Trickle Charger for Sprinter Batteries

Gamma1966

2013 Chassis /14 Unity MB
While on my trip back from the LTV rally in Winkler, I experienced a "Dead Battery" situation. I left a cooler plugged in over-night, using the power outlet below the Radio console, which is fed from the Engine Batteries. I was able to "jump start" the engine starting battery using a cable from the "Battery Boost Point" located in the engine compartment and my coach Battery system under the floor in the van. I made the jumper cable from a 30 Ft #2 welding cable and a pair of insulated Alligator Clamps; which I now keep stored in the driver’s door storage compartment. I have since made up another single jumper cable, stored in the passengers door storage compartment, in case I need to jump start another vehicle from my Van.

While at the LTV rally I met with one owner who had hooked up a trickle charge system using the power of the coach batteries to "trickle Charge" the engine starting batteries. Perhaps that owner, or others may have also done this; if so can they share the details of how they accomplished this feature.
 

aljimenez

'13 LTV Serenity on '12 3
A different solution: search Trik-L-Start for a device that charges the engine battery as long as the house batteries have plenty of juice as when they are on charging with external power. I installed one in my now sold Pleasure Way and it is covered in this post:

http://www.sprinter-source.com/forum/showthread.php?t=1150&highlight=Trik-L-Start

I have also installed this device in my current Serenity. I never have to worry about my engine battery discharging any more... Al
 

jackfish

Active member
I was going to install the Trik-L-Start, but since I have solar capacity using the Blue Sky SB3024 solar charging controller I used the 2 amp auxilliary chassis battery charger. When the coach batteries are in acceptance or float charging, 2 amps are diverted to charge the chassis battery.

The Trik-L-Start is a good solution for your application.
 

joeframer44

2014 Unity MB/U-lounge
Pardon me for becoming confused once again. Is it not the case that if we are hooked to shore power in storage that the converter/charger ( 3 stage currently used in the newer Unitys) will keep the house batteries safely charged, and 'trickle over' to also top off the chassis battery as long as the house battery switch is left ON?

Until I can understand all of this I'm not sure if I shouldn't turn off the main breaker to my real house so I don't use up all of the electricity coming in from the pole!:lol:

Joe
2014 Unity MB
 

cdcorpe

2014 Murphy Bed
Only the house batteries charge when plugged in. M/B supplies a disconnect behind the gas (diesel) pedal.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
Too true! My MB sat for several months on shore power without being started - and when I arrived and tried to drive away, the chassis battery was quite low. My 2012 has the isolator with the emergency switch that feeds house power to the engine in this circumstance, so I was on the road - and of course, the chassis battery then came right back up. So I can't speak for all Sprinters, but mine certainly doesn't charge the chassis battery from shore power. There are several other threads here about this, mostly discussing the Trik-L-Start IIRC...
 

Gamma1966

2013 Chassis /14 Unity MB
Jackfish talked about he had a --> Blue Sky SB3024 <-- charge controller installed in his Unity; can he show us where it is physically installed? I am looking to replace the LTV supplied GO Power SC30 Charge controller. The Blue Sky unit is physically bigger than the GO Power charge controller, so I am interested to see where it was installed in the coach?
 

israndy

2007 LTV Serenity
I love my Blue Sky, but I waited until the 3000i was available. It too has the 2 amp trickle, but I purchased the trik-l-start too as it is separate and allows my chassis to charge from any source, not just solar. I like distinct systems that work when others go on the fritz. Plus I use the other circuit to drive my fridge off battery until the battery runs too low and then it turns off the fridge, preserving the bottom half of the battery from being eaten in case I leave the fridge on 12v when I am at the in-laws.

-Randy
 

joeframer44

2014 Unity MB/U-lounge
Any tips on installing the Trik-L-Start in the Unity MB specifically?

Thanks.

Joe
2014 Unity MB
 

blue

2011 LTV Unity CB
Re: Posts #5 and #6 - more confusion! The manual for my 2011 Unity CB says "The Bi-Directional Isolator Relay Delay constantly senses the voltage of the coach and chassis batteries. If either voltage is above 13.3 volts, which indicates the batteries re being charged, the control closes the isolator relay. This parallels the batteries, charging them both." This tells me that the chassis battery would be charged if plugged into 120V or running the generator, but probably not from solar panels.

My Mercedes manual says that there is a Battery Isolating Switch near the accelerator pedal, but there is no switch to connect the coach battery to the chassis battery in that area.
 

cdcorpe

2014 Murphy Bed
My post was based on my 2014 Unity. I called Leisure Van & asked if they used a bi -directional isolator & they said M/B would not let them. Under the accelerator is the M/B battery disconnect. (on my 2014) Sorry for any misinformation.
 

joeframer44

2014 Unity MB/U-lounge
Now I am totally confused. So does LTV saying that there is no isolator block near the house batteries mean that hooking up a Trik-L-Start is impractical?

