade with 2 group 27 wet cells and a better charger / wiring / fuse set-up so that the generator will replenish the 2 batteries using the on-board charger to 90% in 2 - 3 hours. Less if you haven't fully depleted the batteries.

I forgot you already upgraded your charger when I re-read your post on that. So you are all set it seems if you have adequate wire AWG run from charger to battery - and appropriate fuses. What wire size do you have ?? Did you change the old 30 amp fuse ?? Keep us posted and particularly if you ever get a true amp read with your charger running on 2 depleted group 27's in bulk charge mode. Would be interesting....

Steve

Steve

Yes it seems we are on the same track. Last year I upgraded the converter as the one I had I could not get parts for the obsolete model and the cement mixer fans had to go…. So I started the boondocking setup with the charger.

The coach was used and I bought 1 new Group 27 battery at the time of sale. But the way Sunline made the battery rack on the T310 they would not fit. So the dealer threw in a left over Group 24 so I could get home as he did not want to fiddling with making a new bracket and I did not want him fiddling….. I reconditioned the throw in one and have been using it now for over a year. This spring I made a new battery holder to convert the group 24 to a 27 and I installed the one 27. My son bought a 12 year old PU this spring and it had no battery and his funding was in strain. So I gave him the old one and put the new one on the TT that has been sitting on the Battery Minder now for the last year.

I bought a Honda Eu2000i this year but have not made it to doing anything different yet with the wire from the converter to the battery. If I change the wire the disconnect may need an upgrade too. Have not dig that deep yet.

I’m still learning along the battery charging trail and have not yet figured out what is the limiting thing in charging. My converter is 60 amps supply, your converter is 55 amps, both are hooked to the battery with a 30 amp breaker in the middle. There is nothing in my converter box to separate the battery from the main 12 VDC buss. There is nothing stopping the buss from feeding the battery all 60 amps of my supply if it wanted it. Yet the 30 amp breaker doe not trip.

The wire in the middle is about #8 or 6 from battery to converter. I did not measure it yet. I know about the voltage loose part but what is stopping the battery from charging any faster? What is regulating the current? Or is it that a Group 24 that Sunline puts in will only pull 20 to 25 amps at full charging? If we drop in a Group 27, will it try and draw more? Something is limiting the current. What?

Since my Group 27 has never drained down yet I do not know if I will trip that breaker. But now as of your post I’m even more curious.

Also where did you find Group 27 batteries with 125 Amp hour ratings? What brand model etc. I have not found one that big until group 31.

I have an RV buddy in VA who is Mr. Battery. I will email him and see what he says about what limits a battery from charging and how long it takes for recharge to 90%. May take a couple of days or so to get an answer.

John

**Tweety** · 05-11-2009, 09:10 AM

Hi John,

The battery I got is from WalMart and is a "EverStart Marine MAXX-29" rated at 125 AH. Maybe this is a group 29 ?? It is a big sucker and I couldn't fit 2 on the standard Sunline rack. I only have the one now paired with original 50 AH Sunline dealer battery.

Yes - do see what "Mr. Battery" says - as you and I are bewildered about the same things at this point.

BTW - typical "clamp-on" ammeters will not handle DC as they are based on inductance (hard to induce current via DC with no waveform). They do make clamp-on DC ammeters - but a specialty item. Anyway - I am saddened to admit that I have no ideas how to actually measure the charge current. Perhaps "Mr Battery" has some answers for us.

Mr Tweety

**JohnB** · 05-11-2009, 10:31 AM

Quote:

Originally Posted by Tweety

Hi John,

The battery I got is from WalMart and is a "EverStart Marine MAXX-29" rated at 125 AH. Maybe this is a group 29 ?? It is a big sucker and I couldn't fit 2 on the standard Sunline rack. I only have the one now paired with original 50 AH Sunline dealer battery.

Yes - do see what "Mr. Battery" says - as you and I are bewildered about the same things at this point.

BTW - typical "clamp-on" ammeters will not handle DC as they are based on inductance (hard to induce current via DC with no waveform). They do make clamp-on DC ammeters - but a specialty item. Anyway - I am saddened to admit that I have no ideas how to actually measure the charge current. Perhaps "Mr Battery" has some answers for us.

