Skip to main content ↑ ↓
Topic: BatteryMINDer 2, 4 or 8 amps for trickle (Read 696 times) previous topic - next topic

BatteryMINDer 2, 4 or 8 amps for trickle

I've been keeping my starting batteries on a BatteryMINDer with the setting at 2amps while in storage and I also keep the coach plugged into to a 30 amp plug. I don't disconnect anything in the coach and the battery master switch is always on and because of this I assume there is some draw - even parasitic draw.

Question: Is a 2 amp trickle charge too little amperage to keep them topped off?

Should I try for 4 or 8 amps? Thoughts. The batteries are 18 months old.

Pat

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #1 –
I presume the Battery Minder is connected to power and also the chassis batteries, and the 30A shore power is powering the inverter/charger which in turn is charging the house batteries.  You should be fine.

If you already have a voltage sensitive relay (or add one), you won't need the battery minder.
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: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #2 –
Hi Tom,

Thanks - Yes, I have the Battery Minder charger plugged into the 110 outlet in my wet bay compartment on the coach and my 30 amp into the shore power which feeds the inverter/charger.  I assumed that the charger/inverter does not cross connect to the engine battery unless I have the boost switch on - which I figured draws power - so I just keep them both separate.

My starter batteries have been low that last few times and I have had to use the boost switch to start - not sure why.

Pat

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #3 –
Quote from: pibutler –
I have the Battery Minder charger plugged into the 110 outlet in my wet bay compartment on the coach and my 30 amp into the shore power which feeds the inverter/charger.  I assumed that the charger/inverter does not cross connect to the engine battery unless I have the boost switch on - which I figured draws power - so I just keep them both separate.

My starter batteries have been low that last few times and I have had to use the boost switch to start - not sure why.
I think you have answered your own question.

The way you have things set up and connected should be working fine, IF the 2 amp setting on the trickle charger is sufficient.

BUT, your start batteries "have been low the last few times..."

SO, it seems the 2 amp setting is not sufficient, which would suggest that a slightly higher setting is called for.

If it was me, I'd try the 4 amp setting, and see how that works.  If that doesn't keep the start batteries topped off, then try 8 amps.

What kind/type of start batteries, and how many?

Is it only the start batteries that are showing low voltage?

How often do you get by the coach to check on things?
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"

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #4 –
Thank you,

I keep it at a storage facility where they keep it plugged in (but I have been there in the past when they had another coach plugged into my outlet), so perhaps it was not always plugged in. I did some further research on my charger and it recommends 4-8 amps for RV - hopefully, this can be a starting point. The batteries are called "American Eagle" never heard of them - it states that they are from Escondido, CA. (photo)

Currently, my BatteryMINDer shows the batteries at 1/2 - so they are definitely low. I'll see what 8 amps does for the next 36 hours.

My coach batteries (3 AGM) are great and my Xantrex 3000 keeps them in good shape.

Thanks for all the input.

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #5 –
You might consider moving the black charge connection from the front battery negative to the rear battery negative post.  This allows the charger to span the battery bank.  Many consider this a superior arrangement.

The same applies to the black and red power cables to the engine.  Both are connected to the rear battery.  If you chose to follow this suggestion, then move one of them to the other battery post to allow the load to span the bank.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #6 –
I just put a jumper from HWH panel lighter plug to dash lighter plug. Fused each end at 5 amps at the jumper plug. LED to show both have power. Keeps both sets of batteries (conventional engine and AGM house) up with our solar in use or on shore power. Jumper is removed when the engine is running, coach is moved or underway. Have been using this for years with no problems.

You have to insert the plug straight into the outlet or it will pop the 5 amp fuse.

Tiny white spots in photos are from sanding outside that blew in open window.

