Reply
 
Thread Tools Display Modes
 
Old 03-19-2018, 05:58 PM   #1
New Member
 
Join Date: Dec 2017
Posts: 6
Trickle Charge Battery For Power while Drawing on it?

Hi there,

I've read through a bunch of forums and I still don't have a solid answer to my scenario, though I think I know it.

I'm building a party bus and I wanted to run the stereo from the rear of my blue bird. I have 120 A/C power (from a genset) run under all of the seats and to the rear of the bus. I planned on using 2 stereo specific batteries to power the stereo system (head unit, 400 watt amp, 1200 watt amp) but I don't want to draw any from the existing bus batteries or alternator.

My question is, can I use a trickle charger, powered by the 120 outlet, to provide the continual power to the stereo system, and will it be able to keep up? I'm looking at using something like this https://www.amazon.com/NOCO-G1100-Ul...t%2Bpower&th=1

In theory, this is how laptops work...the wall charger charges the laptop, even when you're using it.
BigSteveATX is offline   Reply With Quote
Old 03-20-2018, 11:15 PM   #2
Bus Geek
 
Join Date: Sep 2017
Location: Owasso, OK
Posts: 2,627
Year: 1999
Coachwork: Thomas
Chassis: Saf-T-Liner MVP ER
Engine: Cummins 6CTA8.3 Mechanical MD3060
Rated Cap: 46 Coach Seats, 40 foot
Generally no, you can't.

Most battery chargers won't even switch on unless they detect a battery attached.

Presumably the equipment you want to run is 12V or you'd just plug it into the genset.

Why can't you just buy a 120V to 12V power supply to run it?
__________________
Steve Bracken

Build Thread
Twigg is offline   Reply With Quote
Old 03-21-2018, 05:39 AM   #3
Bus Nut
 
superdave's Avatar
 
Join Date: Mar 2015
Location: hills of sw virginia
Posts: 889
Year: 1996
Chassis: thomas
Engine: 8.3 cummins
Rated Cap: 11 window
look for an inverter/charger. its charge function will keep up with the biggest of stereo's. it will invert your battery power to 120 ac until you plug that inverter into shore power. when you plug it in the inverter it becomes a charger and will charge your batteries or keep them topped off.
__________________
living in a bus down by the river.
my build pics
https://www.skoolie.net/forums/membe...albums942.html
superdave is offline   Reply With Quote
Old 03-21-2018, 08:08 AM   #4
Bus Crazy
 
somewhereinusa's Avatar
 
Join Date: Nov 2010
Location: Andrews,Indiana
Posts: 2,193
Year: 1991
Coachwork: Bluebird
Chassis: AARE
Engine: 3116 Cat 250hp
Rated Cap: Just the two of us.
I have this, it will do what you want and power a bit more. $75 plus shipping if you're interested. It works, I just out grew it.

somewhereinusa is offline   Reply With Quote
Old 03-21-2018, 08:16 AM   #5
Skoolie
 
Join Date: Dec 2017
Location: southern maine
Posts: 114
Year: 2010
Coachwork: Coach & Equipment MFG
Chassis: ford E350 superduty
Engine: 5.4 liter v8
Rated Cap: 7 passenger
my calculations show you will need a charger that supplies 13.3 amps to keep up with the stereo,
__________________
2010 ford e350 superduty v8 7 passenger bus
pbeggs is offline   Reply With Quote
Old 03-21-2018, 10:19 AM   #6
Bus Geek
 
Join Date: May 2016
Location: Eastern WA
Posts: 6,340
Year: 2002
Coachwork: Bluebird
Chassis: All American RE (A3RE)
Engine: Cummins ISC (8.3)
Rated Cap: 72
Quote:
Originally Posted by pbeggs View Post
my calculations show you will need a charger that supplies 13.3 amps to keep up with the stereo,
I am not sure I follow your math?

I=P/V

Max power = 1600 watts

Battery voltage 12 volts

I suspect that you may have slipped a decimal point. I come up with 133.33 amps. That would be peak load and you are unlikely to run the amps at full output for any period of time.

