Going from 2 AGM to 1 12V 300Ah LiFePO4 Battery

[Scubawise]

I ordered the BIM 225.
Question gong from 2 chained do I put all current + terminals on the 1 Lithium battery & all - from both to 1 negative on lithium?

 

[dkoldman]

Not sure I follow the question?

I think you are asking do you put all of the positive cable from both AGMs to one positive post of new Lithium and same for Negative. If so, the answer is maybe depends on how many and the sizes. You really need pictures it could be simple. But some may say to use a connector block for positive and negative if you have more than 3 wires.

In my case, I had 4 wires, but I went to Ace Hardware and carefully found a longer screw for the battery post. You have to measure the thickness of the lugs to how much longer the screws need to be so you can tighten down without damaging the battery.

Your BIM install should be simple as they have diagrams. I would do the BIM 1st and then do the battery

 

[16ACE27]

The BIM 225 is a wire-by-wire swap with your existing BIM 160.

As far as the battery swap goes:

Get two different colors of electrical tape.
Put one color tape around each cable going to a negative post on the existing AGM batteries.
Put a different color tape around each cable going to a positive post on the existing AGM batteries.
Picture time.
Disconnect from SP
USE/STORE to STORE

Disconnect all negative cables from your existing AGM batteries.
Disconnect all positive cables from your existing AGM batteries. WARNING: do not touch any of the positive cables to any metal part of your RV. Wrap the exposed ends in an insulator and/or tape if needed.

You will now have two cables you can completely remove from your battery compartment:
One with a positive colored tape on each end
One with a negative colored tape on each end

Store these away. You no longer need them.

Remove the existing AGM batteries.
Install the replacement LFP battery
Connect all remaining positive cables to the LFP's battery positive terminal. You may need a longer bolt for this.
Connect all remaining negative cables (probably only one) to the LFP's battery positive terminal.

USE/STORE to USE
Plug in to SP if desired.

 

[ducksface]

I had to cut my original bim out of its mounting place by sawing off one mounting lug.
Thor mounted the bim then installed the front cap over one of the bim screws.

I had to make one new hole for the new bim to mount and turn it all sideways.

Be prepared.

Pics are somewhere in my signature thread.

 

[Mark54]

I ordered the BIM 225.
Question gong from 2 chained do I put all current + terminals on the 1 Lithium battery & all - from both to 1 negative on lithium?

Hopefully you ordered the "LI-Bim 225"... for lithium batteries. It will be green.
(There is a white one that is just 'Bim 225' as well- not the one you want for lithium)

 

[dkoldman]

Hopefully you ordered the "LI-Bim 225"... for lithium batteries. It will be green.
(There is a white one that is just 'Bim 225' as well- not the one you want for lithium)

Oops, I hate when Mfgs do that.

I can't tell you how many times I almost ordered (had in the cart because of the great price) the Victron BlueSolar Controller versus the Victron SmartSolar Controller. They look just alike and some sellers would have a picture of the SmartSolar but listing is for the BlueSolar. I am not sure why anyone would ever want or need a BlueSolar.

Good call out for the Scubzce to verify....

 

[Scubawise]

Hopefully you ordered the "LI-Bim 225"... for lithium batteries. It will be green.
(There is a white one that is just 'Bim 225' as well- not the one you want for lithium)

Thx I have this coming

 

[Scubawise]

The BIM 225 is a wire-by-wire swap with your existing BIM 160.

As far as the battery swap goes:

Get two different colors of electrical tape.
Put one color tape around each cable going to a negative post on the existing AGM batteries.
Put a different color tape around each cable going to a positive post on the existing AGM batteries.
Picture time.
Disconnect from SP
USE/STORE to STORE

Disconnect all negative cables from your existing AGM batteries.
Disconnect all positive cables from your existing AGM batteries. WARNING: do not touch any of the positive cables to any metal part of your RV. Wrap the exposed ends in an insulator and/or tape if needed.

You will now have two cables you can completely remove from your battery compartment:
One with a positive colored tape on each end
One with a negative colored tape on each end

Store these away. You no longer need them.

Remove the existing AGM batteries.
Install the replacement LFP battery
Connect all remaining positive cables to the LFP's battery positive terminal. You may need a longer bolt for this.
Connect all remaining negative cables (probably only one) to the LFP's battery positive terminal.

USE/STORE to USE
Plug in to SP if desired.

Great instructions
My pictures

 

[Scubawise]

I had to cut my original bim out of its mounting place by sawing off one mounting lug.
Thor mounted the bim then installed the front cap over one of the bim screws.

I had to make one new hole for the new bim to mount and turn it all sideways.

Be prepared.

Pics are somewhere in my signature thread.

Getting prepared. The width of the 300 at 7.48 inches. I have 7.1 inch opening but 1 inch lips on both sides. Will double check.
May need to grind a little of see if I can push up from below steps

 

[ducksface]

My Bim now sits sideways so that it would fit behind the frame that Thor mounted for the cab front.

My new Fender Wells are showing(the shiny Kilmat in the picture).
See the mud on my bim?
Yeah, that's not going to happen again.

The extra red wire on the lower lug is the power for my light bar.
You won't have this wire.

 

[Scubawise]

My Bim now sits sideways so that it would fit behind the frame that Thor mounted for the cab front.

My new Fender Wells are showing(the shiny Kilmat in the picture)
See the mud on my bim?
Yeah, that's not going to happen again.

