Converter or Battery Tender?

[Metalhead]

I'm getting a little mixed up on when to use a battery tender and when a converter is needed (such as a PD4045). My build will involve a small 5k bTu A/c, a compact fridge and AC outlets along with a few DC outlets and DC lights.

Please learn me something and let me know if you need clarification in order to answer.

[MtnDon]

If you have something like a PD4045 you do not need a battery tender. The PD4045 does everything; an AC power distribution center, a DC power distribution center and a 4 stage battery charger.

[Metalhead]

Got ya!

What are the pros/cons of going either way? Is one way substantially better than the other route?

[MtnDon]

PD unit
Pro; The PD4045 does everything; an AC power distribution center, a DC power distribution center and a 4 stage battery charger.
Con; more expensive*


battery tender
Pro; cheaper*
Con; only does one thing; you still have to design the DC and AC circuits
* maybe cheaper; once you pick what and how to use for your AC and DC circuits you may spend as much....


IMO, the less handy with electricity and electrical devices you are the better the PD units look.

[Metalhead]

Thanks again! The answer was simpler than I thought it would be.

I'm handy with electrical just never did the AC/DC combo and wasn't sure that the PD did the same thing (in essence) as the battery tender.

[noseoil]

What about provisions for a solar panel? With the PD4045, would a solar panel just go directly through the controller and then to the battery (with its own wiring) run? Not exactly sure how this would work with both systems installed, hooked up & running. If the sun's out and the battery is already charging from solar, what happens if the PD4045 is plugged into shore power? Will they fight or argue, or are they both smart enough not to bother?

[GuitarPhotog]

What about provisions for a solar panel? With the PD4045, would a solar panel just go directly through the controller and then to the battery (with its own wiring) run? Not exactly sure how this would work with both systems installed, hooked up & running. If the sun's out and the battery is already charging from solar, what happens if the PD4045 is plugged into shore power? Will they fight or argue, or are they both smart enough not to bother?

Generally, since the PD will charge your battery when connected to 120VAC, you don't connect the solar load controller to the battery while the PD is plugged in. The PD charges the battery when you have shore power, the solar panel array charges the battery when you don't. But you won't damage anything by having them connected simultaneously. I use a DP3T switch to connect my battery to the truck for charging, the solar load controller for charging, or the PD for charging or when powering accessories from 12 VDC.

<Chas>

[Deediggler]

What about provisions for a solar panel? With the PD4045, would a solar panel just go directly through the controller and then to the battery (with its own wiring) run? Not exactly sure how this would work with both systems installed, hooked up & running. If the sun's out and the battery is already charging from solar, what happens if the PD4045 is plugged into shore power? Will they fight or argue, or are they both smart enough not to bother?

This is what I am struggling with too. Does anyone have an example of a system that uses a PD4000 controller and also solar charging unit? Just trying to wrap my head around this.

Ultimately, I would like to charge my batteries by TV, Solar and shore/Generator. Maybe a wiring diagram with a PD and a solar charger?

Please and thanks

[MtnDon]

The PD units monitor battery voltage and limit the charge accordingly. The separate charge controller used for PV panels also monitors battery voltage and adjusts the charge accordingly. They can coexist. If the battery is very discharged there could be danger of too much current causing the battery to heat up. A top grade PV charge controller will have a remote battery temperature sensor to help regulate the PV charge. The PD's do not have that ability. As the battery approaches 80% to 90% state of charge both units will drop into the lower power charge mode (absorb or normal) and finally into float. The two separate charge systems will likely have different preset points where they switch from bulk/boost to absorb/normal and then into float/storage. That should not cause too much difficulty if the PD is plugged into shore power at the same time the sun is shining on the PV panels.

PD refers to the stages, from high charge rate through to small maintenance charge rate, as boost/normal/storage while in PV systems the terms are bulk/absorb and float.

Does that help?


FWIW, we have an off grid cabin. Most of the power comes from the PV array. If I need to run the generator for some reason I never worry about having both the PV and the generator charging the batteries at the same time. In our case both the PV charger and the generator powered charger have battery temperature sensors so that variable is eliminated automatically. FYI, as battery temperature goes up the charge voltage should be reduced slightly, and vice versa; when the batteries are cold the voltage is raised. Normal temperature is considered to be 75 to 80 F.

[Deediggler]

That clears everything up for me. That's what I was beginning to realize, I just wanted someone more knowledgeable to spell it out for me because of my ineptitude.

Thanks!

[Shadow Catcher]

Our PD and solar controller (Morningstar) play well together. I called Moringstar and Progressive before I hooked them up.

[Diemjoe]

Hi,
I have a PD4045 and am looking to include solar charging in my build. Amazon sells Renogy 100W Mono Starter Kit: 100W Solar Panel+20' Solar Cable+30A PWM Charge Controller+Z Bracket. From the above conversation, it looks like I still need the controller but want to make sure the PD4045 doesn't do the same thing and do they play nice together on the same system.

[Shadow Catcher]

Don
Generally you can do a better job and spend less money if you assemble you own components, if you are paying more than $1 per watt for the panel it is too much and wire included may be too small to keep voltage drop to an acceptable level. As I said our 185W high voltage panel, Morningstar MPPT controller and the Progressive Dynamics converter play well together.

[Diemjoe]

Doing a search on the Morningstar. I see the Mppt controllers are coming in at about $230. Is that price related to how many watts your solar panels produce? I am going to go pretty light on the electric needs I think. A few LED lights, the fan and maybe a radio with speakers and a couple of USB charging stations. I am planning to get 100 watt panels.

[MtnDon]

100 watt panels always cost more per watt than larger size panels do. The big market is for the big panels that are aimed at the grid tie market. They make great off grid systems too, but as Shadow Catcher mentioned to use a 'big' panel effectively you need an MPPT controller to be able to use all the watts the big panel can produce. Deciding between the higher cost 100 watt panels with a cheaper PWM controller or the cheaper higher capacity panels that need a more expensive MPPT controller is sometimes difficult in a small system. The advantage to bigger panels and MPPT is the better performance in less than lab perfect outdoor conditions. That is where MPPT shines brightest.


You do need to match the highest voltage the PV array could produce on a cold day, as well as the total watts the panels can produce to the charge controller capabilities. The total PV watts varies with nominal battery voltage. The amperage rating on a controller is the output of the controller to the battery.