OP did not specify what the battery voltage is but I am assuming that battery powered stereo gear would be 12 volt.
PNW_Steve is offline   Reply With Quote
Old 03-21-2018, 10:20 AM   #7
Skoolie
 
bubb, the real one's Avatar
 
Join Date: Dec 2014
Location: central texas
Posts: 146
Year: 1990
Coachwork: Thomas/International
Chassis: 3700
Engine: 7.3
Rated Cap: 72
stereo

If I read it correct you plan on using a trickle charger connected to two dedicated stereo batteries to power your stereo, I assume you will use an inverter connected to the batteries to connect to the stereo.
If this is accurate you can power your stereo, but the 3.5amp charger will not work.
one amp AC is equal to about 10 amps DC.
Calculate how many amps Ac your stereo will use and them multiply by 10 for the DC equivalent. probably better to multiply by 12 or 13.
Make sure the charger can handle charging for the numbers of hours you need, some may need to rest and cool down after a few hours.
Unless you use bus bars you will probably want batteries with top and side posts to make all your connections.
DC wire diameter matters as well as how long the wires are, keep all DC wires as short as possible. You can find wire size calculators online.
Use only a real deep cycle battery, not a marine battery, not any battery that lists CCA.
Wet lead acid batteries will off gas while charging, you will probably want an AGM battery if you want to keep the battery inside the bus, make sure your charger is made specifically to charge this type of battery, most chargers cant properly charge an AGM battery.
Until we know the AC power draw we cant discuss proper battery size.
But on the other hand if you can power a trickle charger why cant you just plug in the stereo?
__________________
my bus thread, https://www.skoolie.net/forums/showthread.php?t=8860&highlight=bubb
bubb, the real one is offline   Reply With Quote
Old 03-21-2018, 10:35 AM   #8
Skoolie
 
Join Date: Dec 2017
Location: southern maine
Posts: 114
Year: 2010
Coachwork: Coach & Equipment MFG
Chassis: ford E350 superduty
Engine: 5.4 liter v8
Rated Cap: 7 passenger
i dropped a 3 in there my mistake
__________________
2010 ford e350 superduty v8 7 passenger bus
pbeggs is offline   Reply With Quote
Old 03-21-2018, 10:41 AM   #9
Bus Geek
 
Join Date: Sep 2017
Location: Owasso, OK
Posts: 2,627
Year: 1999
Coachwork: Thomas
Chassis: Saf-T-Liner MVP ER
Engine: Cummins 6CTA8.3 Mechanical MD3060
Rated Cap: 46 Coach Seats, 40 foot
Let's not get carried away with the apparent enormous power here.

Amplifiers rated at 1400W do not consume 1400 watts of electricity. Depending on how they are rated (RMS or PMPO), they could be consuming as little as 1/10th of that, even cranked up.

The 1400W figure is usually an estimate of the maximum, and fleeting technical capacity often only reproducible in a lab for a fraction of a second.

The true RMS output is considerably smaller, and even that is only for the maximum highs.

Speaker loudness, and what the amp can drive is more a function of impedance and sensitivity.
__________________
Steve Bracken

Build Thread
Twigg is offline   Reply With Quote
Old 03-21-2018, 10:51 AM   #10
Bus Nut
 
superdave's Avatar
 
Join Date: Mar 2015
Location: hills of sw virginia
Posts: 889
Year: 1996
Chassis: thomas
Engine: 8.3 cummins
Rated Cap: 11 window
Quote:
Originally Posted by bubb, the real one View Post
If I read it correct you plan on using a trickle charger connected to two dedicated stereo batteries to power your stereo, I assume you will use an inverter connected to the batteries to connect to the stereo.
If this is accurate you can power your stereo, but the 3.5amp charger will not work.
one amp AC is equal to about 10 amps DC.
Calculate how many amps Ac your stereo will use and them multiply by 10 for the DC equivalent. probably better to multiply by 12 or 13.
Make sure the charger can handle charging for the numbers of hours you need, some may need to rest and cool down after a few hours.
Unless you use bus bars you will probably want batteries with top and side posts to make all your connections.
DC wire diameter matters as well as how long the wires are, keep all DC wires as short as possible. You can find wire size calculators online.
Use only a real deep cycle battery, not a marine battery, not any battery that lists CCA.
Wet lead acid batteries will off gas while charging, you will probably want an AGM battery if you want to keep the battery inside the bus, make sure your charger is made specifically to charge this type of battery, most chargers cant properly charge an AGM battery.
Until we know the AC power draw we cant discuss proper battery size.
But on the other hand if you can power a trickle charger why cant you just plug in the stereo?
wrong! ac and dc amps are the same, its a unit of measurement.
__________________
living in a bus down by the river.
my build pics
https://www.skoolie.net/forums/membe...albums942.html
superdave is offline   Reply With Quote
Old 03-21-2018, 12:16 PM   #11
Bus Geek
 