The extra red wire on the lower lug is the power for my light bar.
You won't have this wire.

Great saved pictures.
Will photo mine & wire LI 225 the same as the 160 thx

 

[Scubawise]

My current bim 160. Will follow exact wiring for the li bim 225

 

[dkoldman]

Getting prepared. The width of the 300 at 7.48 inches. I have 7.1 inch opening but 1 inch lips on both sides. Will double check.
May need to grind a little of see if I can push up from below steps

You might have greater issue with how deep? The new battery is 9.64 and that vMax tank may be a tad south of that when you account for the screws. I do think you will need a longer screw, if I had a knock with Newtipower that 16mm length for a screw is just to short. If you bought two it will be okay because you can share the post. I had plenty of roo so I just got a longer screw. You may check the vMax tank may be longer, I don't remember.

If it were not for the handles on both sides, I could easily drop two in existing battery compartment. I asked NewtiPower about cutting the handles off and they freaked out. Begged me not to and said they would void the warranty if I did. When it is out of warranty and if I ever want a 2nd 300ah I will take it out and cut handles. If no issues, I will by a 2nd one and cut the handles of it and screw the warranty. I have never bought a bad battery no matter how cheap or how expensive.

 

[dkoldman]

btw, now that I have portable 200watt solar panels and a 15amp Victron Controller, for play I keep both of my vMax tanks fully charged. I am still working on how I will use, but the point is you may wish to keep the vMax tanks,

 

[dkoldman]

Did you ever find a Tech in New Mexico like you have in Montana?

 

[Scubawise]

You might have greater issue with how deep? The new battery is 9.64 and that vMax tank may be a tad south of that when you account for the screws. I do think you will need a longer screw, if I had a knock with Newtipower that 16mm length for a screw is just to short. If you bought two it will be okay because you can share the post. I had plenty of roo so I just got a longer screw. You may check the vMax tank may be longer, I don't remember.

If it were not for the handles on both sides, I could easily drop two in existing battery compartment. I asked NewtiPower about cutting the handles off and they freaked out. Begged me not to and said they would void the warranty if I did. When it is out of warranty and if I ever want a 2nd 300ah I will take it out and cut handles. If no issues, I will by a 2nd one and cut the handles of it and screw the warranty. I have never bought a bad battery no matter how cheap or how expensive.

Yes. We measured 10 inches from base of existing batteries. Hopefully with posts/ screws under 10.

 

[Scubawise]

Did you ever find a Tech in New Mexico like you have in Montana?

There is a place I go to for oil & lube.
I thinks they work on rigs.
I have been self fixing based on you guys gals..

 

[Scubawise]

Did you ever find a Tech in New Mexico like you have in Montana?

If needed

 

[jawzilla]

You might have greater issue with how deep? The new battery is 9.64 and that vMax tank may be a tad south of that when you account for the screws. I do think you will need a longer screw, if I had a knock with Newtipower that 16mm length for a screw is just to short. If you bought two it will be okay because you can share the post. I had plenty of roo so I just got a longer screw. You may check the vMax tank may be longer, I don't remember.

If it were not for the handles on both sides, I could easily drop two in existing battery compartment. I asked NewtiPower about cutting the handles off and they freaked out. Begged me not to and said they would void the warranty if I did. When it is out of warranty and if I ever want a 2nd 300ah I will take it out and cut handles. If no issues, I will by a 2nd one and cut the handles of it and screw the warranty. I have never bought a bad battery no matter how cheap or how expensive.

Just did this on a ACE 29.4, (your swap looks a bit tighter) and you WILL need a longer screw. I happened to have a box of TV mounting screws with (lucky) me at the campground when I did the swap.

 

[dkoldman]

Just did this on a ACE 29.4, (your swap looks a bit tighter) and you WILL need a longer screw. I happened to have a box of TV mounting screws with (lucky) me at the campground when I did the swap.

I agree that the OP's space is tight and longer screws will likely be needed. I would buy 2 of the next size longer than the 16mm. I am advising the OP to simply go to ACE Hardware or the equivalent. On this forum I like to recommend ACE Hardware as you can't go wrong with ACE

With that said, I had to argue with some RV experts because they wanted me to add a block instead of a longer screws. I listened to them, but didn't do as they said.

FWIW, my setup from 2 AGM to one Lithium looks like the below. Excuse the dirt as I didn't get a chance to clean out the battery compartment.

If OP wishes to go for the gold, now is a good time to add the SmartShunt. I had no idea how much I would use that thing. I got really lucky going with the 50 amp Victron DC to DC over Renogy. Pay more, get more because I now have a small family of 3 Victron products, Orion XS 50 amp, 15 amp Solar Controller (Portable in my application) and the Smart Shunt.

It just nice to know you can go days and have the SOC on your phone tell you what time you will be down to 14%. You can easily plan around. I only have 56 lbs of batteries. Right now a 2nd 300ah Lithium is not even a nice to have, because if I can't run the ACs it has no real value for me.

Update:

It is worth noting that all of this was done as a DIYer step by step over a period of months as I learned what those things could do, especially the DC to DC. I think many get caught up thinking a DC to DC is only to protect their alternator from burning up, that may be true in a small number of cases, but some miss the real value of steady control of 50 amps max based on your preferred battery profile. It turns itself on/off automatically, and adjust the current as required. Works in tandem with my 45 amp Lithium profile converter when genny is running. If I am low around 83%, we can charge up fast.