Sterling Battery Chargers

I would like to connect my 12volt house battery system to the Mercedes Sprinter (2016) Auxiliary Battery package with a Sterling Battery to Battery Charger. Sterling suggests two units: one is a 25amp unit (BBW1212) for $320 and the other is a 50amp unit (Bb1250) for $420. Supposedly, the 50amp unit will recharge our house battery (150ah) twice as fast as the cheaper unit. I would like to hear the pros and cons of these two units. I would also listen to any conversions suggesting to not connect to the MB auxiliary battery system. We are a low power use 12 volt conversion and I have attached our 12v electrical wiring setup with our electric consumables installed.

BBW1212:
http://www.sterling-power-usa.com/ProCharge-B-waterproof-dcinput-battery-charger-12volt-12volt.aspx

Bb1250:
http://www.sterling-power-usa.com/SterlingPower12volt-12volt45ampbatterytobatterycharger.aspx

What is the recommended charge rate of your battery/bank?






.

150 Ampere Hour Capacity @20 Hour Rate

from Lifeline Technical Manual:

Another less expensive choice is to power a pure sine inverter from the vehicle 12 volt system. Use the output to power your 3 stage battery charger.

A side benefit is you have 120 volt power available as you drive for other uses.

We have an inverter/battery charger. See attached diagram. We want to recharge while driving.

as long as you have the B to B charger, it should be fine, and since you are hooking up to the extra battery, no worries about disconnects.....

the one thing you have not said is how you plan to use it.

the AGM will like to be charged up fully most of the time, and not driven around at 60-80% all the time.

you say you are light consumers, but the devil is in the details.

if your use will have it plugged in most stops, no issue,

if you plan to camp for days at a time with only a drive in between, the higher capacity could be a better choice.

the wire size will vary depending on your choice, as will fuses required.

This is really a great way to use some of the extra 100 or so amp hours in the MB aux battery. (which will only be recharged as you drive)

what, if anything, is hooked up to the 2016 MB aux battery?

gordo019 said:

We have an inverter/battery charger. See attached diagram. We want to recharge while driving.

Click to expand...

After reading the Lifeline spec's and that it can, go with the 50A charger to maximize the amount of aH's going into the battery per drive time.






.

re: what, if anything, is hooked up to the 2016 MB aux battery?

Nothing has been hooked up to the MB aux. battery with our conversion work. I believe it only supports the starter battery. Possibly our MB aux battery powers the pre heater option that we had installed but don’t know for sure.

Might want to figure it out.

I think by design the MB aux battery charges from the alternator when the engine is running and charging, but not connected when the engine is not running or when the engine start sequence is ongoing.

it is there for other use.

could be hooked up for the pre-heater, but I would think not (just a guess) ( you can disconnect it and see if the pre-heater will work..)

your B to B charger referenced will only charge while the engine is running.

if you went with a different unit (including an inverter coupled to a charger as earlier suggested..) it could be configured to effectively give you more AH to use. (for longer dry camping, for example)



you would want to have some way to monitor charge (or at least voltage) of the MB aux battery? might want the option to manage how far you discharge it separate from the house battery. you really have lots of options this way, use up the aux battery first, then the house, or visa versa, or in between.

from the 2017 order guide

SPRINTER 906 E28
ADDITIONAL BATTERY FOR RETROFIT
DETAILS & TECHNOLOGY
In addition to the standard battery, a 12 V/100 Ah auxiliary battery with long cycle life is mounted in the
engine compartment. The AUX battery supply voltage is separated from the vehicle electrical system through
a cutout relay. An electrical connector box is installed inside the driver seat base. Remove cover to attach your
electrical connection and install an appropriate fuse as close as possible, ensuring cover is seated properly
when closing.

BENEFITS
Allows operation of additional electrical consumers.

REMARKS
When shutting down the engine, the AUX battery is separated from the vehicle electrical system via a cutout relay.

after reading the info on the sterling charger, it will only draw power when the alternator is charging the MB aux battery,

will edit back a couple posts.

gordo019 said:

We have an inverter/battery charger. See attached diagram. We want to recharge while driving.

Click to expand...

What I was trying to say was instead of a B to B charger from the aux. battery you could have a second inverter powered by the vehicle that provides 120 volt AC while you drive. The 120 volt "shore power" can be used like real shore power to charge your house battery.

See block diagram:

http://www.ortontransit.info/electric.php

http://www.invertersupply.com/index...ucts_id=1464&gclid=COji_unj2tICFVi4wAodKIQHGA

If you purchase a second inverter, ($350) you would not only have a spare, but could hook it up similar to what Dave has done. would need a relay or switch to select the 110 v input to your existing inverter to connect to either shore power or the engine sourced inverter.

http://www.homedepot.com/p/Gardner-Bender-20-Amp-Double-Pole-Toggle-Switch-1-Pack-GSW-16/100210997 would work for you

https://www.amazon.com/NTE-Electronics-R04-11A30-120-Multicontact-Arrangement/dp/B00DWIKF2A could also be used

either would need a box

since your inverter has an internal transfer switch, the second inverter would supply 110v when operating from the MB aux battery, and also charge the house battery. it would work whenever you turned it on, engine on or engine off. by wiring control of the second inverter to a switch, you could control it to manage how much you want to discharge the aux battery.

To select real shore power or "shore power" from the vehicle powered inverter I use a manual 3 position switch. Select real shore power or "shore power" from inverter or off.

Using Blue Sea # 9009 for the switch. It is a 30 amp rated switch. I have a 15 amp real shore power connection. No need for a typical 30 amp shore power connection in a small van conversion IMO. Max. charging rate of my charger is 50 amps DC or about 6 amps AC.

OK.... Sounds like if I go with a Sterling battery to battery charger, I should get the 50amp model, so that my house battery is quickly recharged and kept at the fully charged state at all times if possible. I could only recharge my house battery when driving with this type of charger.

I also have the Orten option of getting a second (vehicle powered) inverter to charge my house battery. This inverter would run off the MB aux. battery. It seems like this option would be more efficient (aHs) but would require a more complicated wiring setup, including a way to monitor the aux battery charge level. I could recharge my house battery with this option at any time, as long as my MB aux battery had recharging capacity.

Am I more knowledgeable or more confused?

I think you have the basics

gordo019 said:

I also have the Orten option of getting a second (vehicle powered) inverter to charge my house battery. This inverter would run off the MB aux. battery. It seems like this option would be more efficient (aHs) but would require a more complicated wiring setup, including a way to monitor the aux battery charge level. I could recharge my house battery with this option at any time, as long as my MB aux battery had recharging capacity.

Am I more knowledgeable or more confused?

Click to expand...

The inverter powered by the aux. battery should only be used with the engine running. Would not think you would need to monitor the aux. battery. If you did want to monitor it a simple less than $10 voltmeter would work.

Using a vehicle powered inverter is not very efficient because you lose 15% going from 12v to 120v and another 15% going from 120 volts back to 12 volts in the charger. Not efficient but also not important. Doubt very much if you could find much difference in your MPG due to the loss of efficiency.