Another Battery Charge Inquiry

I just bought a 2004 3023 with the Parallax 7300 converter. I will mostly be boon docking so I installed 2 golf cart batteries (225AH) on the A frame. My goal is to recharge in as short a time as possible. I am not considering solar panels but will buy 1KW "quiet" generator. I plan on adding the Progressive Dynamics PD9145 or PD9160 with the Charge Wizard. There is #10 wire from the battery back to the converter.
(1) Does anyone have an opinion on how difficult it would be to replace this #10 with #6 or # 8 wire? I am talking about the difficulty of physically pulling the wire in tight spaces.

50 feet of #6 has about 0.02 ohms. 50 Amps would see a voltage drop of about 1 Volt. The PD allegedly puts out 14.4 volts initially so the battery would only see only 13.4 V
(2) Seems this voltage drop would prevent the PD from charging at the 50 Amp rate for any significant length of time. Your comments / experience will be appreciated.

My gut feeling at this time is to:
Leave the Parallax 7300 as is.
Buy the PD9145, connect it directly to the battery with 2-3 feet of #4 booster cable with alligator clips and plug it into my 1KW generator. Then the PD can do its thing charging the battery intelligently. Since this unit is housed in my garage, this arrangement seems feasible during storage.

Bert

I had the same fear about the charging of the PD9160, that it would charge too fast for the battery. However, I am yet to blow the OEM 30A fuse. That could be because I haven't run my battery very low since installing the PD. I charge with an older 750/800 Watt Honda quiet generator. When I first plug the TM in, the motor pulls down significantly which is a big surprise to me. Even 30A (fuse rating) at 14V (PD) charging voltage is only 14X30-420 Watts which is well below the Honda output. This loading only lasts a half minute or so and the motor unloads for the remainder of the time. I don't have an ammeter to read the current into the battery yet.

I can't answer the question on pulling wire, but it can't be too bad. Thinking of my 3326, the distance is maybe 6 feet (tub to rear storage area) and if I had to, I could even go thru the floor with it and use conduit. I don't know where your battery is located. I don't think you will need to replace wiring in your TM. I don't think the battery charge will be affected much at all by short duration of the high charge rate I would be concerned about charging my OEM battery at 60A for very long as well. I don't think it would be very good for your golf cart batteries either, but certainly they would handle it better than the OEM battery. There is a rule of thumb for charging at a certain %Capacity that was described a few days ago... Probably by Rocky Mountain Ray.

If I was buying a generator, I would be looking closely at the 2000 Watt Honda. People are somehow using it to run their A/C. It will also run a microwave oven. For both these applications, I suspect the battery should be somewhat charged before starting either, the way mine pulls down initially.

The PD9100 series uses a high frequency chopper circuit and is able to function efficiently with very light weight transformers. My 60A only weighs 6# and the removed 6330 was 13#. The newer 7300 may use this technology also. I would look in the battery and see if it is bubbling. The 9100 really cut down the bubbling during all parts of the charge cycle. The 6330 kept bubbling forever best I can tell by watching it last winter.

You know that the PD9100 is a pretty easy install? You remove 4 screws, cut 5 wires on the old one, slide it out and slide the 9100 back in. It attaches to the same 5 wires. Great web info including pictures of this operation. I would recommend that over what you would be doing to use it externally as a charger. Nevertheless, I would use the OEM unit until I had good reason to replace it, rather than doing it based on the scanty numbers you will find describing these two units.

Better go. Best wishes.

Bob

[RockyMtnRay]

Originally Posted by hingarfi

I just bought a 2004 3023 with the Parallax 7300 converter. I will mostly be boon docking so I installed 2 golf cart batteries (225AH) on the A frame. My goal is to recharge in as short a time as possible. I am not considering solar panels but will buy 1KW "quiet" generator. I plan on adding the Progressive Dynamics PD9145 or PD9160 with the Charge Wizard. There is #10 wire from the battery back to the converter.
(1) Does anyone have an opinion on how difficult it would be to replace this #10 with #6 or # 8 wire? I am talking about the difficulty of physically pulling the wire in tight spaces.

50 feet of #6 has about 0.02 ohms. 50 Amps would see a voltage drop of about 1 Volt. The PD allegedly puts out 14.4 volts initially so the battery would only see only 13.4 V
(2) Seems this voltage drop would prevent the PD from charging at the 50 Amp rate for any significant length of time. Your comments / experience will be appreciated.

My gut feeling at this time is to:
Leave the Parallax 7300 as is.
Buy the PD9145, connect it directly to the battery with 2-3 feet of #4 booster cable with alligator clips and plug it into my 1KW generator. Then the PD can do its thing charging the battery intelligently. Since this unit is housed in my garage, this arrangement seems feasible during storage.

As Bob notes above, true deep cycle batteries should never be charged at a rate higher than 20% of the rated capacity and are best charged at rate that's about 10% of their rated capacity. That converts to about 45 amps maximum and around 23 amps optimum. The problem is true deep cycle batteries have very thick plates...that thickness leads to long lifespans but also severely restricts the amount of electrical/chemical exchange with the surrounding electrolyte. Very high charge rates will likely cause damage to the plate structure that in turn will greatly reduce the battery's capacity. Same thing on discharge...deep cycle batteries should not be subjected to more than momentary high discharge currents (over about 20% of their capacity). By comparision, automobile batteries (which are primarily designed to provide very high currents for starting) have very thin plates and can safely accept high rates of charge (100 amps plus). The bottom line is a high rate of charge (preferred because it greatly reduces charge time) that's fine for an automobile starting battery would be very damaging to a true deep cycle battery.

