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Topic: Charging both House and Start Batteries (Read 1072 times) previous topic - next topic

Charging both House and Start Batteries

Having searched on this forum for answers, I found info on the Echo Charger.  Doing some further research, I ended up on FOT home page and they are having a special on a VSR (voltage sense relay) that combines the House and Start batteries for charging while plugged into shore power.  This should eliminate the need for the boost switch when start batteries are low.
Any discussions on pros/cons or any other device for tying the two systems together from members on here would be most helpful.

Thanks in advance!
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Charging both House and Start Batteries

Reply #1 –
What brand/model VSR?

Any link?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Charging both House and Start Batteries

Reply #2 –
I have one on mine, works great makes happy start batteries. The ACR closes when it sees any voltage over 13.20 then opens up when voltage drops below 12.85. Never know it's doing it's thing. It's hooked to the house and chassis terminals on the isolator. Also works with solar if you have it.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Charging both House and Start Batteries

Reply #3 –
Yes. Most any of the "smart combiners" are good.  If just used as a chassis battery maintainer, they don't need to be the high-amp rating ones.

If used in lieu of a battery isolator, they need to be very close to the amp rating of the alternator.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Charging both House and Start Batteries

Reply #4 –
Quote from: wolfe10 –
What brand/model VSR?

Any link?

Brett;  there was no name that I recall on the FOT website, just that they were running a special on that unit.
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Charging both House and Start Batteries

Reply #5 –
Quote from: bbeane –
I have one on mine, works great makes happy start batteries. The ACR closes when it sees any voltage over 13.20 then opens up when voltage drops below 12.85. Never know it's doing it's thing. It's hooked to the house and chassis terminals on the isolator. Also works with solar if you have it.

Which one do you have?
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Charging both House and Start Batteries

Reply #6 –
Is this it: MARINCO Digital Voltage Sensing Relay, 12/24V | West Marine
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Charging both House and Start Batteries

Reply #8 –
Would not use the Cyrix. 

It auto combines on starting.

My guru mentioned that covers up the true engine start batteries condition.

The blue sea 500 amp unit with the remote replacing the boost switch is seemingly fool proof.

ML-ACRs - Blue Sea Systems

On purpose no combiner on start.

Plus manual lockout for safety
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Charging both House and Start Batteries

Reply #9 –
Quote from: Caflashbob –
Would not use the Cyrix. 

It auto combines on starting.

My guru mentioned that covers up the true engine start batteries condition.

Quote from: Caflashbob –
Would not use the Cyrix. 

It auto combines on starting.

My guru mentioned that covers up the true engine start batteries condition.

The blue sea 500 amp unit with the remote replacing the boost switch is seemingly fool proof.

ML-ACRs - Blue Sea Systems

On purpose no combiner on start.

Plus manual lockout for safety


The blue sea 500 amp unit with the remote replacing the boost switch is seemingly fool proof.

ML-ACRs - Blue Sea Systems

On purpose no combiner on start.

Plus manual lockout for safety
Where do you and your guru get this information Bob?  I have voltmeters side by side for coach and house.
When I start coach, start batteries drop down to low 12's and high 11's, and coach batteries stay where they were, [high 12's], so obviously not combining. It works exactly the same as the more expensive blue sea combiner I had on a previous coach.

"the Cyrix-Ct battery combiners have microprocessor controlled heavy duty relays that automatically connect batteries in parallel when one battery has reached a preset voltage (indicating that the battery is being charged), and disconnects when the voltage decreases below float level (indicating that one or both batteries are being discharged)."

Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Charging both House and Start Batteries

Reply #10 –
https://baymarinesupply.com/media/catalog/product/c/y/cyrix-ct-table.png

The chart shows "start assist" for 30 seconds

My optimas will drop into the low 11's on startup first crank

Your actual reading sound like no assist. Just reading the chart says it does.

I read the chart.  Do not have your unit,

Wanted the 500 amp and manual lockout for safety

The ip 66 rating covers high pressure spray on the blue sea

The picture shows a start assist sensor wire if not hooked up no start assist

For sure more money. 
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Charging both House and Start Batteries

Reply #11 –
I've had the Blue Sea ACR on mine for five years now, wouldn't even know it's there , it just works.
Tom Lang K6PG (originally  KC6UEC)
and Diane Lang
2003 38 U295 build 6209
2016 Jeep Grand Cherokee Summit Ecodiesel
still have tow-ready 2006 Acura MDX 
Temple City, California
Motorcade 16681 California Chapter President
SKP 16663 member of SKP Park of the Sierra, Coarsegold California
FMCA F071251
Retired electrical and electronic engineer

Re: Charging both House and Start Batteries

Reply #12 –

I have a cole-hersche smart relay that contacts are normally closed to the start battery, once it hits 13.2 volts it switches to charge the house battery whether plugged in or via alternator.  Been great for Almost 1.5 years about $120-130 for the 200 amp unit iirc. Smart part is separate from the solenoid, so if something happens to the solenoid you just buy that peice. The old isolator goes into the dumpster. With no diode in the system you may have to reduce alternator voltage.
Amazon.com: Cole Hersee 48530 Smart Battery Isolator 200A: Automotive

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Charging both House and Start Batteries

Reply #13 –
Quote from: juicesqueezer –
Which one do you have?
Blue Sea M-ACR
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Charging both House and Start Batteries

Reply #14 –
Quote from: Caflashbob –
https://baymarinesupply.com/media/catalog/product/c/y/cyrix-ct-table.png

The chart shows "start assist" for 30 seconds

My optimas will drop into the low 11's on startup first crank

Your actual reading sound like no assist. Just reading the chart says it does.

I read the chart.  Do not have your unit,

Wanted the 500 amp and manual lockout for safety

The picture shows a start assist sensor wire if not hooked up no start assist

For sure more money. 

If you read the whole description, "The time delay depends on the voltage deviation from the trend."
If a fractional voltage variation it might stay connected for a while. But if in a start situation where there is a 1 or more volt drop in the start batteries, disconnect is immediate.  Victron is a overseas company, but it's combiner works exactly the same as the Blue Sea.

Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Charging both House and Start Batteries

Reply #15 –
Soooo  ----  Is this just one of those expensive gimmicks or is there a practical need for one ???  I desire to keep the start battery and house batteries separated.  I charge the house batteries every couple of weeks and the engine battery about once a month.  If for some reason the engine battery fails, I use the boost sw to cross connect. (this has never happened, but could).  Just wondering, maybe I'm missing some thing!  Have a great day  ----  Fritz
Fritz & Kathy Johnson
1991 36'

Re: Charging both House and Start Batteries

Reply #16 –
Since I installed the ACR on mine, I don't give the start batteries a second thought. Not a gimmick just a modern up date.  When my isolator fails I will go with heavy duty ACR. As always DWMYFG as they say. 😎
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Charging both House and Start Batteries

Reply #17 –
Quote from: fkjohns6083 –
Is this just one of those expensive gimmicks?

I desire to keep the start battery and house batteries separated.

If for some reason the engine battery fails, I use the boost sw to cross connect.

Just wondering, maybe I'm missing some thing!
I don't think you are missing anything.

It is up to you how you manage your batteries.  If you want to treat your two battery banks as entirely separate systems, and only combine them in a (rare) emergency, then just keep doing what you are doing.  You do have to take personal responsibility for keeping them both properly charged, but it sounds like you have that covered.

A few of our members have connected their chassis and coach battery banks permanently together into one big battery bank.  This also works OK, as long as the operator is diligent about monitoring the SoC, and never lets the batteries get so depleted that they can't start either engine.

In short, if it works for you, then that is all that matters.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"