Multiple charging sources

[markcouz]

A couple of notes...

There is nothing wrong with your basic layout according to your diagram in post #1, no need to change anything there.

There is no problem having multiple chargers with similar settings charging the same bank (although it can be done better with networked chargers as with Victron Smart Network)

Your voltages given in post #1 describe an alternater system that is working correctly;
13.92V at start battery indicates ALT charging correctly,
13.76V at DC2DC input indicates volt drop (from 13.92) due to current flow as expected,
13.36V at DC2DC output and 13.25V at LFP bank similarly due to volt drop as a result of current flow.

The 13.25 volts at the LFP bank is because the bank was at a low state of charge, with LFP this will rise VERY slowly until voltage measured gets to about 13.6V - at which point voltage will rise quickly to your setting of 14.2V.

The low V seen at the output of DC2DC is because your charger controls V output in order to limit current flow to the set value - the best way to check for correct operation would be the use of a DC clamp meter at the DC2DC outut to confirm that the current flow is as expected.

Note that while motoring your DC2DC output will supply DC loads first, with any available excess going towards charging the battery - this can often be less than expected with autopilot/instruments/VHF/AIS/Radar etc all possibly running.

[marciaanddave]

So I think my main charging issue is that I am only able to use the renogy dc/dc charger in the 20 amp mode instead of the 40 amp. When I run the engine with the 40 amp setting on the charger, I get negative amps on the victron battery monitor. When I change it to the 20amp setting I get positive amps going into the lithium. When on shore power the 40 amp setting works as it should.

[markcouz]

Originally Posted by marciaanddave

So I think my main charging issue is that I am only able to use the renogy dc/dc charger in the 20 amp mode instead of the 40 amp. When I run the engine with the 40 amp setting on the charger, I get negative amps on the victron battery monitor. When I change it to the 20amp setting I get positive amps going into the lithium. When on shore power the 40 amp setting works as it should.

Sounds weird, the only explanation that I can think of is that the alternater is unable to satisfy the input requirements of the DC2DC in 40amp mode.

So the DC2DC waits for the input voltage to reach a set value before switching on, when that value is reached the DC2DC starts sending 40amps momentarily, causing input voltage to drop below switch off voltage and DC2DC shuts off - rinse and repeat...

When in 20amp mode the alternator is able to maintain "switch on" voltage and so works as expected, same for 40amp mode when using shore power.

If you are able to program the "switch on/switch off" voltages on your DC2DC then try more forgiving values and see if that solves the issue.

[marciaanddave]

That makes sense to me. When I get back to the states I will pull the starter battery out and have it checked.

[plittle2005]

Originally Posted by markcouz

Sounds weird, the only explanation that I can think of is that the alternater is unable to satisfy the input requirements of the DC2DC in 40amp mode.

So the DC2DC waits for the input voltage to reach a set value before switching on, when that value is reached the DC2DC starts sending 40amps momentarily, causing input voltage to drop below switch off voltage and DC2DC shuts off - rinse and repeat...

When in 20amp mode the alternator is able to maintain "switch on" voltage and so works as expected, same for 40amp mode when using shore power.

If you are able to program the "switch on/switch off" voltages on your DC2DC then try more forgiving values and see if that solves the issue.

Should there not be diodes (low voltage drop) in each charging current source line? Is any back-feeding possible?

Also, it seems that when the wind isn't blowing (wind gen's are very inefficient) and the sun isn't shining .....all you've got is 40A max from a FLA source...?

[flightlead404]

Originally Posted by brazenarticle

The Victron Dc to DC charger manual mentions "When the engine shutdown detection has been switched off in Victron Connect (‘forced charging’) current will be drawn from the starter battery even if the engine is not running."

I just installed a Victron Orion Tr Smart. I disabled the auto engine shutdown detection, but I connected the L pin to the +12v engine switch so that it goes high when the key is in the RUN position. Only a short test at the dock but appears to work perfectly with no parasitic draw or “back flow” (not sure how that would even happen with a dc-dc charger).

[ClarkeB]

The way you have set your charging up from what I understand is:-
You are charging your acid batteries 1st and when (alternator) reaches the float stage it drops the charge to trickle hence the house batterries(Lithium) only gets the trickle and everything running off your house batteries.
Send all your charging (Incoming) devices to one buzz bar (All charging in, solar, alternator, wind, AC charger)then to your Lithium batteries then to your outgoing buzz bar, everything that uses power here) your DC/DC charger (Outgoing buzz bar)to your start batteries. This then charges the house batteries first and while it is above the 12.5v the DC/DC charger is almost always feeding your start batteries.
Otherwise a switch to manually charge either start or house batteries, not ideal,
Good luck and don't loose heart.

