Fitz’ 2016 Sprinter 4x4 RB 150S Build - Page 63

Fitz · 02-04-2019, 01:20 PM

Quote:

Originally Posted by Scalf77

A lot would depend on what separtor you actually have .... Let me know which unit you have, and I would be happy to help you out.

-greg

Greg,

Thank you for the excellent information. My build documentation doesn't specify what unit was installed, I will have to pull the driver's seat off in order to see. I'm currently gathering a few parts and pieces to do something else under there, will pull the seat at the earliest opportunity and then look forward to learning more from you.

Thank you!

Tim

mkkbven · 02-04-2019, 08:02 PM

I have the same documentation from Sportsmobile, but I could not find anything resembling an isolator under the drivers seat. I do have a blue seas 7620 isolator mounted under the bench seat. Only two control wires are being used, which I believe are to enable the batteries to be isolated during start. ( I would have to take the loom apart to check wire colors to be sure.)

As it is set up, there aren’t many options and troubleshooting the batteries can be difficult because there is no way to isolate them (without removing the fuse. As scalf mentioned, the new ACRs are equipped with a switch allowing better control. I found one at Amazon for only $13, so I plan to retrofit it. Here is a screen shot if anyone is interested.

Scalf77 · 02-04-2019, 10:20 PM

Sportsmobile must purchase the 7620 in bulk without the switch. It boggles my mind why they don't include it. The 7620 only needs the the two battery cables and a ground wire (Black)to work. The yellow wire is the low side of the indicator circuit. The red wire is the control wire, if left open or floating, it would allow the unit to work as intended, monitoring the voltage of each battery. It is conceivable that sportsmobile tied the red wire to the "Run Circuit" as 12 volts on the red wire forces the 7620 to combine the batteries. Grounding the red wire disconnects the battery. It is possible in their state of confusion with the Surepower unit they came up with this idea. The brown wire is the one that you would use to hook to the "start circuit" this would isolate the batteries during start.

If the red control wire is hooked up to the run circuit, you basically loose any value of the voltage monitoring features of the unit. You could use a cheaper option to accomplish that. The minimum of 3V on the engine battery in your documentation would not apply to the 7620, it has a low voltage lock out at 9.6 volts.

-greg

Fitz · 02-06-2019, 07:20 PM

I didn't pull the seat off, rather I contacted (the always helpful) Brian Dollar in Austin. His response: The battery separator we use is a Sure Power Model 1314-200. The link below will provide more information. Brian also confirmed that the separator allows current to flow from the auxiliary battery to the engine battery only when the ignition switch is in the on position.

It looks like we have discovered another difference between Fresno and Austin. Mark's Fresno build has the Blue Sea 7620 ML-ACR Automatic Charging Relay, https://www.bluesea.com/products/762...ay_-_12V_DC_1A, my Austin build has the Sure Power Model 1314-200 Battery Separator, https://www.ase-supply.com/Sure_Powe...p-1314-200.htm

Regarding the operation of the Sure Power Separator, from the specification outline: The 1314-200 (unidirectional) is a 200A battery separator module with an integrated relay for 12V systems. The unit monitors both the main and auxiliary battery banks. If the main battery is above the connect threshold, the relay connects the two banks together. If the main battery is below the disconnect threshold the unit will open the relay. The connect threshold is set to a nominal voltage of 13.2V, which would only be reached when the charging system is operating. This will cause the relay to close and the charging system can charge both banks of batteries. The disconnect voltage is set to a nominal 12.8V, which is near the full charge resting voltage of the batteries. This will cause the relay to be opened shortly after the engine is stopped, attempting to preserve 100% of the starting battery capacity for engine cranking. When the engine is started, the start signal causes the controller to check if the auxiliary battery is within about 0.85V of the main battery; if so, the relay is closed. Thus providing the starter system with maximum battery voltage available.

Regarding Assist In Engine Starting, from the Sure Power web site: When the engine starter is activated the battery separator compares the voltage of both battery banks. If the chassis' battery is lower than the auxiliary battery bank, the battery separator will engage allowing the auxiliary battery bank to aid in vehicle starting. The start signal must be at least three volts for the operation to occur.

