Time to replace my TAB 400 batteries

warbler_road · March 2023

The batteries in my 2020 400 are no longer holding a charge, after about 3.5 years, which is a drag since we didn't even use them so much. We always ended up in places with power, save the occasional overnight at a Walmart.

I think the short life is due to me keeping it plugged in all the time when at home, under the carport? Never ran them down.

Is changing them a simply a matter of unhooking the old, pulling them and dropping in the new? If it's a more complex procedure, is it here in the community somewhere? (I have been searching; not quite content with answers.)

Also, are there some cheaper options for someone who doesn't boondock as much? There's lead acid, but even with the vented compartment those would be right under the bed. :-/

WayneW · March 2023

Have you considered a 100 aH lithium as a replacement? Depending on your power needs, that might be an option. No venting issues, long life, less weight and less space. A decent one without self-heating can be had for $300-600.

That would give you 80-90 aH of useable energy. If you’re almost always at a place w power, that might be sufficient. Or look for a 120-150 aH battery which would give you more juice than you currently have.

VictoriaP · March 2023

FYI, if you want to leave the trailer plugged in all the time in storage, just turn off the battery cutoff switch. You’ll have power to everything, but won’t be overcharging your batteries. I’ve done this for almost four years now, and my AGM is still trucking along just fine with an occasional topping off.

pthomas745 · March 2023

There are plenty of owners who keep their trailers plugged in, and there does not appear to be any issues with that. So...don't blame yourself for that method.

Batteries can fail on their own. It happens.

If you were always at electrical sites, those "occasional overnights", if you didn't pay attention to battery state of charge, etc, "might" be more of an issue. If the batteries made more than a couple of trips to the "less than 50 percent charge" area, it could have shortened the number of "cycles" available.

So, don't beat yourself up over it. You seem to have gotten 4 years from yours.

What set of batteries are in the trailer? Have you opened the battery area up and take a look? Should be the dual 6v battery setup. A new set of 6V batteries can drop right in. (Take a picture of the battery wiring to put them back together properly).

NorthIsUp · March 2023

I'm in the process of changing out the batteries in our 2019 Tab 400 BL due to age and decreased performance. I decided on a lithium upgrade, but in your case with limited need for boondocking, AGM replacements are the best choice.

What you're looking for are two 6-volt batteries in the 190 or greater amp/hour(AH) range in size GC2, and you'll need to buy 2 of them. Two 6-volt batteries properly configured equals the required 12-volts. The original (2019 at least) batteries were 224 AH. Here's an example of what you need made by Duracell: https://www.driveduracell.com/pub/media/wysiwyg/1688.pdf Just make sure that it says AGM on it and is size GC2 and it should be a direct replacement. Other good AGM brands are Trojan Motive https://www.trojanbattery.com/products/t105-agm-6v-battery and Lifeline https://lifelinebatteries.com/products/marine-batteries/gpl-4ct/

Less expensive AGM batteries are also available that may not have nationally-familiar brand names. They may also have less amp hours of power available than those I noted.

warbler_road · March 2023

Thank you for the wealth of info my friends! Including the links to battery brands.

My 400 came with the dual 6V Harris HBDAGMGC6-A 's. I had opened up the compartment back when I first got the camper, so knew how to open it again for the fateful multimeter test.

I read something about the lithium batteries also requiring a new converter or some such. Anyway, the AGMs are really all I need.

Here's a pic of the battery compartment a couple of months after we bought the TAB. I was installing the Victron battery monitor. (Note the white junk around the positive pole of the right battery. Didn't think anything of it at the time.)

Finally, when I swap them, should I just have the battery switch off and that's it? Plugged into shore power or will that cause a problem? I imagine I will be resetting all the Bluetooth settings for the solar and Victron BMV afterwards.

Once again you all are a big help!

Image: https://us.v-cdn.net/5021717/uploads/editor/l8/s1u8p8vpl7bk.jpg

Tabmanic · March 2023

For the price of AGM you can get lithium for not much more and you don't have to worry about discharge or over charge, you can have a full discharge and not damage the battery, a few discharges below 50% on AGM or any lead acid will start damaging the battery and Lithium doesn't need a ventilated in closer. One lithium has battery has the same discharge capacity as 2 AGM and about half the weight. Also you don't have to change out your converter, just set your solar controller to charge Lithium (14.4v) and that will top off your batteries, I have done this and it works fine.

