FB - move batteries to rear of trailer

[Brav]

Ohio - after moving the batteries under the fridge - where did you mount the converter/charger? I am considering doing the same, but I will also have solar.. so trying to decide where to drop my solar power wire in.. front curb side in closet or street side for the fridge area.

[Ohiobrits]

Brav,

The main converter/charger as supplied with your AS (the one that charges your battery when on AC power) should remain where it is. For me that was under the sliding storage units on the curb side of the AS adjacent to the range.

I mounted the solar charge controller in the closet on a panel (with my cellular router). Pic below. This is essentially "dead" space in the closet so a good spot to use. Shown in the photo is the BlueSky unit I used before I changed to all Victron. The Victron BlueSolar is in this location also.

The wires from the solar panels come into the top of the closet on the left at the front (not shown in photo), under the bottom shelf and up into the charger controller. A local disconnect switch is used to isolate the solar cells on the positive leg from the panels. You can see that in the photo just to the left of the charge controller. The fridge and batteries are just to the left in the photo.

You should connect direct to the battery with the output from the solar charge controller ensuring there is a suitably rated fuse/breaker on the positive leg as close to the battery as possible.

[Ohiobrits]

Pictures of one of the solar panels and JB. I bought all my gear from AM Solar - GREAT company to deal with.

I mounted the junction box they sell close to the fridge vent. The 4 ga wire comes into the AS directly out of the bottom of that box. Since this picture I added 2 more panels.

[Brav]

Originally Posted by Ohiobrits

Brav,

The main converter/charger as supplied with your AS (the one that charges your battery when on AC power) should remain where it is. For me that was under the sliding storage units on the curb side of the AS adjacent to the range.

I mounted the solar charge controller in the closet on a panel (with my cellular router). Pic below. This is essentially "dead" space in the closet so a good spot to use. Shown in the photo is the BlueSky unit I used before I changed to all Victron. The Victron BlueSolar is in this location also.

The wires from the solar panels come into the top of the closet on the left at the front (not shown in photo), under the bottom shelf and up into the charger controller. A local disconnect switch is used to isolate the solar cells on the positive leg from the panels. You can see that in the photo just to the left of the charge controller. The fridge and batteries are just to the left in the photo.

You should connect direct to the battery with the output from the solar charge controller ensuring there is a suitably rated fuse/breaker on the positive leg as close to the battery as possible.

Perfect, thank you... good idea for solar controller. I also am going with all Victron components, and also from AM Solar.

I have a 25FB so my charger/converter (now a PD4655 multi stage) is under the aft side of the front bed.. so wiring becomes a mess unless I mount on the curb side of the trailer. Not sure how I can relocate the batteries away from the bed without also moving the charger/converter.

I was trying to do all of my upgrades in stages, which is proving to be quite difficult, if I dont want to continually re-wire. Stage 1 is 400 watt solar implementation (wiring and controller to accommodate 600+). Stage 2 is relocate and upgrade batteries (hopefully to Lithiums) as well as the Victron inverter/charger. Stage 3 would be to add capacity to both batteries and solar array.

PS - How do you like the Color Control? no Victron MPPT? I plan on going with bluetooth and using iPad

[lewster]

Originally Posted by Brav

Perfect, thank you... good idea for solar controller. I also am going with all Victron components, and also from AM Solar.

I have a 25FB so my charger/converter (now a PD4655 multi stage) is under the aft side of the front bed.. so wiring becomes a mess unless I mount on the curb side of the trailer. Not sure how I can relocate the batteries away from the bed without also moving the charger/converter.

I was trying to do all of my upgrades in stages, which is proving to be quite difficult, if I dont want to continually re-wire. Stage 1 is 400 watt solar implementation (wiring and controller to accommodate 600+). Stage 2 is relocate and upgrade batteries (hopefully to Lithiums) as well as the Victron inverter/charger. Stage 3 would be to add capacity to both batteries and solar array.

PS - How do you like the Color Control? no Victron MPPT? I plan on going with bluetooth and using iPad

No Need for the MPPT Control when using the Color Control Monitor. You WILL need the BMV- 702 battery monitor though and the Digital Multi Control 200/200A if you intend to use the MultiPlus inverter/chargers.

[Ohiobrits]

The Color Control is AMAZING.

