VSR or DCDC Charger - Which should I use?

[coopec43]

In my previous thread on using the solar panels to charge the House Bank or Starting bank I was confused when people suggested I use a DCDC Charger.

I did further research and came up with excellent article which others may find helpful explaining when to use either VSR or DCDC Charger.

https://offroadliving.com.au/blogs/1...rge-my-battery

[goboatingnow]

Originally Posted by coopec43

In my previous thread on using the solar panels to charge the House Bank or Starting bank I was confused when people suggested I use a DCDC Charger.

I did further research and came up with excellent article which others may find helpful explaining when to use either VSR or DCDC Charger.

https://offroadliving.com.au/blogs/1...rge-my-battery

I just use a diode splitter. Works perfectly

[coopec43]

Originally Posted by goboatingnow

I just use a diode splitter. Works perfectly

Now you've really got me confused. Geeez!

[goboatingnow]

Originally Posted by coopec43

Now you've really got me confused. Geeez!

My solar output goes to a conventional diode splitter the output gird to the two battery banks. The solar is using battery terminal voltage sensing anyways

[CaptainRivet]

Originally Posted by goboatingnow

My solar output goes to a conventional diode splitter the output gird to the two battery banks. The solar is using battery terminal voltage sensing anyways

only works if your output voltage of the solar is in the range of your batteries

[CaptainRivet]

Originally Posted by coopec43

In my previous thread on using the solar panels to charge the House Bank or Starting bank I was confused when people suggested I use a DCDC Charger.

I did further research and came up with excellent article which others may find helpful explaining when to use either VSR or DCDC Charger.

https://offroadliving.com.au/blogs/1...rge-my-battery

Never use a VSR on a boat, as simple as that.

Multiple lead, even different chemistries banks use a spliting diode, Victron ArgoFet at best because voltage drop is very low.

For solar panels always use a MPPT, as this gets most AH out of your solar panels. 12V or 24V panels have a very bad efficency per sqm surface and as surface is a very big premium on every sailboat use the highest efficency panel you can fit. And that means bificial ones that mostly run above 35V, means you need a MPPT.

A DCtoDC charger you only need with a LFP bank in combination with a lead starter to limit the current of your alternator not to fry it by heat or when the BMS shuts the charge off. Alternativly you charge your LFP directly with the alternator that can be externally regulted and then your lead starter via DC to DC charger from the LFP.

[CaptainRivet]

Originally Posted by coopec43

Now you've really got me confused. Geeez!

goboatingnow often has a bit special/not common solutions that work well if you really know what you are doing (he does) and have a special setup.


Most boaters using an MPPT charger to charge your bank from solar.
If you have more then one bank, use a splitting diode (eg Victron ArgoFet) to split the charge from whatever charge source (MPPT, Alternator...) between the banks starter and house (and bowtruster), never ever a VSR on a boat.

Reason is the VSR let current flow between the connected banks what you don't want. The starter must be always full and is only trickle charged in 98% of the time, (same a bowtruster bank), while your house normally cycles much deeper means using a VSR current would flow from the fully charged starter into the low SOC house what you don't want.

A splitting diode prevents that as it isolates the banks (one or more batteries for the same purpose) from each other and only let current flow in but never out/between the banks.


DCtoDC see above.

[Wotname]

Originally Posted by CaptainRivet

....
Most boaters using an MPPT charger to charge your bank from solar.
If you have more then one bank, use a splitting diode (eg Victron ArgoFet) to split the charge from whatever charge source (MPPT, Alternator...) between the banks starter and house (and bowtruster), never a VSR on a boat.

Do you have a reason for this bit of peculiar advice?

[s/v Jedi]

Coopec, do you have the same chemistry for both battery banks? If so, then this product works great: https://www.victronenergy.com/upload...e-input-EN.pdf

[coopec43]

Originally Posted by s/v Jedi

Coopec, do you have the same chemistry for both battery banks? If so, then this product works great: https://www.victronenergy.com/upload...e-input-EN.pdf

Yes all batteries (Starting/House) a Century AGM.


Very interesting. Thanks for that

[Uncle Bob]

Originally Posted by Wotname

Do you have a reason for this bit of peculiar advice?

Wottie, surely a man of your experience would know that the words of wisdom handed down from a captain should at all times be heeded.

[Wotname]

Originally Posted by s/v Jedi

Coopec, do you have the same chemistry for both battery banks? If so, then this product works great: https://www.victronenergy.com/upload...e-input-EN.pdf

That is a reasonable approach but it would entail Coops buying additional equipment. Coops earlier advised he already has a suitable VSR (Victron Cyrix) along with the solar panels and MPPT controller.

My guess is that he wasn't aware that he already had the right stuff when he opened this thread.

[Wotname]

Originally Posted by Uncle Bob

Wottie, surely a man of your experience would know that the words of wisdom handed down from a captain should at all times be heeded.

Oh dear - my bad. As you know, in Oz, we tend to take advice from Uncles (and particularly, Aunts) so I should heed your words...

[RaymondR]

Single direction VSRs are available.

Diodes generally have a 0.6 volt voltage drop.

[coopec43]

Originally Posted by Wotname

That is a reasonable approach but it would entail Coops buying additional equipment. Coops earlier advised he already has a suitable VSR (Victron Cyrix) along with the solar panels and MPPT controller.

My guess is that he wasn't aware that he already had the right stuff when he opened this thread.

That is correct: I wasn't aware I had everything I needed.

I can't wait to sit down and study what you guys are saying but that will have to wait until I get the deck hatches finished before the hot summer weather sets in. (Hopefully I can start looking at the electrical set-up next week)