SLJ · March 2023

Those lead acid batteries are a lot of weight you don't need. One 100AH Lithium is half the weight of a comparable 100AH Lead Acid and will have twice the power. It will last four or five times longer and won't get damaged by running it down below fifty percent. They are down to between $300 and $400 now. When you factor in replacing AGMs at a shorter life span or if you run them below 50% and kill them then Lithium is a better way to go.

Image: https://us.v-cdn.net/5021717/uploads/editor/tv/uvrgku09z4ui.jpg

Denny16 · March 2023

True, the Lithium batteries are lighter than a comparable AGM. But the batteries on a 2020 TaB 400 are behind the axle, where they help reduce the tongue weight.
cheers

SLJ · March 2023

Denny16 said:

True, the Lithium batteries are lighter than a comparable AGM. But the batteries on a 2020 TaB 400 are behind the axle, where they help reduce the tongue weight.
cheers

Throw a rock in there then and still have better power. Or make the back lighter and have less chance of sway.

pthomas745 · March 2023

I have a lithium, and recognize the advantages, and work around all the discussions of temperatures, charging, converters, etc. It isn't hard.

But: some owners can get pretty discouraged reading threads about lithium batteries full of charts and graphs and all the new things you might need: DC-DC chargers, temperature sensors, battery heaters, new converters.

Some owners enjoy the discussions of equipment. Some owners might not. For an owner like Warbler with his camping style, a simple replacement of the AGM's is simple, easy, no-fuss.

There are 200 ah Renogy AGM's selling for 360 at Amazon tonight. It is big, and huge, yes.

https://www.amazon.com/Renogy-Self-Discharge-Discharge-Appliances-Maintenance-Free/dp/B075RGX1WR/ref=sr_1_4?crid=C2NJWBQJT4GB&keywords=200+ah+agm&qid=1679368281&sprefix=200+ah+agm,aps,149&sr=8-4

warbler_road · March 2023

Thanks for this info, @Tabmanic - maybe I will use it "down the road" when we hope to be using the camper with more frequency. For now I'm going to replace the AGMs ...

warbler_road · March 2023

@pthomas745 , you are always super helpful. I got some new AGMs for $280 apiece, got them in there, have shore power unplugged, solar covered, battery switch off (vertical in my case -- definitely off). Hooked up the wires, but when I went to attach the last negative cable, BIG spark. Like, pow.

What is asking for all this power? Carbon monoxide detector? Converter? Any fuses I should pull?

Horigan · March 2023

Some spark is normal even with no load. There is some capacitance in the entire negative side of the circuit that drifts away from 0V while unattached, until to attach the negative terminal.

warbler_road · March 2023

Thanks @Horigan . This is a BIG spark. POP! Just slap it on there anyway? I hesitate ...

gulfarea · March 2023

That is not right! Art

Horigan · March 2023

warbler_road said:

Thanks @Horigan . This is a BIG spark. POP! Just slap it on there anyway? I hesitate ...

It shouldn't be a big spark. A normal spark is when you reconnect the negative cable on a car battery. Are you sure you have the two 6V batteries wired correctly, in series? I could see that causing a big spark if not wired correctly.

I would also really confirm nothing is turned on in your system. It sounds like you may have a short somewhere in the system. Do you have a multi-meter? With the battery disconnected and the battery switch off, is there any resistance other than open circuit between the positive and negative battery cables, not attached to the battery? It should read open circuit (infinite resistance).

warbler_road · March 2023

Thanks again @Horigan: Yes I am certain the batteries are wired properly. Just took the old ones out this morning. Here's a picture though (with the final negative connection not made). And I just checked resistance as you said, with one multimeter probe on the unattached +cable and one on the -cable. Open line. This is with no fuses removed and battery switch off. The batteries both read 6.6 or so, also tested with multimeter.

Time to sleep on it I guess.

- Alec

Image: https://us.v-cdn.net/5021717/uploads/editor/dh/11cmuihppx7l.jpg

Tabmanic · March 2023

Do you have an inverter in the system, these will make a spark/pop as the power is draw into the capacitors, I just seen that you do have an inverter, just put it on you will be good to go, or get a resistor and slowly fill the inverter, that way you will have no spark. I just did this yesterday and I just popped it on and no worries.

warbler_road · March 2023

I used a carpenter's pencil as suggested on another thread as a resistor to charge up the capacitors in the inverter. It worked! No more spark! Charging my new batteries now.

THANKS EVERYONE!

Horigan · March 2023

Great news and good to know! I'm receiving my new LiFeO4 batteries today and will try the pencil trick.

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