Joe
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
What is making this confusing is that LTV has apparently used at least 2 different types of isolators over the last few years. The isolator in my 2012 MB is apparently a hybrid, that is, software controlled and with solenoid contacts. It has a dashboard switch that allows you to start the RV from house batteries if your chassis battery goes dead. Nice idea - but apparently there were some issues with blowing a large line fuse when you used that feature. I haven't had that problem; I've started the RV twice from the house batteries. I understand that now they're using a different kind of isolator. I don't know any more than this - haven't had the RV in my hands long enough to check out what's there in detail. When we were taking our first trip in the RV I asked about the isolator (and a million other things <g>...), and the replies were also confusing until we figured out the different isolator issue.
 

Bone Head

2014 LTV Unity MB
I have installed the Trik-L-Start in my 2014 Unity MB on a 2013 chassis. It was a simple matter of hooking the leads to the opposite sides of the relay which closes to allow the alternator to charge the house batteries. It is located under the drivers seat and I was able to do the connections without removing the seat. It well may have been easier to just remove the seat, but at the time I didn't have the necessary socket to remove the seat bolts.
I mounted the Trik-L-Start controller on the drivers seat pedestal so I can see the indicator lights when I open the drivers door.
There is not a good way to take a picture of the wiring, but it really is easy.

Bob
 

joeframer44

2014 Unity MB/U-lounge
Just thinking, why is a Trik-L-Start type of trickle charger not part of the standard complement of electrical components in our RVs, when it is highly likely that it may be stored for extended periods of time, even with shore power? I know, cost , cost , cost, but still.

Joe:thinking:
 

avanti

2014 GWV Legend 3500 I4
I just installed a Trik-L-Start this morning. A pleasant experience. Looks like it "just works". I did discover that the main house battery disconnect switch disconnects the wire to the battery isolator and hence, to the Trik-L-Start. Not good. I will have to fix that.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
Let me make sure I understand this gadget. Is it true that its only function is to charge your chassis battery from your house batteries? So it gives you 2 things:

* If you're away from the RV for a long time and you have shore power, it keeps your chassis battery up, and the house batteries are kept up by the RV charger?

* And if you had no shore power for a long time, it would keep your chassis battery up at the expense of the house batteries, which presumably have enough capacity if the time span isn't too long. This would only be useful if you don't have the isolator setup with the switch that lets you start the RV off the house batteries.

Am I missing anything, or is that what it does?
 

avanti

2014 GWV Legend 3500 I4
Let me make sure I understand this gadget. Is it true that its only function is to charge your chassis battery from your house batteries?
Not exactly.
* If you're away from the RV for a long time and you have shore power, it keeps your chassis battery up, and the house batteries are kept up by the RV charger?
Yes.
* And if you had no shore power for a long time, it would keep your chassis battery up at the expense of the house batteries, which presumably have enough capacity if the time span isn't too long.
No. It does not take power from the house batteries. It only charges the chassis battery if the voltage on the house side is above a certain threshold that should only occur if a charging source is present. The idea is to piggyback on the house battery charging source (shore power, genset, or solar) to also maintain the chassis battery.
This would only be useful if you don't have the isolator setup with the switch that lets you start the RV off the house batteries.
Well, if you don't mind letting your chassis battery going dead, then, yes. But that is very bad for the battery. The real idea is to keep the chassis battery healthy. The benefit accrues if you leave your vehicle plugged in during storage or (as in my case) you have solar and park outdoors.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
Thanks Avanti, that's starting to help. So it's checking the voltage on the house batteries, and connecting to the chassis battery and charging it when the house battery is over some threshold voltage? So if the house battery voltage is being held up by at least float charging, it'll connect to the chassis battery, but if there's no charger holding the house battery over 12.8 or so, it won't connect?

On my last RV I put it in my garage for the winter, plugged it in - and when I needed it for an emergency late in the winter, I found that I had a dead chassis battery. I didn't realize until then that at least some RV's don't charge the chassis batteries when plugged into shore power. That seemed very counter-intuitive at the time - I would have thought that RV's would have a smart isolator that would sense when the house batteries are up and then connect and charge the chassis battery. Guess that's why you're buying the Trik-L-Start though... Have I got it right this time?

In your case - when you are storing outdoors and have solar - is it working exactly the same way? - the charger in your solar install raises the battery voltage just like any other charger and the Trik-L-Start senses the voltage and connects the chassis battery?
 

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