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ajwbarnard · 10-16-2017, 04:51 PM

This is cross posted with the only other forum that was talking about trickle charges, but...thought maybe it might be specific to this forum.

We have winterized and said goodbye to our AS for the winter. She is going to be stored at our seasonal site and all issues will have to wait until spring.

But I have brought two GPL-27T Lifeline AGM batteries home with me to care for until spring. I know that I have to keep them charged, but I do not know how to do that. We have had a boat motor that we kept charged with a trickle charger, but we only had one battery not two. Do you need a separate charger for each or can you charge with one? The chargers on Amazon are sold by amp hrs. Do we buy the lowest since we are not technically drawing them down? Any recommendations for a particular brand?

Any help would be appreciated. We are still new to all of this and hope someday to be able to help someone else!

rmkrum · 10-16-2017, 05:26 PM

First question, what is the voltage and amp-hour capacity of each of the AGM batteries?

ajwbarnard · 10-16-2017, 05:42 PM

If I take the part number off the part list supplied by AS - GPL-27T Lifeline, they are 12V and 100 amp hrs.

I read the owner's manual, but it is not in layman's terms.

https://cdn.shopify.com/s/files/1/14...00349951356528

rmkrum · 10-16-2017, 05:45 PM

The best bet would be to reconnect the batteries the same way they were hooked up in the Airstream battery box, then use one battery tender to charge them together. That will keep them charged to the same voltage and maintain them as a pair...

A 3-5 amp multistage charger would be best. You don't need a lot of current to keep them charged. "BatteryTender" is one brand. There are others...

GeocamperAS · 10-16-2017, 06:00 PM

You do need one trickle charger for each.
Between boats, campers and riding lawnmower I have 6 batteries. 2 are AGM. My charger has a switch for standard or AGM. And a switch for 2amps or 10amps or 50amps. I set it for 2amps and switch between AGM or standard. On the 1st of each month I hook up battery #1 and leave it on the whole day. On the 2nd I charge battery #2. On the 3rd I charge #3 and so on. Then the next month I do it all over again.
However a with trickle charger you could leave it on an not bother with it all winter. But I’m to cheap to by 6.

uncle_bob · 10-16-2017, 06:46 PM

Hi

As I posted in your other thread on the same topic - get a device designed specifically as a trickle charger. A Battery Tender is a good example, there are lots of other. Don't get some sort of monster "do it all" charger. They are far more likely to do harm to the batteries. The trickle chargers are cheap enough that I can't see why you would buy something else. Get one for each battery and move on ....

https://www.amazon.com/Battery-Tende...battery+tender

Plenty good enough if it's running in your basement.

Bob

lyleapgmc · 10-17-2017, 12:23 PM

Quote:

Originally Posted by uncle_bob

Hi

As I posted in your other thread on the same topic - get a device designed specifically as a trickle charger. A Battery Tender is a good example, there are lots of other. Don't get some sort of monster "do it all" charger. They are far more likely to do harm to the batteries. The trickle chargers are cheap enough that I can't see why you would buy something else. Get one for each battery and move on ....

https://www.amazon.com/Battery-Tende...battery+tender

Plenty good enough if it's running in your basement.

Bob

To Bob and others who have mentioned trickle chargers;

Trickle chargers are old school. They put out a constant voltage and current which can be damaging to batteries over time. They continue that rate no matter the state of charge of the battery. I have a trickle charger made by the same company that now makes a wide variety of smart chargers. I don't use it. It is basically a 12 volt power supply.

Smart chargers are the best way to go for long term battery maintenance. They provide a customized charge profile that better reflects the needs of the specific battery being maintained. They provide a higher charge rate to charge the battery to full then reduce the current to keep the battery charged. Even battery manufacturers advocate for smart chargers.

Trickle chargers are not a good idea for protecting and maintaining batteries as they do not adjust the charge rate to reflect the state of charge of the battery. This can result in over heating of the battery, evaporation of the electrolyte and subsequent damage to the battery.

It may be a matter of semantics to some in the discussion but correct terminology is important.

Lyle

us3rnam3 · 10-17-2017, 01:13 PM

Quote:

Originally Posted by rmkrum

The best bet would be to reconnect the batteries the same way they were hooked up in the Airstream battery box, then use one battery tender to charge them together. That will keep them charged to the same voltage and maintain them as a pair...

A 3-5 amp multistage charger would be best. You don't need a lot of current to keep them charged. "BatteryTender" is one brand. There are others...