Its expensive but adds a ton of functionality: -

• If your AS has internet access you can view status of all connected Victron systems via the internet. Data logging, email alarms the whole deal. Amazing stuff.
• You can change settings (using VEConfigure) on the MultiPlus over the internet - no hardwire connection required. I do this over WiFi sitting in the AS with my laptop. Firmware updates must however be done via a hardwire connection.
• The screen is excellent - great active visual display of current flow, power etc.
• You can adjust basic settings on the MultiPlus (switch to On/Off/Charge only, set max input current setting etc).

I do have a Victron MPPT (Blue Solar 150/70) works very well. I have seen 600W a few times which is my system rating. I run my solar cells wired 2 in series then 3 in parallel for 48V. I do not use the BlueTooth feature since I use the VEDirect port to connect to the Color Control and then view on the screen or remotely via the internet. Looks like Victron now has some MPPT units with built in BlueTooth so the VEDirect port would still be available for connection to the Color Control.

I have a Victron MultiPlus Inverter/Charger - the 3000VA unit which has now replaced my AS charger and 1000W AS inverter. I have this installed at the rear in the storage cabinet under the dinette. It weights about 50lbs. A lot less than the 120 lbs of AGM's I had back there for a while (see earlier posts). This should be installed as close to the batteries as possible. Probably a bit further away than i'd like but works well. Victron seems less concerned about cable distance then Magnum.

My battery uses CALB CAM 72 AHr cells (x48, 864 AHr) and is mounted on the underside of the AS just rear of the rear axle using a custom aluminum hanger I fabricated. There is some reinforcement of the floor cross members required and a cover to fabricate from aluminum sheet to protect the batteries from the weather. The compartment is heated via the furnace for below zero use/charging. It is much cooler for the batteries down here in the summer since they are not inside the coach which can reach +105F when in storage with no A/C. Cooler storage temps will prolong life. This unit weights just over 200lbs with bus bars. Incredibly light for the AHr capacity. I can run the AC for about 4 hrs straight with this setup with a bit of solar assist. Small DC and AC loads (TV's etc) can be supported for several days even with minimal solar assist.

For your setup, for now, there is no issue leaving your AS charger under your bed. My original setup with AGM's under the fridge was about 2x your cable run from battery to charger since my charger was amidships on the opposite side to the fridge. Cable from the battery ran from the fridge all the way to the front and then back to the middle of the AS to the charger. Use 2ga wire from the battery back to the charger and you will be just fine.

If/when you install an inverter, it is important to have your inverter as close to the battery as possible to limit losses. You might be pulling 300 Amps or more. This is a lot different to the 50A or so the charger is putting out. The charger derives its power from your AC shore connection - a bit of losses is insignificant here when you have a 30A x 110V incomer as the power source.

If you have any more questions I'd be glad to help out. I just spent the best part of 6 months doing my upgrades. I also did it in stages.

• AGM batteries in the rear to reduce tongue weight
• AGM's moved under the fridge due to weight concerns (see earlier posts)
• 400W solar first - but wired for 600W
• Victron Multiplus install (still using AGMs), Color Control, BMV 702 and Blue Solar MPPT. I did most of the wiring for Lithium batteries (contractors etc) at this point.
• Lithium batteries and BMS last - this was the most problematic and time consuming not least because of the battery installation location under the AS. That is a PITA to do....

Even if you plan this out you will get good at making up cables, using heat shrink and applying crimp connectors because you WILL rewire this thing several times before you are done....

[GenXair]

Hi Ohiobrits,

I just finished reading your amazing journey in reducing the tongue weight and have a few questions.

Did you remove the original battery cables or used them to connect the new wires? Do you have a photo of this?

Why did you downgrade the 12v batteries to 6v?
12V are also lighter 56lbs
6V 66lbs

[rmkrum]

Many of us have upgraded to a slightly larger and taller battery box so we can install two golf cart 6 volt batteries in series.

Gets same voltage with increased capacity. It's not a downgrade.

Paralleling 12 volt batteries is another way to get more capacity, but IMHO is touchy if the batteries don't match exactly.


Sent from my pocket Internet using Airstream Forums

[Ohiobrits]

Originally Posted by GenXair

Hi Ohiobrits,

I just finished reading your amazing journey in reducing the tongue weight and have a few questions.

Did you remove the original battery cables or used them to connect the new wires? Do you have a photo of this?