My bottom line: The Sure Power 1314-200 battery separator will allow both batteries to charge when the engine is running and it will connect the batteries together to assist with engine starting if the engine battery is low, but it will not allow the on-board charger to charge the engine battery when plugged into shore power UNLESS the ignition key is in the ON position. I like knowing that the on-board system has the ability to charge the engine battery when connected to shore power if needed, but I don't like the idea of routinely leaving the ignition key in the ON position, thus I will continue to use my stand-alone CTEK charger for the engine battery for those times when I feel it is needed.

Greg, did I get this right?

This has been a good learning experience, thanks to Mark and Greg for pushing me to learn more about the system I have.

If anyone has any other thoughts, please put your fingers on the keyboard and bring 'em on!

tlg · 02-06-2019, 07:44 PM

Fitz,
Just FYI, lots of forum members have switched out that sure power model for the blue sea ml-acr variant. Performs much better (with the optional remote switch installed) is quieter, and lasts longer. Greg could give you a better technical readout on why one should make the “switch”. I did it after my sure power neared the end of its life due to excessive switching (caused by a loose wire at the solar controller).

Scalf77 · 02-07-2019, 06:08 AM

Fitz, you do have it correct. The 1314 is unidirectional and the 1315 is bidirectional. I will say that in my opinion the Surepower unit is a much weaker solution. I also do not like the start assist feature, I believe it just hides the fact that your starter is going bad. I also have concerns when they say that the that the start assist work in the "on" position, what is on. I have also seen that this has been set up incorrectly by sportsmobile ( West At least). They have been know to connect to the"run Circuit" instead of the "start circuit" The difference is that the start circuit only has 12 volts while the key is in the start position. The run circuit will have 12 volts when the key returns to the run position. So if they mean On to be the "run position" they would be wrong.

A better way to hook up the start assist feature would be to hook thru momentary switch to a 12 volt vehicle powered circuit. This would allow you to use it more efficiently. You could also hook it up to a spst switch to house battery power, this would allow you to charge the starting battery from your shore power . It is just important, to remember to turn off when the starter is topped off.

The surepower documentation has at times shown and not shown a 10 amp fuse on the ground connection. I do recommend that a 10 amp fuse is installed on the ground. Since it get's it power thru usually non-fused battery connection, the fuse on the ground will help keep the unit from becoming a flame thrower if something goes wrong. I used to also put a switch on the ground wire, that acted like a disconnect switch. It can help in debug, nice to have when taking it in for work, etc.

Better yet, put it on your list to upgrade to a Blue Sea unit. It has twice the cycle life of the Surepower unit. A common problem of the high power solenoids is contact resistance on internal contacts, this builds up resistance across the connection, reducing the charging capabilities.

-geg

Scalf77 · 02-07-2019, 06:18 AM

I forgot, another important feature of the blue sea 7620 is that it is a magnetic latch, meaning it only uses power during the state change. The surepower is a continuous duty solenoid, there is always power to keep it connected. It can get pretty hot.

-greg

Fitz · 02-09-2019, 12:13 PM

Thank you everyone for the great information. As I said earlier, I have to be under the seat for another project soon, that will be my opportunity to scope out what is needed to make the switch to the Blue Sea unit. Would it make sense to install the switch shown by Mark in Post #622 above in the driver's seat base in immediate proximity to the ACR?

And my goal for 2019 was to work my way down my accumulated list of to-do's...oh well, it's a never ending list, now it has a new entry!

Mer1039 · 02-09-2019, 02:09 PM

Like Mark's, SMBW installed a 7620 under the rear bench seat of my Sprinter with no remote control switch. As far as I can tell I don't have an isolator under driver seat.

I'll be following this thread closely because having a simple switch to facilitate combining house battery with starter battery for "start assist" would be a nice feature to add to my rig (for that rare emergency).

Ron

Scalf77 · 02-09-2019, 04:19 PM

Fitz, others,

I have my control switch in my overhead visor unit. I like having accessible.

I had put this demo video together a while back. http://www.sportsmobileforum.com/for...2-a-16340.html It may help in understanding the features of the unit and install.The Blue Sea documentation is pretty straight forward. If you purchase a new 7622 it now usually comes with the switch.

greg