Free 7 Day Trial RV GPS App RV Trip Planner Campground Reviews RV Maintenance Free 7 Day Trial ×
 


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 02-28-2021, 11:12 AM   #1
Winnebago Camper
 
Join Date: Feb 2021
Posts: 6
New to lithium. Questions about charging

I have a 2017 Via and purchased a 100ah Battle born battery about a month ago. I previously had 2 Trojan 6v batteries. I havenít done any dry camping with the battery yet but what Iíve found is that the charging characteristics are much different and require some pretty major changes to the stock charging system. I have 2-100watt solar panels and just purchased a upgraded Victron energy MPPT 100/30 smart charge controller because my previous controller could not be easily changed to 14.6 level needed to charge the battle born. I do like this controller better as it has Bluetooth and can monitor the battery easily. I plan on adding one more battle born but I wanted to try dry camping first to see if itís necessary. Now Iím understanding that I possibly have to purchase a DC to DC Orion converter to protect my alternator and better charge my batteries while driving. Is this necessary or will my solar controller boost the battery sufficiently while Iím driving to fully charge the batteries? I wasnít planning on changing my charge controller for the RV house batteries because I figured my solar would be adequate. I would rarely run my generator that much to charge my batteries with my 6v Trojans. The solar was plenty. I guess my question is whatís the best way to do all of this? I did purchase a portable charger the IP 65 to charge my batteries fully when Iím in the garage at home. I was told by battle born that I could plug this in while running the generator to boost the volts running to my batteries if I didnít have adequate solar.
Thanks for your responses,
Derek
2010 Reyo
2017 Via
N. Ca
DLindy is offline   Reply With Quote
Old 02-28-2021, 01:45 PM   #2
Winnebago Master
 
Join Date: Feb 2020
Posts: 529
From what you describe, when you just had the two GC batteries, your solar power would keep them fully charged at the end of the day. So I would assume that would be the case with the lithium taking their place. That should not put a significant load on the alternator if the battery is fully charged. That won't always be the case though.

But....... The Via uses the Mercedes Sprinter chassis and I have read that you need to limit auxiliary output from the alternator to 40 amps. If you get into a situation perhaps with a cloudy day with little solar and the lithium is discharged then it can pull more than 40 amps. But it all depends on wire size to the alternator and what kind of BIM the Via has.

I would do some experimenting with a clamp on DC ammeter. These can be bought for about $75. Run the lithium down and start up your chassis engine and measure the alternator output with and without the lithium connected and see what it is.

I am not a big fan of installing a DC to DC converter between the chassis alternator and the coach as it is not bidirectional. The aux start switch won't work with it installed.

Another imperfect solution is to replace your BIM setup which is probably the old BIRD/Trobetta relay with a Precision Circuits BIM 225 Li. This turns the alternator connection on and off every 15 minutes to limit overheating of the alternator.

But you may be surprised that the wire size limits the current. Try that first.

David
DavidM is online now   Reply With Quote
Old 02-28-2021, 01:58 PM   #3
Site Team
 
creativepart's Avatar
 
Join Date: Sep 2009
Location: Spring Branch, TX
Posts: 3,704
I agree the Victron Solar Controller is vastly better than the usual ZAMP PWM controller in most of WBGO's motorhomes. I made the same change.

With 2-6v batteries you probably had 200 amp hours of storage and yes, you could only use 50% without damaging the batteries. So, it's like having 100 aH available. Hence, one 100 aH Battleborn should do the trick. Right?

But wait, you shouldn't take the lithium down to zero, so what now you have 90 aH available?

I can understand not wanting to spend another $900 for an additional 100 aH. But really, you'd be better off and worry a whole bunch less if you bite the bullet and installed the 2nd battery.

I agree with David, you'll probably be fine without the DC to DC charger. But it would be good to know for sure.
__________________
2017 Winnebago Adventurer 37F
2016 Lincoln MKX Toad
creativepart is online now   Reply With Quote
Old 02-28-2021, 04:15 PM   #4
Winnebago Camper
 
Join Date: Feb 2021
Posts: 6
Iíll get the DC ammeter. Good idea. Where would I find the right wire to test the amps? Is it coming out of the alternator? Or coming in to the house batteries? To test it without the lithium connected can I just hit the house battery disconnect? Do alternators fluctuate a lot? Or if I see 30 amps several times in a few minutes that should tell me? I plan on getting another battery so I probably should test it again after I get the 2nd battery? Thank you!
Derek
2017 via
N Ca
DLindy is offline   Reply With Quote
Old 03-01-2021, 06:51 AM   #5
Winnebago Master
 
Join Date: Feb 2020
Posts: 529
Quote:
Originally Posted by DLindy View Post
Iíll get the DC ammeter. Good idea. Where would I find the right wire to test the amps? Is it coming out of the alternator? Or coming in to the house batteries? To test it without the lithium connected can I just hit the house battery disconnect? Do alternators fluctuate a lot? Or if I see 30 amps several times in a few minutes that should tell me? I plan on getting another battery so I probably should test it again after I get the 2nd battery? Thank you!
Derek
2017 via
N Ca

You have to start with somewhat discharged batteries so there will be a significant load on the alternator. So disconnect from shore power and leave all of the lights and fans on for the better part of a day to draw down the battery.

Ideally use the wire coming from the batteries to measure the alternator charging current, which runs through the coach's BIM and then connects to the chassis alternator. But like my MH you may have several wires connected to the battery and it probably isn't obvious which is that one.

First measure the current through each of the wires. Ignore the small gauge ones. This wire has to be pretty big, probably at least #2. Note the current in each wire.

Then start the engine, wait a minute for the chassis electronics to fully turn on the alternator and measure again. You should see one of the wires jump 20 or more amps. That is the one.

