148 replies to this topic

[BerkeleyCarlos]

I wouldn’t be adding any new equipment, so beer money is safe.

[pawleyk]

Sounds good. Report back and let us know how it works!

[pawleyk]

I do have 210w of solar to my Victron MPPT. It gets a decent amount of sun. I should unplug from shore power and see how many
Watt Hours it is pulling in during the day.

I am still running the stock 90ah AGM, but going with LifePo4 soon(ish). I think I need to move the DC2DC closer to the battery , getting different charge status from the MPPT and DC2DC while running both. MPPT , which is 6” from the battery , 8g wire . DC2DC is 10-12’ of stock 10g wire to the battery.

The MPPT tells me I am in “Float” , the DC2DC will show bulk,absorb and then float after driving for 45 mins.

 

The biggest issue is the stock 10awg. Just install the correct sized wire for 30amps at that distance. And make sure they're programmed the same.

 

Otherwise, don't worry about it too much. As long as the battery is charged, your beer will be cold.

[Vic Harder]

The fattest wire that will fit in your DCDC chargers is 6 AWG.  At 12', your voltage drop is less than 3% which is acceptable.  Of course, moving your converter to be closer to the battery would be ideal.

[IDPaddler]

Hello

first, thanks to KP for the great thread! Rather than start a new thread I'll just ask here...

 

I installed a Renogy 12v 50A dcdc this weekend. I ran 4 gauge wire for the whole system. All the lights came on properly. I selected the correct battery (single 12v AGM, 90ah). Attached the small wire to "override" the Smart alternator. I am using a Victron smart shunt and only seeing ~9ah being pulled while driving when battery is at 92%. This doesn't sound right. Any thoughts? Does the battery need to be drained further in order to pull higher current?

Thanks

[pawleyk]

Hello

first, thanks to KP for the great thread! Rather than start a new thread I'll just ask here...

 

I installed a Renogy 12v 50A dcdc this weekend. I ran 4 gauge wire for the whole system. All the lights came on properly. I selected the correct battery (single 12v AGM, 90ah). Attached the small wire to "override" the Smart alternator. I am using a Victron smart shunt and only seeing ~9ah being pulled while driving when battery is at 92%. This doesn't sound right. Any thoughts? Does the battery need to be drained further in order to pull higher current?

Thanks

 

I the battery is truly at 92% that sounds like it totally could be right. Charging will taper off near full into an absorption state (higher voltage/lower amperage) to top the battery off completely when it's near full. 

 

What kind of amperage do you see when the battery is at say, 50%?

[IDPaddler]

I the battery is truly at 92% that sounds like it totally could be right. Charging will taper off near full into an absorption state (higher voltage/lower amperage) to top the battery off completely when it's near full.

What kind of amperage do you see when the battery is at say, 50%?

That was my thought….charging tapered off at near full SOC.

I ran the heater last night and it only dropped to 92%. In reality I’m not sure I’ve ever even run it down to 50%. I’ll keep the heater going and turn on some lights to try to get it to run down further… Then recheck.

Thx!

Edited by IDPaddler, 29 December 2022 - 04:44 PM.

[IDPaddler]

Update,

 

This morning the Renogy DCDC50A pulled up to 43ah with the battery down to 70% (solar disconnected, alternator only). So it seems to working just fine. As above, the charge rate must drop when is goes into absorption state if the battery is near full...like in the 90% SOC range. 

 

 

It charged from 70% to 78% after driving for just 10 min or so. I'm totally stoked with this performance! IMO it's a fantastic upgrade. 

[Jon R]

A dc-dc charger can only do so much within its design parameters. My guess is you are still either wire-limited or alternator-limited on your current if you are only getting 43 amps with your battery that low. But so what? If you are satisfied with that nearly full charger capacity current, call it good. Many of us are happy with the 30 amp output of other units. Bigger copper is expensive and difficult to run, and 43 amps will serve you well and keep your charger at a lower operating temperature.

[pawleyk]

Update,

 

This morning the Renogy DCDC50A pulled up to 43ah with the battery down to 70% (solar disconnected, alternator only). So it seems to working just fine. As above, the charge rate must drop when is goes into absorption state if the battery is near full...like in the 90% SOC range. 

 

 

It charged from 70% to 78% after driving for just 10 min or so. I'm totally stoked with this performance! IMO it's a fantastic upgrade. 

 

I'd say it sounds like it's working pretty good. I'm not familiar with the Renogy DCDC50, but 43amps out of a Renogy sounds pretty good to me. We typically see 25-32 from the 30amp Victron units.