Therefore, since 40 amps is about the highest safe charge rate you should subject the batteries to (and 20 to 25 amps would be much better), I would strongly recommend that you simply leave the existing TM wiring alone since a 10 Ga wire is more than sufficient for 40 amps. Also consider that battery voltage gradually rises to around 13 volts during charging...and that alone will cut the charging current to around 20 to 30 amps anyway.

Personally I'd just replace the Parallax unit with the PD and let it intelligently handle charging of the battery from its position in the TM power center. Then simply plug the TM's shore cable into the generator.

As a point of reference, I'm still happily getting by with the old 6300 series converter in my trailer...despite it's relatively small 8 amp battery charging section. I've thought about retrofitting a 7300 series or a PD converter but simply haven't seen a need even though I do have dual Golf Cart batteries. The reason is that my solar panels provide enough power every day that the batteries never go much below 70% charge even after 3 to 5 days of boondocking...and usually are back to 100% of charge by early afternoon every day. And even if I have several days of cloudiness, one overnight at a campsite with an electrical hookup is enough time for the 6300 to bring the batteries back to full charge. After 4 camping seasons, I've learned that the TM's water limitations (mostly waste water and potentially the toilet) tend to make boondocking for more than 2 or 3 days at a time a bit of a hassle. So I no longer really even plan to stay at one boondock campsite for more than 3 or 4 days at a time.

If you're going to be mostly camping where sunshine is fairly common and the campsites are not very shaded, solar is much better for battery recharging than a generator. The reason is that solar's typical low (10 to 20 amps depending on array size) but steady current is an ideal match with the optimum recharging current requirement of deep cycle batteries.

I have been following this panel and have noticed that there is a lot of discussions regarding charging the trailer battery for refrigeration. The obvious solution is generally the solar panel recharging the battery for more than 2 days of dry camping or buy a gas generator which can be an issue.

So has anyone thought of buying or renting a portable solar generator for weekend use? I am from California and this would be possible for most of the year. A portable system cost about $2000 and is too costly for occational use, what about renting at $20 a day? I am asking because I am interested in reselling or renting portable solar generator to RV owners.

I recognize this may not be a very profitable business but I am interested in solar industry and dealing with RV owners, so this would be a great way to do both.

I believe that most of us use propane to cool our refer when boondocking. Of course anywhere there is electricity, we run the refer on it.

Hal

b195...

I for one would not be interested in renting. The exception would be 1X to see if my conclusion on solar (for me) is accurate. For that, I would rent!

* The bother of getting it, taking it back would be a burden at a time when I am getting home tired, it is 105 degrees or thereabouts, and the rental shop is closed on Sunday.
* Also, how does one haul such a device? It must be fragile. I see some solar units that look like a roll-up tape. Those would eliminate that problem.
* I guess you could supply all the apparatus needed such as the charge controller so the user would just clip to the battery leads.
* Also, myself and here in Az, I park in the shade every chance I get. That will definitely cut the solar output. If you have one on a cord, that would actually be a benefit as it might be possible to reach a sunny area.

My solution is to use a small generator to charge the battery. I have an older Honda 750 watt that does just fine for that. I run it about 1 hour a day. If I could tell my charge state, that could probably be 1/2 hr every other day! A nice advantage is I just bought a small $20 vacuum cleaner that I can clean the sand and dust out with when the generator is running. So far, I have been dry camping only with my TM in a group of other campers (toy haulers with ATVs) and we all turn on generators -- mostly for cooking at mealtime.

My 2 cents... you did ask!

Bob
In sunny Arizona.
'04 3326KS

Thanks for the input. from your description, solar power will not be feasible for RV for a long time, except high end motor homes as permanent installations for prestige.

One day, when solar generator is less than $500, then maybe people will buy the solar genreator instead of gas generator. Right now, the cost is over $2000 which is too costly and inconvenient.

the only advantage is that solar energy is free.

B1950..

Just as a clarification, I didn't say solar was not feasible for me. I did say renting was not feasible for me. There are people who do very well with solar. And that might include me at some point in time.

As they say, ymmv. And in this case, that is very likely to be the case. If you can park in the sun and like that, solar becomes a viable source.

Bob

Hi, Bob;

In the next 5 years, you will see 100w solar panel that will generate enough DC power for dry camping for under $200. When that happens and we can also get satellite internet, dry camping will be much more interesting.

[Bill]

One day, when solar generator is less than $500, then maybe people will buy the solar genreator instead of gas generator. Right now, the cost is over $2000 which is too costly and inconvenient.

Just for the record, I'm not sure where the $2000 number comes from. The panels themselves cost about $4.50 per watt. A good charge controller costs about $100. For a 200-watt system, this totals up to about $1000. Add a few dollars for wire and mounting brackets - well, I'm still a long way from $2K.

Many of us (including myself) get along fine with an under-200-watt system. Sure, I wish panels were $2 per watt instead of $4.50, but I'm enjoying solar power now - at least in the west, where there is typically more sun available.

Bill