Mod #4: Battery Charger

Mod #4: Battery Charger

Submitted on: 06/08/08

     Category: electrical
Mod Rating: 12345

(24 ratings)

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Mod Description:

Battery chargers come in all shapes, sizes, and charging abilities. There are automotive chargers, trickle chargers, portable chargers, smart chargers, and dumb chargers. You name it, there is a charger made for it. Arguably, the two most popular used in modding your RV are the Vector (or Black and Decker) smart charger and the Intellipower PD9100/9200 series charger. The Vector is a portable and the the PD is a permanent mount, typically used when upgrading the charger section of your RV’s converter. These are both so-called “smart” chargers because they each offer several charging profiles that are much more friendly to your batteries than a single stage or “dumb” charger. Here is why.

Mod Difficulty:

A typical “dumb” 12-volt battery charger provides a constant voltage, usually around 13.6 volts, while the charge current is determined by the internal resistance of the battery. What this means is that when the battery is deeply discharged, it has low internal resistance and thus will draw as much current as can be supplied by the dumb charger. As the battery charges, the internal resistance increases, decreasing the current draw on the charger down to a trickle. Charging in this manner can cause several problems. The battery can get too hot and be damaged because the charge current may be too great. If the battery is not overheated during charging, leaving it on a dumb charger can boil the electrolyte out of the battery because the charging voltage is too high.

The typical “smart” charger provides a way to charge a battery in stages, which are commonly referred to as bulk (or boost), absorption, and float. The bulk stage provides a safe constant current while increasing the voltage high enough (14.2-14.4 volts) that the battery can be rapidly recharged to around 90%. At some predetermined time, or when the current draw cannot be held constant, the charger will switch to absorption mode. This mode reduces the voltage to 13.6 volts and supplies current as needed to finish the charge. At this point, the charger will switch to a float mode voltage of 13.2 volts, provided there is no demand on the battery.

So how does this help you mod your RV? Well, it really doesn’t but it will give you peace of mind at 3AM when you’re thinking about what to do when your batteries are boiling themselves dry. Simply hookup the Vector, select the current level, and go back to sleep. The Vector will do the rest for you. If you want to get fancy and not have to hookup a charger each time, then do the Intellipower charger mod.

This involves removing the converter/charger section within your AC distribution panel, and substituting the Intellipower charger. This can be done relatively easy if you have basic electrical skills. There is another mod that details how to upgrade your converter so I won’t go into detail here. But I have included some links below that should help you get a feel for what’s involved. As always, be sure to disconnect shore power, battery power, and/or solar power before attempting this mod.

ModMyRV recommends these parts for this mod:
Battery Tender 021-0123 Battery Tender Junior 12V Battery Charger
Black & Decker VEC1093D Smart Battery Charger with 110 Amp Engine Start and 40/20/10/4 Amp Rates
Amptronix 45Amp 12V Multi-stage Smart Charger with 2-Bank (ABC-1245A2)

General Reference
Wikipedia Smart Charger Reference

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8 Comments For This Mod

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  1. fncampn

    Thanks for the tips! I have a WFCO 55 amp charger and I’m in the process of relocating the charger closer to my batteries for better charging. Any one else done this?

  2. cccale

    The portable chargers are handy to have. I bring one with us incase the atv/motorcycle batteries die.

  3. ModMyRV

    I’ve had a Vector 35 amp smart charger for 3 years now and not only use it for RV battery charging, but for charging the lawn mower and million candlepower flashlight batteries. Still works great and it gets a lot of use.

  4. Bob Vaughn

    I bought a charger that has an automatic setting that only comes on when the battery drains down…I have started using it instead of the charger in my converter… I can use it in my tow vehicle…

  5. tvman44

    Just bought 2 of these and love them, they are no longer sold by Vector but by Black & Decker now.

  6. dowry

    I’ve been using the Vector chargers for about two years. Two things to note:

    First, the fan runs whenever the charger is charging (even at a low charge rate), so it can be a nuisance if you enjoy your peace and quiet.

    Second, I’ve had to replace both of them as the fans have failed within one year, and one of the replacements has just failed. The only one that hasn’t failed has only been used a few times. Fortunetly, they have a 5 year warranty, so at this rate I’ll be on my ninth and tenth chargers by then.

  7. ModMyRV

    Interesting. I have used a Vector 35 amp charger for the last 6 years without any issues. I got it for a birthday present and immediately put it to use in the TT I had at the time. It had a crappy Magnatek single stage charger so I hard-wired the charger in its place. Worked very well for around a year. Then I sold the TT but kept the Vector.

    Now I use the Vector to charge my lawnmover, generator, and any spare batteries I have laying around. Granted that I’m not using the charger at full duty cycle but it is enough to give it a good workout. Maybe I got one of the “good ones”?

  8. kc7cbf

    Intellipower with charge wizard- love how it maintains the batteries- and has an anti-sulfation mode. Worth the upgrade, and not to hard to install.

1 Trackbacks For This Post

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