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Chassis Battery Charging

Our solar charges our 3-8D house batteries in the absence of shore power or generator charging thru the inverter/charger or alternator charging. How are chassis batteries charged in the absence of shore, generator or alternator charging?  Our inverter does not appear to be involved in charging other than when connected to shore or generator power.

If the Boost switch is on will solar charge chassis battery in the absence of shore, generator or alternator charging?

Thanks

Randy

Randy (N4TDT) and Karen Crete
Sarasota, Florida
SOLD:  2000 U270 34' WTFE Build 5756 "Ole Red"

Re: Chassis Battery Charging

Reply #1 –
Trik l Start
Amp l Start

Xantrax echo charger

I don't think they are all that reliable - so I have two Trips k L starts

a small number of solar charge controllers can charge two separate battery banks as well

Tim Fiedler

Sure Start Soft Start

TCER Direct generator-gas-prod 630 240-9139
Gen-Pro
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Chassis Battery Charging

Reply #2 –
Charge from solar cab be distributed via your isolator, connect the power to the center post. Of course you'll have the losses from it to deal with as well.

Or get a second zero voltage drop isolator like these  Victron Argofet Battery Isolator and use it to distribute charge with almost no losses..
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Chassis Battery Charging

Reply #3 –
Quote from: floridarandy –
If the Boost switch is on will solar charge chassis battery in the absence of shore, generator or alternator charging?


Yes, but I would not do that as a long term permanent solution.  Reply number one has better options for you. Here is a way to wire one of them in the photo.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Chassis Battery Charging

Reply #4 –
Thank you Dan for the picture, and Tim, why do you have two Trik L Start units, is one a spare or do you have them hooked up differently than the previous diagram?

Found this link usefull:
  TRIK-L-START

I also notice the 5 amp Trik L Start appears only available at the mfg LSL Products / LSLProducts.com - Problem-Solving Gear & Gadgets  and not available at some big retailers like Amazon and LSL Products TLS-OEM 5 Amp Starting Battery Charger 

LSL Products AMP-L-START 15 Amp Starting Battery Charger

For my needs the 5 amp, Trik L Start, unit will be more than adequate, if I add one.  I just am not sure I need a combiner at all other than the FT manual switch at the drivers seat I have now.  To avoid any parasitic draw, I am programmed to disconnect the ground switch I installed at the engine chassis battery I installed to protect their life.  I also continually monitor both banks of batteries for their voltage.
97 U295 40, Build #5040, 6C8.3 325 HP
Oregon Continuous Traveler
Samsung Residential #RF20HFENBSR,
Xantrex SW2012, (3)AGM8D Hse, (2)AGM Grp24 Eng, Victron BMV-712, 1800w Solar 4 LG & 2 Sunpower
Extreme Full Body Pt w/hdlmps, new furn/floor, 4 down Lexus 2004 GX470 AWD curb weight 4,740 lbs
Prev: 1990 Barth, 10L 300 2 yrs; 91&92 Monaco Signature, 10 yrs, 10L C 300 &  6C8.3 300; 1997 ForeT 6C8.3 325 since May 2017.  Employed by Guaranty RV 14+ yrs.  Former VW New Car Dlr/Service Dlr, Sales Mgr, Rv Sales, and Service Adviser from 1968-2017
"Don't criticize what you can't understand" Bob Dylan

Re: Chassis Battery Charging

Reply #5 –
no, I have two hooked up exactly as in the diagram

they are $55 a piece.  they are my primary battery charger when in storage, and I can leave the coach unattended for 1-2 months at times. Unlikely both will fail, so one always working.

I also have a batteryminder 1500  across all three of the chassis batteries - legacy from pre-solar days when I was generally plugged in when in storage

Xantrax echo charger failed with Green LED on and cost me two sets of chassis batteries before I figured it out - Trik L Start good, but some have not had great longevity - so i went with two - and 1180 watts of solar on roof

Originally had half that amount of Solar and the first charge controller could charge two banks off the solar array - current larger one could not, so this was the low cost and easy solution for charging chassis batteries off solar AND having redundancy - didn't want $500 worth of batteries getting replaced (AGAIN!) because a $60 electric device failed.

