2xLiFePo4 under driver/passenger seat in a T6.1 Ocean 2023 with tow-bar

[jmstockholm]

Purchasing the wattcycle 100Ah underseat batteries and when delivered discovered that they are about 25 mm to long to fit into the original AGM battery holders. I (1) hade to skip the rear battery compartment and install the second battery under the drivers seat (2) cut out space for the driver seat holder with an angle grinder. Well, not all bad as to have both batteries in the front will place them in somewhat equal temperature, which would not have been the case at the warderobe battery which is considerably colder when out in like -20 C. And as these batteries don't have self heaters, it's also beneficial having them in front to be heated up from the front cabin's heaters. The dc/dc charger is also placed under the drivers seat with a +5C cut-off point, and the batteries taking charge down to 0C I hink it will work out fint. The first I had to do was to cut out the battery holder to fit the battery. White paint is rust protection. I just cut the left side to place the battery slightly to the left to leave space for the dcdc charger to the right. You then have to bend the front lip a bit forward on the left side to have it fit as there is a "heal" in the left forward corner that will lift the battery. This will create another issue with the + pole getting to close to the seat rails. I have seen another forum member drilling out the spot welds, then you could grind of the "heal" as well - I think that might be a good idea. Or you could place the dcdc in another spot and place the battery in center avoiding the +pole interference with the seat sliders. 

 

 

For the passenger's seat I purchased the Kiravans VW Transporter T5 to T6.1 (2003-2024) Battery Bracket, that works nicely. I moved the hitch components to the side and made a bracket for the larger component, cut down the fuse holder and mounted it on a bracket as can be seen here. 

 

A pole fuse would have been better, but it was delayed and I had a Mega fuseholder laying around so I mounted it here and put in a 125 A fuse.

 

 

Mounted the Victron Orion XP 12/12 50A and a plus pole terminal.  

 

 

 

 

Bearbeitet vor 1 Stunde von jmstockholm
Van model included

[jmstockholm]

Mounted the fuse holder in place of the former charge relay. You can identify the cable leading to the battery and the cable coming from the floor i.e. from the generator. They will be the input (generator) and output (battery) on the Victron dcdc sharger. The black contact can just be disconnected and put away. the dcdc charger will operate on a threshold voltage from the generator.

 

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The Victron Smart Shunt 300 A was mounted on a aluminium plate at the bottom with a whole for the seat base bolt to keep it in place (same was done for the L bracket in the passenger seat).

 

 

The new +terminal will collect the dcdc Input, the existing cable coming directly from the generator that was connected to the charger relay before and the aux voltage sensor cable on the smart shunt which then will display the starter battery voltage which is handy.  

 

The fuse block has an 80A fuse (at the bottom in the picture) on the incoming + from the driver seat battery and the incoming cable from the + from the passenger seat is connected directly to the busbar at the bottom of the picture (fused with 125A under the passengers seat as shown before). From the bus bar the dcdc charger's output is connected with a 60A Midi fuse (the blue ones in the pictur) ad the the old cable leading to the warderobe battery is also connecte with a 60A fuse as I want to use it to power electronics at the back warderobe (and potentially incoming future solar if needed). 

 

[wunderwuzi]

Tnx for your effort , but PLEASE put / use a few more paragraphs and spaces

 

Especially your 1st posting is almost unreadable and is probably causing eye cancer 🧐

Bearbeitet vor 1 Stunde von wunderwuzi

[jmstockholm]

Connecting the AGM charger. The empty space is the place for the 30A  incoming fuse from the AGM charger, identify which is the outgoing cable from the fuse holder, cut it and extend it and connect it to the + terminal (together with the incoming generator cable, the input to the dcdc charger etc.). This will then first charge the starter battery, and when reaching the threashold voltage in the dcdc charger, start charging the lithium battery bank. 

 

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[jmstockholm]

I pulled two 35 mm2 cable between the batteries and connected them in parallell this way. This will create unequal cable lengths that the batteris sees at load creating a certain unequal discharge /charge pattern du to differences in voltage drops - thus the battery with the longer cables will discharge / charge less then the battery with shorter cables. However, this become material att high current loads, say over 100 amps, at lower loads - say 20-50 amps discharge /charge - the voltage drop is so small that it wont affect the batteries much at all. The proper way to do it is to pull three cables and have the load comping from the + on one battery and - on the other - this will create equal cable lengths. So an alternative is to use eg. 16 mm2 and pull three cables, as 3x35mm2 did not fit din my van. So I chose the 2x35 mm2 for simplicity and it would actually allow me to occasionally draw some 200 amps load in the future if I would see the need. 

 

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Carefully tuck the calbe under the batteries when mounting!

 

[jmstockholm]

I pulled two 35 mm2 cable between the batteries and connected them in parallell this way. This will create unequal cable lengths that the batteris sees at load creating a certain unequal discharge /charge pattern du to differences in voltage drops - thus the battery with the longer cables will discharge / charge less then the battery with shorter cables. However, this become material att high current loads, say over 100 amps, at lower loads - say 20-50 amps discharge /charge - the voltage drop is so small that it wont affect the batteries much at all. The proper way to do it is to pull three cables and have the load comping from the + on one battery and - on the other - this will create equal cable lengths. So an alternative is to use eg. 16 mm2 and pull three cables, as 3x35mm2 did not fit din my van. So I chose the 2x35 mm2 for simplicity and it would actually allow me to occasionally draw some 200 amps load in the future if I would see the need. 

 

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Carefully tuck the calbe under the batteries when mounting!

 

[jmstockholm]

Some tricky contacts, this airbag contact needs to have the black tab pulled backwards and the pushed at the back to release the locking pigs, can be tricky to get them to release.

 

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This guy under the passenger seat has to be released with a screw driver pushing up the lock on the female with the seat tilted to the back (i.e. not tilted to the front as normal)

 

 

 

 

[jmstockholm]

Some other pointers:

- Be very very careful when crimping. Use high quality cable lugs and a proper crimping tool as well as carefully controlling that the cable and the cable lugs are the proper combination. As a reference I spent EUR 100 on cable lugs in this installation.

- The issue with the +pole on the driver side, forced me to dismount the original polecontact/fuse holder and connect the battery to the new fuse holder. Luckily there where just enough (two) spare midifuse holders (have no photos for this). You can either be fine with the 80A Maxifuse in the fuse holder or install a pole fuse if you want the short cable from the battery to the fuseholder to also be protected.
- Charge the AGM batteries full, then disconnect the battery sensors (and the batteris obviously). This will lock the CU to 100% charge and you have to monitor the state of charge through the shunt/ Victron app or the batteries bluetooth / app.

-I sure have forgotten a lot of things, but most of them are probably self evidents if you are thinking about doing this installation yourself.

[jmstockholm]

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Ah, to late, I gave it a try but it's locked...