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 > Tow vehicle charging RV batteries

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blaczero

USA

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Posted: 12/04/20 04:19pm Link  |  Quote  |  Print  |  Notify Moderator

How slow is it? Is there a mod you can do to make it charge quicker?

I was watching a video where some ppl that like to boondock said the alternator doesn't charge the batteries on your RV very quickly. Is this correct?

* This post was edited 12/04/20 07:41pm by blaczero *

KD4UPL

Swoope, VA

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Posted: 12/04/20 04:43pm Link  |  Quote  |  Print  |  Notify Moderator

The problem is mostly that it's a long way from the alternator to the batteries and the vehicle manufacturers use wire that is too small for this circuit. It's often something like #14 or so. It really needs to be more like #6 or larger to get good current flow. People who really want to set things up well for this will run a heavy charge line from the battery tot he rear of the tow vehicle with something like #2 welding cable. Then, you use connectors meant for a lift gate trailer or perhaps some Anderson Powerpole style connectors rated for 100A. Of course this require the matching connector and more #2 cable on the trailer to the batteries.
The other problem is that in the ever present race to improve vehicle MPG many modern vehicles actually lower the alternator's output voltage when the vehicle is just "cruising down the road". Usually turning on the headlights or putting the transmission into tow/haul mode will raise the charge voltage back up.

mobeewan

Hampton, Va

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Posted: 12/04/20 04:44pm Link  |  Quote  |  Print  |  Notify Moderator

It is pretty much a trickle charge, if the vehicle is set up to do it. Alternators are usually sized to supply the demand the vehicle will be needing. You would have to have a much larger amperage alternator or install a second alternator if you have room for it in order to put a dent in charging the house batteries.

Lwiddis

Near DVNP, California

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Posted: 12/04/20 04:53pm Link  |  Quote  |  Print  |  Notify Moderator

Smart Boondockers use solar and backup with a generator.


Winnebago 2101DS TT & 2020 Chevy Silverado 1500 LTZ Z71, 300 watt solar-Lossigy 200 AMP Lithium battery. TALL flag pole. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist 14 yr. Army -11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad


vermilye

Oswego, NY, USA

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Posted: 12/04/20 04:58pm Link  |  Quote  |  Print  |  Notify Moderator

Some have used a DC to DC converter in the trailer charge line to increase the voltage high enough so that charging is better. If you do, be sure to include a way to power the trailer breakaway switch - DC to DC converters are one way devices...


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wanderingbob

monticeeo, fla

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Posted: 12/04/20 04:59pm Link  |  Quote  |  Print  |  Notify Moderator

Thats not to say that it is useless . A good 6 or 8 hour drive will bring my batts back up . Sitting at idle waiting for a battery to recharge , ya better bring your lunch !

wanderingbob

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Posted: 12/04/20 05:00pm Link  |  Quote  |  Print  |  Notify Moderator

Thats not to say that it is useless . A good 6 or 8 hour drive will bring my batts back up . Sitting at idle waiting for a battery to recharge , ya better bring your lunch !

Lwiddis

Near DVNP, California

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Posted: 12/04/20 05:00pm Link  |  Quote  |  Print  |  Notify Moderator

If you aren’t pulling, you aren’t charging regardless of modifications. Solar with a generator backup.

deltabravo

Spokane, WA

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Posted: 12/04/20 05:18pm Link  |  Quote  |  Print  |  Notify Moderator

blaczero wrote:

Is there a mod you can do to make it charge quicker?


Bigger cables on a dedicated charge line.

This is how I did it

My truck has dual alternators


2009 Silverado 3500HD Dually, D/A, CCLB 4x4 (bought new 8/30/09)
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old idaho guy

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Posted: 12/04/20 05:21pm Link  |  Quote  |  Print  |  Notify Moderator

If you are trying to charge your battery while camping, use jumper cables from battery to battery

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