Why did you downgrade the 12v batteries to 6v?
12V are also lighter 56lbs
6V 66lbs

GenXair, the cables from the factory battery box run up through the floor into the front storage locker (on an FB, I assume this is similar for other varients) and terminate on a positive and negative bus bar in this area. The wires to the batteries could be left connected and in place so long as you disconnect the positive from the bus bar so it is not live. I opted to remove them. You will need to extend the positive supply wire from the tongue jack back to the positive bus bar in the front storage locker since this is normally connected directly to the battery. Removing the batteries frees up the battery box for other uses....I now store my Anderson levelers, some pads for the stabilizer jacks, a wrench for my ProPride and can of spray lubricant in there.

On reuse of the battery cables - When you have relocated the batteries you will need to run suitably sized positive and negative cables from the batteries back to the same bus bars to power the coach. Since you will want to use larger wire gauge for this and since the cable runs will be much longer you will want to use new cables. I used 2ga, the original cables were 4ga I believe. Make sure you add a breaker on the positive wire close to the battery to protect the cables in the event of a short.

On the reason for 6V v 12V batteries - Connecting 2 x 6V batteries in series gives you a 12V battery with the same AHr as a single 6V battery (2 x 200 AHr 6V batteries in series = a 12V 200AHr battery). In contrast, 2 x 12V batteries connected in parallel gives you a 12V battery with the sum of the AHrs (2 x 100 AHr 12V batteries in parallel = a 12V 200 AHr battery). The batteries appear to be equivalent but the 6V units will have slightly thicker plates and will in general be more able to handle abuse / heavy discharges than the 12V solution. A battery made of 2 x 6V units is therefore seen as an upgrade although differences are likely not noticeable to the average camper.

Attached is a photo in the front storage locker. The white circle is the negative bus bar, red is the positive bus bar and purple (hard to see) is where the cables come up through the floor from the battery box. The silver box you can see mounted on the side wall is the factory 1000W inverter, the black box is the 7 pin junction box (cable to hookup to your TV terminates here). You can also see the "store/use" solenoid which isolates most of the coach 12V users when in store mode.

[GenXair]

Thanks for the battery info rmkrum.

And thank you Ohiobrits for answering my questions.

I'm planning to make these mods sometime during the fall, after our October trip, and I'm sure I'll have more questions as I get ready for it.

Thanks again.

[BoldAdventure]

Originally Posted by Ohiobrits

My battery uses CALB CAM 72 AHr cells (x48, 864 AHr)

Do you really have forty-eight individual cells? Basically twelve 12v banks?

My sixteen cells weigh 110lbs. Impressed your forty-eight only weighs 200lbs. Wonder if that is the difference between my 100aH cells and your 72aH cells.

[Ohiobrits]

Originally Posted by BoldAdventure

Do you really have forty-eight individual cells? Basically twelve 12v banks?

My sixteen cells weigh 110lbs. Impressed your forty-eight only weighs 200lbs. Wonder if that is the difference between my 100aH cells and your 72aH cells.

Yep. They are arranged as 4 sets of 12 cells (3.2V/864 AHr) connected in series to produce a 12.8V/864 AHr battery - 12P, 4S.

The BMS monitors the four 3.2V, 12 cell batteries and balances them relative to each other. Since the 12 cells in each of these 3.2V batteries are connected in parallel, the individual cells will self balance across the bus bars.

To ensure an individual cell failure is detected, the BMS monitors each 12 cell battery against baseline values such as resistance and other parameters and will give a fault if one of the 12 cell batteries is starting to drift (a cell failure, buss bar loose etc). This is flagged as a "Weak cell" error. You would then need to the inspect the individual cells in the "weak" battery to see where the fault is. This should ensure an individual cell failure will not damage the other 11 cells in a 3.2V battery without some warning.

Relative to weight, the 3.2V cells weigh 4.2lbs each so just over 200lbs for the batteries alone. The hanger is constructed from Aluminum and engineered carefully to minimize thickness and section sizes. Just checked my notes and half of my battery fully assembled with supports and buss bar was 107lbs so 214lbs for everything. The battery is split into 2 sections to ease handling under the AS and the 2 blocks connected with solid copper bus bars. Positioning using a trolley jack is mandatory. No way you would want to even try this with muscle power alone

As you say, this is ridiculously light for the AHr (0.233 lbs/AHr - battery only). This was the lightest I found (but not the cheapest). That honor rests with the CALB CA100 - these are however quite a bit heavier and more bulky at 0.3 lbs/AHr. Weight and compactness (given my installation location and # of cells required) closely followed by cost were my main drivers for battery selection.