Join Date: Sep 2017
Location: Owasso, OK
Posts: 2,627
Year: 1999
Coachwork: Thomas
Chassis: Saf-T-Liner MVP ER
Engine: Cummins 6CTA8.3 Mechanical MD3060
Rated Cap: 46 Coach Seats, 40 foot
Quote:
Originally Posted by superdave View Post
wrong! ac and dc amps are the same, its a unit of measurement.
They are the same, but for an equivalent power you need a lot more amps at 12V than you need at 120V, hence the much bigger cables and their associated losses.
__________________
Steve Bracken

Build Thread
Twigg is offline   Reply With Quote
Old 03-21-2018, 03:46 PM   #12
Bus Nut
 
superdave's Avatar
 
Join Date: Mar 2015
Location: hills of sw virginia
Posts: 889
Year: 1996
Chassis: thomas
Engine: 8.3 cummins
Rated Cap: 11 window
Quote:
Originally Posted by Twigg View Post
They are the same, but for an equivalent power you need a lot more amps at 12V than you need at 120V, hence the much bigger cables and their associated losses.
that is incorrect sir, if a radio uses 5 amps on ac power it will use 5 amps on 12 volt or 24 volt that don't change. line loss does affect dc current more than ac absolutely, but it don't use any more. you need a bigger wire to get that 5 amps there.
__________________
living in a bus down by the river.
my build pics
https://www.skoolie.net/forums/membe...albums942.html
superdave is offline   Reply With Quote
Old 03-21-2018, 04:35 PM   #13
Bus Geek
 
Join Date: May 2016
Location: Eastern WA
Posts: 6,340
Year: 2002
Coachwork: Bluebird
Chassis: All American RE (A3RE)
Engine: Cummins ISC (8.3)
Rated Cap: 72
Quote:
Originally Posted by superdave View Post
that is incorrect sir, if a radio uses 5 amps on ac power it will use 5 amps on 12 volt or 24 volt that don't change. line loss does affect dc current more than ac absolutely, but it don't use any more. you need a bigger wire to get that 5 amps there.
Learn something new every day don't we Twigg.........

I am going to have to track down that Ohm guy and straighten him out....

I guess it really isn't "Easy as P=I*E"..... Sorry, I couldn't help myself.
PNW_Steve is offline   Reply With Quote
Old 03-21-2018, 05:58 PM   #14
Bus Crazy
 
david.dgeorge07's Avatar
 
Join Date: May 2017
Location: Chattanooga, TN
Posts: 1,406
Year: 2001
Coachwork: Thomas
Chassis: Thomas
Engine: CAT 3126
Pretty sure amps = Watts/volts. A = W/V. A cable is rated for a certain ampacity, but the actual energy used is the wattage. 1200 Watts at 120 volts is 10 amps. 1200 Watts at 12 volts is 100 amps. Thatís why we are all running 2/0 awg to our inverters, but 12 awg to our appliances. The higher the voltage the lower the amperage for a given wattage
__________________
My Build Thread:

https://www.skoolie.net/forums/f11/4-...ner-18205.html
david.dgeorge07 is offline   Reply With Quote
Old 03-21-2018, 05:59 PM   #15
Bus Geek
 
Join Date: Sep 2017
Location: Owasso, OK
Posts: 2,627
Year: 1999
Coachwork: Thomas
Chassis: Saf-T-Liner MVP ER
Engine: Cummins 6CTA8.3 Mechanical MD3060
Rated Cap: 46 Coach Seats, 40 foot
Quote:
Originally Posted by superdave View Post
that is incorrect sir, if a radio uses 5 amps on ac power it will use 5 amps on 12 volt or 24 volt that don't change. line loss does affect dc current more than ac absolutely, but it don't use any more. you need a bigger wire to get that 5 amps there.
You may want to rethink that ... or not.
__________________
Steve Bracken