Tim Fiedler

Sure Start Soft Start

TCER Direct generator-gas-prod 630 240-9139
Gen-Pro
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Chassis Battery Charging

Reply #6 –
Don't leave the boost switch on to solar charge your batteries. That's not what is was intended to do. It uses quite a bit of juice and gets hot while switched on and while it's rated continous duty, prolonged use/abuse is probably what causes so many solenoids to fail. The amount of juice the solenoid uses will mean fewer useable watts out of your solar.  I just plug my jumper in and relax.

We have conventional batteries for the engine and AGMs for the coach. The jumper keeps both voltages perfect.

A latching solenoid could be installed as they don't use any juice while in operation. Foretravel's VW headlight latching relay for the water pump is an example of a latching relay. For a better explanation, see: http://www.omron-ap.com/service_support/FAQ/FAQ02822/index.asp

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Chassis Battery Charging

Reply #7 –
I connected a very small solar panel that is designed for battery maintenance on my chassis batteries. I measured the voltage in full sun and was surprised that it is 20.1 volts. Will this damage my batteries. I am sure the amperage is very low. The solar panel is about 12" x 9".
2000, U320 36' with Cummins 450, Toad - 2016 Ford CMax Energi
Previous MHs; 1970 Winnebago, 1973 FMC 2900R, much later a heavily modified 1975 FMC 2900R.

Re: Chassis Battery Charging

Reply #8 –
Did you measure the voltage when it was connected to the batteries? Open circuit voltages are usually quite a bit higher than voltage under some load.  My 24 volt panels can read close to 40 volts until you actually hook them up.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Chassis Battery Charging

Reply #9 –
Roger, I will check again under load.  Thanks
2000, U320 36' with Cummins 450, Toad - 2016 Ford CMax Energi
Previous MHs; 1970 Winnebago, 1973 FMC 2900R, much later a heavily modified 1975 FMC 2900R.

Re: Chassis Battery Charging

Reply #10 –
Ken,

You want your chassis batteries to be between 12.8 (fully charged, but charger not on) to a max of about 14 2 (short term/bulk charge rate).  Float in the 13.2 range is best.  You may need a controller if voltage is not in this range.
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: Chassis Battery Charging

Reply #11 –
Quote from: Pierce & Gaylie Stewart –
Don't leave the boost switch on to solar charge your batteries. That's not what is was intended to do. It uses quite a bit of juice and gets hot while switched on and while it's rated continous duty, prolonged use/abuse is probably what causes so many solenoids to fail.
Pierce

How is this different than the ignition solenoid which is always on when the key is on? Same type solenoid. I have never seen anything wrong with leaving the boost switch on except eventually the light bulb will burn out.
1994 U280, Build 4490
Deming, NM.

Re: Chassis Battery Charging

Reply #12 –
Help..

  I purchased an old 1985 Oshkosh V917 chassis.  I'm finding out about the issues at hand.  It has 2 battery's for the chassis and 2 battery's for the living quarters.

Today I rolled under looking up and I find a battery box for two battery's that is empty.  Another box over by the holding tanks. The ground cable was still present. The holding tank had 4 wires with 2 not connected. I'm wondering when new how many battery's did this unit have and what did they service?  I hope someone can help me.

Also the solenoid on the chassis battery's is very hot to touch all the time.  I'm just a shade tree mechanic but I think the solenoid is only to start the engine.  This thing has some funny stuff going on the previous owner did some shoddy work.

Everything is fine as long as I ensure all circuits are OFF.  That battery issue is where I need to start.

Hope someone can help.

Philip
Philip M Mahoney

1985 V917 Cat3208 w/ Allison auto 4 speed
build #7433
 

Re: Chassis Battery Charging

Reply #13 –
Unless a special order the 85 oskosh v917 chassis had one 8d battery for the house and one 8d battery for the chassis. They were both under the floor as you step into the coach. So it looks like someone did some creative adding batteries. Looks like time to trace out where the wires are going. The boost solenoid was located under the floor where you step into the coach on the frame rail. The starter so0lenoid that sent power to the starter and its solenoid was mounted on the inside of the frame rail if I remember correctly on the passenger side of the vehicle. I don't remember which side of the coach the starter is on but the solenoid I mentioned is on the frame rail closest to the starter.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins