solar charging house battery and trickle charge starter

[alpinefd]

Hi guys,

I have a camper van project, and looking to install a solar panel with controller. The van is a 2003 Ford E350 Diesel 7.3L. It has 2 starter batteries wired in parallel (12v).

I'm looking to add another house battery.
The van can sit for months unused, so the solar has to charge the house battery and top off the starter battery.

What i like to do is charge the house battery using solar, then when it's full, it'll trickle charge the starter battery. If it can do DC to DC charging when the engine is running, that'll be even better.

Are there any charger that's designed for this?

[daveb]

The question I'd need to know is what type of battery system are you planning to use? Most solar controllers switch to a trickle or float charge once the battery reaches a full charged state. What I ended up doing was to add a larger alternator and a smart regulator, and along with that and my solar, the two 210AH AGM house batteries have lasted me over 10 years. A blue Sea separator keeps my starting batteries up to par while adding a bit of protection. Going with a lithium system is where it gets a bit more complicated and requires equipment to interface with most of those type batteries. I have two 135 watt panels and while more is better, there just isn't enough room for a solar array that matches a 2000 watt generator or shore power. I'm working on a project right now building a work trailer that has a 2000 watt inverter/charger and a single 210AH AGM battery. All I need is a limited amount of battery reserves during daytime operations and then the trailer will be parked hooked up to shore power. But I'm thinking to add a small 100 watt panel that can keep the battery topped off without the need for shore power. The inverter will only be activated for bulk charging when needed. It's up to you to research the pros and cons of each type of system but I stuck with AGM. YMMV

[BCam]

I have a 2005 E350 wheelchair van (we need the lift) that I'm building out for day trips and the occasional overnight. We have one starter battery.

In addition to adding house power, I wanted to take the load of the lift off the starting battery except in the case of a house battery failure.

I installed two, 110AH AGM house batteries and a 100W solar panel. I installed a Renogy 20A DC-to DC charger along with a GoPower GP-PWM-30 PWM solar controller that can serve two battery banks. I already had the controller from another project. Otherwise I probably would have gone with the Renogy controller with built in DC to DC charging. In that case I would have installed an Amp-L-Start or other device to allow the starter battery to charge via the house batteries/solar.

I also installed a rotary battery switch that lets me switch my lift between the house and starter batteries along with allowing me to interconnect them for emergency starting.

I realize now, that the DC-to-DC charger probably wasn't necessary for my AGM batteries and limits the charging current from the starting battery but I wanted to match the AGM charging profile as close as possible. I suppose I could have gone with a larger DC-to-DC charger but I wanted to keep the expense down.

My van, like your's sits for months, and so far, the system is working like a charm, including this winter. By the way, I installed my solar panel with home made L brackets made from aluminum angle stock and 3m VHB tape (no screws) and it's as solid as a rock:



The roof isn't that narrow, it has a narrow crown running it's full length.

[alpinefd]

Thanks guys

I’m planning to use a single 100ah agm deep cycle house battery

Bcam. It sounds like your current gooower charger is charging both the starter bank and the house battery at the same time ?

I thought about going this way as well but the zamp Solar dual battery bank charger I looked at doesn’t seem to isolate the charging during engine start
Wouldn’t that cause issues during engine start ?

[BCam]

Originally Posted by alpinefd

Thanks guys

I’m planning to use a single 100ah agm deep cycle house battery

Bcam. It sounds like your current gooower charger is charging both the starter bank and the house battery at the same time ?

I thought about going this way as well but the zamp Solar dual battery bank charger I looked at doesn’t seem to isolate the charging during engine start
Wouldn’t that cause issues during engine start ?

It does charge both at the same time, I never thought of that and never have noticed a problem. My general understanding is that the controller will sense the alternator charge and "back off" but I'll be interested to what others will have to say.

[BCam]

I did find this video which addresses the issue with respect to boats. Note that it doesn't mention any major issues but does speak to the issue of a tachometer possibly not operating properly. I don't know if this is an issue with vans.

https://www.youtube.com/watch?v=vywtM_a6Yxs

[VOLT]

Yes , Renogy has a Dc to Dc charger with built in Mppt controller. Other wise use a cheaper Mppt controller and a dual bank battery isolation switch.