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[GMCnet] News for those who use big inverters. [message #222425] Sat, 14 September 2013 06:52 Go to next message
Peter Garry is currently offline  Peter Garry   United States
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Registered: July 2011
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A little off the main topic.
How does one work out how long it would take a 2000 watt Honda suitcase generator to charge 2 T105 Trojan golf cart batteries that start out at say 20 or 30% full?

Peter Garry
Calgary Alberta
'73-23' (once a painted desert)
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Re: [GMCnet] News for those who use big inverters. [message #222465 is a reply to message #222425] Sat, 14 September 2013 21:50 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Peter Garry wrote on Sat, 14 September 2013 07:52

A little off the main topic.
How does one work out how long it would take a 2000 watt Honda suitcase generator to charge 2 T105 Trojan golf cart batteries that start out at say 20 or 30% full?

Peter Garry
Calgary Alberta
'73-23' (once a painted desert)

Peter,

If you are trying to charge the T105s from the 12v output of the Honda, FOREVER is probably a safe bet.... (8 Amps doesn't go very far.)

In all seriousness, the question comes more to the converter/charger's capability. Even if you have a PD9260 (a good 60 amp unit) it will only draw about 700 watts - well within the Honda's reach.

Now things get complex. You are trying to replace about 180 Ampere-hours. Even if you were to tell the PD to run at bulk (you can do this) it would still take 3 hours to match that

- BUT -

There are a couple (maybe more than two, but we will stick with 2 for the moment) of things that come to bite you...
* First is the cell heating caused by charging at that high a rate. This burns off charge current for which you get no gain.
* Second is the reverse of the Peukert exponent. This is a nasty little factor published by a 19th century German that says if you do things to a Lead/Acid battery fast, you don't get what you paid for.

My quick calculations, based on the above, say that even if you charge at a PDs bulk rate for four hours, you will get at best 85~90% charge. It takes time at a reduced rate to hammer that last ~10% back in.

There is a pretty good write up about this on the Progressive Dynamics site.

Matt - I used to answer this question for cruisers all the time.


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: [GMCnet] News for those who use big inverters. [message #222473 is a reply to message #222465] Sat, 14 September 2013 22:26 Go to previous messageGo to next message
hal kading is currently offline  hal kading   United States
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Registered: February 2004
Location: Las Cruces NM
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Peter,

You may already know this, but in case you don't, lead acid battery life is seriously decreased if they are discharged below about 50% of capacity.

Hal Kading 78 Buskirk Las Cruces NM
Re: [GMCnet] News for those who use big inverters. [message #223006 is a reply to message #222425] Wed, 18 September 2013 13:41 Go to previous messageGo to next message
Kudzu is currently offline  Kudzu   United States
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Location: Marshville, NC
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What is the amperage output for the Honda generator? What is the
capacity (Ahr) of the T-105s? What is the throughput of your charger?
You are at 30% life (BTW, sulphation has probably occurred), so:

Battery_Capacityx2*(%_To_Fill)/Output_of_Generator

Assuming 225 Ahr per battery and down to 30% life and generator with
charger is outputting 8amps.

225*2*0.70/8=39 hours

But as was mentioned, this will probably only get you to about 90%.

Dan in NC
1976 Eleganza II

On 9/14/2013 7:52 AM, Peter Garry wrote:
> A little off the main topic.
> How does one work out how long it would take a 2000 watt Honda suitcase generator to charge 2 T105 Trojan golf cart batteries that start out at say 20 or 30% full?
>
> Peter Garry
> Calgary Alberta
> '73-23' (once a painted desert)
> _______________________________________________
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> Unsubscribe or Change List Options:
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1976 Eleganza II 1996 Chevy Impala SS 1999 Kawasaki Vulcan Nomad
Re: [GMCnet] News for those who use big inverters. [message #223013 is a reply to message #222425] Wed, 18 September 2013 14:51 Go to previous messageGo to next message
lqqkatjon is currently offline  lqqkatjon   United States
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I have a xantrex battery meter.

it seems to take a while for it to charge up the golf cart batteries.

I would think running a honda is the same as being plugged into 110v.

but it does not seem to take too long to bring them from 30% up to 80%. but to get from 80% to 100% it seems to take a while longer.





