Help confirming assumptions on Sterling BB1260

Calbiker, John61ct and Mark and others,
Ok guys. I seem to be able to attach pics only in a response. So here is where I'm at.

Winnebago clearly color coded the wiring plus I studied the electrical diagrams. Here's an AS IS of what I have. Also, there's a floorplan showing where I'd like to put the B2B. It's on the outside end of that lower cab, so plenty of air. Please let me know if there is information missing that's needed.

Question: How do I best wire in the Sterling BB1260?

I sized up some cables in an above post assuming I did not try to reuse the 1GA existing cable. I honestly don't know what's best. I don't care if I loose the trick L start device. Obviously, I need to maintain the hot feed to the DC load center, which is where all the motorhome's DC fuses reside. Keeping the disconnect relay would also be useful. The battery boost switch on the dash is open for whatever makes sense. I assume it will be eliminated, along with the battery mode solenoid.

I can come out of the PDC on the chassis battery with a 100 amp fuse and put the other one next to the B2B in the holder shown above in the cable link.

Thanks so much!!

John

You really have solenoids on the brain

The DCDC is remote switchable, no need to kill its input.

john61ct said:

You really have solenoids on the brain

The DCDC is remote switchable, no need to kill its input.

Click to expand...

Yes, I'm using Cole Hersee solenoids for stocking stuffers this Christmas.

I just want to order the stuff and get this over with.


Yes, I figured I'd get the remote for the DCDC and put it up in the cab for driving.

LOL

john61ct said:

LOL

Click to expand...

There is a missing piece that I omitted for simplification. The DC load center is the motorhome's AC/DC center where the AC shore power comes in. When the "disconnect relay" is closed", the 45 amp converter/charger can charge the house batteries. I do not anticipate using the charging section of the AC/DC load center, so I don't have a strong preference. But if it's not that much of an issue, it may come in handy and may be nice to have. For example, if my inverter/80 amp charger were broken or stolen, I'd go to that Winnebago installed charger in the load center as a last resort and it can be powered by my Honda 2000 generator. Just throwing that in.

KISS

I'd make sure fallback options are not online in normal usage.

Hey another spot for a solenoid!

1. Use the existing 1 awg cable from chassis battery to combiner relay (Batt Mode Solenoid).

2. Keep combiner relay in place. Use as a cable connection post (the other side of relay is unconnected).

3. Connect 1/0 awg cable from combiner relay stud (same connection as cable from chassis battery) to Sterling 12V input.

4. Determine wire size from Sterling output to house battery:

Assume 7 ft cable length one way. Need 14 ft for round trip (both plus & gnd cables).

Design to 1% voltage drop at 60A.

Calculate cable resistance:

R = Vdrop / I = 14.5V * 0.01 / 60 A = 2.4 mohm

Cable ohms per foot = R / Length = 2.4 mohm / 14 ft = 0.17 mohm/ft

Looking at table for best size:
https://www.powerstream.com/Wire_Size.htm

2 awg has 0.17 mohm/ft resistance.
1/0 awg has 0.1 mohm/ft resistance.

1/0 awg sound good to me.

An alternative to mounting Sterling to outside cabinet wall is to locate it behind the draws to the right of the sink. I have my 55A Iota converter mounted there. Check to see if there's a clearance issue when drawer is closed.

outwestbound said:

Question: How do I best wire in the Sterling BB1260?

Click to expand...

outwestbound said:

Calbiker, John61ct and Mark and others,
Ok guys. I seem to be able to attach pics only in a response. So here is where I'm at.

Click to expand...

For the View/Itaska owners with similar year models, I want to post this revision of the AS IS. I didn't show all the white fuses next to the relays, but the "hot bus" bar that was shown was in error. It is two bars, so that a hot 6 AWG wire may come off each relay to it's own bus bar.

I'm not certain and suggest further research if relevant, but I "assume" that this configuration allows the stairs, and possibly the light, etc., to continue operating with the batt mode solenoid open. I'm not a big fan of this because the same contributes to a phantom load on the chassis battery, but it's practical.

calbiker said:

3. Connect 1/0 awg cable from combiner relay stud (same connection as cable from chassis battery) to Sterling 12V input.

1/0 awg sound good to me.