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

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #7 –
Thanks for the great input.
Pat

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #8 –
Quote from: Pierce & Gaylie Stewart –
I just put a jumper from HWH panel lighter plug to dash lighter plug.
Pierce,

Not saying your "jumper" idea isn't clever - it is.  But, there is one problem with using this device on a coach in storage.  If shore power is lost to the coach, and there is a substantial drain (of any kind) on one of the battery banks, then both battery banks will be discharged.

Exactly the same problem would occur if a coach owner leaves the boost switch energized to keep both battery banks charged.  As you well know, this practice is discouraged on this Forum, lest the owner be left unable to start either engine due to dead batteries.

Of course, as long as the coach is being monitored on a frequent basis, neither charging method is likely to get one in trouble.  Still, I personally believe it is prudent to keep the battery banks separated and thereby (hopefully) avoid a inconvenient "no start" situation.
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"

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #9 –
Chuck,

If both battery banks are fully charged, totally disconnecting the batteries is the best way insure they make it through the winter in the north. I bought a couple extra AGMs that I put on the shelf. Still fully charged over a year later. If fully charged, batteries will not freeze. Conventional batteries won't make it a year and will self discharge in a month or two in summer. That's why the DieHard commercials showed the battery incased in ice throughout the winter with full charge when the ice was chipped away.

When not traveling, our coach is stored at our house and has either the solar on or shore power. The solar can stay on year after year without a problem but when covered/garaged, it has to be plugged in.

Pierce



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

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #10 –
My experience is that having any battery at 50% charge for any length of time causes a loss of capacity and/or service life.

To avoid this the rv industry has switched to auto combiners

ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A - Blue Sea...
"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: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #11 –
Great articles for trickle chargers. My question is it ok for me to plug into a 15a circuit for the Canadian north winters to keep the house batteries charged  through my inverter or is the amperage to low?  I do not have a 30a plug-in available. Also do I charge the starter batteries Left in the coach (3) with a battery minder with three connectors or do I remove them and put them in a in heated garage on tenders?
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #12 –
15 amps is fine for charging the batteries and leave your battery minder on. As long as the batteries are fully charged the cold
weather won't bother them,
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #13 –
Quote from: pibutler –
Thank you,

I keep it at a storage facility where they keep it plugged in (but I have been there in the past when they had another coach plugged into my outlet), so perhaps it was not always plugged in. I did some further research on my charger and it recommends 4-8 amps for RV - hopefully, this can be a starting point. The batteries are called "American Eagle" never heard of them - it states that they are from Escondido, CA. (photo)

Currently, my BatteryMINDer shows the batteries at 1/2 - so they are definitely low. I'll see what 8 amps does for the next 36 hours.

My coach batteries (3 AGM) are great and my Xantrex 3000 keeps them in good shape.

Thanks for all the input.

If I was storing my coach away from home and the place I was storing it unplugged and then "hopefully" plugged it back in, I would be worried. I would charge the batteries to a full charge then disconnect them to isolate them but leave the charger on.
Your coach probably has more parasitic loads than you would think.
1995 U320C SE 40'
Jeep 4x4 Commander - Limited - Hemi
"The Pack"  Yogi and Diesel our Airedales -  Charlie our Boxer/Akita mix. Gone but NEVER forgotten Jake our yellow Lab.
NRA Law Enforcement Firearms instructor - Handgun/shotgun
Regional Firearms instructor for national Armored Transp. Co.

Re: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #14 –
Trying to charge the batteries can fail the trickl charger. 
"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: BatteryMINDer 2, 4 or 8 amps for trickle

Reply #15 –
Two amps should keep both house and engine batteries charged. It does on ours. I just do a lighter to lighter jumper at the dash. Keeps both around 13.5 volts. I use a regular battery charger with the switch set to 2 amps.

Batteries with a charge won't come close to freezing. Batteries disconnected when charged in Winter will still have a full charge in Spring. Remember the Die-Hard ad with the battery frozen in an ice block?  Just the opposite in warm weather where a battery may discharge in a month depending on type.

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