Mr Tweety

OK that sort of explains how you ended up with such a big amp hour. Yes that sounds like a Group 29 not a Group 27. I looked at those batteries too. Any idea on who makes them for Wal-Mart? They may be an option for me since the 1 Grp 27 I got from Schaffers is not a very high end one either.

I may have one of those fancy AC/DC clamp on’s. I have used it to measure the brake coil current when clamped on the emergency break away switch feed line. And it gave me a reading of what sure lined up with 4 brake coils current draw. I was surprised it actually worked. The old way is to use an actual amp meter in series with the load. I will read up on the manual of it to explain to me that it is really reading DC current.

Here is mine in action in the AC world measuring current draw on the Dometic fridge electrical heating element. A group of us where trying to figure out what was up with the recall before the official recall started. Us inquiring minds type need to know…

Oh, I made up and pressure treated wood adapter bottom to go from Group 24 to Group 27 that just lays in the Sunline battery tray. If you have not already made yours, it might spark some ideas on how you can use that concept on yours. My battery rack is 90 degrees to your, but same concept can apply. I’ll make a post of the pics.

In case you want the advanced version follow this link to a bunch more pics. The worded version soon to come. JohnB’s battery holder conversion

I’ll let you know what “Mr. Battery” comes back with.

John

PS make sure you drill some drain holes in the battery storage case. Mine, 1/2" dia I drilled on the side as the new battery holder seals off the bottom. If you do not do this, the case can fill with water.

**Tweety** · 05-11-2009, 11:24 AM

Hi John,

I have no clue who really makes the WalMart battery. I hae been very happy with it so far as it takes alot to drain the monster.

Your tray mod is great - I will plan on just about exactly the same. And lastly, of course you have the fancy ammeter ---- what was I thinking ??? Waht else would John B have ??? My primitve sears DVM will measure amps in series - but only up to 10A.

Keep us posted on your progress and any info from "Mr Battery" as it is fun to "de-mystify" this battery stuff which can be tricky ......even though we may be the only ones into this....

Steve

**JohnB** · 05-12-2009, 07:06 AM

Quote:

Originally Posted by Tweety

Hi John,

Snip

And lastly, of course you have the fancy ammeter ---- what was I thinking ??? Waht else would John B have ??? My primitve sears DVM will measure amps in series - but only up to 10A.

Keep us posted on your progress and any info from "Mr Battery" as it is fun to "de-mystify" this battery stuff which can be tricky ......even though we may be the only ones into this....

Steve

Steve

LOL!!!!!! I have not had a laugh that hard in a long time….

THANKs!! Between prior owning a Fruit farm and bringing many of my big toys with me to Ohio and being in the industrial automation machinery world, the bag – O – tricks accumulates. When you get to the point in life of having a rolling coach to go play with, complete with the kitchen sink, these high end techno toys come in handy….

I’ll try the amp meter again to make sure it does the DC charge rate on the battery. If you want I’ll bring it to Buttonwood and you can go play with it on yours. Let me know.

Oh, and are your testing us to see if we would pick up on the typist behind the screen??? Mr. Tweety makes a post. Then Tweenty make replies to is on and off with a Mr. Tweety in the middle a few times. Now I know “Mrs”. Tweety is really into Sunlines and knows her stuff, and she even tows the Sunline some times. Is Mrs Tweety into the flow of electrons too?? Cool!

We will find the answer out to this charge rate and what makes the battery accept charge. Use inquiring minds type need to know… Now that I have that bug about, well how does this thing work??I can’t leave it alone until I figure it out. Or you do and solve the mystery and let me off the hook…..

Have good one

John

Lode · 05-12-2009, 07:25 AM

[quote="JohnB"]

Quote:

Originally Posted by Tweety

I looked at those batteries too. Any idea on who makes them for Wal-Mart? They may be an option for me since the 1 Grp 27 I got from Schaffers is not a very high end one either.

I use the same batteries as Steve from Walmart

I use 2 I bought in 07 for my boat... here are the specifics off the label of the batteries.

Manufactured- 22 Mar 07
EverStart Maxx Marine (trolling, starting, deep cycle, RV)
875 cranking amps
125 Amp hours
Part no- Maxx 29
18 month free replacement
18-24 month pro rated discount replacement

I think they ran about $120/each give or take core charge returns.

I know a few people who have had problems with them but they've simply returned them for a brand new battery without a hassle.

Hope that helps a little to finding better batteries for your coach.

Take care,
Lode

frank · 05-12-2009, 08:06 AM

Just chiming in with a couple of thoughts.

I have a WFCO converter as well, which I do believe is a 89XX series. I have not yet measured the charge current, but I will do so after I complete my charge cable upgrades (delayed due to kitchen remodel).

Someone mentioned wal-mart batteries. Last I had heard, those were produced by Johnson Controls. I've dealt with a few of their automotive batteries over the years and never had any issues with them. No experience with their deep cycle stuff though.

Current measurement - As John illustrated above, a quality current clamp is great. Another way to measure "high" current is by using what's called a meter shunt. A meter shunt is a device that you install in-line (series) of the circuit you need to measure. The shunt introduces a small (less than one ohm), stable resistance into the circuit. You then use a voltmeter to measure across the shunt. This reading is then translated into the current. A common value for shunts is 1 microvolt per ampere.

Meter shunts are an application of ohms law. Here's what an inexpensive commercial one looks like:

I'm a really bad artist but maybe this picture will help explain how it is hooked up in the circuit:

For a one-time, or occasional use, you can easily make a shunt from a short length of wire. Here's a web page that illustrates how to make one from a short length of stranded 8 AWG wire: http://www.motorcycleproject.com/mot...ext/shunt.html. That's certainly simple enough to make, and will allow anyone with an inexpensive digital multimeter with a millivolt scale to easily make current measurements in the 30A range.

- Frank

Viking · 05-12-2009, 08:28 AM

John & Steve,
No, you are not the only ones in this.
Even though I am still a Sunline-wannabe, I have found this forum a very good source of knowledge, so I keep reading and learning.
We have two Group 24 batteries, and they seem to fill up the battery boxes
with no room to spare. I have not run across any larger battery boxes. Where do you find boxes to house Group 27, 29 or larger batteries?
As a side comment, I was told that when you use more than one battery, you always use them together as a pair, so when one of ours failed last year, I replaced both. Was I wasting my money?
Roar

**Tweety** · 05-12-2009, 10:51 AM

The only question Tweety can answer on this discussion is why it appears that Tweety and Mr Tweety are taking turns posting. Tweety's computer is set so that it automtically signs her in when she clicks on the Sunline link in her favorites. Mr Tweety doesn't care to bother to sign out Mrs Tweety before posting his reply, and opts to just sign at the bottom. Mrs Tweety has NO interest in this AT ALL except to make my computer and TV set work while boondocking....couldn't care less how the engineers figure out how to make that work....just happy that there are engineers to do it!

MACK C-85 · 05-12-2009, 11:19 AM

Tweety, gotta watch those auto log-ins, no telling what can show up attributed to you......

My better

half, mdfiregal, is a system administrator where we both work. I found out the hard way when I was setting up for a high level briefing and had "Chinese Mambo #5" start up on the conference room screen as I was logging into get my briefing slides.....

Someone, love ya honey, had "slipped" it into my auto run folder!!!

Must not have been too bad though, I still married her

sunnyseagull · 05-12-2009, 03:58 PM

HI Steve and John this is very interesting and educational but my head is spinning

trying to keep up with all this LOL !!!

Dan

**Tweety** · 05-13-2009, 03:25 PM

We may not have the exact same battery as Lodeline because ours was only $70 or $79 (we didn't trade one in).
Pam

**JohnB** · 05-13-2009, 09:31 PM

Quote:

Originally Posted by Viking

John & Steve,
No, you are not the only ones in this.
Even though I am still a Sunline-wannabe, I have found this forum a very good source of knowledge, so I keep reading and learning.
We have two Group 24 batteries, and they seem to fill up the battery boxes
with no room to spare. I have not run across any larger battery boxes. Where do you find boxes to house Group 27, 29 or larger batteries?
As a side comment, I was told that when you use more than one battery, you always use them together as a pair, so when one of ours failed last year, I replaced both. Was I wasting my money?
Roar

Roar, You keep being a Sunline wannabe and soon you will turn into one...