[flightlead404]

Originally Posted by ClarkeB

The way you have set your charging up from what I understand is:-
You are charging your acid batteries 1st and when (alternator) reaches the float stage it drops the charge to trickle hence the house batterries(Lithium) only gets the trickle and everything running off your house batteries.
Send all your charging (Incoming) devices to one buzz bar (All charging in, solar, alternator, wind, AC charger)then to your Lithium batteries then to your outgoing buzz bar, everything that uses power here) your DC/DC charger (Outgoing buzz bar)to your start batteries. This then charges the house batteries first and while it is above the 12.5v the DC/DC charger is almost always feeding your start batteries.
Otherwise a switch to manually charge either start or house batteries, not ideal,
Good luck and don't loose heart.

No that’s not the way it works. Your 1st para is incorrect. Typed a lengthy reply which was lost. I may try to retype it tomorrow lol but no, doesn’t wait for start battery to get to float

[marciaanddave]

Yes the way I have it set up is to charge my FLA from the alternator and the house lithium from solar and wind. The alternator must go through the dc/dc to get to the lithium. My rationale was the older balmar regulator didn’t have a lithium profile, nor did my shore power iota battery charger. So this “saved” me from having to buy a new regulator and charger. But I think the best option is to bite the bullet and buy the regulator… send alternator to the lithium then through the dc/dc to the FLA. I guess that means I will need a separate shore power charger for the lithium?

[markcouz]

Originally Posted by marciaanddave

Yes the way I have it set up is to charge my FLA from the alternator and the house lithium from solar and wind. The alternator must go through the dc/dc to get to the lithium. My rationale was the older balmar regulator didn’t have a lithium profile, nor did my shore power iota battery charger. So this “saved” me from having to buy a new regulator and charger. But I think the best option is to bite the bullet and buy the regulator… send alternator to the lithium then through the dc/dc to the FLA. I guess that means I will need a separate shore power charger for the lithium?

There is nothing wrong with the way you are set up - you need to investigate why the DC2DC is shutting off on 40amp setting.

From post#1 you had 0.2v drop between FLA and DC2DC on 20amp setting, so you will have 0.4v on 40amp setting which may be enough to drop below "switch off" setting of DC2DC - i dont know your equipment but there may be a way to address this;

1. change [switch on/switch off] voltages if programmable,
2. use alternative method to control [switch on] if available (relay?),
3. increase cable size between FLA and DC2DC in order to improve volt drop at 40amp setting.

If all else fails then either accept the 20amp charge rate or start throwing boat bucks at the problem.

[rgleason]

"My rationale was the older balmar regulator didn’t have a lithium profile, nor did my shore power iota battery charger. So this “saved” me from having to buy a new regulator and charger"

You can set your own profile to lfp batts even with the acr5 reg. You should have batt and alt temp sensors I think. Program no float for sure.

[flightlead404]

You still want the dc2dc charger to prevent alternator damage in the event of a bms “load dump”. The dc2dc should be sized and half the alternator max rated output

[marciaanddave]

We decided to make the following changes: balmar alternator with new regulator temperature sensor and protection module, all charging sources will feed the lithium bank. Dc2dc will charge the FLA starter battery. I’m working on programming the voltage regulator now and was advised to throttle the alternator back so it doesn’t work at full capacity.

[pushstudios]

That sounds right. Do you have a diagram or schematic for the way you have it set up now?

I'm just about to start on the same exact project.

[Maine Sail]

This article may help:

https://marinehowto.com/drop-in-lifepo4-be-an-educated-consumer/

IME Renogy is a despicable company to deal with and the products are very hit or miss reliability wise. They quickly became the #1 failure prone brand we saw in the marine market within 2 years of them hitting the market BACK IN 2011 or 2012, solar panel fires, solar controller fires, failed inverters, failed solar controllers, solar panels that did not even come close to meeting spec batteries that were sold 30% below rated capacity, broken studs on DC TO DC chargers etc..even all that would not be horrible but the way they handle customer service & warranties (they don’t) is what pushes them into the despicable category. we used to install customer sourced products. Renogy ruined that and forced us to stop installing customer suppled anything. Oh and I don’t recall a single customer who was reimbursed or got warranty satisfaction..