charging truck and camper batteries with solar, using a battery isolator

[hpcbmw]

I've got a Surepower 1314a battery isolator (i've got the recall replacement unit). I'm hooking up my 80w solar panel and charge controller and want to charge the truck and camper batteries at the same time. Anyone know where I should attach the charge controller wires to accomplish this? In the past, I wired it directly to the camper battery. This kept the camper battery charged, but I don't think it was charging the truck batteries. The truck/camper sit unused for weeks or months at a time, and it's a pain to run an extension cord for a battery tender.

I've emailed Surepower/Cooper with this question, but haven't heard back yet.

Thanks for any ideas!

 

[wuck]

The 1314 is a uni-directional isolator, no back charging the truck. A surepower model 1315 is bi-directional, connecting batteries together if either side rises above 13.2 v

Surepower datasheet

View attachment BUS_CBT_INST_180126a.pdf

 

[mynxd]

In theory, you could wire the solar to the truck battery. Whenever the truck battery is over the ~13.2V from the solar, it should open the solenoid to permit charging the camper battery.. I have no idea how "stressful" this would be on the separator twice a day minimum (whenever the panel rises above the 13.2V output and falls to less than 12.8V(disconnect voltage)).

 

[Casa Escarlata Robles Too]

I have had my truck and camper battery s charging off the solar for 4 years now. And it works great.
I had a 1314 Surepower separator,a recalled version.
It was replaced from ATC in Aug of 2011,with a battery isolator. It's what they have used since the recall.
IMO I would go with the isolator type and ditch the Surepower.Mainly because of all the heat it produces.
Do you have a recalled model? If so get in touch with Surepower for a replacement/reimbursement.
Frank

 

[wuck]

Here's the recall info

Depends on model & serial number

 

[DrJ]

Besides being able to charge the truck from your solar, what are the other benefits of using this type of separator over the stock FWC isolator?

Would it make a difference in truck charging camper batteries when they are too low?
Our current setup (stock) does not charge camper batteries if they are too far discharged.

 

[Casa Escarlata Robles Too]

Here's the recall info

Depends on model & serial number

Thanks for posting that info.
Member UglyScout posted it in 2011 and I couldn't find it to pass along.
Frank

 

[Casa Escarlata Robles Too]

Besides being able to charge the truck from your solar, what are the other benefits of using this type of separator over the stock FWC isolator?

Would it make a difference in truck charging camper batteries when they are too low?
Our current setup (stock) does not charge camper batteries if they are too far discharged.

Do you have a separator or isolator?
The separator gets very hot as it's a solenoid and the isolator isn't.
That's about all the info I can give.
Someone on the forum will have a more technical answer.
All I know is that it works for me.
Frank

 

[hpcbmw]

The unit I have, the 1314a, is what they sent me as a replacement for my original unit that was recalled. It appears to be a battery seperator. Can someone tell me if the heat is a serious issue? It's mounted to the wooden sidewall under the front seat of my mid 1990's FWC. It's got a foot or so of space around it, but there's really no airflow. If I replace it, what would be a good replacement for a solar setup that will be charging daily, to charge truck batteries (2) and camper battery (only 1). Will it build heat while getting electricity from the solar panels and charge controller?

I'm thinking of attaching the solar charger input to the 1314a input battery posts. In my mind (with little to no real electrical knowledge) this would charge the truck batteries all the time, and charge the camper battery whenever the solar setup is putting out over 13.2v.

Any ideas?

 

[Trailbob]

I'm going through the same thing right now with newly installed solar on the camper, hoping it will also keep the truck battery charged. I'm no electronic expert, but I do know that voltage drop is a huge issue with solar installations. If the solar controller is connected to the truck side of the Surepower, you will likely experience some voltage drop (before the charge reaches your camper battery) from the Surepower itself, as well as the additional wire connections. Also, unless you have large wires between the camper and your truck battery, there will be significant voltage drop at the truck battery.