The battery boxes, Atwood Mobile is one company who makes them. Actually Walmart even has a brand of them other then Atwood. The Marine type stores, even some Auto parts stores. And the camping stores.

There are also on line. Here is some at “Tweety’s” http://www.tweetys.com/batteryboxest...holddowns.aspx Seems Mr. Tweety and Tweety have their own camping store…

.LOL

I have bought from them on line and had a good experience. There are other site that have them too.

Changing batteries, Yes they say change them out at the same time as a rule of thumb. What they do not explain is the actual age reason. If you are only a few months apart, maybe even 6 months, if the batteries are conditioned well, (being desulfated often) then I would think they would still blend well. What I believe they are saying is, when you get 2 batteries that are a year or more apart and one has been working hard, adding a fresh one in parallel to it then the 2 batteries want to equalize. The weaker one draws from the stronger one and then the 2 of them settles out when they equalize. Does it work, sure, doe it work at efficient as it can, well no. This is what I “believe’ they are referring to.

Good luck

John

Viking · 05-14-2009, 06:01 PM

Hi John,
Yeah, it looks like I will continue as a Sunline Wannabe for a while longer. As stated earlier, I needed to sell of my big bikes to raise some money for a Sunline.
I got lucky and sold one, and thought I could go shopping, but another project I have going, is coming in waaaay over budget, so there went my Sunline money. If not this year, possibly next.
It is not helping any that my employer of over 36 years is now in bankruptcy. That is bound to have a very negative impact on our finances in the future.
I appreciate your information on batteries.
I guess I did the right thing by replacing both when one went on strike. They were close to five years old. Unfortunately we do not have a "smart" power supply / charger in our present "coach", so I suspect that fact was a big factor in the short life of the batteries.
What in the world is a "ferro resonant rctifier" anyway? I once asked an"EE" about that, and he did not know.
May be it would be a good idea to disconnect from shore power during the day and sleeping time at night, when there is very reduced load on the 12V system. What do you think?
Thanks for the info on battery boxes. Places where I had seen them seemed to just stock the size for Group 24.
Regards,
Roar

BobNKaren · 05-27-2009, 08:51 AM

I took the easy out. Needed to extra battery capacity to run my C-Pap machine at night. As we do a lot of dry camping I added a group 27 deep cycle battery in addition to the group 24 that came with my rig and added switches to connect one or both. I soon found out that even running the generator up to 8 hours a day and using the onboard converter/ charger I soon ran out of battery. I tried a charger that I had but the output was too low to recover the lost charge. I did some surfing on the web and found out about 3 stage chargers that provide the fastest means to recharge a battery. The article gave the stages as Bulk (a high amp rate), Absorption (a controlled rate at a constant voltage) Top off Charge (low current rate to a predetermined voltage.). While doing the mall crawl I found a "Smart Battery Charger" at wally world. The unit I got was the 4/10/20/40 amp charge rate with 110-amp engine boost start.

I have been using the charger for about 4 years now and found I can get the group 27 charged up enough in 4 hours To be used again. Some Federal parks only have 4 hours of generator use time. 4 hours in not enough time to fully recharge the batteries but will give enough of a charge to handle my night needs. In 4 hours the charger usually is in the Top off Mode. What I do is leave one battery switched on the trailer system and the one that is off line I charge with the Smart Charger. At the end of the day I then switch on the charged battery and switch off the battery that was in use. The next day charge up the off line battery and then switch again at night. By alternating charging and switching I have been more than a week off the grid with limited hours to run the generator. When I get to a park with power I then charge each battery independly until the charger cycles off. When I have both batteries charged I then switch on both batteries to maintain the charge while on shore power.

I also use this charger to keep my fleet of toys batteries maintained. One of the other features is a de sulfsufation mode and used it save an old lawnmower battery for another year use.