Jon Roche 75 palm beach EBL EFI, manny headers, Micro Level, rebuilt most of coach now. St. Cloud, MN http://lqqkatjon.blogspot.com/
Re: [GMCnet] News for those who use big inverters. [message #223020 is a reply to message #223013] Wed, 18 September 2013 15:51 Go to previous messageGo to next message
robert caudle is currently offline  robert caudle   United States
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Registered: January 2004
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Junior Member
I use an IOTA 55amp charger set at 14.8 volts and 15.4 for equalization
and run it from a honda 2000. If your batteries are down to 30% you need
about 12 hours with my setup. The first hundred amps go in fairly easy
but the higher % you get the harder it is to push the juice into the
battery.
Trojan wants you to charge T-105's at 14.8 for as long as it takes to get
the
specific gravity up to 100% (1.277) but at least a
couple hours after getting to 14.8 So once you get the batteries charged
they should read 12.7 or higher static (nothing connected). Since 11.7 is
a discharged battery 0% then every tenth from 12.7 to 11.7 is a 10% drop.

The reason for the lengthly chaging is like putting air in a tire with a
hand pump
the first 20-30 pounds go fairly easy, but if you have to go to 45 pounds,
anyone
who has ever done this will tell you that last 15 pounds take three or four
times
the effort and time the first 30 took.....similar idea with
batteries.....you have to
really push hard to get the last 10% from 90 to 100, so ideally...don't let
your
batteries get that low. When checking your battery voltage with a meter
remember 11.7 is a fully discharged battery, 12.3 is 40% discharged, the
values are not figured from 0-12 volts but from 11.7 to 12.7

If you are charging trojan T-105 batteries and your charger will not put out
14.8 volts at the battery terminals....you never will get 100% charge

Ok, I' done <bg>


On Wed, Sep 18, 2013 at 2:51 PM, Jon Roche <lqqkatjon@gmail.com> wrote:

>
>
> I have a xantrex battery meter.
>
> it seems to take a while for it to charge up the golf cart batteries.
>
> I would think running a honda is the same as being plugged into 110v.
>
> but it does not seem to take too long to bring them from 30% up to 80%.
> but to get from 80% to 100% it seems to take a while longer.
>
>
>
>
> --
> 75 palm beach
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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Re: [GMCnet] News for those who use big inverters. [message #223032 is a reply to message #223020] Wed, 18 September 2013 18:26 Go to previous message
Mr ERFisher is currently offline  Mr ERFisher   United States
Messages: 7117
Registered: August 2005
Karma: 2
Senior Member
sort of like this
http://www.gmcmhphotos.com/photos/buzz-box-converter-problems-and-replacement/p17533.html

and the following slide



On Wed, Sep 18, 2013 at 1:51 PM, robert caudle <rlcaudle1014@gmail.com>wrote:

> I use an IOTA 55amp charger set at 14.8 volts and 15.4 for equalization
> and run it from a honda 2000. If your batteries are down to 30% you need
> about 12 hours with my setup. The first hundred amps go in fairly easy
> but the higher % you get the harder it is to push the juice into the
> battery.
> Trojan wants you to charge T-105's at 14.8 for as long as it takes to get
> the
> specific gravity up to 100% (1.277) but at least a
> couple hours after getting to 14.8 So once you get the batteries charged
> they should read 12.7 or higher static (nothing connected). Since 11.7 is
> a discharged battery 0% then every tenth from 12.7 to 11.7 is a 10% drop.
>
> The reason for the lengthly chaging is like putting air in a tire with a
> hand pump
> the first 20-30 pounds go fairly easy, but if you have to go to 45 pounds,
> anyone
> who has ever done this will tell you that last 15 pounds take three or four
> times
> the effort and time the first 30 took.....similar idea with
> batteries.....you have to
> really push hard to get the last 10% from 90 to 100, so ideally...don't let
> your
> batteries get that low. When checking your battery voltage with a meter
> remember 11.7 is a fully discharged battery, 12.3 is 40% discharged, the
> values are not figured from 0-12 volts but from 11.7 to 12.7
>
> If you are charging trojan T-105 batteries and your charger will not put
> out
> 14.8 volts at the battery terminals....you never will get 100% charge
>
> Ok, I' done <bg>
>
>
> On Wed, Sep 18, 2013 at 2:51 PM, Jon Roche <lqqkatjon@gmail.com> wrote:
>
> >
> >
> > I have a xantrex battery meter.
> >
> > it seems to take a while for it to charge up the golf cart batteries.
> >
> > I would think running a honda is the same as being plugged into 110v.
> >
> > but it does not seem to take too long to bring them from 30% up to 80%.
> > but to get from 80% to 100% it seems to take a while longer.
> >
> >
> >
> >
> > --
> > 75 palm beach
> > St. Cloud, MN
> > http://lqqkatjon.blogspot.com/
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>



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“Give a man a fish; you have fed him for today --- give him a URL and
-------
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