Build Thread
Twigg is offline   Reply With Quote
Old 03-21-2018, 05:59 PM   #16
Bus Geek
 
Join Date: Sep 2017
Location: Owasso, OK
Posts: 2,627
Year: 1999
Coachwork: Thomas
Chassis: Saf-T-Liner MVP ER
Engine: Cummins 6CTA8.3 Mechanical MD3060
Rated Cap: 46 Coach Seats, 40 foot
Quote:
Originally Posted by PNW_Steve View Post
Learn something new every day don't we Twigg.........

I am going to have to track down that Ohm guy and straighten him out....

I guess it really isn't "Easy as P=I*E"..... Sorry, I couldn't help myself.
Apparently Ohm's Law is fake news
__________________
Steve Bracken

Build Thread
Twigg is offline   Reply With Quote
Old 03-21-2018, 06:08 PM   #17
Bus Nut
 
warewolff's Avatar
 
Join Date: Sep 2016
Location: NY
Posts: 483
Year: 2000
Coachwork: Carpenter
Chassis: International 3800
Engine: T444E
Quote:
Originally Posted by superdave View Post
that is incorrect sir, if a radio uses 5 amps on ac power it will use 5 amps on 12 volt or 24 volt that don't change. line loss does affect dc current more than ac absolutely, but it don't use any more. you need a bigger wire to get that 5 amps there.
You're grossly incorrect. A 1kW load will use just 8.33 amps at 120v, but will use 83.33 amps at 12v. Voltage = Amperage x Wattage. Amps = Watts/Volts. Might want to brush up on your education before you start correcting people who know what they're talking about ...
__________________
Roads? Where we're going, we don't need ... roads.
warewolff is offline   Reply With Quote
Old 03-21-2018, 08:27 PM   #18
Bus Crazy
 
roach711's Avatar
 
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,921
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
Quote:
Originally Posted by superdave View Post
that is incorrect sir, if a radio uses 5 amps on ac power it will use 5 amps on 12 volt or 24 volt that don't change. line loss does affect dc current more than ac absolutely, but it don't use any more. you need a bigger wire to get that 5 amps there.
While it is true that a given appliance will draw the same wattage whether powered from a 120v source or a 12v source, the amperage drawn from the power source will be different according to the voltage of the source.

For example, your radio that draws 5 amps at 120 volts (600 watts) will draw 50 amps from a 12 volt battery bank (also 600 watts) through an inverter. This ignores the power draw of the inverter itself.

Watts is "true power" (doesn't change with voltage) while amps change with the voltage of the system.
__________________
The Roach Motel
roach711 is offline   Reply With Quote
Old 03-21-2018, 08:49 PM   #19
Bus Nut
 
superdave's Avatar
 
Join Date: Mar 2015
Location: hills of sw virginia
Posts: 889
Year: 1996
Chassis: thomas
Engine: 8.3 cummins
Rated Cap: 11 window
well when my fridge is on 3.1 amps ac it draws 3.1 amps dc on my 24 volt system. that's just reality. try again
__________________
living in a bus down by the river.
my build pics
https://www.skoolie.net/forums/membe...albums942.html
superdave is offline   Reply With Quote
Old 03-21-2018, 08:51 PM   #20
Bus Nut
 
superdave's Avatar
 
Join Date: Mar 2015
Location: hills of sw virginia
Posts: 889
Year: 1996
Chassis: thomas
Engine: 8.3 cummins
Rated Cap: 11 window
Quote:
Originally Posted by warewolff View Post
You're grossly incorrect. A 1kW load will use just 8.33 amps at 120v, but will use 83.33 amps at 12v. Voltage = Amperage x Wattage. Amps = Watts/Volts. Might want to brush up on your education before you start correcting people who know what they're talking about ...
back at ya
__________________
living in a bus down by the river.
my build pics
https://www.skoolie.net/forums/membe...albums942.html
superdave is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 09:30 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
×