Click to expand...

The largest wire that will fit in the Sterling input and output connections is AWG4. That is why I used two AWG4s. I put hex crimped lugs on the ends of the two AWG4 and connected one side to a bolt on the battery and the other to a nut, bolt, 2 flat and 1 lock washer to connect three lugs together. The third lug is on one end of a short piece of AWG4 and that goes to the Sterling. I put shrink sleeve over the bolt/lug connections.

How I do it is here:

https://sites.google.com/site/marksrvmods/home/battery-wiring

The hex lugs crimped like that have been very reliable, not like the crappy ones the RV came with.

I used Blue Sea power posts and they come in singles too, or just stainless steel hardware works. The Blue Sea will connect four lugs easily.

Regards,

Mark

calbiker said:

1. Use the existing 1 awg cable from chassis battery to combiner relay (Batt Mode Solenoid).

2. Keep combiner relay in place. Use as a cable connection post (the other side of relay is unconnected).

3. Connect 1/0 awg cable from combiner relay stud (same connection as cable from chassis battery) to Sterling 12V input.

4. Determine wire size from Sterling output to house battery:

Assume 7 ft cable length one way. Need 14 ft for round trip (both plus & gnd cables).

Design to 1% voltage drop at 60A.

Calculate cable resistance:

R = Vdrop / I = 14.5V * 0.01 / 60 A = 2.4 mohm

Cable ohms per foot = R / Length = 2.4 mohm / 14 ft = 0.17 mohm/ft

Looking at table for best size:
https://www.powerstream.com/Wire_Size.htm

2 awg has 0.17 mohm/ft resistance.
1/0 awg has 0.1 mohm/ft resistance.

1/0 awg sound good to me.

An alternative to mounting Sterling to outside cabinet wall is to locate it behind the draws to the right of the sink. I have my 55A Iota converter mounted there. Check to see if there's a clearance issue when drawer is closed.

Click to expand...

Guys. I saw Mark's post. For now, I'd like to get the major connections correct, than focus on cables after that.

Calbiker, this attempts to illustrate your comments. After reading your comments, I wasn't sure how to continue providing power to the motorhome's DC load center. I relocated the existing cable from the house battery to the combiner solenoid onto the disconnect relay. I'm not certain on this, but I assume the disconnect switch will continue to function and the cabin get power.

I noticed also that the pos from the chassis to the sterling now flows over the combiner post, which also has the 6 AWG cable to energize some adjacent fuses. This 6AWG powers the stairs, I believe, for practical reasons in case the vehicle is not running. I assume this is ok, because the stair motor will be operating while the Sterling is on (vehicle idling in park).

The boost switch and tric L start are eliminated.

I am not at all sure about the grounds. I included the shunt and just took a stab at it. How should they work. I've posted Sterling's manual and a pic below. Sterling seems to imply two trips to the chassis battery and back. Is that necessary?

Note just because a thick AWG is used to prevent V drop, does not mean you can't step it down close to the end / device.

Asymmetric butt connectors, ferrule "pin" terminals, even going to a buss bar are all fine.

Nothing you want counted should go between the bank negative and the shunt.

calbiker said:

A fan is a good idea when operating the generator for longer periods of time. Do you use a 120V ac fan?

Click to expand...

I used a DC automotive, high heat weatherproof fan: https://www.amazon.com/gp/product/B01M1BSLNX/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1.

My pan drops down a little more under the Honda and I did the back of the compartment is sheet metal, so just put this in behind the Honda with a switch in the compartment. There must be clearance under the vehicle frame back there.

Originally, I was going to plug it into a female DC socket on the Honda and the manual said that DC outlet didn't reduce the AC output, so great. Then when the fan arrived, I realized I had the companion model which doesn't have the DC female socket. Oh well. It works really well.