Be careful with"Battery Tender" brand charger You buy. After I lost two batteries I received the following from Battery Tender tech support,

" If you are using just that one unit on two batteries and the batteries do not reach a full charge within 72 hours the safety timer will stop the unit from charging after 72 hours and you will then get the alternating lights from amber to green. If that is happening in your case that tells me the unit you are
using is too small to handle both batteries and you would need either
another 022-0185G-DL-WH and use one on each battery and you would not have to disconnect the batteries. Or a 3, 4, or 5 amp unit to handle those
batteries."

uncle_bob · 10-17-2017, 06:47 PM

Hi

Do as you wish. I have seen a number of automotive "smart chargers" destroy batteries in under a month. I also know of a few hundred people who use the "old style" stuff very successfully for years and years. Much of it is on vintage auto's but it's the same principle. Since a "smart charger" and a "trickle charger" both put the same float voltage on the battery the fact that they work is not a big surprise.

A trickle charger *will* cut out on a discharged battery. The alternative is to source a lot of current into the battery. If you have a cell short, this is *not* what you want happening in your basement, or in any storage area. A "smart charger" will indeed source the current and you will have a massive mess (if not an explosion).

Bob

Tbeck11931 · 10-17-2017, 07:02 PM

I bought a DeWalt battery charger from Home Depot that will tend two batteries at once. Not to mention all the other features it provides.

SMLJeep · 10-17-2017, 07:06 PM

IMHO these are the best: https://no.co/products/charging/multipurpose

waninae39 · 10-17-2017, 07:33 PM

Quote:

Originally Posted by Tbeck11931

I bought a DeWalt battery charger from Home Depot that will tend two batteries at once. Not to mention all the other features it provides.

me two

i use them to trickle charge the batteries i took out when my AS is in winter storage

guskmg · 10-17-2017, 07:41 PM

Just fully charge AGM batteries and then disconnect the negative lead to the TT frame and let them sit for the winter. If, they are in serviceable condition when you start, they will last a lot longer than winter. Lewster discovered this by accident with Lifelines he forgot about in his storage facility. Trickle charges have progressed to the point they have smart circuits, if you select the right type battery on the charger, you can leave it on forever. If you have Lithiums, just bring them down to 50-60% charge, isolate them from all loads and charging, and forget them until you want to use them again. They will last as long as you will need them. You get the longest overall battery life doing the above.
guskmg

MWBishop · 10-18-2017, 05:55 AM

I just have 2 "normal" batteries in our 26U.
Afraid if I pull the batteries I'd never get them properly reconnected again (lots of wires).
Can I not just leave them in the trailer and connect to shore-power for a couple of days every 2-3 weeks or so?

uncle_bob · 10-18-2017, 07:07 AM

Hi

If you do the "just leave them" approach on batteries, understand that they can freeze. That damages them. The temperature at which they freeze depends a lot on their state of charge. If the battery charge is low, it freezes at a higher temperature. A battery with nothing attached will "self discharge". Some manufacturers consider a discharge rate in the 10%/ month range "normal". That might leave you in a bad situation with a 5F cold snap in late February.

Bob

MWBishop · 10-18-2017, 10:43 AM

Thanks.
Rarely gets that cold in North Bama, but it's not impossible.
So I guess I really should pull them out and alternate them on my Battery Tender.
Just need lots of pictures and diagrams of the rat's nest as I disconnect.

MWBishop · 10-18-2017, 11:15 AM

Oh,
Should I plan to pull the batteries at the storage facility?
Afraid if I pull them at home the lights/tongue-jack will no longer work even when connected to TV. I can connect to shore-power in both locations to perhaps get tongue-jack to operate, but do the lights work under tow with no batts?

paiceman · 10-18-2017, 11:22 AM

MWBishop - Tongue jack is directly wired to the batteries, will not work if batteries are missing or low. I used to pull mine in our storage facility, but worked out a deal to keep it plugged in when in storage and changed out converter to charge and then dropt to trickle. So far works great.

MWBishop · 10-18-2017, 11:52 AM

Well, since my storage facility is very close to home, I think I'll just stop by once a week or so to monitor the batts and throw on charge for a day or so every week or so. I currently do that anyway. If we have a mild winter this should be ok, but with a backup plan of pulling the batts if a frigid spell is headed our way.
Thanks for all the info everyone.

lynnsr · 10-18-2017, 04:16 PM

I've had 3 batteries in my boats.
And I've had 2 batteries in my campers for years.

I've used AGM's as soon as I felt they were perfected.

I keep them both hooked up year-round when they're in.

I've never had a problem.

Why in the world would you go to all the work of taking them out of your camper.

Make life more fun.

LynnSr