question

It's output voltage is measured at the charger, so it's unaware of voltage drop.

1. Minimise voltage drop by using adequate cable sizes.
2. Voltage drop depends on and is proportional to current.
3. It's possible to increase the absorption voltage in the settings.However as the battery becomes more charged, current drops, so there's less voltage drop and an excessive increase in the absorption voltage will lead to overcharging.
4. If you don't increase the absorption voltage, as the battery becomes charged, current drops and there's less effect on charging due to voltage drop. Voltage drop will tend towards to the tail current at float voltage. Net result is that batteries will charge fully, given sufficient time.
5. I'd look at the numbers, taking into account how much time you will be driving. I've a similar situation, but in a campervan with a 5M run at 24V. It charges fine, but never gets the battery up to 100%. And that's with a 2M run in heavy cable to the Orion.

Hi Kev,

Thanks for the reply.

1. Agree
2. Agree
3. Good point. Will need to measure at the battery point to determine correct charge voltage during a bulk phase. Would a BMS system monitor & prevent this?

4. Good point
5. You have just given me an idea. I may put the electrical system in the vehicle to reduce cable run. This may allow the system to also be portable.

Cheers!

I suggest you to use solarpanels for better charging.

If you use a SmartSolar MPPT 75/15, you can add for example three (better use three panels in series as one big one because even if it is cloudy you get a much higher output) 150Wp solarpanels in series (roughly 54Vmpp of 66Voc) and can perfectly charge your 24V battery.

Hi Michelle,

Thanks for the reply.

Due to size & weight restrictions I have opted for a single residential panel with NMOT 56Voc & 48Vmpp. The intention is to couple this to a 120/45 MPPT. This will allow more solar capability if needed down the track & series parallel setup if required.

Cheers!

The SmartSolar MPPT 150/45 can handle 620W @12V or 1240W @24V and is in my opinion completely overkill and expensive

Since you write about the Orion-Tr 12/24V-15A 360W I would suggest you simply the SmartSolar MPPT 75/15 (realy inexpensive) for the single solarpanel and IF you want to add solarpanels later, add another one.

Why?

Since you have a weight and size restriction (and probably installed flat), adding later more panels to the existing one can lead to non-desirable effects do to the different orientations.

Hence if you want to use later 2-3 mobile Solarpanels on a shelf with a tracker for example (I do this with 3x100W panels) it is better, to have another SmartSolar (I use a SmartSolar MPPT 75/15 in addition to the 2x 200W on the roof which use a SmartSolar MPPT 100/20 du to the high Voc of 73V)

Thanks Michelle. I do like this idea. I will have a dedicated MPPT 75/15 for vehicle solar & sperate MPPT for 2 parallel panels 100/30. The 30 is just in case I want to parallel 3 panels at any stage, making the vehicle solar panel lockable/removable.