Just as a follow up, I got this pricing at Bay Marine Supply today: https://baymarinesupply.com/

Has anyone had issues with a relay switch clicking on and off under the driver seat with the 60amp charger? It seems to be related to low voltage and happens when the ac is turned on. I’m measuring 13.5-6 at idle with AC off and then it drops as low as 13.2ish when ac is on at idle. While driving it’s hard to hear if the switch is clicking but it seems as if it is not. Started after I installed the sterling charger. I received an upgraded model from sterling with green stripe at the top of the unit. I’m not convinced this will solve the issue but I’m going to swap it anyways.


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Jburklow@gmail.com said:

Has anyone had issues with a relay switch clicking on and off under the driver seat with the 60amp charger? It seems to be related to low voltage and happens when the ac is turned on. I’m measuring 13.5-6 at idle with AC off and then it drops as low as 13.2ish when ac is on at idle. While driving it’s hard to hear if the switch is clicking but it seems as if it is not. Started after I installed the sterling charger. I received an upgraded model from sterling with green stripe at the top of the unit. I’m not convinced this will solve the issue but I’m going to swap it anyways.


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Click to expand...

What was the explanation for the meaning of the green stripe? I ordered my stuff ignorant of that. I'll see how it goes. Which Sprinter do you have?

FUTURE EDIT: Alan Ferber, Bay Marine Supply, alan@BayMarineSupply.com, phone: 619-320-5899 emailed me back. He said the "green strip" updated versions of the DC/DC (B2B) models have been out in the US for 60 days and that's what he's sending me. He said the AC/DC models (PCU1260) haven't changed since 2014 and he hopes they never will. I've been impressed with Bay Marine AND they were the cheapest. I think they do a lot of US volume for Sterling (eg, listed first on Sterling's web site).

outwestbound said:

What was the explanation for the meaning of the green stripe? I ordered my stuff ignorant of that. I'll see how it goes. Which Sprinter do you have?

Click to expand...

I have a 2004 dodge 3500. New hardware and software was the stated reason. It was a 1 minute conversation with the tech support. They didn’t want to go any further in the problem solving step while I was running the red striped unit.


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This is my most recent diagram. I decided to swap my 150A alternator for a 200A new Bosch. I ran out of room on the house batter terminals, so I added some posts that are already installed. The only AC wiring shown is the AC shore power bypassing the AC/DC load center and feeding directly into the Sterling AC/DC charger. This rig is for overland international travel in South America, Europe and Australia. The power strategy is to live off the inverter and stay off unreliable AC shore power, which varies between 110-120V to 230-240V systems of greatly varying quality. However, it does make sense to plug in the Sterling AC/DC charger by opportunity. This charger is universal/global and accepts 90-250V or so. I've got a 277A surge protector in parallel with a 2 pole, 15A breaker between the PCU1240 and shore power.

The solar and battery bank are built. I'm adding the Sterling chargers and shunt, plus a butt load of cabling.

Please have at it. All is welcome. I'm a novice at this. Thanks.

https://drive.google.com/open?id=1zjUdqRwpcflQvOA2pj1EltsC11zixdtn

Not sure why outbound PMs aren't working for me, so responding here

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I don't give feedback at that level of detail, nor use PMs for what should be public.

However if you choose one or two sample calculations, post the variables chosen using Circuit Wizard, I'd confirm that and answer questions you might have, in order to increase your confidence calculating for yourself.

john61ct said:

Not sure why outbound PMs aren't working for me, so responding here

_______
I don't give feedback at that level of detail, nor use PMs for what should be public.

However if you choose one or two sample calculations, post the variables chosen using Circuit Wizard, I'd confirm that and answer questions you might have, in order to increase your confidence calculating for yourself.

Click to expand...

Good morning. Fair enough, so here's the calculations I used for the diagram. These new AGMs I have may last 375 cycles, then I'll go to a lithium bank of 300 - 400 Ah, so I'm showing 4/0 cables for that reason. I'll be living full-time in this rig during a 14 month tour of South America.

I'm including what's being added. The battery bank and other components are installed already.

Thanks

John