Sorry: Batteries again!

obgraham · 04-09-2016, 06:50 AM

I know, we've beat the battery issues to death here.

However, I just returned north having left both cars there on Battery Tenders. Worked great -- 5 months, started with no hesitation at all.

Next winter I'll leave the RoadTrek E-Trek up north, too. If I leave it plugged in, I have to leave the inverter running on mine. Don't like that idea. For the Chassis battery I'll pull the Sprinter's switch.

What about a Battery Tender on the House batteries? Anyone ever do that with a 4 or 8 AGM E-Trek?

markopolo · 04-09-2016, 06:08 PM

24V E-trek?

If it were mine and in covered parking I'd put a 24V Battery Tender on it for that length of time. My van is always parked in the garage and plugged in. I'm probably in the minority here as it doesn't seem that most plug their vans in all the time when stored.

The solar should keep the batteries charged if outside unless you get lots of snow that doesn't get a chance to melt.

Arlo · 04-09-2016, 11:45 PM

Might need to have a battery balancer installed to keep the 12v side fully charged. Interesting experiment?

obgraham · 04-10-2016, 03:42 AM

OK Arlo, forgive my battery ignorance:

In the 8 battery E-Trek, each battery is 6 volts, when you measure across its terminals. If I put a 6-volt Battery Tender on one, are the others connected such that they will also be "tended"?

Arlo · 04-10-2016, 04:15 AM

Wish I had the knowledge to confidently answer that question. There is a link between the 24v and 12v banks in the E-Trek configuration, but the fact that a 24v-to-12v equalizer is required to keep the 12v bank full charged in some situations is why I raised the question. I recently had the equalizer installed in my 2013 E-Trek and it does help maintain the charge in the 12v bank. How all of this will play out with a battery tender on the 24v side is unclear to me.

wincrasher · 04-10-2016, 05:36 AM

Leave the Etrek plugged in with the onboard charger maintaining the house battery bank. You are not going to do any better maintaining those batteries than that. Put the chassis battery on a battery tender. You could hard wire the battery tender and run the cable inside and plug it into a 110v outlet inside, so that when the shore power is connected, you are also maintaining the chassis battery.

avanti · 04-10-2016, 12:19 PM

If you have continuous shore power (or reliable solar), then installing Trik-L-Start is the way to go for maintaining the chassis battery. It is a small, DC-DC maintenance charger that steals a bit of power from the coach charger to keep the chassis battery charged. A 3-wire install. If you have a battery isolation relay, it is a 10 minute job. Cheap, easy, and effective. Install it and forget it.

markopolo · 04-10-2016, 01:11 PM

Quote:

Originally Posted by obgraham

OK Arlo, forgive my battery ignorance:

In the 8 battery E-Trek, each battery is 6 volts, when you measure across its terminals. If I put a 6-volt Battery Tender on one, are the others connected such that they will also be "tended"?

No. I'm basing that on the info from photolimo's etrek. Only 2 of the 8 batteries were parallel connected at 6V.

In his etrek, all eight batteries would charge when connected to shore power or from solar. Both solar & the inverter/charger were 24V. The 12v "part" was just a "tap" in at first and an equalizer installed later. His was a 24V system at heart so 24V charging would be the way to go IMO.

If using a Trik-L-Start for the chassis battery then the 12v power source for that would have to be from the "center tap" or equalizer.

Edit: I'll just add that a 24V charger would have to be connected to a point in the system that is 24V. And, there could be variations among etreks that make them not the same. What works for one etrek might not be applicable to any other. I'm adding that for future reference as the units change hands to second, third, fourth owners etc.

booster · 04-10-2016, 02:26 PM

That brings up an interesting question for the center tapped if it has a balancer. I assume the goal of using a Battery Tender is so the inverter can be off while stored, but will that kill all the load off the 12v side too, as the inverter is 24v. If it does kill all the 12v power, would the balancer also be shut off?

8 batteries may be too much load for a Battery Tender anyway, capacity wise, depending on their condition and float current needs. If there is any extra load for anything, it would just make it worse.

How big a Battery Tender can you get? It might be necessary to go to a small battery charger if Tenders aren't big enough

markopolo · 04-10-2016, 03:14 PM

Good point Booster. You'd have to make sure the batteries were fully charged before putting them on the battery tender. This 24V model - 022-0158-1 - can supply 2.5A.

It brings us back to what Wincrasher points out here:

Quote:

Originally Posted by wincrasher

Leave the Etrek plugged in with the onboard charger maintaining the house battery bank. You are not going to do any better maintaining those batteries than that. Put the chassis battery on a battery tender. You could hard wire the battery tender and run the cable inside and plug it into a 110v outlet inside, so that when the shore power is connected, you are also maintaining the chassis battery.

Why not just plug it in? A 110V 15A circuit would easily handle that maintenance use.

You can gather some baseline info on the installed inverter/charger using a clamp on ammeter.- http://www.classbforum.com/forums/f6...meter-999.html Work off of the battery connections on the inverter/charger.

Check voltage and amps without disconnecting anything. You might have to plug in for more than a day to get readings in float mode. It likely won't be 100% accurate re: the amps but good enough for this purpose.

Reporting that info back to the forum would be very useful to others.

Arlo · 04-10-2016, 04:14 PM

Quote:

Originally Posted by booster

That brings up an interesting question for the center tapped if it has a balancer. I assume the goal of using a Battery Tender is so the inverter can be off while stored, but will that kill all the load off the 12v side too, as the inverter is 24v. If it does kill all the 12v power, would the balancer also be shut off?

My balancer does continue to operate when 12v power is turned off via the battery disconnect switch. The led on the balancer indicating flow from 24v to 12v remains illuminated until the batteries are balanced.

obgraham · 04-10-2016, 08:52 PM

Quote:

Originally Posted by markopolo

Why not just plug it in? A 110V 15A circuit would easily handle that maintenance use.

Reporting that info back to the forum would be very useful to others.

1.I will leave for 6 months straight next winter, and the idea of leaving the rig plugged in and the inverter running continuously for that time (which is required in the ETrek) doesn't thrill me.
2.This winter I was in Arizona and the rig was parked outside. The solar kept everything topped off. But up here she's stored indoors. No solar input.
3.Last winter I left it indoors unplugged for just over 2.5 months and there was still good voltage in the AGMs and also on the chassis battery on my return. I'm wondering if 6 months is pushing it.

Meanwhile, thanks everyone for input. Not sure yet what is the best route, but always looking to learn more.

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