Another way is to measure the current from the lug on the alternator. But that also includes current to operate the chassis which with modern electronically controlled vehicles can be significant. So shut off the use/store switch, start the engine, measure the current from the alternator, then open the switch and measure again. The difference should be the charging current from the alternator to the coach. You can confirm this by finding the wire at the coach battery that has similar current.

Sorry for this long detailed explanation. What sounds simple to do gets complex when dealing with a MH where you can't trace the wires because they head off into the unknown.

David
DavidM is online now   Reply With Quote
Old 03-01-2021, 06:13 PM   #6
Winnebago Camper
 
Join Date: Feb 2021
Posts: 6
Thanks David. So it sounds like I can find this wire under my steps where the coach batteries are. This sounds pretty simple. Even for me :-) thanks for the help. So I guess if I measure under 40 A then I should be OK?
DLindy is offline   Reply With Quote
Old 03-01-2021, 08:20 PM   #7
Winnebago Master
 
Join Date: Feb 2020
Posts: 529
Quote:
Originally Posted by DLindy View Post
Thanks David. So it sounds like I can find this wire under my steps where the coach batteries are. This sounds pretty simple. Even for me :-) thanks for the help. So I guess if I measure under 40 A then I should be OK?
Yes, anything under 40A should be good. But be aware that if you add a second battery, or a third........, the charging current will go up. But if it is limited as I expect it is by voltage drop in the wire then it shouldnít go up much.

David
DavidM is online now   Reply With Quote
Old 03-06-2021, 11:06 AM   #8
Winnebago Camper
 
Join Date: Feb 2021
Posts: 6
Is it possible that I am only pulling 1 amp. I purchased a Klein tools 400A AC auto ranging digital clamp meter. I ran the battery down then started the vehicle engine and the highest number it pulled out the negative wire going to the coach battery was 1.6 a. It was pretty much 1a for the entire 5 minutes I ran the engine. I did not go under the hood to check the alternator. Does this seem possible? I did rev up the engine off and on. Thanks
Derek
2017 Via
N. Cal
DLindy is offline   Reply With Quote
Old 03-07-2021, 04:21 AM   #9
Winnebago Master
 
Join Date: Dec 2007
Posts: 976
Quote:
Originally Posted by DLindy View Post
Is it possible that I am only pulling 1 amp. I purchased a Klein tools 400A AC auto ranging digital clamp meter. I ran the battery down then started the vehicle engine and the highest number it pulled out the negative wire going to the coach battery was 1.6 a. It was pretty much 1a for the entire 5 minutes I ran the engine. I did not go under the hood to check the alternator. Does this seem possible? I did rev up the engine off and on. Thanks
Derek
2017 Via
N. Cal
Is there an option on the digital clamp meter to measure "DC" voltage, or is that a typo that you bought an "AC" meter?

The current you are measuring is DC, not AC household current.
__________________
Al & Sharon
2006 Winnebago Journey 36G
https://downtheroadaroundthebend.blogspot.com/
al1florida is offline   Reply With Quote
Old 03-07-2021, 02:13 PM   #10
Winnebago Camper
 
Join Date: Feb 2021
Posts: 6
Yes thank you. I thought this was an AC and DC meter. It was just measuring AC. I went back and got a AC and DC meter. It is measuring 31 amps. Everything looks good. Looks like I wonít need the DC DC charger. Iíll post back my findings as I use this further and if I add another battery. Thanks for the help!
Derek
2017 Via
N Cal
DLindy is offline   Reply With Quote
Old 03-07-2021, 02:54 PM   #11
Winnebago Master
 
Join Date: Feb 2020
Posts: 529
Good information! That is the first piece of data I have seen on charging current into a lithium battery from a Mercedes alternator. But.....

What was the state of charge of your batteries when you measured this current? If they were topped up to 100% then the current would not be much, but if they were like 50% it would be much higher.

David
DavidM is online now   Reply With Quote
Old 03-07-2021, 08:47 PM   #12
Winnebago Camper
 
Join Date: Feb 2021
Posts: 6
My battle born battery was about 70%. I will test it again at a lower % to see if itís different. When I first turned on the sprinter it read about 40a then within 30 seconds settled down to 35a for approximately 2 minutes, then dropped to 30amps a couple minutes later and stayed for several minutes. I ran the test for about 8 minutes and there wasnít really any fluctuations up it was just gradually lowering the amp draw. I was inside a garage and idling so no solar was active. I did rev the rpmís up to 2500 which seemed to do nothing as far as changing the amp draw. Thanks, David
Derek
2017 Via T
N. Cal
DLindy is offline   Reply With Quote
Old 03-08-2021, 04:45 AM   #13
Winnebago Master
 
Join Date: Feb 2020
Posts: 529
OK, at 70% you were probably getting as much current as you will ever get, but do check it at lower SOC to be sure. Sounds like you are in good shape, at least with your single battery.

David
DavidM is online now   Reply With Quote
Reply

Tags
charging


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Charging performance lithium phosate batteries Elkman Electrical | Charging, Solar and Electronics 2 11-07-2020 05:33 PM
2020 Navion Purch/Order Questions (Lithium & AGS) RickoJ Winnebago General Discussions 2 12-26-2019 10:23 AM
questions about battery charging/draining jrt13 Electrical | Charging, Solar and Electronics 13 11-18-2019 12:07 PM
Battery Charging Questions INSPECTORBOB Electrical | Charging, Solar and Electronics 14 10-20-2010 09:26 AM
General Battery Charging Questions LK23 Electrical | Charging, Solar and Electronics 23 08-19-2005 05:15 AM

» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Winnebago Industries or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 08:03 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
×