I ran #6 wire directly from the solar controller to the camper battery (fused)- probably overkill for a 160w panel, but I had it. I have a volt meter that plugs in the cig lighter in the truck so I can keep track of the voltage on the truck battery (there is a little voltage drop between the truck battery and the cig lighter which can be determined with a digital meter by checking each). It appears that if I begin with the truck battery charged, the Surepower separator will remain closed (connected) and allow the camper solar panel to also charge the truck. But if the truck battery drops too much, the separator will open and disconnect the two batteries (at which point only the camper will be charging). The Surepower separator that is installed in my camper will not close again unless the truck is charged up to a specific voltage.

I have only been experimenting with this for a few days, but I am amazed at the phantom power drain on my 2015 Silverado and how fast it brings down the truck batteries. I'm not sure yet if the camper solar will keep the truck fully charged-- especially with the near winter sun low on the horizon and the frequent storm we are getting.

 

[wuck]

Can someone tell me if the heat is a serious issue?

I measured mine, a model 1314 (vintage 2004ish). It draws 0.75 amp from the battery to close the solenoid, or about about 9 watts. 9 watts can heat a small area up if totally enclosed, on our campers I doubt anywhere is air tight enough to cause problems. I'll hook it up to close the solenoid and measure after an hour so.

Your 1314a might use a different amount of current, best to measure it.


Will it build heat while getting electricity from the solar panels and charge controller?

Heat will build when the solenoid is closed, regardless of the power source.


I'm thinking of attaching the solar charger input to the 1314a input battery posts. In my mind (with little to no real electrical knowledge) this would charge the truck batteries all the time, and charge the camper battery whenever the solar setup is putting out over 13.2v.

This should work (Nice idea!), the truck battery will take precedence over the camper battery. You'll get slightly less charge current (that 3/4 amp to close the solenoid), but that would be true with a 1315 bidirectional separator also. If your batteries are different technology (flooded/AGM), then there are differences in the charge profiles, set on the solar controller. You'd have to pick the best one for your installation, which could cause some long-term damage to one battery.

 

[hpcbmw]

Thanks for the info Wuck. I've just hooked mine up as described, but I won't be mounting the camper on the truck for a week or two. I'm not sure if it will charge the camper battery through the separator without a battery on the truck end, but I'll keep an eye on it and see if everything seems ok. The camper is sitting outside with the solar panel on it. Once I hook up the truck, I'll check it in full sun vs. no sun and see if there is much heat buildup. You're correct that the battery area where the separator is located is nowhere near airtight. All my batteries are standard flooded batteries, and I'll have all batteries topped off via charger or battery tender when I hook it all up.

I'll try to post back after a few weeks of it all setup.

 

[wuck]

I'm not sure if it will charge the camper battery through the separator without a battery on the truck end

It may not charge with no truck battery, depending on the charger technology and on the separator circuit details that we don't know. I don't think it's a good idea to drive that solenoid directly from the solar controller without a battery also connected, it could harm the controller and/or the separator solenoid.

 

[ntsqd]

The controller wires to the camper's battery bank want to be as short as possible. I'd use a dual sensing ACR/VSR if you want to also charge the truck battery(ies). Something like this: https://www.bluesea.com/products/7601/m-Series__Automatic_Charging_Relay_-_12_24V_DC_65A
Just note the under-voltage lock-out set at 9.5 VDC on that unit. Means that it won't close if a battery that it's connected to is below that voltage. Which is inconvenient at best because you'll need to somehow charge it external to the system, but is a good idea as then you won't have a fire or worse.

I got the old, single sense version in our camper here: http://www.delcity.net/store/Blue-Sea-Systems-m!ARC-Automatic-Charging-Relay/p_809087 and I've been tempted to replace it with a dual sense unit.

There are some solar controllers that will charge two battery banks. This is simultaneous, not sequential. The one that we have, that I would not buy again, asks you to set the charging ratio to either 50/50 or 90/10. There are no other options. In hindsight I should have bought the single battery bank version of that controller.