Removing and replacing batteries--advice needed

FriendsofMario · August 11

Looking for some advice regarding the replacement of the original AGM batteries in our 2019 400 BDL. We're replacing the Harris batteries with a new set of 6V AGMs from US Battery. I know that I have to remove the bed platform and the battery box in order to access the batteries. I will have the battery disconnect switch turned off so that the batteries are not connected to any loads, and I plan to remove them after dark so that the solar panels are not yielding any voltage.

What I need to know is: Is there any special procedure, or sequence, for removing the wiring from the existing batteries, and then reconnecting when the new ones are set in place? I'm still not as well-versed in 12V systems as I'd like to be, and I don't want to do anything that may cause arcing or any other sort of damage, either to the new batteries or to any of the wiring or other components.

Any wisdom will be appreciated.

qhumberd · August 11

@FriendsofMario We also have a 2019 400 and we changed out the AGMs as well. You have to remove that battery box and that is a pain. The bed panel on the passenger side also needs to come up. When you have access you should disconnect the negative terminal first for safety and of course keep the positive and negative wires away from each other and any grounds.

Those AGMs are heavy and the new AGMs will be very heavy. If not able to lift out then one member laid them on their side and slid them out the passenger access door. Dropping the new ones in is just lining up and reconnecting positive first and finishing with the negative. The existing cables should fit the new AGMS just make sure you put them in series (+ to -) so that you have 12 V where your connect to the trailer cables. That is the limit of my electrical expertise so others may have some better ideas.

Having said that I would want you to consider a lithium replacement if you have not already. Price not significantly more and capacity and life much longer, plus nearly 90 lbs lighter. You can get a 230 Ah or a mini 300 Ah now. We love our 230 Ah LiTime and it was nearly a perfect fit with some left over.

And if you have the smaller frig you may gain a 20A plug tucked away near the battery disconnect. We use that for the small Lithium charger when on shore power.

Good luck

FriendsofMario · August 11

Thanks, @qhumberd. Just the sort of info I was after. Much appreciated.

I assume I'll follow the same pattern with the cable that goes between batteries: disconnect the + first, then the -.

We've decided to stick with AGMs for two reasons. 1.) Our WFCO converter is not compatible with lithium batteries. We are blessed to have a really good nuCamp dealer near us. The service manager there showed us how to check the converter for lithium compatibility, and ours isn't. So, we don't want to incur the additional cost of changing out our converter. 2.) The two new AGMs are going to cost about $300 less than the average lithium battery, at least as far as I've researched to this point.

Yes, the weight of AGMs is a drawback, but the new ones have better specs than the OEM Harris batteries, and only weigh 3lbs. more apiece.

Now, ready for a laugh? We looked at a Trojan battery, excellent performance ratings, USA-made, etc. The only slight downside was that each battery weighed 89lbs! 😨😂

Horigan · August 11

Always disconnect the negative first, then the positive. When connecting, connect negative last. This eliminates the risk of shorting the battery when disconnecting the positive terminal. More an issue with vehicles that have metal bodies near the positive terminal.

pthomas745 · August 11

The "non-lithium" converters continue to confuse people. The "non-lithium" converter will charge a lithium battery, but "only" to around 85 percent. Most owners simply skip dealing with the converter swap, and use either solar or the many options for using a "stand alone" lithium charger that is much more dependable than even a "lithium converter" from WFCO. (The Auto Detect versions also seem to Auto Forget). Solar is perfectly capable of charging a lithium battery "completely".

But, enjoy your new batteries. Some pictures of your battery area and the big box removal would be very interesting to see!

qhumberd · August 11

@FriendsofMario just take your time and a couple of pictures before you start. It helps those of us that can't seem to remember what they just saw…

And I have to mention that once you remove the battery cover, you may be ready to NOT stand on your head and seal it back up again. It is a really tight spot in our 2019 stuck over in the corner. Just take your time.

I am not very limber at my age and once that cover was out, I was inclined to research options that did not require it to be replaced. That was when I made the jump to lithium. And honestly I do not regret it.

pthomas745 · August 12

ready to NOT stand on your head

Ouch…yes, removing that box with that big battery combines the worst of Tab Yoga and Tab Weightlifting!

FriendsofMario · August 13

I can't wait…..

Removing and replacing batteries--advice needed

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