Best Solution for three batteries

[scottma]

Problem:
I camp for over four days and deep cycle battery in trailer that powers 63 qt Edgestar only runs for three days. I have a dual battery system but it is not connected to the trailer battery and even if it was I would not drive with the trailer durring the stay so no way to cahrge trailer battery.
Solution:

I am thinking of getting a generator to charge battery/ run Edgestar. Can I put a charge to the battery while running the Edgstar. What size gernerator would I need?

 

[R32GT-R]

alten 12v dc generator

 

[dwh]

Yes you can charge a battery while there are also loads running from it. Happens when you drive with the radio or lights on anyway.

If you have a modern multi-stage charger then sometimes running loads from it while also charging can fool it into overcharging the battery. That doesn't happen with an older dumber charger.

To prevent that problem, you use a 2-stage smart charger instead of a 3-stage smart charger if you have loads running.

An Iota charger is a two-stage by default so just get one and plug it into a small generator and that's an excellent way to recharge batteries.


I bought one of these a couple months ago to replace a Honeywell generator that I had problems with:

http://www.championpowerequipment.com/42431.php

Love it. Noisy little sucker, but it actually gets better fuel economy than a Honda inverter generator. Mine will run for 14 hours on a 1.2 gallon tank of fuel running nothing but my battery charger. Runs 12 hours on a gallon.

Unfortunately, my battery charger is old and takes a long time to recharge the battery. I'll be replacing it with a Samlex SEC-1215a which is a 15a smart charger that can be set to 2-stage mode.

With the Samlex charger I should be able to recharge my battery easily in 6 hours tops. At that point, I'll just put a gallon of gas in the generator, and be able to do two battery charging "sessions" from a single gallon of gas.

The only problem with the gen I have now is the noise. If I were really worried about noise, I'd have gotten an inverter type generator, such as the Honda or Yamaha or the new one from CPE:

http://www.championpowerequipment.com/73531i.php

You can get the CPE inverter gen at Costco for $500.


It doesn't take a huge generator to charge one or two batteries. My little 1200w gen could easily run a 30a or 40a charger. I don't need that much though, so I'm just going to buy a 15a charger.

Don't even think about the "12v" outlet on a small generator for battery charging. Just forget it's there. It'll do in a pinch, but it's not regulated and can overcharge a battery and also with an inverter generator you have to run the gen with economy mode turned off to use the 12v AND often can't use 12v and 120v at the same time. Better to use a decent charger plugged into the 120v of the gen.

 

[scottma]

Thank you I have probably been over thinking this. I recently replaced the power supply in my trailer with an IOTA DLS- 55. I have been looking at the new Champion Inverter Generator and reading reviews on it. Actually went to Sam's and almost bought it last week but didn't. I just have not been sure but you have validated my thinking .............I need a generator. Charging off the alternator is not a practical solution.

Thank you very much.

 

[dwh]

I think the CPE inverter gen might be right on the edge of running a -55. I think it would run a -45 just fine, but the -55...maybe not.

The Honda eu2000i would run it though. It has a 100cc engine vs. the 80cc engine in the CPE (same size as my 1200w/1500w gen).

There is a megathread about the CPE inverter gen here:

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/24022161/srt/pa/pging/1/page/1

 

[scottma]

Could you please explain why it might not work? I thought I would just plug the shore 110 plug into the generator and the IOTA would charge the battery. Are you saying it might not be able to run the IOTA charger? It runs when I plug it it into a standard outlet. Excuse my ignorance. I am not electronically inclined.

 

[dwh]

Are you saying it might not be able to run the IOTA charger?

Yup, that's what I meant. The CPE inverter generators are new on the market and there hasn't been a lot of testing posted on the net yet. From what has been posted, they appear to be a bit more sensitive to overload than the Hondas.

I know it would run a 45a charger...but a 55a...that's right on the limit of what it could handle.

It runs when I plug it it into a standard outlet.

Well most of the "2000w" inverter generators all have the same basic specs - they can supply 1600w continuous loads, and can handle up to 2000w momentary surge loads.

A normal wall outlet in a building is rated at 15a.

15a x 120v = 1800w

But a lot of times there are several of those on one circuit being fed by a 20a breaker.

20a x 120v = 2400w

So it would take a 2400w load to trip the breaker. Either way, it's more than what the small 1600w/2000w inverter generators can supply.


What happens when you first power up the Iota if the battery is low is that it tries to supply the full 55a to the battery, and it also has an internal capacitor that it charges at the same time. So for a split-second it can draw up to 30a. That's called the "inrush" current.

30a x 120v = 3600w

which is way more than any little 1600w/2000w inverter generator is rated for. But, since it happens so fast and for such a short time it generally doesn't cause problems, but it seems the CPE inverter gen is a little more sensitive to inrush than the Honda.



However, there is good news just today! This morning, The Professor posted a real world test of the CPE inverter generator. He has an 80a charger in his fifth wheel trailer, but he also has a 55a charger in his Volvo semi that he uses to tow the trailer.

He tried the CPE on both and it would not run the 80a charger when the charger was pulling full power - but it would run the 55a. Here's his report:

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/24022161/gotomsg/25109283.cfm#25109283


(Note, when The Prof refers to the "boost mode" on his Progressive Dynamics 80a charger, what he is referring to is the PD has a button to push to force it to enter into "bulk stage" charging. The Iota is a 2-stage charger and will enter bulk stage as soon as you turn it on whenever the battery's voltage is low. The Prof's WFCO 55a charger apparently behaves the same as the Iota.)




So the odds are good that the CPE will run your DLS-55a when the -55 is pulling full power (bulk stage charging). Yesterday I had my doubts, but today I feel a bit more confident about it. I was hedging because I didn't want to recommend something that I didn't know for sure would work. (And if you notice...I'm still hedging. )

 

[scottma]

Hedge all you want. I really appreciate the help and education you have given me. I am going to buy the CPE 2000 this weekend and will let you know how it works.

Thank You

 

[dwh]

Hedge all you want. I really appreciate the help and education you have given me. I am going to buy the CPE 2000 this weekend and will let you know how it works.

Thank You

No worries. Think of it as paying it forward. If you want, you can pay it back by joining the rv.net forum and posting your own experiences on the CPE inverter gen mega thread.

 

[4671 Hybrid]

Any thoughts of just buying another battery that you charge up at home between trips? That'll give you 6 days of fridge run time and in a pinch, you could always swap one of the dead trailer batteries for one of the dual batteries in your rig and charge it back up.

 

[BorntoVenture]

Here's what I did to accomplish the same goals, I needed to charge battery(s) some way other than by my truck's alternator. Solar still scares me because of it's high costs and low output potential so I went with a small Inverter/Generator. The model I chose was a Ryobi RYi2000 from Home Depot for $599. It's around the same price as a good starting solar setup but has many more uses. It's very quiet especially if the load is small enough for the generator to run at a lower idle but even at full throttle you can carry on a conversation right next to it. I used it this past weekend to charge my "house" battery while at the NC Rally and it worked great. I could have stretched the whole weekend without charging but running a 120v fan in the tent at night was what drained the battery the most.

 

[SWbySWesty]

Solar is so efficient now that if you are only powering the fridge from the battery that a small quality 50w solar panel would keep your levels up. Or I agree with whomever mentioned adding a second battery to your trailer. Just wire it in parallel so it becomes one big battery.

That's what I did in my van. Big starting battery and two Optima yellowtops under the rear seat to extend my stays without starting.